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BDS4 > CDS Orthodontics > Flashcards

CDS Orthodontics Flashcards

1
Q

Two components of IOTN

A

Aesthetic component
Dental health components

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2
Q

Aesthetic component of IOTN

A

Scale of ten colour photographs showing levels of dental attractiveness

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3
Q

Grade 1 aesthetic component IOTN

A

Most attractive

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4
Q

Grade 10 aesthetic component IOTN

A

Least attractive

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5
Q

What is used to assess the IOTN aesthetic component from dental casts?

A

Black and white photos

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6
Q

How to assess the patient’s opinion of their own dental attractiveness

A

The photos can be shown to the patient and the patient asked “Here is a set of photographs showing a range of dental attractiveness. Number 1 is the most and 10 the least attractive arrangement. Where would you put your teeth on this scale?”

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7
Q

IOTN aesthetic component grades 1/2/3/4

A

No/slight need for treatment

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8
Q

IOTN aesthetic component grades 5/6/7

A

Moderate/borderline need for treatment

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9
Q

IOTN aesthetic component grades 8, 9 and 10

A

Need for orthodontic treatment

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10
Q

What are the limitations of the aesthetic assessment of the IOTN?

A

Subjective
Photos are 2D
This assessment is not standardised

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11
Q

Dental Health Component of IOTN

A

Dental health component records the various occlusal traits of a malocclusion that would increase the morbidity of the dentition and surround structures

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12
Q

Dental health component grades

A

1 - no need for treatment
2 - little need for treatment
3 - borderline need for treatment
4 - needs treatment
5 - needs treatment

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13
Q

Which feature is recorded when determining the IOTN score?

A

Only the worst occlusal feature

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14
Q

Purpose of the IOTN hierarchal scale

A
  1. To provide a guide which enables the examiner to survey the dentition in a systemic manner and thus ensures all relevant occlusal anomalies are identified
  2. When two or more occlusal anomalies are found to achieve the same dental health component grade the hierarchal scale is employed to determine which occlusal anomaly should be recorded. In this situation the occlusal anomaly higher up the order is recorded
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15
Q

What is MOCDO?

A

Hierarchal scale to determine the worst occlusal feature
Missing teeth (including congenital, ectopic and impacted teeth)
Overjet (including reverse)
Crossbite
Displacement of contact points
Overbites (including open bites)

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16
Q

Dental Health Component Ruler

A

Single use clear plastic ruler designed containing all the information necessary to record the DHC
Information is collected regarding competence of the lips, displacement on closure and masticatory/speech problems

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17
Q

What reference point is used to record the overjet?

A

Most prominent aspect of the upper incisors

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18
Q

How to determine the IOTN DHC grade of a patient

A

Do MOCDO then read up the list from the occlusal feature found, to ensure nothing further up the list is present

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19
Q

Assumptions to be made if assessing IOTN DHC from casts

A

Overjets 3.5-6mm - assume the lips are incompetent and award the grade 3a
Crossbites on dental casts - assume a discrepancy between RCP and ICP of greater than 2mm is present and award grade 4c
Reverse overjets - assume that masticatory or speech problems are present

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20
Q

DHC 1

A

Extremely minor malocclusions including contact point displacements less than 1mm

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20
Q

Why undertake an orthodontic assessment?

A

To identify if any malocclusion is present, to identify any underlying causes and to decide whether treatment is indicated

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21
Q

When should orthodontic assessment be done?

A

Brief examination often at age 9
Comprehensive exam when premolars and canines erupt (age 11-12)
When older patients first present
If a malocclusion develops later in life - eg periodontal disease, growth in the condyles

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22
Q

Andrews 6 keys

A

The ideal occlusion
I. Class I molar relationship
II - Crown angulation (mesio-distally)
III - Crown inclination
IV - No rotations
V - no spaces
VI - flat occlusal planes

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23
Q

Why must root length be considered before ortho tx?

A

IF short roots, fixed may not be suitable as it can cause further root resorption

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23
Q

Unofficial 7th Andrews key

A

If you have a small lateral incisor, all of the teeth in that segment need to be slightly further forward

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24
Q

Normal occlusion

A

Minor deviations from the ideal that do not constitute an aesthetic or functional problem

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25
Q

What could a history of trauma mean for orthodontic tx?

A

Teeth may be RCTed, have root resorption, could be ankylosed

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26
Q

Habits relevant to ortho

A

Thumb sucking
Lower lip sucking
Tongue thrust
Chewing nails

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27
Q

Guidelines used to define malocclusions

A

British Standard Institute BSI

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28
Q

BSI definition of Class II division I malocclusion

A

The lower incisor edges lie posterior to the cingulum plateau of the upper incisors, there is an increased overjet and the upper central incisors are proclined or of average inclination

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29
Q

Reasons to treat Class II div I

A

Concerns about aesthetics
Concerns about dental health - trauma

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30
Q

Skeletal pattern A/P class II div I

A

Usually associated with class 2 skeletal pattern
Commonly due to retrognathic mandible (maxillary protrusion is less common)
Do see with skeletal class 1, very rarely with class 3 but its possible

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31
Q

What causes an increased overjet?

A

Skeletal pattern, tooth inclination or both

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32
Q

Normal SNA

A

81
+/- 3

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33
Q

Normal SNB

A

78
+/- 3

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34
Q

Normal ANB

A

3
+/- 2

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35
Q

Normal upper incisors - maxillary plane angle

A

109
+/- 6

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36
Q

Normal lower incisors - mandibular plane angle

A

93
+/- 6

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37
Q

Normal maxillary plane to mandibular plane angle

A

27
+/- 4

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38
Q

Normal LAFH/ TAFH

A

55%

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39
Q

Why might lips be incompetent?

A

Prominence of incisors and/or underlying skeletal pattern

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40
Q

Where should lines continuous with mandibular plane and maxillary plane meet?

A

Occiput

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41
Q

Lower lip potential feature in increased overjet

A

Lower lip trap

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42
Q

Dental factors associated with incompetent lips

A

Increased OJ - proclined or average incisors
Overbite varies
Can be aligned/spaced/crowded
Habitually parted lips may lead to drying of gingivae and exacerbation of any pre-existing gingivitis

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43
Q

Sucking habits

A

Thumb/fingers
Blanket
Lip
Combination
NNSH no nutritive sucking habits
Effect depends on duration

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44
Q

Occlusal features of sucking habit

A

Proclination of upper anteriors
Retroclination of lower anteriors
Localised AOB or incomplete OB
Narrow upper arch - may see unilateral crossbite

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45
Q

How to treat malocclusion in someone with a sucking habit?

A

Stop habit
Allow spontaneous movement
Treat residual malocclusion if required

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46
Q

How to stop a sucking habit?

A

Positive reinforcement
Removeable appliance habit breaker
Fixed appliance habit breaker

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47
Q

5 Management options of malocclusion

A

Accept
Attempt growth modification - first choice of tx if pt correct age, difficult beyond age 14
Simple tipping of teeth - more applicable to older patients
Camouflage
Orthognathic surgery - more severe, if pt has concerns about jaw position

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48
Q

What class II malocclusions would it be appropriate to accept?

A

Mildly increased overjet
Significant overjet but not unhappy - might present later when they are more concerned

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49
Q

What must be done if the option of accepting a class II malocclusion is decided upon?

A

Pt must be made aware of risk of trauma
Advice re mouthguard

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50
Q

Methods for growth modification orthodontics

A

Headgear
Functional appliance

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51
Q

How does headgear work?

A

Tries to restrain growth of the maxilla, horizontally and/or vertically
Has most effect by distalising the teeth

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52
Q

How do functional appliances work?

A

Utilise, eliminate or guide the forces of muscle function, tooth eruption and growth to correct a malocclusion

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53
Q

Which type of malocclusion are functional appliances most useful for?

A

Used mostly for Class II div I
Can use for div 2
Limited use for class III

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54
Q

What is the purpose of a functional appliance for a class II div 1?

A

Posture the mandible downwards and forwards
Restrains maxillary growth

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55
Q

Twin block

A

Functional appliance in which lower teeth are held forward, muscles retract upper teeth
For class II

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56
Q

Herbst appliance

A

Fixed functional appliance used to correct skeletal class II

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57
Q

Therapeutic effects of functional appliances on class II div 1

A

Mostly dento-alveolar changes - distal movement upper dentition, mesial movement of lower, proclination of upper incisors and retroclination of lower incisors
Minor degree of skeletal change - suggested maxillary restraint and mandibular growth only has 1-2mm effect

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58
Q

When to use functional appliance?

A

During growth
If possible coincide with pubertal growth spurt
Options for early use about 10 years old for 2 phase tx or later use with permanent or late mixed dentition for 1 phase tx

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59
Q

Potential disadvantages of early tx with URA

A

Early skeletal effects not maintained in long term
Overall tx time increased - 2 phase treatment with fixed in early permanent dentition
Research shows little difference between those treated early and those who waited until permanent dentition

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60
Q

Potential advantages of early use of URA (3)

A

Improve appearance earlier - teasing and potential psychological benefit
Reduce risk of trauma
Often better compliance with appliance wear

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61
Q

URA to retrocline incisor teeth, following distalisation of the canines

A

Active component - Roberts retractor 0.5mm HSSW in tubing
Retention - Adams clasps 16 and 26 0.7mm HSSW
Anchorage - stops mesial to 13 and 230.7mm flattened HSSW
Baseplate - Self cure PMMA and FABP OJ+3mm

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62
Q

Orthognathic surgery for class II skeletal relationship

A

Carried out when growth is complete
Skeletal discrepancy is severe in A/P and/or vertical dimension
Usually involves mandibular surgery, can also involve maxillary
Fixed appliance required before/during/after surgery

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63
Q

Extra oral ortho pt examination

A

Skeletal bases
Soft tissue - lip competence, smile line
TMJ

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64
Q

Why is it sometimes helpful to look at patient’s parents when doing ortho assessment?

A

Consider growth potential
Malocclusion - esp class III

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65
Q

What does an increased cranial base angle mean?

A

Mandible is positioned further back
Increased tendency for a large overjet

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66
Q

What is the maxilla connected to?

A

Anterior cranial base

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67
Q

What is the mandible connected to?

A

Posterior cranial base

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68
Q

3 planes that skeletal pattern is considered in?

A

Antero-posterior
Vertical
Transverse

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69
Q

What position should a patient be in for orthodontic assessment?

A

Frankfort plane parallel to the floor

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70
Q

Frankfort plane

A

Top of the external auditory meatus to the inferior border of the orbit

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71
Q

What reference points are used to determine antero-posterior skeletal class?

A

Inner most curvature of the lips

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72
Q

Class I skeletal relationship

A

Maxilla 2-3mm in front of the mandible

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73
Q

Class II skeletal relationship

A

Maxilla more than 3mm in front of the mandible

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74
Q

Class III skeletal relationship

A

Mandible in front of or less than 2mm behind the maxilla

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75
Q

FMPA

A

Frankfort mandibular planes angle
Lines drawn continuous with these should join at the occiput

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76
Q

Vertical assessment of skeletal relationship

A

FMPA

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77
Q

Lateral assessment of skeletal relationship

A

Assess symmetry, considering interpupillary line, mid-sagittal plane
Cupids bow normally in midline
Ignore tip of the nose
Compare chin point to the line
If asymmetry suspected, view pt from behind/above

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78
Q

Increased FMPA

A

Lines meet further forward than occiput
Expect minimal overbite or AOB, because back teeth will meet first

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79
Q

Reduced FMPA

A

Lines meet behind the occiput
Expect deep bite, jaws too close together

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80
Q

Soft tissue considerations in ortho assessment

A

Lips - competent or incompetent, lower lip level, lower lip activity
Tongue - position, habits, swallowing
Habits - thumb, digit sucking
Speech - lisp, straightening teeth will not fix a lisp as it is learned

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81
Q

Competent lips

A

Meet at rest with relaxed mentalis

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82
Q

Incompetent lips

A

Not together with relaxed mentalis

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83
Q

Lip trap

A

Upper incisors sit ahead of lower lip
Can procline them
May lead to relapse of overjet if persists at the end of tx - ensure lips are competent at end of tx

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84
Q

Effect of hyper active lower lip

A

Could retrocline lower incisors
Indicates likely instability at end of tx

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85
Q

Dental feature associated with tongue thrust on swallowing

A

AOB

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86
Q

Effects of digit sucking habit

A

Can cause symmetrical or asymmetrical problems
Proclined uppers and retroclined lowers
Narrow upper arch +/- unilateral posterior crossbite
Localised AOB or incomplete OB

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87
Q

How does digit sucking lead to unilateral posterior cross bite?

A

Tongue is held lower, cheeks push in the upper posteriors, bringing teeth cusp to cusp and eventually causing a crossbite to get intercuspation

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88
Q

TMJ assessment

A

Path of closure
Range of movement
Pain
Click
Deviation on opening
Muscle tenderness
Mandibular displacement
Discrepancy between ICP and RCP - over 4mm causes problems
Ortho can not cause and can not treat TMJ problems (possible exception of crossbite)

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89
Q

Intra-oral exam for ortho assessment

A

Teeth present
OH
Perio health - BPE
Teeth of poor prognosis
Crowding/spacing/rotations
Inclination/angulation
Palpate for canines if unerupted (especially under 13s)
Not teeth of abnormal shape
Absent teeth
Extra teeth

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90
Q

Normal angulation of incisors to mandible

A

90 degrees

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91
Q

Normal angulation of incisors to maxilla

A

110 degrees

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92
Q

Lower arch exam

A

Degree of crowding - uncrowded, mild, moderate, severe
Presence of rotations
Inclination of canines - mesial, upright, distal
Angulation of incisors - upright, proclined, retroclined

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93
Q

Upper arch exam

A

Uncrowded/mild/moderate/severe
Presences of rotations
Mesial/upright/distal inclination of canines
Angulation of incisors to frankfort plane - upright/retroclined/proclined

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94
Q

Examination of teeth in occlusion

A

Incisor relationship
Overjet - biggest of all incisors
Overbite/open bite
Molar relationship
Canine relationship
Cross bites
Centrelines

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95
Q

Mild crowding

A

Less than 4mm space deficit

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96
Q

Moderate crowding

A

4-8mm space deficit

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97
Q

Sever crowding

A

8+mm space deficit

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98
Q

Class I incisor relationship

A

Normal OJ and OB
Lower incisor edges occlude with or lie immediately below the cingulum plateau of the upper incisors

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99
Q

Class II div 1 incisor relationship

A

Lower incisor edges occlude posterior to the cingulum plateau of the upper incisors, upper incisors are proclined or of average inclination and there is an increased OJ

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100
Q

Class II div 2 incisor relationship

A

Lower incisor edges occlude posterior to the cingulum plateau of the upper incisors and upper central incisors are retroclined
OJ usually minimal or may be increased

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101
Q

Class III incisor relationship

A

Lower incisor edges lie anterior to the cingulum plateau of the upper incisors
OJ is reduced or reversed

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102
Q

How to measure overjet

A

Measure the biggest OJ of the 4 incisors with pt in maximum intercuspation

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103
Q

Overbite

A

Overlap of the teeth

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104
Q

Average overbite

A

Upper incisor covers 1/2 to 1/3 of the lower incisor crown

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105
Q

Reduced overbite

A

Upper incisor covers less than 1/3 of the lower incisor crown

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106
Q

Increased overbite

A

Upper incisor covers more than half of the lower incisor crown

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107
Q

Anterior open bite

A

No overlap of the incisors at all - measure how big this is at maximum and which teeth are involved

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108
Q

Increased and complete overbite

A

Increased overbite covering entire lower incisor crown, can contact teeth or palate or can not contact anything

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109
Q

How to describe an overbite

A

Reduced
Average
Increased - incomplete or complete, contacting tooth or palate

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110
Q

Angles classification

A

Used to be used to define malocclusion using buccal segment relationship

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111
Q

Class I molar relationship

A

Mesiobuccal cusp of upper 6 occludes with buccal groove of lower 6

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112
Q

Class II molar relationship

A

Mesiobuccal cusp of upper 6 occludes anterior to buccal groove of lower 6

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113
Q

Class III molar relationship

A

Mesiobuccal cusp of upper 6 occludes posterior to buccal groove of lower 6

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114
Q

Canine relationship

A

Class I - upper canine behind lower canine
Class II - upper canine in front of lower canine
Class III - Upper canine far behind lower canine

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115
Q

Full unit discrepancy

A

Teeth are aligned one cusp from the ideal occlusion

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116
Q

Half unit discrepancy

A

Teeth are aligned 1/2 cusp from the ideal occlusion and so will meet cusp to cusp

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117
Q

Ligature

A

Holds archwire to each bracket
Tiny elastic or a twisted wire

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118
Q

Archwire

A

Tied to all of the brackets
Creates force to move teeth into proper alignment

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119
Q

Brackets

A

Connects to the bands or directly bonded to the teeth and hold the archwire in place

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120
Q

Metal band in fixed ortho

A

Band cemented ring of metal wrapped around a tooth

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121
Q

Elastic hooks and rubber bands

A

Elastic hooks used for the attachment of rubber bands, which help move teeth toward their final position

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122
Q

Transpalatal arch used

A

Anchorage
Rotation
Limited widening or contraction

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123
Q

Transpalatal arch

A

0.9mm HSSW
Most commonly attached to upper 6s with the use of ortho stainless steel bands to which the appliance is attached with the use of spot welding/soldering

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124
Q

Palatal arch with nance button

A

0.9mm HSSW
Constructed in a rigid fixed manner and requires minimal adjustment prior to fitting
Most commonly attached to the upper 6s with the use of ortho stainless steel bands to which the appliance is attached with the use of spot welding/soldering

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125
Q

Palatal arch with nance button

A

Anchorage

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126
Q

Quadhelix uses

A

Bilateral expansion
Asymmetrical expansion
Fan style expansion
Rotation of molars
Expansion in cleft palate
Modified to procline incisors
Assist in habit breaking

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127
Q

Quadhelix

A

Highly versatile
can be adapted for a number of scenarios
0.9mm HSSW
Constructed in a rigid fixed manner and requires minimal adjustment prior to fitting
Most commonly attached to the first permanent molars with the use of orthodontic stainless steel bands to which the appliance is attached with the use of spot welding/soldering

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128
Q

Fixed ortho advantages

A

Bodily tooth movement
Rotations easily fixed
Can be used as easily in lower arch as upper
Individual force can be applied to every tooth
Not easily removed by patient
Works 24/7
Precise 3D movement of the teeth
Less invasive of tongue space
Minimal palatal coverage

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129
Q

Fixed ortho disadvantages

A

Increased risk root resorption
Decalcification
Can be perceived as visually unattractive
Can cause soft tissue trauma
Cost
High motivation required to oral hygiene
Poor anchorage
Highly trained specialist training required
Etching teeth is a destructive process

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130
Q

Advantages or removeable ortho

A

Tipping of teeth
Excellent anchorage
Generally cheaper than fixed
Shorter chairside time required
Oral hygiene easier to maintain
Non-destructive of tooth surface
Less specialised training required
Can be easily adapted for overbite reduction
Can achieve block movements

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131
Q

Removeable ortho disadvantages

A

Less precise control of tooth movement
Can be easily removed by pt
Generally only 1-2 teeth can be moved at one time
Specialist technical staff required to construct appliances
Rotations very difficult to correct

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132
Q

If the aim is to extrude a tooth, would you move the bracket up or down the tooth?

A

Up

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133
Q

How is radiology dose limited to ALARP?

A

Adequate staff training
Equipment - correct operation and maintenance
Justification - only take radiographs when required and select the most appropriate view

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134
Q

Why is it important to limit radiology dose to ALARP?

A

There is a significant increased risk of fatal cancer from the larger extra-oral films and larger volume CBCT compared with an intra-oral periapical or bitewing

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135
Q

What is collimation used for?

A

To reduce field of view and therefore radiology dose
e.g. dentition only in an OPT = 50% dose reduction

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136
Q

Why use OPT as part of a new patient assessment in ortho?

A

State of development - presence or absence of permanent teeth
Presence and position of ectopic or supernumerary teeth
Stage of development of individual teeth
The morphology of unerupted teeth
State of the alveolar bone (periodontal disease)
State of the teeth - size of restorations, gross caries, periapical infection, other pathology

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137
Q

Before taking a radiograph, what must be recorded in the patient notes?

A

What view is being taken and the justification as to why

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138
Q

Justification for taking radiographs in orthodontics

A

The benefit to the pt from the diagnostic information should outweigh the detriment of the exposure

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139
Q

After taking a radiograph what must be recorded in the patient notes?

A

Once you have viewed the radiograph report on your radiographic findings in the patients clinical records

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140
Q

What must always be done before taking radiographs of a patient?

A

The patient must be examined clinically

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141
Q

How to examine radiographs

A

Systematically
Teeth present
Roots of teeth - apical pathology/resorption
State of crowns - caries/restorations/hypoplasia
Alveolar bone loss
Other pathology such as bone cysts
Reason for the film request

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142
Q

Reasons for faults in OPT

A

Limitations in the width of the focal trough (particularly front of mouth)
Patient positioning wrong
Patient moving during exposure

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143
Q

How long does OPT exposure take?

A

18-20 seconds

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144
Q

Which patients may we have particular trouble positioning within the focal trough?

A

Those who can not bite edge to edge within the groove on the bite block

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145
Q

How do structures outwith the focal trough appear?

A

Blurred or completely invisible

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146
Q

Pt too far forward in OPT machine

A

Teeth appear narrower
This is because the teeth are further from the centre of rotation and the xray beam therefore passed more quickly through these teeth relative to the speed of the image receptor

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147
Q

Pt too far back in OPT machine

A

The teeth will look wider on the film because the teeth are closer to the centre of rotation and the xray beam therefore passed more slowly through these teeth relative to the speed of the image receptor

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148
Q

Ghost image

A

Shadow created on the opposite side and slightly higher up the opt from the object which caused them
Can be caused by metal objects, restorations, earrings or by normal anatomic features

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149
Q

Why are ghost images seen slightly higher than they are?

A

Xray beam is angled 8 degrees upwards

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150
Q

Why request a standard upper occlusal view?

A

To look for pathology in the upper anterior region of the maxilla
To confirm the presence of unerupted teeth
Root resorption (PA view better for this)
To aid localisation of unerupted teeth in combination with another radiographic view (parallax)

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151
Q

Why request a PA view?

A

To assess root resorption
To look for evidence of periapical infection
To assess if a tooth might be ankylosed
To aid localisation of unerupted teeth in combination with another radiographic view (parallax)

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152
Q

Why request a bitewing?

A

To assess caries status
To provide more information on tooth prognosis
To get more information on alveolar bone levels

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153
Q

Radiographic views required for localisation of unerupted teeth?

A

OPT and anterior occlusal maxillary
OR
Two periapical views

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154
Q

Radiographic views for vertical parallax

A

Anterior occlusal maxillary and OPT

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155
Q

Radiographic views for horizontal parallax?

A

Two PAs

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156
Q

Principles of parallax

A

There must be a change in position of the Xray tube between the two radiographs
Objects further away from the beam will move in same direction
Objects closer to the beam will move in the opposite direction

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157
Q

Indications for taking a lateral cephalogram

A

To aid diagnosis
Treatment planning
Progress monitoring

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158
Q

Patient position for lateral cephalogram

A

Frankfort plane horizontal
Teeth in RCP
Soft tissues contacted at nasion and bilaterally with ear rods in EAM

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159
Q

Cone beam computed tomography

A

3 dimensional radiograph similar to CT scan
A scanning image produced by the machine moving around patient’s head and creating a cylindrical or spherical field of view
Computer software produces images in axial, sagittal and coronal planes and can scroll through these images

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160
Q

When to use CBCT?

A

Localisation of impacted teeth if we need more information of their proximity to adjacent teeth and the possibility of resorption
To get a better view of structural anomalies
Some orthognathic cases
Some cleft palate cases

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161
Q

Why not use CBCT more often if we get more detailed information?

A

Radiation dose considerably higher
Patient set up takes longer, patient may have to stay still for a longer exposure
Reporting - additional training beyond BDS required to interpret and report
Cost

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162
Q
A
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162
Q

Only take a radiograph when …

A

You have examined the pt
The information gained will influence your treatment plan
You can not get the information any other way

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163
Q

What can cause a skeletal class III malocclusion?

A

A small maxilla, a large mandible, or some degree of both

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164
Q

What must we warn patients before undertaking presurgical fixed ortho for class III malocclusion?

A

Their class III appearance will worsen during this phase of treatment

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165
Q

Incidence of class III malocclusion in the UK

A

3-8%

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166
Q

Typical dental features commonly presenting in a class III malocclusion

A

Class III incisor relationship
Proclined upper incisors
Crowded upper arch
Well aligned lower arch

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167
Q

When treating class III malocclusion, what other device may accompany headgear?

A

rapid maxillary expansion device

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168
Q

How many hours per day must head gear be worn for treatment of class III malocclusion?

A

14

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169
Q

Class III incisors

A

Lower incisor edge occludes anterior to the cingulum plateau of the upper central incisor. The overjet is reduced or reversed

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170
Q

Aetiology of class III malocclusion

A

Strong genetic link (pattern controversial - autosomal dominant/recessive)
Environmental factors - Cleft lip and palate, acromegaly
Can be skeletal or dental

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171
Q

Skeletal base relationship of class III incisors patient

A

Usually have class 3, can present with class 1 or rarely class 2

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172
Q

Which class III cases are hardest to treat?

A

Those with the greatest A-P discrepancy
Increased FMPA and AOB also make treatment more complex

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173
Q

Vertical skeletal relationship associated with class III

A

Can be average, increased or reduced

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174
Q

How is vertical skeletal relationship investigated?

A

FMPA
Facial height proportions (LAFH:TAFH)
Lateral cephalometry

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175
Q

Link between class III A-P relationship and transverse skeletal relationship

A

Retrusive maxilla sits on a wider part of the mandible, often leading to bilateral crossbites

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176
Q

Dental features of class III

A

Vary
Class III incisors
Class III molars (not always)
Tendency to reverse overjet
Reduced overbite, AOB may be present
Crossbites - anterior or buccal
Alignment - maxilla often crowded, mandible often aligned or spaced
Dentoalveolar compensation - proclined upper incisors, retroclined lower incisors
Tendency for displacement on closing

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177
Q

Soft tissue involvement in class III

A

Not involved in aetiology
Do encourage dentoalveolar compensation
Tongue proclines upper incisors
Lower lip retroclines lower incisors

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178
Q

Dentoalveolar compensation in class III

A

Proclined upper incisors
Retroclined lower incisors

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179
Q

Why treat a class III?

A

Aesthetics - dental and profile concerns
Dental health - attrition, gingival recession, mandibular displacement
Function - speech and mastication

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180
Q

Factors making class III tx more difficult

A

> number of teeth in anterior crossbite
Skeletal element in aetiology
A-P discrepancy
Presence of anterior open bite

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181
Q

Facial growth considerations when treating class III malocclusion

A

Tends to be unfavourable
Mandibular growth continues for longer
Potential for class III to get worse
Do not do anything irreversible until growth has stopped - could affect future treatment if surgery required

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182
Q

Class III cases to accept and monitor

A

Mild class III
Unsure how growth and development will progress
No dental health indications

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183
Q

How would you treat a Class III by early interception with a URA?

A

Early correction of incisor relationship

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184
Q

Camouflage treatment for class III

A

Accept underlying skeletal relationship and correct incisors to class I

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185
Q

Interceptive tx works best for class III if…

A

it is a mild malocclusion

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186
Q

What is the advantage to correcting an anterior crossbite in the permanent dentition early with interceptive treatment?

A

Further forward mandibular growth may be counter-balanced by some dento-alveolar compensation

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187
Q

Under what circumstances is correcting a lateral incisor crossbite with interceptive orthodontics appropriate?

A

If permanent canines are high above the lateral roots - delay if canines have dropped down into buccal position as risk of resorption to lateral incisor

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188
Q

What will help maintain stability of interceptive orthodontics used to correct an anterior crossbite?

A

Big OB at the start

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189
Q

When does growth modification for class III pts work best?

A

10-14

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190
Q

What is the aim of growth modification for class III malocclusion?

A

Reduce/redirect mandibular growth and encourage maxillary growth

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191
Q

Frankel III

A

Pellotes (shields) labial to upper incisors to hold lip away
Palatal arch to procline the upper incisors
Lower labial bow to retrocline the lower incisors

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192
Q

What is a good way to check whether a class III is mild enough to be treated by URA?

A

Can the pt meet edge to edge incisors before tx

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193
Q

Functional appliances for class III

A

Reverse twin block
Frankel III

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194
Q

Force exerted by protraction headgear

A

400g/side

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195
Q

How many hours of the day does protraction headgear need to be worn?

A

14 hour/day

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196
Q

Best age for protraction headgear use?

A

8-10

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197
Q

How does rapid maxillary expansion device work?

A

Disrupts circum-maxillary sutures, so ideally used before these fuse

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198
Q

When would bollard implants be used?

A

Late mixed and permanent dentition

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199
Q

Where are bollard implants placed?

A

Infrazygomatic crest and lower canine region

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200
Q

Why are bollard implants unpopular?

A

Mucoperiosteal flaps must be raised for insertion and removal - two surgical procedures

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201
Q

Favourable features for camouflage of a class III

A

Growth stopped
Mild to moderate class III skeletal base and AND not <0 degrees
Average or increased overbite
Able to reach edge to edge incisor relationship
Little or no dentoalveolar compensation

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202
Q

Extraction pattern for orthodontic camouflage of class III

A

Extract further back in the upper arch
Extract further forward in the lower arch
Classic pattern - upper 5s and lower 4s
Not always possible - dental health may dictate extraction pattern

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203
Q

Aims of camouflage of class III

A

Aim for class I incisors
Procline upper incisors
Retrocline lower incisors
Correct overjet

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204
Q

Orthognathic surgery

A

Surgical manipulation of the mandible and/or maxilla to produce optimal dentofacial aesthetics and function
Pt usually has aesthetic or functional concerns and a moderate/sever skeletal discrepancy
Growth completed before

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205
Q

Multidisciplinary team involved in orthognathic surgery

A

Orthodontist
Maxillofacial surgeon
Technician
Psychologist

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206
Q

Presurgical orthodontics for orthognathic class III case

A

Approx 18 mo to level, align, decompensate and coordinate
Uppers 109 degrees
Lowers 90 degrees

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207
Q

How long do post surgical orthodontics for orthognathic surgery to correct a class III usually take?

A

Approx 6 months

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208
Q

What is the GDP role in treating a class III malocclusion?

A

Identify the class III
Refer to hospital service or specialist practitioner
Potentially URA tx to correct anterior cross bite

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209
Q

Common maxilla alignment in class III

A

Crowded

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210
Q

Common mandible alignment in class III

A

Often aligned or spaced

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211
Q

Dentoalveolar compensation for class III

A

Proclined upper incisors
Retroclined lower incisors

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212
Q
A

Transpalatal arch

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213
Q

Transpalatal arch uses

A

Anchorage
Rotation
Limited widening or contraction

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214
Q
A

Transpalatal arch with nance button

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215
Q

Palatal arch with nance button uses

A

Anchorage

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216
Q
A

Quadhelix

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217
Q

Uses of quadhelix

A

Bilateral expansion
Asymmetrical expansion
Fan style expansion
Rotation of molars
Expansion in cleft palate
Modified to procline incisors
Assist in habit breaking

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218
Q

Advantages of removeable orthodontics

A

Tipping of teeth
Excellent anchorage
Generally cheaper than fixed
Shorter chairside time required
Oral hygiene easier to maintain
Non-destructive to tooth surface
Less specialised training required to manage
Can be easily adapted for overbite reduction
Can achieve block movements

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219
Q

Disadvantages of removeable orthodontics

A

Less precise control of tooth movement
Can be easily removed by the patient
Generally only 1-2 teeth can be moved at one time
Specialist technical staff required to construct the appliances
Rotations very difficult to correct

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220
Q

Advantages of fixed orthodontics

A

Bodily tooth movement
Rotations easily fixed
Can be used as easily in the lower arch as well as the upper
Individual force can be applied to every tooth
Not easily removed by the patient
Works 24/7
Precise 3D movement of teeth
Less invasive of tongue space
Minimal palatal coverage

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221
Q

Disadvantages of fixed orthodontics

A

Increased risk of root resorption
Decalcification
Can be perceived as visually unattractive
Can cause soft tissue trauma
Cost
High motivation required in regards to oral hygiene
Poor anchorage
Highly trained specialist training required
Etching teeth is a destructive procedure

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222
Q

Appliance types for maintenance following orthodontic treatment

A

Conventional removeable retainers
Thermoplastic retainers
Bonded retainers

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223
Q

Which requires more force, intrusion or extrusion?

A

Intrusion requires a lot more force

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224
Q

Why are corrected diastemas and rotations indications for fixed bonded retainers?

A

These have a high incidence of relapse

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225
Q

Class II division 2

A

The lower incisor occludes posterior to the cingulum plateau of the upper incisor and the upper incisors are retroclined
Overjet is reduced but can be increased

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226
Q

Approx incidence of the different malocclusions

A

Class I 60%
Class II div 1 15-20%
Class II div 2 5-18%
Class III 3-8%

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227
Q

Placement of brackets for fixed ortho

A
  1. Choose gold standard tooth - most desirable angulation
  2. Visualise long axis and horizontal plane
  3. Place bracket where the two lines meet, with horizontal slots for archwire parallel to the occlusal plane
  4. Visualise long axis and horizontal plane of the next tooth
  5. If the goal is extrusion, place the bracket slightly further up
  6. If this is a smaller tooth than the gold standard, move the bracket 1-2mm closer to the incisal edge, to avoid over extrusion
  7. If you want to change the angulation of a tooth, place the bracket at the desired horizontal plane
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228
Q

What force is at work in fixed ortho?

A

Shape memory of the archwire

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229
Q

How should a fixed ortho bracket be placed on a tooth with unacceptable angulation?

A

Along the desired horizontal plane

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230
Q

Aetiological categories contributing to malocclusion

A

Skeletal
Soft tissue
Dental
Pathology

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231
Q

Antero-posterior skeletal tendencies of class II div 2 malocclusion

A

Usually underlying mild or moderate skeletal class 2
Can also be class 1 or 3

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232
Q

Vertical skeletal tendencies of a class II div 2 malocclusion

A

Typically reduced - reduced FMPA
Often associated with a forward rotational pattern of growth of the mandible
Prominent chin

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233
Q

Soft tissue features of class II div 2

A

High resting lower lip line - secondary to decreased lower face height, retroclines lower incisors
Marked labio-mental fold
High masseteric forces
Upper 2s have shorter clinical crown so escape the effect of the lower lip, trapping the lower lip

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234
Q
A

Class II division 2

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235
Q

Why must you be very careful making extraction decisions in class II div 2 cases?

A

Tend to have high masseteric forces and therefore space closure problems

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236
Q

Dental features of class II div 2

A

Retroclined upper and lower incisors
Deep OB
OJ usually reduced
Class II buccal segments
Increased interincisal angle
Upper laterals thin with poorly developed cingulum

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237
Q

Developmental dental anomalies and class II div 2

A

50-55% of cases have a form of congenital dental anomaly
20-33% with impacted canine
~15% lateral incisor microdontia

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238
Q

Why treat class II div 2

A

Aesthetic concerns
Dental health concerns - traumatic overbite, IOTN DHC 4f

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239
Q

IOTN score for increased and complete overbite with soft tissue trauma

A

4f

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240
Q

Treatment options for class II div 2 depend on.. (4)

A

Severity of malocclusion
Age and motivation of patient
Dental health
Patient concerns

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241
Q

When would you opt to accept a class II div 2 malocclusion?

A

Acceptable aesthetics
Patient not concerned or not suitable
Overbite is not a significant problem

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242
Q

When would you opt for growth modification as treatment for a class II div 2?

A

Growing patient (~12F 14M, adolescent growth spurt)
Mild to moderate skeletal 2 pattern

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243
Q

What is the process for growth modification of class II div 2?

A

Convert class II div 2 to class II div 1 by proclining the upper incisors with a URA
- Modified twin block
- Spring or screw
- Upper sectional fixed appliance
- ELSA
Detail the occlusion with fixed appliances if crowding/rotations

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244
Q

Camouflage method of treatment for class II div 2

A

Accepting the underlying skeletal base relationship and aiming for class I incisor relationship
Suitable for mild to moderate class II skeletal pattern
Careful extraction decision - space closure is difficult in low angle cases
Usually fixed appliances

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245
Q

Fixed appliances for camouflage of class II div 2

A

Needs OB reduction and correction of inter-incisal angle
Overbite will relapse if not corrected
Inter-incisal angle corrected by combination of palatal torque of upper incisors and proclination of lower incisors

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246
Q

When is orthognathic surgery used to correct a class II div 2 malocclusion?

A

Too severe a malocclusion for orthodontics alone - AP or vertical or combination
Non growing patients
Profile concerns
Usually 18ish

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247
Q

Orthognathic treatment for class II div 2 treatment plan

A

Fixed appliances to decompensate in preparation for the surgery - conversion from class II div 2 to class II div 1 and decompensation
Over jet allows for mandibular advancement
Surgery
Lateral open bites to increase lower anterior face height
Post surgery fixed orthodontics, while posteriors continue to erupt to increase LAFH
Entire process can take 3 years

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248
Q

When to refer Class II div 2

A

Refer to orthognathic surgery if significant skeletal component - after growth completed

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249
Q

Treatment of class II div 2 by GDP

A

Deep OB best corrected when pt still growing, which can be growth modification with functional appliance if AP discrepancy - URA with FABP

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250
Q

Extra oral features commonly associated with class II div 2

A

Reduced FMPA
Reduced lower anterior face height
Prominent pogonion

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251
Q

Aetiological factors associated with class II div 2

A

Hyperactive mentalis muscle
Forward mandibular growth rotation
High lower lip line retroclining the upper incisors
Lack of an effective occlusal stop on the cingulum plateau of the upper incisors

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252
Q

Why is the inter-incisal angle corrected in treatment of class II div 2 malocclusion?

A

To maintain stability of the treatment result

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253
Q

Class II div 2, compared with the other malocclusions, has increased incidence of..

A

Unerupted ectopic canine and peg laterals

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254
Q

Soft tissue oral surgery involved in orthodontics

A

Frenectomy - used to be believe fleshy frenum caused diastema, no evidence, this isn’t really done any more
Impacted canines can be exposed - usually buccal apically repositioned flap or palatal open exposure
Impacted premolar exposures

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255
Q

Possible treatments for impacted canines

A

Leave alone and monitor
Extract the canine
Surgical exposure and orthodontic alignment
Transplant

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256
Q

Why is transplant not always advisable?

A

Causes damage to the PDL

257
Q

How to reduce PDL damage during tooth transplant?

A

Minimal handling of the tooth
- Radiograph both sites to estimate size of the hole required
- CBCT of the area, cobalt chrome replica model of the tooth made to make sure it fits before extracting the tooth

258
Q

Process of the minimal surgical exposure of an upper 3 in the line of the arch

A

Removal of the retained upper C
Removal of overlying mucosa and follicle with scalpel
Removal of overlying bone with Rongeurs
Pack the socket with whiteheads varnish gauze to prevent gingivae from growing over it again
Place a horizontal mattress suture
The erupting upper 3 will then be bonded onto fixed ortho

259
Q

Indications for canine transplant

A

We cannot reasonably get a result by exposure and traction
There is potential for damage to other teeth
Space is available or can be made available without premolar extraction
The older patient who is seeking a quick fix

260
Q

Process of canine transplant

A

Raise a flap completely
Remove the canine and store in sulcus or in saline
Prepare the bone and place the canine into anatomical position
Treat as avulsed tooth - splint 2 weeks
Will require RCT - some are done before transplantation, some after
Flap then closed with sutures

261
Q

Are buccally or palatally placed impacted canines easier to access?

A

Buccally placed

262
Q

Why are teeth that are surgically exposed not luxated?

A

Increased chance of ankylosis

263
Q

What is the long term outcome for most transplanted teeth?

A

Ankylosis

264
Q

Apically repositioned flap process

A

For buccally placed canines
Three sided flap is raised
Flap is repositioned apically and sutured in this position
As the canine comes down it will bring the attached mucosa with it

265
Q

What is the effect of an open exposure for a buccally placed canine?

A

Poor gingival margin as there is no attached gingivae

266
Q

Open exposure

A

Cut a hole to expose an impacted tooth and leave it open
Never done on buccal side
Not suitable if the tooth has a long way to move because by the time it moves the gap will have closed over

267
Q

Closed exposure for impacted tooth

A

If tooth very deep or high up, raise flap, take away the bone to uncover the tooth then bond a chain to it and stitch the flap closed again

268
Q

What is the most common reason that primary teeth submerge?

A

They are ankylosed

269
Q

Frenectomies

A

Surgical removal of fleshy labial frenum

270
Q

Two types of frenoplasty

A

V to Y
Z plasty

271
Q

Why are implants the ideal orthodontic anchor, and why are they not used for this?

A
  1. Pt compliance unnecessary
  2. Absolute anchorage as there is no periodontal ligament
  3. Easily used under a variety of treatment modalites
  4. Easily placed
  5. Removeable, if necessary
    It is tempting to use implants but this is not suitable as they can integrate into the jaw and be difficult to remove
    Only titanium has osseointegration property to fuse to the bone
    Stainless steel mini implants are used instead
272
Q

Corticotomy

A

Removes the cortical bone that strongly resists orthodontic force in the jaw and keeps the marrow bone to maintain blood circulation and continuity of bone tissues to reduce risk of necrosis and facilitate tooth movement

273
Q

Annual incidence of cleft births

A

100 births per year in Scotland
1000 in UK
Cleft palate is more common in females
Cleft lip and palate more common in males

274
Q

What classification is used for cleft lip and palate?

A

LAHSHAL classification

275
Q

What is L in LAHSHAL classification

A

L - lip cleft
l - partial lip cleft

276
Q

How is a partial cleft classified using LAHSHAL classification?

A

Lowercase letter

277
Q

What is A in LAHSHAL classification?

A

Alveolus

278
Q

What is H in LAHSHAL classification?

A

Hard palate cleft

279
Q

What is S in LAHSHAL classification?

A

Soft palate

280
Q

LAHSHAL classification

A

LAHS

281
Q

Classification

A

LAHSHAL

282
Q

Classification

A

HS

283
Q

Ratio of CLP to Cleft palate

A

In England and Wales 2:1
In Scotland 1:1

284
Q

Genetic aetiological features of cleft lip and palate

A

Syndromes associated
Family history
Sex ratio (CP F>M CLP M>F
Ethnic predisposition - Asian, Hispanic, Native American
Laterality - more common on left

285
Q

Environmental aetiological considerations of cleft lip and palate

A

Social deprivation
Smoking
Alcohol
Anti-epileptics
Multivitamins

286
Q

If your first child has cleft lip and palate, what is the likelihood that your second child will too?

A

5%

287
Q

Types of implications of UCLP

A

Aesthetics
Speech
Hearing
Airway
Dental

288
Q

What is the most immediate problem for babies born with CLP?

A

They can not feed
Children and mothers in UK are seen without 24 hours to teach mothers to feed with special bottles

289
Q

Why must a cleft lip be fixed?

A

Purely for aesthetic reasons
There are no health implications

290
Q

What part of the anatomy is not working properly when those with CLP have speech difficulties?

A

Soft palate

291
Q

Hemifacial Microsomia

A

a condition in which one side of the face is smaller or underdeveloped or has parts that are missing

292
Q

Apert’s Syndrome

A

a genetic disorder that causes fusion of the skull, hands, and feet bones
characterized by deformities of the skull, face, teeth, and limbs

293
Q

Effects of cleft affecting the alveolus on teeth in that area

A

Microdontia
Hypodontia
Teeth coming through severely rotated/out of place

294
Q

Patient journey with UCLP

A

3-6 months lip closure
6-12 months palate closure
8-10 years alveolar bone graft
12-15 years definitive orthodontics
18-20 years surgery

295
Q

3 compulsory parts of the CLP journey

A

Lip surgery
Palate closure
Alveolar bone graft

296
Q

CLP IOTN score

A

5.p

297
Q

What is the basic aim of cleft lip closure surgery?

A

Orbicularis oris repair

298
Q

Why is palate closure not done sooner?

A

because babies are obligate nose breathers until 6 months. If done too early is could block their airway

299
Q

5 Dental implications of CLP

A
  1. Missing teeth
  2. Impacted teeth
  3. Crowding
  4. Growth tendencies - 20% have class III tendencies, top jaw tends not to come forward from about 10 or 11
  5. Caries
300
Q

Most common missing tooth in CLP patients

A

UL2

301
Q

What is the main cause of crowding in CLP patients?

A

Constricted upper arch

302
Q

Caries and CLP

A

Teeth come through in difficult places to clean, can be hypoplastic, and cleft is associated with lower socioeconomic background which also has increased caries risk
Caries is a problem because strep bacteria present in the mouth at the time of bone graft could be very dangerous

303
Q

Multidisciplinary team involved in CLP patients

A

GDP
Paediatric dentist
Dental therapist
Orthodontist
Orthodontic therapist
Restorative dentist
Oral surgeon

304
Q

Orthodontics

A

Branch of dentistry concerned with facial growth, development of the dentition and occlusion, and the diagnosis, interception and treatment of occlusal anomalies

305
Q

Ideal occlusion

A

Where the teeth are in the optimum anatomical position, both within the mandibular and maxillary arches and between the arches when the teeth are in occlusion

306
Q

Malocclusion

A

Term used to describe dental anomalies and occlusal traits that represent a deviation from the ideal occlusion
It is rare to have a truly perfect occlusion and malocclusion is a spectrum reflecting variation around the norm

307
Q

Prevalence of malocclusion

A

Depends on age, race, criteria for assessment, methods used (eg whether radiographs are considered)
In UK 9% of 12 year olds and 18% of 15 year olds are undergoing ortho tx, with a further 37% of 12 year olds and 20% of 15 year olds requiring tx

308
Q

What determines ortho need for tx?

A

The impact of the malocclusion and whether treatment is likely to provide a demonstrable benefit to the patient
To judge tx need, potential benefits are balanced against the risk of possible complications and side effects in a risk benefit analysis

309
Q

Why is demand for orthodontics higher now than in the past?

A

Increased awareness and acceptance of appliances
Increasing availability of less visible appliances
Increasing dental awareness and the desire for straight teeth

310
Q

Dental conditions for which there is no indication that orthodontics is beneficial

A

Caries
Plaque induced periosontal disease
TMD

311
Q

Occlusal anomalies where evidence suggests orthodontic correction would provide long term dental health benefit

A

Localised periodontal problems
-Crowding causing tooth/teeth to be pushed out of the bony trough, resulting in recession
-Periodontal damage related to traumatic OB
-Anterior crossbites with evidence of compromised buccal periodontal support on affected lower incisors
Increased overjet with increased risk of dental trauma
Unerupted impacted teeth with risk of pathology
Crossbites associated with mandibular displacement

312
Q

Dental trauma and incisor relationship

A

Risk of injury is more than doubled in individuals with an overjet greater than 3mm
Increases with overjet size and lip incompetence

313
Q

When does tooth impaction occur?

A

When normal tooth eruption is impeded by another tooth, bone, soft tissues, or other pathology
Supernumerary can cause impaction and if judged to be impeding normal dental development, orthodontic tx may be required

314
Q

Ectopic teeth

A

Teeth that have formed, or subsequently moved, into the wrong position. Often ectopic teeth become impacted

315
Q

Why is important to consider tx options of impacted teeth?

A

Unerupted impacted teeth may cause localised pathology, most commonly resorption of adjacent roots or cystic change.
This is most frequently seen in relation to ectopic maxillary canine teeth which can resorb roots of the incisors and premolars

316
Q

Direct influences on caries

A

Hygiene
Fluoride exposure
Diet

317
Q

When could caries risk be an indication for orthodontic treatment?

A

In caries susceptible children for example with special needs, malalignment may reduce the capacity for natural tooth cleansing an potentially increase the risk of caries, orthodontic tx methods for reducing food stagnation such as extraction or simple alignment to reduce localised crowding would be considered

318
Q

Association between plaque induced periodontal disease and malocclusion

A

Very weak
Increased dental awareness and positive OH and diet habits can follow orthodontic treatment BUT poor plaque control is a contraindication for ortho tx

319
Q

TMD

A

Comprises a group of related disorders with multifactorial aetiology including psychological, hormonal, genetic, traumatic and occlusal factors
Research suggests that depression, stress and sleep disorders are major factors in the aetiology of TMD and parafunctional activity

320
Q

Orthodontic treatment and TMD

A

Lots of debate
Ortho tx does not cause or cure TMD
Where signs of TMD are found it is wise to refer the patient for a comprehensive assessment and specialist management before embarking on ortho tx

321
Q

OHRQoL

A

Oral health related quality of life
Can be negatively affected by issues relating to dental appearance, masticatory function, speech and psychosocial well-being

322
Q

Common malocclusions to report difficulty eating

A

AOB
Markedly increased or reverse overjet
Severe hypodontia

323
Q

Articulation (speech)

A

The formation of different sounds through variable contact of the tongue with surround structures, including palate, lips, alveolar ridge, dentition

324
Q

Speech and ortho tx

A

It is unlikely that ortho tx will significantly change speech in most cases, as speech patterns are formed early in life before the permanent dentition is present
Teeth are only one component in this complex neuromuscular process

325
Q

When is ortho tx likely to make a difference to speech?

A

Where patients cannot attain contact between the incisors anteriorly, this may contribute to the production of a lisp. In these cases, correcting the incisor relationship and reducing interdental spacing may reduce lisping and improve confidence to talk in public

326
Q

Malocclusion and psychosocial well being

A

Malocclusion has been linked to reduced self-confidence and self esteem, with more sever malocclusion and dentofacial deformities causing higher levels of oral impacts

327
Q

Indication for bonded retainers

A

Diastemas or rotations have been corrected

328
Q
A

South end clasp for retention in the anterior region

329
Q
A

Adams clasps 16 14 24 26
Palatal finger spring 12

330
Q

Wire for active components

A

0.7mm HSSW

331
Q

What retention is offered by the baseplate?

A

Adhesion cohesion

332
Q

Primary use of transpalatal arch

A

anchorage

333
Q

Wire for transpalatal arch

A

0.9mm HSSW

334
Q

Archwire properties

A

Nickel titanium
Can be different diameter depending on need
Can be round or square rectangular

335
Q
A

A - Hard palate
B - Soft palate
C - Dorsum of tongue
D - Oropharynx
E - Oropharynx

336
Q
A

1- Middle cranial fossa
2- Inferior nasal concha
3-Infra orbital rim
4- Nasal septum
5- Orbit
6-Zygomatic arch
7-Articular eminence
8-Nasopharynx
9- Soft palate
10- Maxillary sinus
11- Hyoid bone
12- Mental foramen
13- Hard palate
14-Outline of dorsum of the tongue

337
Q

Female patient age 11, radiograph report

A

Unerupted UR873 UL378 LL7 LR75
Missing Lower 8s
The upper left second permanent molar may be partially erupted, further information from clinical examination would be required to confirm. On the right it appears as though there is a faint radiopaque shadow overlying UR7 indicating that mucosa is covering this tooth
Roots - dilaceration UR4 and UL4 Tooth roots otherwise normal for age of patient
Possible caries - LL6o, UR5d, UL5d, bitewings would be required to confirm
Alveolar bone levels - normal
Any other pathology - NAD in maxillary sinuses, surrounding bone, TMJ
Unerupted canines may be palatal. Clinical findings +/- an anterior occlusal maxilla radiograph would be required to confirm the position of these teeth

338
Q

What is the fault?

A

Pt too far forward in the OPT machine - anterior teeth blurred and very narrow

339
Q

Why do ghost images appear higher than the item causing them?

A

The Xray beam is angled up at 8 degrees

340
Q

What is the fault?

A

The Frankfort plane has not been horizontal, the patient is looking downwards creating the smiley face

341
Q

Where are the canines?

A

Palatal

342
Q
A

Palata

343
Q
A

Buccal

344
Q
A

Sella
Nasion
A point
B point
Anterior Nasal Spine
Posterior Nasal Spine
Porion
Orbitale
Gonion
Menton
Pogonion

345
Q

Porion

A

Superior border of the external acoustic meatus

346
Q

Nasion

A

Midline bony depression between the eyes where the frontal and the two nasal bones meet, just below the glabella

347
Q

Sella

A

Midpoint of the pituitary fossa

348
Q

Point A

A

The point at the deepest midline concavity on the maxilla

349
Q

Point B

A

The point at the deepest midline concavity on the mandibular symphysis between infradentale and pogonion

350
Q

Gonion

A

Constructed point of intersection of the ramus plane and the mandibular plane

351
Q

Pogonion

A

The most forward projecting point on the anterior surface of the chin

351
Q

Orbitale

A

Inferior border of the orbit

352
Q

Menton

A

Most inferior point on the mandibular symphisis

353
Q
A

A - sella nasion
B - Frankfort plane
C - Maxillary plane
D - Occlusal line
E - Mandibular plane

354
Q

Normal ANB angle

A

2-4 degrees

355
Q

What does an increased ANB indicate?

A

Class II skeletal pattern

356
Q

What does a decreased ANB angle indicate?

A

Class III skeletal pattern

357
Q

Average age of eruption lower central incisors

A

6

358
Q

Average age of eruption of upper central incisors

A

7

359
Q

Average age of eruption lower lateral incisors

A

7

360
Q

Average age of eruption upper lateral incisors

A

8

361
Q

Average age of eruption first permanent molars

A

6

362
Q

Average age of eruption second permanent molars

A

12

363
Q

Average age of eruption lower canines

A

9

364
Q

Average age of eruption upper canines

A

11

365
Q

Average age of eruptions upper premolars

A

10-11

366
Q

Average age of eruption lower premolars

A

10-11

367
Q

After eruption of a permanent tooth, within what time frame would you expect the contralateral to erupt?

A

6 months

368
Q

Dimensions of a FABP

A

OJ +3mm

369
Q

What is the purpose of a flat anterior bite plane

A

To reduce overbite by propping the anterior teeth open so that eruption of the posteriors can continue and prop the anteriors more open

370
Q

How to determine whether a tooth is a retained deciduous tooth?

A

Root morphology on radiographs
Colour of enamel
Size
Mobility
Palpate for the missing permanent

371
Q

How would you check for presence of an unerupted permanent upper canine?

A

Palpate palatally and buccally
Check for mobility of the C
Check radiographs

372
Q

Possible aetiology of an ectopic canine

A

Ectopic tooth germ
Trauma to primary
Genetic
Associated with other dental anomalies like missing other teeth such as laterals, peg laterals, supernumerary - long path of eruption believed to be guided by position of the lateral, explaining the link
Crowding

373
Q

Incidence of ectopic canines

A

1.5%

374
Q

MOCDO

A

Missing teeth
Overjet
Crossbites
Displacement of contact point
Overbite/open bite

375
Q

Treatment aims for a patient with ectopic 23, mild crowding in both arches and class II skeletal relationship

A

Facilitate eruption of 23
Align upper and lower arches
Correct class II skeletal relationship
Produce class I incisors
Produce class I molar relationship

376
Q

In a case of a missing upper canine with a C retained, what are the considerations when doing interceptive removal of the C?

A

How likely is the 3to come into place?
- How horizontal is it angled in relation to the sagittal plane
- How high is it - at or above apical third is not good
- How far mesially has it moved - canine crown more than halfway across the lateral incisor is not good

377
Q

Risks of leaving unerupted ectopic canine

A

Root resorption
Cyst
Ankylosis
Eventual loss of primary canine and complex restorative solutions
Crown resorption of the ectopic tooth - rare

378
Q

When would you choose to surgically remove an ectopic canine?

A
  • Pt does not want complicated treatment
  • Position of the canine is too ectopic to move into place
  • Ectopic tooth is causing root resorption
379
Q

When is a closed surgical exposure of an ectopic tooth technique used?

A

When the tooth is deeper

380
Q

At what age would you palpate for ectopic canines?

A

10-11

381
Q

Why is hypodontia relevant to GDPs?

A

Bridgework etc carried out and maintained by GDPs

382
Q

Hypodontia

A

Congenital absence of one or more teeth (not including third molars)

383
Q

Congenital absence of which teeth does NOT constitue hypodontia?

A

Third molars

384
Q

Anodontia

A

Complete absence of teeth

385
Q

Severe hypodontia

A

6 or more congenitally absent teeth

386
Q

How long after the eruption of a tooth can you expect the contralateral to have erupted by?

A

6 months

387
Q

Prevalence of hypodontia

A

6%
(6.3% F 4.6% M)

388
Q

Is hypodontia more common in females or males?

A

Females
(6.3% : 4.6%)

389
Q

Prevalence of missing upper laterals

A

1-2% population

390
Q

Prevalence of hypodontia in primary dentition

A

0.9%
(much less than in permanent)

391
Q

Commonly affected teeth by hypodontia

A

L5 U2 U5 lower incisors

392
Q

Associated features with missing upper laterals

A

Ectopic canines

393
Q

What is the pattern for the most commonly missing teeth in hypodontia?

A

Last in the series more commonly missing

394
Q

Width of central incisors

A

~9mm

395
Q

Width of lateral incisors

A

~7mm

396
Q

Aetiology of hypodontia

A

Non syndromic - this can be familial or sporadic
Syndromic - >100 craniofacial syndromes associated such as CLP, anhydrotic ectodermal dysplasia
Environmental - trauma or radiotherapy/chemotherapy

397
Q

Presentation of hypodontia

A

Delayed or asymmetric eruption
Disorder in sequence
Retained or infra-occluded deciduous teeth
Absent deciduous tooth
Tooth form

398
Q

Problems associated with hypodontia

A

Microdontia
Short roots
Impaction
Delayed formation/eruption
Malformation of other teeth
Crowding and/or malposition of other teeth
Maxillary canine/first premolar transposition
Taurodontism
Enamel hypoplasia
Altered craniofacial growth

399
Q

Taurodontism

A

developmental disturbance of a tooth in which body is enlarged at the expense of the roots. An enlarged pulp chamber, apical displacement of the pulpal floor and lack of constriction at the cementoenamel junction are the characteristic features
Most common/most difficult in 7s

400
Q

Special investigations for hypodontia patients

A

Study models
Radiographs
Photographs
Conebeam CT

401
Q

Why would a restorative dentist be interested to have cone beam CT in a hypodontia case?

A

To investigate the volume of the alveolar bone for potential implants

402
Q

Canine crown width

A

~8.5mm

403
Q

Assessment and planning structure for hypodontia

A

History
Extra oral exam
Intra oral exam
Investigations
Problem list
Definitive plan

404
Q

Hypodontia management options (categories)

A

Accept
Ortho only
Restorative only
Ortho and restorative

405
Q

Why is the success rate of a bridge placed in 3 position lower?

A

The canines are important in lateral excursions (canine guidance)

406
Q

Disadvantage of implants to treat hypodontia

A

Can’t be done until age 21+
Need minimum 6.5-7mm space
Root separation
Often bone grafts needed
Technically very demanding in aesthetic zone
Significant cost

407
Q

Potential problems arising from hypodontia

A

Spacing
Drifting
Over-eruption
Aesthetic impairment
Functional problems

408
Q

Hypodontia care pathway

A

GDP recognition
Referral to specialist orthodontist
Seen in GDH
Initial assessment in orthodontics and allocate when appropriate to hypodontia clinic for orthodontic and restorative input

409
Q

Which disciplines will have input on a hypodontia clinic?

A

Restorative and ortho

410
Q

Keys to successful management of hypodontia

A

Inter disciplinary team
Joint assessment and treatment planning with precise aims
Joint collaboration at transitional stages of treatment
Follow up of treated cases

411
Q

The hypodontia treatment plan of choice will do what 3 things?

A

Satisfies expected aesthetic objectives
Be least invasive
Satisfies functional objectives (both immediately and long term)

412
Q

Partial dentures for hypodontia

A

Not the most popular choice but can have good aesthetics
Good for multiple replacements in different areas and good for soft tissue replacement
Easy to do, not destructive to tooth surface and can be used as an intermediate option

413
Q

Resin bonded bridgework for hypodontia advantages

A

Relatively simple
Can do when young
Non destructive
Can look good
Can be placed on a semi permanent basis

414
Q

Resin bonded bridgework for hypodontia disadvantages

A

Failure rate
Appearance sometimes not good - try again, new material
Orthodontic retention needs are high

415
Q

Why is the success rate of a bridge replacing a canine lower than replacing a lateral incisor?

A

The canines are important in lateral excursions e.g. canine guidance

416
Q

Disadvantages of implants for hypodontia

A

Cant do until age 21
Must have 6.5mm space (the whole way up root length)
Often need bone graft
Root separation
Significant chairside time
Significant cost

417
Q

Advantages of space closure plus treatment for hypodontia

A

No prosthesis, relatively low maintenance
Good aesthetcs with appropriate orthodontic and restorative techniques
Can be done at an early age

418
Q

What condition might be treated by “space closure plus” and what is meant by this?

A

Hypodontia
Closure of spaces left by absent teeth as well as adjustments to the teeth present such as extrusion/intrusion or occlusal adjustments, to make them appear more like a normal dentition

419
Q

Fixed appliance

A

Appliances that are fixed to the teeth by the clinician and can not be removed by the patient

420
Q

What type of tooth movement is done by fixed appliances?

A

Precision tooth movement
Full control over movement of tooth and root

421
Q

What type of tooth movement is done by removeable appliances?

A

Simple tooth movement - tipping

422
Q

Advantages of fixed ortho over removeable?

A

Less dependent on compliance
3D control
Complex tooth movement
Control of root

423
Q

Disadvantages of fixed ortho over removeable?

A

Require excellent OH
Risk of iatrogenic damage
Poor intrinsic anchorage

424
Q

Advantages of removeable ortho over fixed

A

Less risk of iatrogenic damage
Good intrinsic anchorage

425
Q

Disadvantages of removeable ortho over fixed?

A

Can be lost
Only simple tooth movements - tipping
No control over other movement
Greater compliance required

426
Q

When do we use fixed ortho?

A

Correction of mild to moderate skeletal discrepancies (camouflage)
Alignment of teeth
Correction of rotations
Centreline correction
OB and OJ reduction
Closure or creation of spaces
Vertical movements - intrusion/extrusion

427
Q

Ideal treatment goals of fixed orthodontics

A

Andrew’s 6 Keys
- Tight approximal contacts with no rotations
- Class I incisors
- Class I molars
- Flat occlusal plane or slight curve of spee
- Long axis of teeth have a slight mesial inclination except the lower incisors
- The crowns of the canines back to the molars have a lingual inclination

428
Q

Fixed appliance components

A

Bracket/tube
Band
Archwire
Modules
Auxillaries
Anchorage components
Force generating components

429
Q

What can be added to fixed ortho to proved intermaxillary anchorage?

A

Elastics

430
Q

Molar bands

A

Stainless steel bonded in place with GI
Not always needed
Molar tubes more common which are easier to keep clean and less traumatic to the soft tissues
Pre- welded attachments such as tubes or cleats will be on the bands
Require space before placement - usually needs separator visit

431
Q

When would you need a separator visit before placing fixed ortho?

A

If using molar bands

432
Q

Orthodontic bracket materials

A

Most commonly SS
Sometimes CoCr, Ti, Au
Ceramic and polycarbonate available - more aesthetic

433
Q

Components of fixed ortho brackets

A

Bracket slot
Tie wings
Bracket base

434
Q

What is meant by tip?

A

Mesial-distal angulation

435
Q

What is torque in ortho, and what determines torque in fixed ortho?

A

Buccal-lingual inclination
Thickness of bracket base and slot angle

436
Q

What does a bracket prescription do?

A

Determines the tip, torque and in/out control

437
Q

How are molar bands bonded to teeth?

A

GI

438
Q

How are ortho brackets bonded to teeth?

A

Composite via acid etch
Photo initiation using light cure 440-480nm wavelength
Micromechanical retention

439
Q

What kind of force is achieved when brackets are bonded to teeth with composite?

A

Micromechanical retention

440
Q

Archwire materials

A

SS, NiTi, CoCr, beta-titanium, composite/glass

441
Q

Which type of archwire are you likely to start with?

A

Light force
NiTi is good for light continuous force, by shape memory

442
Q

What material is likely to be used in archwires in later stages of fixed ortho?

A

Stainless steel

443
Q

What does it mean if an archwire material is “formable”? Give an example of one that is and one that isn’t

A

It cannot be bent into a loop or a deflection, it will return to it’s original shape
NiTi - not formable
Stainless steel - formable

444
Q

Self-ligating appliances

A

No elastomeric modules required
Little gate on bracket opened chairside to release the wire and replace
Can be a plaque trap and become difficult to open and close

445
Q

What are NiTi push coil springs used for?

A

Making space

446
Q

Bumper tubing

A

Used where extraction spaces are quite large, to give it rigidity and help wire stay in place on biting

447
Q

Force generating components that work by sliding mechanics

A

Elastomeric power chain
NiTi coils
Intra-oral elastics
Active ligatures

448
Q

How do force generating components cause movement?

A

Teeth move by utilising the energy stored in the elastic or spring

449
Q

Why would you see patients with elastomeric power chains more often?

A

Elastics degrade very quickly so they lose a lot of force in the power chain in the first 24-48 hours

450
Q

Newton’s 3rd law

A

Every force has an equal but opposite reactionary force

451
Q

When choosing which teeth to use for anchorage, what must be considered?

A

Root surface area

452
Q

Compound anchorage

A

Linking groups of teeth together as a unit increasing the root SA to use for anchorage

453
Q

Reciprocal anchorage

A

Equal root SA, equal tooth movement
E.g. closing a diastema

454
Q

What can be used for absolute anchorage?

A

TADS temporary anchorage devices
Non osseointegrating mini screw

455
Q

What can be used for cortical anchorage?

A

Transpalatal arch
Lingual arch
The cortical plates provide increased resistance to tooth movement, maintaining intermolar width

456
Q

Class III elastics

A

Lower canine to upper first molar

457
Q

Class II elastics

A

Upper canine to lower first molar

458
Q

Retention (after ortho)

A

Maintaining the final tooth position with a passive orthodontic appliance

459
Q

High relapse potential features, and what can be provided to prevent this?

A

Pre-existing spacing, rotations, instanding laterals, ectopic teeth, AOB, proclined lower incisors, diastemas
Fixed retainers

460
Q

Typical retainer wear pattern

A

2 weeks full time wear except during eating and drinking, then night early
OR
Straight to nights only

461
Q

Removeable appliances used for retention

A

Pressure formed retainers
Hawley removeable retainer

462
Q

When are fixed retainers provided?

A

Usually when there has been a high relapse potential feature
Must have enough occlusal clearance
Must have good OH

463
Q

Disadvantages of fixed retainers

A

Composite can debond and go unnoticed by the patient, leading to relapse or caries
Multistranded twist wire - if this starts to unravel they can become active
Requires careful monitoring and ID cleaning

464
Q

Main risks of fixed ortho treatment

A

Decalcification
Root resorption
Relapse

465
Q

What risk is increase with ceramic brackets?

A

Tooth wear
Ceramic brackets are harder than enamel so can cause wear, ensure no contacts

466
Q

Patient journey fixed ortho

A

Assessment and diagnosis (including treatment aims)
Treatment plan
Commence treatment (average case 18-24months, orthognathic cases 24-30 months)
Routine adjustments 4-8 weeks

467
Q

Initial problems encountered with fixed ortho

A

Pain
Mucosal irritation
Ulceration
Appliance breakage

468
Q

GDP role in patient with fixed ortho

A

Continue to see patient for routine care and check ups - reinforce OHI and diet advice
Liaise with orthodontist if concerned
Make appliance safe in case of an orthodontic emergency - snipping jaggy wire or removing lose components

469
Q

Do molar bands provide anchorage?

A

No

470
Q

Name 4 anchorage providing components

A

Palatal arch
Inter-maxillary elastics
Baseplate of an upper removeable appliance
Osseo-integrated mini screw

471
Q

Management of a digit sucking habit

A

Behaviour management techniques, nail polish FIRST
Habit breaker appliance if this has not worked and child still motivated

472
Q

Cases suitable for growth modification

A

Class II div I case with increased OJ in the mixed dentition
Mild skeletal class III with class III incisors in mixed dentition
Deep OBs (utilise eruption potential)

473
Q

Why is it important to break a digit sucking habit as young as possible?

A

More eruptive potential

474
Q

Aetiological factors of AOB

A

Digit sucking habit
Tongue thrust
Trauma
Underlying skeletal vertical excess

475
Q

What would be put on a removeable digit sucking habit breaker?

A

1 or 2 palatal goal posts

476
Q

Describe a fixed appliance digit sucking habit breaker

A

Molar bands with a palatal arch with a vertical wire tongue rake on it

477
Q

Would you balance an extraction of a first permanent molar and why?

A

No it is far enough from the midline than it is not necessary

478
Q

If extracting an upper 6, would you compensate this extraction?

A

No

479
Q

Why are you more likely to compensate a lower extraction than an upper in first permanent molars?

A

This is because of the potential for overeruption of the upper 7 with removal of the lower 6, preventing the lower 7 from erupting into the ideal position.
Overeruption much less common in the lower

480
Q

If you were extracting a lower 6, would you compensate this extraction?

A

Not routinely
You would consider it, if you think the upper is going to remain unopposed for a long time
Potential for overeruption of the upper preventing the lower 7 from erupting into ideal position

481
Q

Interceptive orthodontics

A

Any procedure which will reduce or eliminate the development of a feature of malocclusion

482
Q

Around what age would you be doing extractions of 6s of poor prognosis?

A

8-10

483
Q

Where would you be able to palpate unerupted premolars?

A

If the tooth is in normal position you wont be able to, as premolars develop between the roots of primary molars
If it is ectopic it is more likely palatal

484
Q

What can cause ankylosis of a primary tooth?

A

Trauma
Missing permanent

485
Q

When must you act quickly on an ankylosed primary tooth?

A

If it is submerged below the contact point

486
Q

How would you treat an ankylosed primary molar?

A

If there is a permanent successor - extract and space maintain
If there is no successor, consider
1. Retain and provide a crown/onlay
2. Extract and close the space
This depends on prognosis of the infraoccluded tooth and on how this options would fit into treatment plan of any other malocclusal features

487
Q

If crowding has caused an upper 2 not to erupted, which way is it more likely pushed?

A

Palatally

488
Q

URA treatment for anterior crossbite

A

Z spring and posterior bite plane

489
Q

Why can’t you treat anterior crossbite with anterior bite plane?

A

It would decrease OB, which is bad for relapse of crossbite

490
Q

Why bother treating impacted 6s?

A

Caries risk to partially erupted
If you can disimpact, you maintain arch length and space for the rest of the dentition

491
Q

Tx options for impacted 6s caused by retained Es

A

XLA E
Distal discing - however this can cause loss of space
Try spacers for 1 week

492
Q

Aetiological causes of midline diastema

A
  • Low frenal attachment
  • Missing teeth eg lateral
  • Microdontia
  • Normal sized teeth but large arch
  • Unerupted supernumerary
493
Q

Dens in dente

A
  • Pulp has invaginated on itself during development
  • Pulp looks as if it is coming right into the clinical crown
  • Poor prognosis because of potentially communication between oral cavity and pulp
494
Q

Priority number 1 when managing orthodontic faults and emergencies

A

Patient safety - ideally without compromising the orthodontics but sometimes there is no choice

495
Q

What must be asked if a URA is brought in with a missing component?

A

Can this be accounted for? Did it break while in the patients mouth? Is it possible it has been swallowed?

496
Q

What is done if a broken off URA component can not be accounted for, and the break happened while in the mouth?

A

Chest Xray immediately

497
Q

Management of fractured south and clasp, palatal finger spring and 16 26 adams clasps PMMA baseplate

A

If early in ortho tx - new appliance made as no orthodontic movement has happened yet
If later, you don’t want pt to go without for any length of time due to risk of relapse
Turn the South End clasp into a C clasp
If tx almost finished and this is adequately retentive, leave
If they will have it for a while longer have a new one made

498
Q

How to turn a south end clasp into a C clasp if fractured?

A

Trim sharp part flush with baseplate
Cut southend clasp in the middle
Fold over sharp edge with Adams 64 pliers

499
Q

Why can’t you smooth broken URA components with rubber wheel?

A

This will thin the wire and make it sharper

500
Q

Why can’t you solder new components to a URA?

A

PMMA will melt or catch fire once melting point for soldering material is reached

501
Q

How to manage fractured adams clasp 16. adams clasp 26, south end clasp and buccal canine retractor

A

Account for missing components - if can’t chest xray
Make the appliance safe by trimming sharp edges
If still retentive - this is fine
If not - the component must be replaced
Send the URA imbedded in an impression of the URA in the mouth or with original working cast
Lab can remove a segment of acrylic and fill with new acrylic and new component

502
Q

Why can’t you send a URA and a new impression of the mouth to have a broken component replaced?

A

The new impression will have a slightly different fitting surface, creating a space between the cast and the URA, new acrylic will flow underneath, contaminating the fitting surface and the appliance will no longer fit - ACRYLIC CREEP

503
Q

How to manage: Pt is on holiday away from home and appliance has been stood on and acrylic has been fractured, goes to local dentist
Acrylic broken in multiple places

A

Extra-oral - do not need to account for missing pieces
Advise patient not to wear in its current state and do not try to repair themself
Give the patient a thermoplastic retainer to prevent relapse

504
Q

How to manage: Fixed lower appliance, archwire, brackets on all teeth and bands on 36 and 46, bracket on 43 has debonded

A

Remove ligature and bracket, send back to orthodontist
Cannot rebond bracket because you do not know the ortho txp and exact location

505
Q

How to manage: Deformed and debonded fixed retainer lower 3-3

A

Take it all off, check lingual surfaced for signs of caries
Offer to leave it, or take impressions to get models, make a new bonded retainer
Offer thermoplastic retainer
If pt wants neither, inform them that teeth will go back to their original position, can make them sign something, must record in the patients notes

506
Q

How to manage: Fixed appliance with brackets ligatures and archwire, metal bands on 16 and 26, and transpalatal arch
Fracture between transpalatal arch and band on 16, wire could traumatise the palate

A

Can not bend this wire as it is 0.9mm HSSW and would exert huge force on the still attached 6, can not solder in the mouth, transpalatal arch is now useless
Wrap floss around omega loop and use slow speed to cut in short bursts when the transpalatal arch meets the band
Plenty of water and short bursts to avoid overheating
The smooth both bands on 6s

507
Q

How to manage: URA with Adams clasps on 16 and 26, south end clasp, palatal finger spring, self cure PMMA base
Adams clasp 26 is fractured at the arrowhead

A

Could be soldered, if this doesn’t work, can cut at other arrowhead to make a single arrowhead clasp, bend wire to make safe
If so badly distorted than can’t be modified, cut the clasp off to make safe and see if appliance is still retentive
If not, get clasp replaced - impression in mouth or URA on old cast to prevent acrylic creep

508
Q

How to manage: Fixed bonded retainer lower 3-3, debonded from 43 and wire distorted

A

Can not push wire to rebond as this would apply force to the tooth
Could cut the wire between 42 and 43 and smooth the wire
Explain this to patient and give option to replace

509
Q

How to manage: Fixed appliance brackets archwire ligature and bands on 6s
26 band GIC has debonded

A

Could cut the wire at 25 and bend it back to make it safe
It is not possible to create a perfect seal without taking the band off fully and rebonding, we do not know the exact angulation of the band

510
Q

How to manage: URA Adams clasps, southend clasp, palatal finger spring
Fracture in the middle of the south end

A

Could make new appliance if start of treatment
Could bend both into C clasps

511
Q

How to manage: Upper fixed, brackets, ligatures, archwire, bands on 6s
Bracket on 11 debonded, on square rectangular wire

A

Bracket will not rotate around square rectangular wire
Ensure with figure of 8 ligature that the bracket is secured to the archwire, inform the patient that this is debonded, show them how to clean underneath and advise to go back to orthodontist ASAP

512
Q

How to manage: URA Adams clasps 16 26 South end buccal canine retractor self cure PMMA baseplate
Adams 26 fractured near baseplate

A

Can’t solder
Cut at the other side arrowhead and bend the arrowhead shut to modify into a single arrowhead clasp
Still getting retention from single arrowhead clasp, other adams and southend and baseplate
If not retentive have a new Adams clasp added

513
Q

How to manage: Upper fixed appliance with archwire, brackets, ligatures and metal bands on 16 and 26
Wire has come out of upper right hand side and slipped round to be over extended at the left

A

Trim over extended wire and bend
Also cut the other end and bend into a retentive tag

514
Q

How to manage: Fixed bonded lower 3-3
Debonded from 31 wire is not distorted

A

Remove composite from this tooth
Check for caries
Check integrity of the wire
Etch bond and reapply composite to this tooth

515
Q

How to manage: Upper fixed ortho with missing brackets, debonded brackets, loose archwire and missing ligatures

A

Most likely cause - trauma
First account for components where possible - chest XRAY if necessary
Carefully take off ligatures and take out archwires
Leave remaining brackets
Trauma stamp
Splint mobile teeth - brackets may be useful

516
Q

Apart from space maintenance, list three uses of a passive URA

A

Retention
Overbite reduction
Habit breaker

517
Q

Pt is having upper 4s extracted to allow eruption of canines, what would a suitable space maintainer URA design be?

A

Adams clasps 16 and 26 0.7mm HSSW
Southend clasp UR1 UL 1 0.7mm HSSW
PMMA self cure acrylic baseplate extending palatal of incisors

518
Q

Three types of space maintainer

A

Band and loop
Fixed palatal arch
URA with extended PMMA baseplate

519
Q

Name 4 active components

A

Buccal canine retractor
Roberts retractor
Palatal finger spring
Z spring
Midpalatal screw

520
Q

How to know a patient has been wearing their URA?

A

Speaks normally
Wearing it at appt
No excess salivation
Can insert and remove easily
Worn appearance of acrylic
Good fit
Indentations on palatal mucosa
Evidence of tooth movement
Active components are passive/clasps loose

521
Q

What is SNA?

A

The angle between Sella, Nasion and soft tissue point A

522
Q

What does increased ANB suggest?

A

class II skeletal pattern

523
Q

Treatment options for class II div I malocclusion

A

Accept
Functional/growth modification
URA - Orthodontic camouflage
Fixed - Orthodontic camouflage
Functional + fixed appliances
Complex surgical correction

524
Q

AIM for URA to correct 12 in anterior crossbite

A

Please construct a URA to correct an anterior crossbite on the 12

525
Q

ARAB for URA to correct 12 in anterior crossbite

A

AC - 12 Z spring 0.5mm HSSW
R 16+26 14+24 Adams clasps 0.7mmHSSW
A moving only one tooth
B Self-cure PMMA Posterior bite plane

526
Q

Why do adults seek ortho tx?

A

Improve dental aesthetics
Refused tx as a child
Lack of earlier opportunity
Unhappy with result of earlier tx due to relapse or poor initial tx
Adjunctive to restorative tx
After periodontal drift
Part of surgical correction of jaw discrepancy

527
Q

What makes adult orthodontics different to treating children?

A

Lack of growth
Potentially periodontal disease, missing teeth, heavily restored teeth
Motivation

528
Q

Growth considerations in adult orthodontics

A

Non growing
Growth modification is not possible so must accept skeletal pattern OR surgery
OB correction more difficult - may need tooth intrusion
Midpalatal suture is closed - can only expand the maxillary base with surgery

529
Q

Can you do orthodontic movement on a previously RCTed tooth?

A

Yes if it is obturated correctly and symptom free

530
Q

Physiological factors of adult orthodontics compared to children

A

Decreased cell turnover, initial movement can be slower
Use lighter forces

531
Q

When might orthodontics in adults be used as an adjunct to restorative tx?

A

To upright abutments to aid restoration
Intrusion of over-erupted teeth
Extrusion to increase crown length

532
Q

Considerations of adult orthodontics in perio patients

A

May see tooth migration
Perio treatment must be stable first
This will require long term retention

533
Q

What is pre-surgical orthodontics usually used for?

A

To align and coordinate dental arches and decompensate incisors

534
Q

Andrews 6 keys

A

Tight approximal contacts with no rotations
Class I incisors
Class I molars
Flat occlusal plane or slight curve of spee
Long axis of the teeth have slight mesial inclination except lower incisors
Crowns of the canines back to the molars a lingual inclination

535
Q

Less visible ortho options

A

Lingual appliances
Clear brackets
Ceramic brackets

536
Q

What are the pros and cons of a lingual fixed appliance?

A

Pros
More aesthetic
If patient gets decalcification it wont be seen
Cons
No wow factor at end of treatment
Difficult to apply

537
Q

Consideration of ceramic brackets

A

Risk of tooth wear abrasion

538
Q

Benefits of orthodontic treatment

A

Improvement in appearance, function, and dental health

539
Q

Which malocclusions see the greatest functional benefit from orthodontic treatment?

A

Large AOB
Severely increased OJ
Marked reverse OJ

540
Q

Dental health considerations of impacted teeth

A

Can cause resorption
Supernumeraries can prevent normal eruption
Can be associated with cyst formation

541
Q

Dental health considerations of overjet increased >6mm

A

Risk of upper incisors trauma increases with size of OJ, worse with incompetent lips

542
Q

Dental health considerations of anterior crossbites

A

Loss of perio support
Tooth wear

543
Q

Dental health considerations of posterior crossbites

A

Significant displacement may lead to
- Asymmetry
- Requiring early correction

544
Q

Dental health considerations of displacement of contact points/crowding

A

Potential increase in caries and perio risk, little evidence but these teeth are more difficult to clean

545
Q

Dental health considerations of deep traumatic overbites

A

Gingival stripping
Loss of perio support

546
Q

Risks of orthodontic treatment

A

Decal
RR
Relapse
Soft tissue trauma
Recession
Loss of periodontal support
Headgear injuries
Enamel fracture and tooth wear
Loss of vitality
Allergy
Poor/failed treatment

547
Q

Decalcification can cause

A

Staining
Cavitation
Caries

548
Q

How is decalcification prevented?

A

Case selection
Oral hygiene
Diet advice
Fluoride

549
Q

Case selection to prevent decalcificaiton

A

Motivated, good OH, low caries risk

550
Q

Oral hygiene to avoid decalcification

A

Toothbrushing, interdental brushing, minimum 2x daily thoroughly, after every meal, diclosing tablets, target gingival margins and around each bracket

551
Q

Diet advice to avoid decalcification

A

Low sugar, avoid snacking between meals, avoid fizzy juice, sports drinks, sweets

552
Q

Fluoride to prevent decalcification

A

Toothpaste 2x+ daily, spit don’t rinse
2800ppmF 2x daily in high risk
Mouthwash 225ppmF in between brushing
Fluoride varnish 22600ppmF 4 monthly

553
Q

Root resorption in ortho

A

inevitable consequence, average approx 1mm over 2 years fixed teeth
Affects any teeth but UI>LI>6s
Mostly unnoticed

554
Q

What % of ortho patients will get severe root resorption?

A

1-5%

555
Q

Risk factors for root resorption in ortho

A

Types of movement (prolonged high force, intrusion, large movements, torque)
Root form (blunt, pipette, resorbed already)
Previous trauma

556
Q

Bridgework after orthodontal tx

A

Have a retainer fit quickly after bridge cementation to prevent relapse

557
Q

Features more prone to orthodontic relapse

A

Lower incisor crowding
Rotations
Instanding 2a
Spaces and diastemas
Class II div 2
AOB
Reduced perio support/short roots

558
Q

How to prevent relapse

A

Case selection
Informed consent
Retainers

559
Q

Prevention of headgear trauma

A

Minimum 2 safety mechanisms
- Snap away traction spring
- Nitom facebow
- Masel strap

560
Q

When is the risk of tooth wear in ortho treatment increased?

A

Ceramic brackets

561
Q

Why does some orthodontic treatment fail?

A

Clinician - poor diagnosis, poor treatment planning, poor operator technique
Patient - unfavourable growth, poor compliance, repeated breaking, poor attendance

562
Q

Approximate prevalence of Class II div 1 malocclusion in the UK

A

15-20%

563
Q

What occlusal features be seen in patients with a digit sucking habit?

A

Increased overjet
Posterior crossbite
Narrow maxillary dental arch
Retroclined lower incisors
Proclined upper incisors
Anterior open bite

564
Q

How would you expect ANB to measure in a patient with a class II skeletal base relationship?

A

Greater than 5 degrees

565
Q

Normal ANB range

A

3-5 degrees

566
Q

What is the main therapeutic effect of functional appliance treatment in a growing child with a class II division 1 malocclusion?

A

Reduction of the overjet and correction of the molar relationship through dentoalveolar change

567
Q

Extra-oral features associated with class II div 2 malocclusion

A

Reduced FMPA
High resting lower lip line
Reduced lower anterior face height
Prominent pogonion

568
Q

Aetiological factors in class II div 2 malocclusion

A

High lower lip line retroclining the upper incisors
Lack of an effective occlusal stop on the cingulum plateau of the upper incisors
Hyperactive mentalis muscle
Forward mandibular growth rotation

569
Q

Why, when treating class II div 2, do we correct the inter-incisal angle?

A

To maintain stability of the treatment result

570
Q

There is an increased incidence of unerupted ectopic canines and peg laterals associated with which malocclusion?

A

Class II div 2

571
Q

Before pre-surgical orthodontics with fixed appliances for a class III patient, the patient should be advised that:

A

Their class III appearance will worsen during this phase of treatment

572
Q

Incidence of class III malocclusion in UK population

A

3-8%

573
Q

Typical dental features commonly associated with class III malocclusion

A

Class III incisors
Proclined upper incisors
Crowded upper arch
Well aligned lower arch

574
Q

When treating a class III malocclusion in a patient using a fixed rapid maxillary expansion device, the accompanying headgear needs to be worn how many hours per day?

A

14

575
Q

What type of ortho tx has poor intrinsic anchorage?

A

Fixed

576
Q

Do molar bands provide anchorage?

A

No

577
Q

Name 4 anchorage supplying components

A

Palatal arch
Baseplate of a URA
Osseo-integrated mini screw
Intermaxillary elastics

578
Q

Which material has not been used to manufacture orthodontic brackets
Nickel titanium
Cobalt chromium
Ceramic
Stainless steel
Gold

A

Nickel titanium

579
Q

Materials used for fixed ortho brackets

A

Cobalt chromium
Ceramic
Stainless steel
Gold

580
Q

What is torque of a tooth?

A

The angulation of the tooth in a bucco-lingual direction

581
Q

Classify this using LAHSHAL classification

A

HS

582
Q

At what age do you take a radiograph to assess a CLP patient for alveolar bone grafting?

A

7 years

583
Q

Important factors in cleft care

A
  • Where appropriate care should be delivered close to home
  • Care should be delivered within a multidisciplinary environment
  • All appropriate clinicians should be present within the multidisciplinary team
  • The patient should see GDP regularly for routine dental care
584
Q

Which tooth is usually considered the most important in determining the age at which a bone graft for a CLP patient is carried out?

A

Canine

585
Q

Name 4 members of a conventional multidisciplinary team for cleft care

A

Cleft surgeon
Speech and language therapist
Psychologist
Orthodontist

586
Q
A

A - Sella (midpoint pituitary fossa)
B - Nasion
C - Porion
D - Posterior nasal spine
E - Orbitale
F - Anterior nasal spine
G - Soft tissue point A
H - Gonion
I - Soft tissue point B
J - Pogonion
K - Menton

587
Q

URA design to retract canines, 1st premolars extracted, and 6mm OJ

A

A - 13 +23 palatal finger springs and guards 0.5mm HSSW
R - 16 + 26 Adams clasps 0.7mm HSSW and 11+21 Southend clasp 0.7mm HSSW
Anchorage - moving only 2 teeth
B - self cure PMMA, FABP overjet +3mm

588
Q

URA design to retract incisors 6mm oj, and reduce OB
(4s have been extracted and canines have been retracted)

A

Active component - Roberts retractor 22 21 11 12 0.5mm HSSW with 0.5mm ID tubing
Mesial stops 13 and 23 0.7mm flattened HSSW
Anchorage - moving 4 teeth
Baseplate - Self cure pmma and FABP OJ + 3mm

589
Q

URA design to expand the upper arch

A

Midline palatal screw
Adams clasps 16 26 14 24 0.7mm HSSW
Reciprocal anchorage
Self cure PMMA and posterior bite plane

590
Q

URA design to retract buccally placed canines, 1st premolars extracted, 6mm OJ, and Reduce OB

A

13 +23 buccal canine retractors 0.5mm HSSW +0.5mm ID tubing
16 26 Adams clasps 0.7mm HSSW
11 +21 Southend clasp 0.7mm HSSW
Moving only 2 teeth
Self cure PMMA and FABP OJ+3mm
FOLLOWED BY
22 21 11 12 Roberts retractor 0.5mm HSSW and 0.5mm ID tubing
Mesial stops 13 and 23 0.7mm flattened HSSW
16 and 26 Adams clasps 0.7mm HSSW
Moving 4 teeth
Self cure PMMA
FABP OJ +3mm

591
Q

URA for 12 in anterior crossbite

A

12 Z spring 0.5mm HSSW
16 26 14 24 Adams clasps 0/7mm HSSW
Moving only 1 tooth
Self cure PMMA with PBP

592
Q

LHS 1-4
RHS 5-7

A

Tag
Baseplate
Leg
Flyover
Arrowhead
Undercut
Bridge

593
Q

LHS 1-3
RHS 1-3

A

LHS
Active arm
Coil
Tag
RHS
Active arm
Guard wire
Coil

594
Q

Describe the URA design and the movement it would cause

A

URA with active components palatal finger sprins on 13 and 23
16 and 26 adams clasps
FABP
This would retract 13 and 23

595
Q

Describe the URA design and the movement it would cause

A

Roberts retractor 12-22
Mesial stops 13 and 23
Adams clasps 16 and 26
FABP
This would reduce the overject and over bite

596
Q

Describe the URA design and the movement it would cause

A

Midline palatal screw
Adams clasps 16 26 14 24
Posterior bite plane
This would expand the upper arch

597
Q

Describe the URA design and the movement it would cause

A

13 and 23 buccal canine retractors
16 and 26 adams clasps 11 21 south end clasp
FABP
This would retract the buccally placed canines and reduce the OB

598
Q

Describe the URA design and the movement it would cause

A

22-12 Roberts retractor
13 and 23 mesial stops
16 26 adams clasps
FABP
This would reduce OJ of 12-22 and reduce OB

599
Q

Describe the URA design and the movement it would cause

A

12 Z spring
16 26 14 24 Adams clasps
Posterior bite plane
This would correct the anterior crossbite on the 12

600
Q

What is interceptive orthodontics?

A

Any procedure which will reduce or eliminate the development of a malocclusion

601
Q

Incidence of ectopic canines in caucasian population

A

1.5%

602
Q

Aetiology of ectopic canines

A
  • Ectopic tooth germ, just developed in the wrong place
  • Trauma to primary (rare)
  • Genetic tendency
  • Ass. with other dental anomalies like missing laterals or other teeth, canines have a long path of eruption, possibly guided by the 2s position which would explain this relationship
  • Crowding - canine often last to erupt
603
Q

What is the aetiology of buccally ectopic canines?

A

Crowding

604
Q

Syndromes or conditions associated with delayed eruption

A

Down syndrome
Turner syndrome
Cleidocranial dysostosis
Hereditary gingival fibromatosis
Cleft lip and palate
Rickets

605
Q

How might you decide if a tooth is deciduous?

A

Root morphology
Shade of enamel
Size
Mobility
Palpate for the permanent

606
Q

Radiographs taken to localise an unerupted canine

A

OPT and anterior occlusal maxilla
OR
2xPA

607
Q

Treatment options for a patient with unerupted palatally ectopic canine, with a retained C

A

Do nothing
Surgical exposure and orthodontic alignment
Interceptive extraction of the C
Surgically remove the ectopic tooth
Autotransplantation - last resort

608
Q

If opting for interceptive removal of a retained C, in a case with a palatally ectopic 3, what must be considered?

A

How likely the tooth is to come into place
- How horizontally is it angled in relation to the sagittal plane?
- How high - at or above apical third is not good
- How far mesially has the canine come? Canine crown more than halfway across the lateral incisor is not good

609
Q

What is the risk % of root resorption of a lateral incisor if leaving an unerupted ectopic canine?

A

40%

610
Q

Risks of leaving an unerupted ectopic canine

A

Root resorption
Cyst
Ankylosis
Eventual loss of the retained deciduous tooth and complex restorative solutions required in the future
Crown resorption of the ectopic tooth

611
Q

When would you surgically remove an ectopic canine?

A

IF the patient does not want complicated treatment or to wear orthodontic appliances
If the position is too ectopic for movement into place
If root resorption of the lateral occurs
If primary canine of good prognosis
If there is no significant risk of damaging adjacent teeth during the surgical procedure

612
Q

Surgical exposure method for ectopic canine

A

Surgical exposure - open or closed depending on the site of the canine
If canine is deep - closed, gold chain bonded during surgery and left sticking out when flap closed
If canine less deep - open - cut a window in the flap over the canine crown, attach traction hook and suture in a surgical pack to be left for around 10 days to prevent healing over

613
Q

When would autotransplantation of an ectopic canine be indicated?

A
  • Malposition of the tooth is too great for orthodontic alignment to be possible
  • No evidence of ankylosis of the canine
  • Canine root development is ideally 2/3-3/4 length root
  • Patient is looking for a quicker treatment option
614
Q

What are the risks of autotransplantation for an ectopic canine?

A

Patient may need to undergo RCT of the transplanted tooth
Patient needs to accept risk of ankylosis or external root resorption of the transplanted root

615
Q

At what age should you assess for unerupted canines?

A

8 years clinically assess and 10-11 palpate for unerupted canines

616
Q

Potential causes of dilaceration

A

Impact on the forming crown
Deflection of the root away from an adjacent supernumerary or cyst

617
Q

Options for replacement of a missing upper central, with a space insuffienct width for a central?

A

Orthodontic fixed appliance to move the upper lateral into central position, and restore this tooth with composite as a central incisor
Orthodontic fixed appliance to open space for an implant, fixed prosthesis, RBB, removeable prosthesis
Autotransplantation if premolars require extraction to address other aspects of the malocclusion
Do nothing and allow further mesial drift, if pt <9years old you may get quite a bit of space closure

618
Q

How long do collagen fibres in the PDL take to remodel following orthodontic movement?

A

Minimum 3-4months

619
Q

How long do gingival fibres take to remodel following orthodontic movement?

A

Minimum 6 months

620
Q

How long do the supracrestal fibres in the gingivae take to remodel after orthodontic movement?

A

12 months or more

621
Q

Procedures which can help prevent relapse following orthodontic tooth movement

A

Circumferential supracrestal fiberotomy
Interproximal enamel reduction
Frenectomy

622
Q

What would influence the risk of instability of a 9mm OJ reduced to 2mm, after treatment?

A

Competent lips - good indicator of stability
(If patient was still growing a functional appliance could be worn at night only as a “retainer”)

623
Q

5 ways to reduce the risk of white spot lesions during orthodontic treatment

A

225ppm 0.05% sodium fluoride mouthwash
Calcium phosphopeptide-amorphous calcium phosphate tooth mousse
Fluoride varnish
Fluoride toothpaste
Diet advice

624
Q

How can you decrease the risk of root resorption during ortho treatment with the type of force used?

A

Light forces for only a short treatment time - less risk

625
Q

Advantage of a Hawley retainer over a pressure formed retainer

A

Hawley is better at allowing the posterior teeth to settle into occlusion after orthodontic fixed appliance treatment

626
Q

What is the most appropriate treatment option for decalcification white spots after ortho tx?

A

ICON resin infiltrate

627
Q

What would be classed as severe root resorption and what percentage of patients can be expected to suffer from this after fixed ortho treatment?

A

Exceeding 4mm or more than one third of the original root length
1-5%

628
Q

Factors contributing to risk of gingival recession following orthodontic fixed appliance treatment

A

Thin gingival biotype
Pre-existing narrow width of attached gingivae
Treatment which will tend to move the teeth towards the cortical plates of the alveolar bone
Poor oral hygiene
Plaque retention

629
Q

What can help prevent relapse in correction of a crossbite?

A

Achieving a good amount of overbite such as 50%

630
Q

Risk factors for root resorption during orthodontic treatment

A

Shortened roots with evidence of previous root resorption
Pipette shaped or blunted roots
Teeth which have suffered previous trauma
Patient habits such as nail biting
Iatrogenic - use of excessive force, intrusion and prolonged treatment time

631
Q

Average amount of root resorption during 2 years fixed appliance treatment

A

around 1mm - not usually clinically significant

632
Q

Factors increasing risk of loss of periodontal support during ortho tx

A
  • Individuals susceptible to periodontal disease
  • movement of teeth outside the envelope of alveolar bone
  • Patients with narrow alveolus
  • Patients with thin gingival biotype
  • Patients with existing crowding that has pushed teeth outside the alveolar bone
  • Higher risk buccally than lingually
633
Q

What is demineralisation in ortho?

A

Early, reversible stage white lesions in the development of caries, occurring when a cariogenic plaque accumulates in association with a high sugar diet
If not managed early they can become permanent damage and eventually caries

634
Q

Which teeth are more at risk of pulpal injury from orthodontic treatment?

A

Teeth which have been previously traumatised

635
Q
A
636
Q

How does orthodontic treatment cause pulpal injury?

A

Excessive apical root movement can lead to a reduction in blood supply to the pulp and even pulpal death

637
Q

Results of enamel demineralisation /decalcification

A

development of enamel opacities on the labial surfaces of the teeth

638
Q

Incidence of decalcification with fixed orthodontics

A

Up to 50%

639
Q

Aetiological factors of decalcification during fixed ortho

A

Poor OH
High sugar diet
High caries risk

640
Q

Treatment options following decalcification after fixed ortho

A

Microabrasion
ICON resin infiltration
Fluoride varnish

641
Q

What is relapse?

A

The partial or full return of the pre treatment features of a malocclusion following active treatment

642
Q

Prevention of orthodontic relapse

A

Fixed retainers
Removeable retainers
Interproximal reduction
Circumferential supracrestal fiberotomy
Frenectomy

643
Q
A

BDS4 (18 decks)

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