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BDS4 Exam Perp > Orthodontics tutorials > Flashcards

Orthodontics tutorials Flashcards

1
Q

What is the name of the legislation dealing with ** occupational exposures and exposure of the general public** ?

A

Ionising Radiation Regulations 2017 (IRR17)

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2
Q

What is the name of the legislation dealing with medical exposures of patients?

A

Ionising radiation Medical Exposure Regulations (IRMER 17)

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3
Q

What is the annual radiation dose for radiation workers?

A

6 mSv/year

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4
Q

What is the annual radiation dose limit for the members of the public?

A

1 mSv/year

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5
Q

What is the job of the REFERRER in IRMER?

A

Provide sufficient medical date to practitioner to justify exposure - patient identification and clinical details

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6
Q

What is the job of the PRACTITIONER in IRMER?

A

Carry out justification and authorisation of each exam complying with employer’s procedures - return request to referrer if invalid justification

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7
Q

What is the job of the OPERATOR in IRMER 17

A
  • Authorisation of justification if not done by practitioner
  • Select equipment and method to limit dose and carry out exposure
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8
Q

What is the job of the EMPLOYER in IRMER 17?

A
  • Provide criteria for referral, authorisation and procedure criteria for carrying out an exposure
  • Ensure staff are competent and work by regulations
  • Provide facilities for clinical evaluation
  • Set procedures for radiographic reporting (indepartment of external)
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9
Q

Who is responsible for carrying out ALARP?

A
  • Practitioner
  • Operator
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10
Q

What 3 information must be provided for justifying an exposure before authorising it? (4)

A
  • Objectives of exposure and efficacy
  • Benefits and risks of alternatives techniques
  • Benefits of exposure to patient or society
  • Risks of exposure to patient
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11
Q

What are Diagnostic reference levels?

A

Tool used to optimise exposures in relation to radiation

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12
Q

What are the Diagnostic reference level for intra-oral mandibular molar?

A

1.7 mGy

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13
Q

What is the Diagnostic reference level for an OPT in adults and children?

A
  • 93 mGy/cm^2 - adults
  • 67 mGy/cm^2 - children
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14
Q

Give 5 patient selection criteria for taking an OPT for an orthodontic patient?

A
  • Presence of ectopic tooth
  • State of development
  • Presence of supranumerary tooth
  • Stages of individual teeth development
  • Caries assessment
  • Periodontal disease assessment
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15
Q

Give 3 contraindications for taking an OPT in any dental situation?

A
  • Unable to fit in OPT machine
  • Pregnant patient
  • Unable to keep still for long time (Parkinson’s)
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16
Q

Give 3 reasons why a fault may arise during an OPT exposure?

A
  • Patient positioning
  • Patient movement during exposure
  • Limitation of focal width
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17
Q

What is the effects of the patient being too far forward in the OPT machine?

A
  • Anterior teeth very blurred and thin roots
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18
Q

What is effect of the patient being too far backward in the OPT machine?

A
  • Anterior teeth wider
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19
Q

Why are ghost images always seen at a higher level?

A

Because the X-ray beam is angled upwards (8 degrees)

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20
Q

Give 4 reasons for requesting an UPPER OCCLUSAL radiograph?

A
  • Localising pathology
  • Confirming Unerupted tooth
  • Localising Unerupted teeth
  • Assess root resorption
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21
Q

Give 4 reasons for requesting a Periapical radiograph?

A
  • Assess ankylosis
  • Localising pathology
  • Localising unerupted teeth
  • Assessing root resorption
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22
Q

Give 4 reasons for requesting a bitewing radiograph?

A
  • Carries assessment
  • Depth of restoration
  • Tooth prognosis
  • Bone level assessment
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23
Q

What radiographs to take for HORIZONTAL TUBE SHIFT parallax?

A

Two periapicals

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24
Q

What radiographs to take for VERTICAL TUBE SHIFT parallax?

A

Periapical + maxillary oblique occlusal

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25
Q

What is the rule of localising unerupted teeth through tube shift?

A

SLOB ( same lingual opposite buccal)

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26
Q

Give 4 reasons for requesting a lateral cephalogram?

A
  • Monitoring growth
  • Monitoring orthodontic treatment progress
  • Treatment planning
  • To aid in research and study
  • Aid orthodontic diagnosis
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27
Q

What 2 features makes lateral cephalogram useful in orthodontics?

A
  • Standardised
  • Reproducible
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28
Q

What are the 3 landmarks used in positioning a patient for a lateral cephalogram?

A
  • Ear rods placed in external auditory meatus (porion)
  • Frankfort plane parallel to the floor
  • Nasion contacting machine
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29
Q

In what 3 ways can we reduce patient x-ray dose delivered during lateral cephalometry?

A
  • Thyroid collar
  • Appropriate Field of view
  • Triangular collimation
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30
Q

Give 3 errors that may occur during lateral cephalometry?

A
  • Projection errors = magnification
  • Measuring errors
  • Landmark identification errors
    ** errors may occur due to poor operator expertise **
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31
Q

Give 2 reasons for taking a CBCT in orthodontics?

A
  • Localising impacted teeth
  • Unerupted canine
  • Viewing developmental abnormalities
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32
Q

Give 4 advantages for taking a CBCT?

A
  • No magnification or distortion
  • Can be viewed from any angle
  • no superimposed tissues
  • 3D reconstruction
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33
Q

Give 4 contraindications for taking a CBCT?

A
  • High radiographic dose that is not justified
  • Patient medically unsuitable (kyphosis or on wheelchair)
  • Soft tissue visualisation is needed
  • High risk of streak artefact (metals inside patients)
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34
Q
  • 9 year old
  • concerned that front tooth is not coming out after XLA of deciduous
  • PDH = trauma at age of 7, prone to accidents , # on incisal of 12
  • O/E - 11 is absent, 3mm spacing in upper arch (well aligned)

What initial clinical examination would you undertake (1)?

A
  • Palpate soft tissues for obvious bump of 11
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35
Q
  • 9 year old
  • concerned that front tooth is not coming out after XLA of deciduous
  • PDH = trauma at age of 7, prone to accidents , # on incisal of 12
  • O/E - 11 is absent, 3mm spacing in upper arch

What other special investigations would you undertake?

A
  • PA or maxillary oblique occlusal ± OPG ( might not justifiable unless future ortho treatment is indicated)
  • If indicated , pre-op CBCT
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36
Q
  • 9 year old
  • concerned that front tooth is not coming out after XLA of deciduous
  • PDH = trauma at age of 7, prone to accidents , # on incisal of 12
  • O/E - 11 is absent, 3mm spacing in upper arch

What is the likely aetiology for the missing 11?

A
  • Dilacerated from trauma to 51
  • Loss of space due to early loss of 51 impacting the eruption of 21
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37
Q
  • 9 year old
  • concerned that front tooth is not coming out after XLA of deciduous
  • PDH = trauma at age of 7, prone to accidents , # on incisal of 12
  • O/E - 11 is absent, 3mm spacing in upper arch

What are 4 risks of doing nothing?

A
  • Worsening of anterior malocclusion
  • Resorption of 11 crown
  • Resorption of adjacent teeth roots
  • Cyst formation
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38
Q

Describe how you would reposition the unerupted (impacted) 11 into the line of the arch?

A
  • CBCT to assess position of 11
  • Create space (9mm for 11) using URA
  • Closed exposure + orthodontic traction with gold chain to URA

URA = split labial bow type arm and z-spring on 12

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39
Q

What are 4 risks associated with repositioning an impacted 11 into arch using gold chain traction?

A
  • Ankylosis of 11
  • Resorption of 11
  • Poor gingival margin of relocated 11
  • Failure of traction
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40
Q

What 3 indications may require extraction of the unerupted 11?

A
  • Patient wishes
  • Failure of traction
  • Ankylosis
  • very severe dilaceration ( tooth not aligned with alveolar bone width)
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41
Q

What 3 risks are associated with the extraction of an impacted 11? (3)

A
  • Damage to adjacent tooth roots
  • Loss of space in arch (if not managed)
  • loss of alveolar bone in area
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42
Q
  • 9 year old
  • concerned that front tooth is not coming out after XLA of deciduous
  • PDH = trauma at age of 7, prone to accidents , # on incisal of 12
  • O/E - 11 is absent, 3mm spacing in upper arch

The patient wants the tooth to be exracted (11)
What 4 ways in which you can manage the missing incisor from the arch?

A
  • Resin bonded bridge
  • RPD
  • Essix retainer with pontic 11 for future implant
  • Space closure and veneer in the future
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43
Q

Give 5 local causes of an unerupted central incisor?

A
  • Supernumeraries
  • Early loss of deciduous primary
  • Retained primary tooth
  • Crowding
  • Ectopic tooth position
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44
Q

Give 5 Generalised causes of an Unerupted central incisors?

A
  • CLP
  • Down’s syndrome
  • Turner’s syndrome
  • Cleidocranial dysplasia
  • Rickets
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45
Q

What is the most common reason for obstructed permanent maxillary incisor eruption?

A
  • Tuberculate supernumerary
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46
Q

What is primary failure of eruption? (PFE)

A

Failure of tooth eruption with no identifiable cause

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47
Q

What are the 3 features of PFE?

A
  • Can be bilateral
  • Commonly involving posterior teeth
  • Posterior open bites
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48
Q

What happens when you apply traction to a tooth affected by PFE?

A

Ankylosis

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49
Q

What 2 factors affect whether you should delay or go ahead with managing an unerupted central incisor?

A
  • Age of patient
  • Maturity of apex
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50
Q

What is the suggested way in which to manage an impacted dilacerated permanent maxillary incisor?

A

Aligned into arch using closed surgical exposure and orthodontic traction

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51
Q
  • 13 year old patient
  • Does not like the appearance of her teeth
  • O/E -
    retained 53 and 63
    bucally placed 13
    clinically absent 23
    Class II div 2 incisors
    Class 3 molar relationship (left and right)

What 3 clinical examination would you undertake?

A
  • Palpate soft tissues for ectopic 23
  • Check mobility and inclination of 22,53,63
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52
Q
  • 13 year old patient
  • Does not like the appearance of her teeth
  • O/E -
    retained 53 and 63
    bucally placed 13
    clinically absent 23
    Class II div 2 incisors
    Class 3 molar relationship (left and right)

What special investigations would you undertake?

A
  • opt and maxillary oblique occlusal or
  • CBCT
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53
Q

What 4 aetiological factors are linked to ectopic maxillary canines?

A
  • Long path of eruption
  • Ectopic position of tooth germ
  • Crowding
  • Genetics
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54
Q
  • 13 year old patient
  • Does not like the appearance of her teeth
  • O/E -
    retained 53 and 63
    bucally placed 13
    clinically absent 23
    Class II div 2 incisors
    Class 3 molar relationship (left and right)

What are the 4 risks of doing nothing to the ectopic canine (23)?

A
  • Resorption of adjacent teeth roots
  • Resorption of 23 crown
  • Ankylosis of canine crown
  • Cyst formation
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55
Q
  • 13 year old patient
  • Does not like the appearance of her teeth
  • O/E -
    retained 53 and 63
    bucally placed 13
    clinically absent 23
    Class II div 2 incisors
    Class 3 molar relationship (left and right)

What are 5 indications for surgical extraction of the ectopic canine?

A
  • Canine not deemed alignable
  • Good prognosis of primary canine and patient happy to retain
  • Unwilling to wear fixed appliances
  • Low risk of iatrogenic damage with XLA
  • Evidence of early resorption of adjacent teeth
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56
Q
  • 13 year old patient
  • Does not like the appearance of her teeth
  • O/E -
    retained 53 and 63
    bucally placed 13
    clinically absent 23
    Class II div 2 incisors
    Class 3 molar relationship (left and right)

What would be the 3 main goals for providing a growth appliance for this patient? and which appliance would you use?

A
  • Convert into class 1 incisor relationship
  • Facilitate mandibular growth
  • Overbite reduction
    ** twin block appliance ** §
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57
Q
  • 13 year old patient
  • Does not like the appearance of her teeth
  • O/E -
    retained 53 and 63
    bucally placed 13
    clinically absent 23
    Class II div 2 incisors
    Class 3 molar relationship (left and right)

Describe how you would resposition the 23 into the line of the arch?

A
  • XLA of primary tooth (63)
  • Open or closed exposure
  • Place gold chain
  • Apply orthodontic traction with fixed appliance
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58
Q

Give 4 indications for autotransplantation of an ectopic canine?

A
  • Canine not deemed alignable
  • Patient unwilling to wear fixed appliances
  • Patient wants a quick solution
  • No evidence of ankylosis
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59
Q

Give 2 risks the patient should be aware of with autotransplantation?

A
  • Will become non vital = need RCT
  • Will almost always become ankylosed
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60
Q

What factors that may indicate that a canine cannot be aligned?

A
  • too close to midline
  • too high (above apices of adjacent teeth)
  • horizontal angulation
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61
Q

At what age should you palpate for ectopic canines?

A
  • from the age of 8
  • if not palpable on buccal sulcus by age 10-11 = suspect ectopic
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62
Q

What are 4 dental abnormalities that can be detected by 6 years of age?

A
  • Hypodontia
  • Supernumeraries
  • Natal teeth
  • Teeth of abnormal morphology
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63
Q

When do the first permanent molars begin to calcify?

A

At birth

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64
Q

When do the third molars begin to calcify? and why is this date significant in interceptive orthodontics?

A
  • 7-10 years
  • It can determines if XLA of 6’s is indicated
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65
Q

When do the third permanent molars complete crown formation?

A

12-16 years

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66
Q

When do the 3rd permanent molars erupt?

A

17-21 years

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67
Q

when do the third permanent molars complete root formation?

A

18-25 years

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68
Q

At what age have all the primary teeth erupted?

A

2.5 Y

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69
Q

Give the order for eruption of all primary teeth?

A

A B D C E

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70
Q

At what age have all the permanent teeth erupted?

A
  • 12 years excluding 3rd molars
71
Q

Give the order for eruption of all the permanent teeth?

A
  • 6 = Upper 6s , lower 1
  • 7 = lower 1 , upper 2
  • 8 = Upper 2
  • 9 = Lower 3
  • 10 = 4s and 5s
  • 11 = Upper 3
  • 12 = 7s
72
Q

What is interceptive orthodontics?

A

Any measure taken to reduce the severity of a developing malocclusion

73
Q

What is an anterior cross-bite?

A
  • abnormal relationship between opposing anterior teeth in a buccopalatal or labiopalatal direction
74
Q

What are 3 risks associated with anterior cross-bites?

A
  • tooth wear
  • gingival recession
  • displacement upon closure
75
Q

What are the indications for favourable interceptive treatment of an anterior crossbite?

A
  • palatally tipped tooth
  • Good overbite - aids stability
  • adequate space to move forward
76
Q

Design a URA for the correction of an anterior crossbite of 11

A
77
Q

What is a posterior crossbite?

A

Abnormal relationship between opposing posterior teeth in a buccolingual direction

78
Q

What are 3 risks associated with posterior cross-bite?

A
  • Facial asymmetry
  • Tooth-wear
  • Displacement upon closure
79
Q

What is the aetiology of a posterior cross-bite? (skeletal)

A
  • Class 2 skeletal relationship - commonly mandibular deficiency
80
Q

What is the aetiology of an anterior cross-bite? (soft tissues)

A
  • hyperactive lower lip
  • lower lip trap
81
Q

What is the aetiology of a anterior cross-bite? (dental)

A
  • Upper incisor proclination
  • Lingual displacement of lower incisors
  • Digit sucking
82
Q

What 2 URA components are used to manage a posterior crossbite?

A
  • Mid-palatal screw
  • T-Spring
83
Q

Design a URA for the correction of a unilateral posterior crossbite?

A
84
Q

How can you manage a posterior crossbite?

A
  • Simple retraction of upper incisors
  • Attempt growth modification
85
Q

What is the therapeutic effect of a twin block?

A
  • enhance mandibular growth
  • restrain maxillary growth
  • remodel glenoid fossa
  • Retrocline maxillary incisors and distalise molars
  • Procline mandibular incisors and mesialise molars
86
Q

What are 2 risks associated with an increased overjet?

A
  • Increased trauma risk
  • Reduced self-esteem
87
Q

What 4 aetiological reasons for an increased overjet?

A
  • Class II skeletal pattern
  • Lower lip trap
  • thumb sucking
  • tongue thrust
88
Q

What component is used in a URA to correct an increased overjet?

A
  • Labial bow
89
Q

What is a reverse overjet?

A

When the lower incisors are infront of the upper incisors

90
Q

What 4 problems are associated with a reverse overjet?

A
  • Eating difficulties
  • Speech difficulties
  • Displacement upon closure
  • Incisal toothwear
91
Q

What 4 etiological reasons for a reverse overjet? (4)

A
  • Class III skeletal pattern
  • Hypoplastic maxilla
  • Prognathic mandible
  • Retained upper primary incisors
92
Q

How can a simple URA be used to manage a reverse overjet?

A
  • Posterior bite plane with z-springs on upper incisors
  • this is an early management for a reverse overjet and promotes dentoalveolar compensation
93
Q

What growth modification options would you use for a reverse overjet?

A
  • Reverse twin block
  • Frankel III
  • Protraction headgear ± rapid maxillary expansion
94
Q

What does orthodontic camouflage entail in reverse overjets?

A
  • Accepting skeletal discrepancy
  • XLA U5’s and L4s
  • Fixed orthodontics to procline uppers and retrocline lowers
95
Q

What are the 3 main actions of a functional appliance used in treating a reverse overjet through growth modification?

A
  • Remodel glenoid fossa
  • Restrict growth of mandible
  • Promote growth of maxilla
96
Q

What are 2 patient related factors which limit the effectiveness of interceptive treatment in reverse overjets?

A
  • Unfavourable growth
  • Poor compliance to treatment
97
Q

What is deep overbite?

A
  • A vertical overlap of the upper inciors over the lower incisors (more than 3mm)
98
Q

What are 2 risks associated with a deep overbite?

A
  • palatal ulceration ( trauma to soft tissues)
  • gingival stripping ( loss of periodontal support)
99
Q

What is the main goal of a URA in interceptive treatment of a deep overbite?

A
  • lower molars eruption
  • achieved with URA with FABP
100
Q

Design a URA for a deep overbite

A
  • FABP
  • Adams cribs on D’s and 6’s
  • southend clasp on incisors
101
Q

What are the occlusal effectcs of a thumb habit?

A
  • Proclined uppers
  • Retroclined lowers
  • Anterior open bite
  • Posterior crossbite
102
Q

Describe the way in which a digit sucking habit produces a malocclusion?

A
  • Thumb sucking proclines upper anteriors
  • Cheeks push and narrow posterior teeth
  • Crossbite as upper arch size
  • It also prevent the eruption of lowers
103
Q

Give 4 management methods for a digit sucking habit?

A
  • Positive reinforcement
  • Bitter tasting nail varnish
  • Glove on hand
  • URA palatal goal post
  • Fixed othrodontics with tongue rake
104
Q

How long do thumb sucking patients usually do it to cause a malocclusion?

A

More than 6 hours

105
Q

Ideally at what age should sucking habit stop?

A

9 years , after the age of 9 the changes to the occlusion may need a more complicated orthodontic treatment

106
Q

What are 4 risks associated with supernumerary teeth?

A
  • Failure of eruption
  • Ectopic teeth
  • Impaction
  • Crowding
107
Q

What are 4 morphological types of supernumerary teeth?

A
  • Conical
  • Tuberculate
  • Odontome
  • Supplemental
108
Q

Which two conditions have an increased risk of supernumeraries?

A
  • Gardner’s syndrome
  • Cleidocranial dysplasia
  • Cleft lip and palate
109
Q

What type of supernumerary is the most common aetiological cause of an unerupted upper permanent incisor?

A

Tuberculate

110
Q

What is the incidence of supernumeraries?

A
  • more in males
  • more in maxilla
  • 80% in anterior maxilla
111
Q

How many % of diastemas are caused by supernumeraries?

A

10%

112
Q

What are the two types of odontome supernumerary?

A
  • Complex
  • Compound
113
Q

When to extract a conical supernumerary?

A
  • If it erupts or imeding tooth movement
114
Q

What is a diastema?

A

Space between 2 teeth

115
Q

What is the biggest complaint for an upper midline diastema?

A

Aesthetics

116
Q

What are 5 aetiological factors for an upper midline (median) diastema?

A
  • Developmental
  • Generalised spacing
  • Hypodontia (absent 2s)
  • low frenal attachment
  • Midline supernumerary
  • pathology
  • proclined upper incisors
117
Q

What soft tissue abnormality is linked to formation of an upper midline?

A
  • Low frenal attachement
118
Q

What is the management options for a midline diastema ?

A
  • Monitor
  • Close space using Fixed orthodontics
  • Frenectomy
119
Q

At what age is a midline diastema most common?

A

Age 6 , 98%

120
Q

What risks are associated with first molar impaction?

A
  • Pulpitis of E
  • Premature exfoliation of E
121
Q

What risks are associated to caries in the developing dentition?

A
  • Early loss of deciduous teeth
  • Enforced loss of first molars
122
Q

What are 4 aetiological factors for an impacted FPM?

A
  • Eruption angle
  • Ectopic crypt
  • morphology of E crown
  • Small maxilla
123
Q

How can you manage an impacted ectopic FPM?

A
  • Monitor for 6 months - may spontaneously erupt
  • XLA E - regain space for premolar or treat crowding later
  • Disimpact E
124
Q

In what ways will you dis-impact an E to manage a FPM?

A
  • Separators - to distalise E
  • Band E and bracket 6 with open coil
  • Discing of E
  • URA with finger-springs and attachment on 6
125
Q

What is the aetiology of primary molar infra-occlusion? (2)

A
  • Ankylosed E
  • Absence of successor
126
Q

What are 3 clinical features of an infraoccluded primary molar? (3)

A
  • High pitched percussion note
  • No physiological mobility
  • Below interproximal contact
127
Q

What are three radiographical signs of an infraoccluded primary molar?

A
  • Blurring or absence of PDL
  • Absence of successor
  • Root resorption of primary
128
Q

What 2 key factors would you consider when managing an infra-occluded tooth?

A
  • Degree of infraocclusion
  • Absence of successor
129
Q

What primary tooth is most likely to get infraoccluded?

A
  • Lower D
130
Q

Incidence of infraocclusion?

A
  • more common in mandible
  • M=F
131
Q

What is the management of primary molar infra-occlusion if the successor is present?

A
  • Monitor for 6-12 months if younger than 7 - will correct spontaneously
  • XLA of primary + maintain space if older than 7 and did not correct itself
132
Q

Give the management of an infraoccluded primary molar if successor is not present?

A
  • Maintain E if in good condition
  • Bad condition =
  • consider XLA and
  • close space or maintain space for future implant/prosthesis
133
Q

What are the 3 aetiological factors related to hypodontia?

A

non syndromic
* familial
* mutations
Syndromic
* CLP
* incontintenta pigmenti
* hurler syndrome
* ectodermal dysplasia
Enviromental
* trauma
* chemotherapy
* radiotherapy

134
Q

What is hypodontia?

A
  • The developmental absence of one or more teeth excluding the 8’s
135
Q

What are 4 clinical signs of hypodontia?

A
  • Absent primary
  • Retained primary
  • Delayed eruption
  • Abnormal tooth form (microdontia)
136
Q

What are the most 3 commonly affected teeth by hypodontia by order?

A
  • 8s
  • Lower 5s
  • Upper 2s
  • Upper 5s

6% of the population , more common in females

137
Q

What dental abnormality is commonly associated with hypodontia?

A

Microdontia

138
Q

Which is the most rarely affected tooth by hypodontia?

A

Maxillary canine

139
Q

How do you manage missing U2s with early intervention? (3)

A
  • XLA 52/62 (remove obstructions)
  • Close space between 11-21
  • maintain space for eruption of 3s
140
Q

How do you manage missing U2 without early interception with space open?

A
  • RRB
  • RPD
  • Fixed bridged
  • Implant (maintain space)
141
Q

How do you manage missing U2 with space closure plus?

A
  • Close space between central incisors
  • Extrude canine to replace laterals - remove cusp ,recountour and bleach
  • Intrude premolar to replace canine - rotate slightly and add composite build up or veneer
142
Q

What is the effect of early loss of A’s and B’s on the midline?

A

No long term effect on midline
* treatment = do nothing

143
Q

What is the effects of early loss of C’s on midline?

A
  • Midline shift in crowded dentitions
144
Q

What is the treatment for Early loss of C’s to prevent midline shift?

A
  • Balancing extractions if dentition is crowded
145
Q

What the effects of early loss of D’s and E’s ?

A
  • Space closure leading to crowding
  • Only D - midline shift if arch is crowded
146
Q

How to manage early loss of D’s and E’s?

A

Maintain space

147
Q

How to manage the early loss D’s ?

A

Balance extraction

148
Q

What factors affect space loss?

A
  • Age at loss
  • Tooth lost
  • Upper or lower tooth
  • Genetics = inherent loss

Effects on upper arch more severe than lower

the further back in the arch the more marked the effect on crowing

149
Q

What is the major cause of impacted 5s?

A
  • early loss of E’s
  • may erupt to the inside of the mouth
150
Q

What is balancing extractions?

A

XLA same tooth on the same arch to minimise midline shift

151
Q

What is a compensating extraction?

A

XLA of same tooth from opposite arch to maintain buccal occlusion

152
Q

In what 4 situations would a space maintainer be indicated?

A
  • Early loss of D’s and E’s
  • early loss of FPM
  • Traumatic loss
  • delayed eruption of maxillary incisor
  • to preserve leeway space
153
Q

Give 4 favourable indications for extracting FPM for space closure? and why?

A
  • Bifurcation of 7 is forming
  • Patient age 8-9
  • Evidence of calcification of 8
  • Mesio-angulation of 7
    ** allows spontaneous space closure between 7 and 5**
154
Q

A situation when you should not compensate for FPM XLA?

A

When extracting upper 6

155
Q

A situation when you should compensate for FPM XLA?

A

When extracting a lower 6 and upper 6 will be unopposed for a prolonged period of time

156
Q

A situation where you should balance XLA of FPM?

A

Only in lower arch and if crowded

Usually premolar unless poor prognosis of first molar

157
Q

What risk is associated with early loss of FPM?

A
  • Distal migration of second pre-molar
158
Q

What risks are associated with late loss of FPM?

A
  • Poor spontaneous closure = spacing
  • Mesial tipping and lingual rolling of 7s
159
Q

Which arch is usually more problematic when it comes to early FPM XLA?

A

Mandibular arch

160
Q

What is orthodontic decalcification?

A

Demineralisations of hard tissues surrounding fixed orthodontic components

161
Q

Give 4 ways in which you can prevent decalcification?

A
  • Encourage oral hygiene with super floss and interdental brushing
  • Diet advice - low sugar, avoid sticky and erosive food
  • Chew sugar free gum
  • Use fluoridated toothpaste, MW and supplements
162
Q

List 4 fluoride delivery methods?

A
  • Mouthwash (225ppm)
  • Varnish (22,600)
  • Fluoridated water
  • GIC
  • High fluoride prescription toothpaste (2800/5,000)
163
Q

What is orthodontic root resorption?

A
  • Horizontal loss of external apical tooth substance associated with orthodontic movements
164
Q

What are the risk factors for root resorption? (4)

A
  • Large bodily movements
  • Torque/root movements
  • Prolonged orthodontic treatment
  • Root form
  • History of trauma to tooth
165
Q

What is the average rate of root resorption in fixed orthodontics? and what is

A

1mm per 2 years

166
Q

What percentage of cases have severe root resorption in orthodontics?

A

2-5%

167
Q

Which teeth are most at risk of root resorption? by order

A
  • Upper 1
  • Lower 1
  • 6s
168
Q

What is orthodonitc relapse?

A

Gradual movement of orthodontically repositioned teeth into their original position

169
Q

Give 5 dental features that have a high relapse potential?

A
  • Diastemas and spaces
  • Rotations
  • Proclined lower anteriors
  • Ectopic canines
  • Instanding Upper 2s
170
Q

Give 3 ways in which orthodontic-related soft tissue trauma may arise

A
  • Arch-wire breakage
  • Arch-wire not made safe
  • Rubbing of brackets on mucosa - ulceration
171
Q

Give 3 reasons of failed orthodontic treatment related to the clinician ?

A
  • Poor diagnosis
  • Poor treatment planning
  • Poor mechanics
172
Q

Give 3 reasons for failed orthodontic treatment related to the patient?

A
  • Poor compliance with appliance wear
  • Poor attendance to appointments
  • Unfavourable growth while treatment
173
Q
A

BDS4 Exam Perp (72 decks)

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