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BDS Exam style questions > Orthdontics > Flashcards

Orthdontics Flashcards

1
Q

What are the possible complications for a patient with 12mm OJ, well aligned arches and ectopic canines?

A

Trauma

Root resorption of adjacent 2s

Difficulty eating

Difficulty speaking

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2
Q

What are the potential complications of a dental retainer?

A

Calculus build up- higher risk of gingivitis and Periodontal disease

Caries- difficulty cleaning

Wire can debond

Wire can fracture

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3
Q

What are the components for correcting a posterior cross bite?

A

Aim- Please construct a URA to fix posterior xbite
A- Midline palatal screw
R- Adams clasps 0.7mm HSSW 4s/6s
A- reciprocal
B- Self cure PMMA with PBP

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4
Q

What is Deviation of the mandible on closing?

A

Mandible displaces in order for teeth to come into occlusion on closing

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5
Q

What are 2 problems that can occur if mandibular deviation goes untreated?

A

TMD

Tooth wear

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6
Q

Which fluoride supplements can be given to patients to prevent decalcification in Orthodontics?

A

FV- 22600ppmF (4 x yearly)

Fluoride mouthwash- 225ppmF (daily)

Duraphat toothpaste- 2800 ppmF (twice daily)

Fluoride tablet- 1mg per day

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7
Q

What are the other ways in which decalfication can be prevented?

A

Good OH
-> Interbracket cleaning after meals
-> Focusing on gingival margin and around bracket when brushing

Improve diet- limit sugar frequency

Chewing gum

FS

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8
Q

What are the risks of Orthodontic treatment?

A

Relapse
Recession
Root resorption
Soft tissue trauma
Enamel fracture
Tooth wear
Loss of vitality
Headgear injuries
Poor or failed tx

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9
Q

How would you assess the AP relationship of a class 3 malocclusion?

A

Palpate the skeletal bases at soft tissue A and soft tissue B

Lateral Ceph

Visual assessment

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10
Q

What special investigations may an orthodontist do for a patient worried about their Class 3 relationship?

A

Study models

Clinical photographs

Lateral ceph

OPT

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11
Q

What are the intra-oral features typical of class 3 relationship?

A

Retroclined lower incisors

Proclined upper incisors

AOB

Reversed or reduced OJ

Displacement on closure

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12
Q

What systemic condition may a patient have if their mandible is growing in adulthood?

A

Acromegaly

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13
Q

Design a URA to fix anterior Crossbite of 12?

A

Aim- please construct a URA to fix cross bite on 12
A- Z spring 0.5 HSSW on 12
R- Adam’s clasps 0.7 HSSW on 4s/6s
A- Yes as moving one tooth
B- Selfcure PMMA with PBP

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14
Q

What characteristics of the dentition would make fixing an anterior crossbite with a URA?

A
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15
Q

What 5 factors can cause displacement of a URA?

A

Gravity

Mastication

Active component

Speech

Tongue

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16
Q

When referring a patient to an orthodontist, what information relevant to their provision of care should be provided?

A

Patient details- age and name
Medical Hx
Radiographs and photographs
Skeletal base
Incisor classification

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17
Q

A patient undergoing orthodontic treatment, attends for a check up with debonded bracket and demineralisation around the remaining brackets. How is this managed?

A

Debonded bracket
-> remove and give to the patient
-> Give OHI and refer to orthodontist

Demineralisation around remaining brackets
-> OHI
-> Diet advice
-> Fluoride supplementation

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18
Q

What are the long term risks of lost upper 1?

A

Poor aesthetics

Bone resorption

Loss of labial profile

Drifting of other incisors

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19
Q

What are the long term risks of using a provisional upper RPD to replace an upper 1?

A
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20
Q

Why would you advise a patient against a crown to replace their upper 1?

A

Destructive treatment

OH must be adequate to place a crown

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21
Q

What advice would you give to a non-compliant patient to maintain their oral health long term?

A

Brush 2x daily with F tooth paste

Spit don’t rinse

Use modified bass technique

HIGH risk- so duraphat 5000ppmF could be offered

Interdental cleaning- floss or ID brushes

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22
Q

What are the uses of a URA?

A

Tipping teeth

Habit breaker

Anchorage

Expand arch

Reduce OB

Space maintainer

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23
Q

What advice is given upon fitting of a URA?

A
  1. Will feel bulky- normal
  2. May have excess salivation- goes away in 24 hours
  3. May affect speech- practise reading aloud
  4. May cause initial discomfort- indicates its working
  5. Wear 24/7- non-compliance increases tx time
  6. Remove after every meal and clean with soft brush
  7. Remove when playing contact sports
  8. Avoid hard/sticky and overly hot foods
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24
Q

What are the steps in delivering a URA?

A
  1. Check right patient- right appliance
  2. Check appliance matches design specification
  3. Inspect appliance for sharp areas
  4. Check integrity of wirework
  5. Insert into mouth- check for areas of blanching or trauma
  6. Check posterior retention
  7. Check anterior retention
  8. Activate appliance
  9. Demonstrate correct insertion/removal
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25
Q

When is the best time to treat an anterior crossbite?

A

When upper 2s erupt

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26
Q

What features make a URA useful at fixing crossbites?

A

PBP

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27
Q

What is the incidence of hypodontia in the UK?

A

6%

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28
Q

What 3 teeth are most commonly missing in hypodontia patients?

A

Lower 5s
Upper 2s
Upper 5s

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29
Q

How does hypodontia present to the GDP?

A

Big midline diastema

Infraocclusion

Teeth not erupting/exfoliating in expected sequence

Tapered and small teeth

Absence of deciduous tooth

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30
Q

What are the treatment options for hypodontia?

A

Accept/montior

Restorative only- bridges, implants, dentures

Ortho only

Combine orthodontic and restorative- open space/close space

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31
Q

Who are the members of the MDT that treat hypodontia?

A

Ortho specialist

Restorative dentist

Paediatric dentist

GDP

SLT

OS

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32
Q

When should you start to palpate for canines?

A

Age 9

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33
Q

How is position of canines localised?

A

Vertical parallax

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34
Q

What radiographs are used for vertical parallax?

A

OPT and occlusal

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35
Q

What age should intervention for ectopic canines be carried out?

A

Age 11

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36
Q

How long after extraction of C should we review an ectopic canine to check for eruption?

A

6 months

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37
Q

What are the treatment options for an ectopic canine when the C has already been extracted?

A

Buccal apically repositioned flap with bone removal

Palatal open exposure with bone removal

Buccal or palatal closed exposure with gold chain attachment

Extraction of 3

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38
Q

What is a supernumerary tooth?

A

Presence of an extra tooth

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39
Q

Where is a supernumerary most likely to occur?

A

Midline of maxilla

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40
Q

What are the 4 types of supernumerary, how are they distinguished?

A

Conical- cone shaped

Tuberculate- barrel shaped

Supplemental- extra tooth of normal dentition (usually smaller and asymmetrical)

Odontome- irregular mass of dental hard tissue
-> Compound and Complex

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41
Q

What is the effect of supernumeraries on the dentition?

A

Delayed eruption

Crowding

Failure of teeth to erupt

Traumatic eruption

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42
Q

What are the signs of thumb sucking habit?

A

Proclined upper anterior

Retroclined lower anteriors

AOB/incomplete open bite

Narrow upper arch (may have unilateral posterior xbite)

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43
Q

What is the BSI definition of Class 2 Div 1

A

The lower incisor edges lie posterior to the cingulum plateau of the upper incisors
-> There is an increased overjet
-> The upper central incisors are proclined or of average inclination

44
Q

What are the ways in which functional appliance can reduce OJ?

A

Growth modification
-> Restricts growth in maxilla, promotes growth in mandible

Mandible postured away from normal rest position
-> facial musculature is stretched generating forces transmitted to teeth/alveolus

Dentoalveolar compensation
-> Reclines upper incisors
-> Proclines lower incisors
-> Mesial migration of lowers, distal migration of uppers

45
Q

What are the signs of impacted canines?

A

Retained Cs

Delayed eruption

Asymmetrical eruption

Distal tipping of 2s

Discolouration of 2s

Mobility of 2s

46
Q

How can you further investigate impacted canines?

A

Vertical/horizontal parallax

ICAT scan on CBCT

47
Q

What are the risk of ectopic canines?

A

Root resorption of 2s

Cyst formation

Ankylosis of deciduous tooth

Aesthetic issues- spaces

48
Q

What are the treatment options for ectopic canines

A

Accept/monitor

Extract C to encourage improvement in position

Retain 3 and observe

Extraction

Surgical exposure and orthodontic alignment

Autotransplantation

49
Q

What is the incidence of CLP?

A

1:700 live births

50
Q

What are the general health implications of CLP?

A

Aesthetic issues

Speech issues- issues with plosive sounds

Dental issues

Hearing/airway issues- more likely to suffer glue ear and ears may not properly form

Other- more likely to have cardiac abnormality

51
Q

What are the dental features of CLP?

A

Missing teeth

Impacted teeth

Crowding

Caries- hypoplastic

Class 3 jaw relationship

52
Q

What are the 5 treatment stages for fixing a CLP?

A

3 months- lip closure

1 year- palate closure
-> done before baby starts to talk/babble to ensure palate is as normal as possible for this

8-10 year- alveolar bone graft

12-15 years- definitive orthodontics

18-20 years- Surgery (secondary)

53
Q

Who are the members of the CLP MDT?

A

Surgeons

Cleft nurses

Paediatric dentist

Psychologist

ENT doctor

Speech therapist

Geneticist

54
Q

What is a class III incisor relationship?

A

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

55
Q

What is dentoalveolar compensation?

A

Soft tissues and teeth are in altered position to compensate for skeletal discrepancy and achieve normal relationship between upper and lowers

56
Q

Which special investigations may be useful when treating patients with Class III jaw relationships?

A

Clinical photos

Study models

Lateral ceph

CBCT

OPT

57
Q

What dental features are associated with Class 3 relationships?

A

Proclined upper incisors

Retroclined Lower incisors

Crossbites- anterior

Attrition

Recession

Crowding

58
Q

What are the treatment options for a Class 3 patient?

A

Accept and monitor

Intercept with early URA to correct incisor relationship/crossbites

Growth modification- reverse twin-block/headgear

Camouflage- accept skeletal base and aim for class I incisors with fixed appliance

Combined orthodontic/orthognathic

59
Q

What are the components of fixed appliances?

A

Brackets

Arch wire

Ligatures

Elastic modules

Auxiliaries- springs, elastomeric chains

Anchorage components

Molar bands

60
Q

Give 4 methods of anchorage?

A

TAD

Baseplate

Transpalatal arch wire

Elastics

61
Q

What is the definition of Class 2 Division 2?

A

Lower incisors occlude posterior to the cingulum plateau of upper central
-> Upper centrals are retroclined
-> OJ may be reduced or increased

62
Q

What are the dental features of Class 2 div 2?

A

Retroclined upper centrals

Increased OB

Shorter arch perimeter- more crowding

Reduced OJ- usually

Crowded upper 2s- mesiolabially rotated

63
Q

What are the soft tissue features associated with C2D2?

A

Marked labio-mental fold- overactive mentalis

High Lower lip line- can retrocline upper incisors

High masseteric force

Trauma to gingivae or palate due to increased OB

64
Q

What are the treatment options for C2D2?

A

Accept and monitor

Growth modification- twin block with ELSA spring

Camouflage- accept underlying skeletal base and give class 1 incisors

Orthognathic surgery if severe

65
Q

What are the common complications of orthodontics?

A

Relapse

Root resorption

Decalcification

Gingival recession

66
Q

How are complications of orthodontics managed

A

Relapse- lifelong retention (fixed or removable)

Decalficiation- OHI, F supplementation diet advice

Root resorption- advise patient of risk, advise that 1mm resorption is normal over 24 month tx, stop nail biting habit, be careful with unusual root forms

Recession- avoid over expansion, warn patient, consider gingival grafting

67
Q

What are the dental features of class 2 div 1?

A

Proclined upper anteriors

Increased OJ

Hyperplastic gingivitis

Varied OB

Class 2 molar relationship

68
Q

What are the soft tissue features of Class 2 div 1?

A

Lip trap

Incompetent lips

Tongue thrust

69
Q

What are the treatment options for class 2 div 1?

A
  1. Accept
  2. Attempt growth modification- twin block/head gear
  3. URA- Simple tipping of teeth
  4. Camouflage- used fixed appliance to achieve class 1 incisors while accepting skeletal base
  5. Orthognathic surgery
70
Q

What are the causes of diastema?

A

Prominent frenal attachment

Ectopic canines

Hypodontia

Supernumeraries at midline

Microdontia

71
Q

How are Diastemas managed

A
72
Q

How is posterior cross bite managed?

A

URA with midline palatal screw and PBP

73
Q

What are the other means of expanding the arch?

A

Quad-helix

Rapid maxillary expansion

74
Q

What teeth are most commonly infra-occluded

A

Lower Ds

75
Q

How do infra-occluded teeth appear clinically/radiographically?

A

C:
Low in the arch- doesn’t maintain occlusal relationship with adjacent teeth, non-mobile, percussion sound

R:
External root resorption
No PDL

76
Q

What are the treatment options for infra-occluded molars?

A

Retain if no permanent successor

Monitor for up to a year if permenant successor

Extract tooth
-> if contact points go sub gingival
-> if root formation of successor is near completion
-> early to encourage space closure if crowding

77
Q

What is SNA, SNB, ANB?

A

SNA- Angle between Sella-nasion line (cranial base) and
maxilla at point A

SNB- Angle between SN line and mandible at point B

ANB- difference is angle of SNA and ANB

78
Q

What are the average values of SNA, SNB, ANB?

A

SNA- 81 (+/-3)

SNB- 78 (+/-3)

ANB- 3 (+/-2)

79
Q

What is the average FPMA angle?

A

27 (+/-4)

80
Q

What is the average incisor inclination?

A

109 in upper

93 in lower

81
Q

What is the ANB for class 2 and 3?

A

Class 2- ANB >5

Class 3- ANB <1 or negative

82
Q

What is the effect of prolonged sucking habit on the posterior dentition?

A

Sucking action pulls cheeks in causing narrowing of maxillary arch (mandible is out of way due to position of thumb)
-> this can cause a posterior cross bite

83
Q

What are the methods of stopping a thumb sucking habit?

A

Fixed habit breaker

Removable habit breaker

Positive reinforcement

Preventive nail varnish

Swap for a dummy- unlikely to continue past school age

84
Q

What are the syndromes associated with Hypodontia?

A

CLP

Anhydrotic ectodermal dysplasia

Down’s

85
Q

What is the incidence of hypodontia in primary and permanent dentition?

A

Primary- 1%

Secondary- 6%

86
Q

What are the affects of supernumerary teeth?

A

Cyst formation

Associated with diastema

Crowding

87
Q

What factors can make early loss of primary teeth worse?

A

Crowding

Lack of permanent successor

Maxilla is worse

Younger age

88
Q

What is balancing and compensating?

A

Balancing- taking out contra-lateral

Compensating- if lost in upper, remove lower

89
Q

When might you consider balancing a primary tooth extraction?

A

Balancing Cs to prevent midline shift

90
Q

When would you consider a compensating extraction?

A

If lower 6s extracted- compensate with upper
-> prevents over eruption and mesial movement of 7

91
Q

What are the signs of a good wearer of a URA?

A

Active components have become passive

Patient demonstrates correct insertion and removal

Patient can speak normally with URA in

Tooth movement has occurred

Patient arrives wearing URA

Signs of wear on palate and appliance

92
Q

What are the different anterior-posterior skeletal relationships?

A

Class 1- maxilla is 2-3mm anterior to mandible

Class 2- maxilla is >2-3mm anterior to mandible

Class 3- mandible anterior to maxilla

93
Q

How is vertical relationship measured?

A

Face height:
Visual- lower anterior face height to total face height is 50:50
Lateral ceph- LAFH:TAFH is 55%

FMPA:
Visual- maxillary and Frankfort planes meet at occiput
Ceph- angle of 27 (+/4) is average

94
Q

How is transverse relationship measured?

A

Look at symmetry from front and above

95
Q

What is OJ and the average value?

A

Gap between the labial most prominent surface of the lower incisors and labial most prominent surface of upper incisors

96
Q

What is OB? What is average?

A

Vertical overlap of incisors
- Uppers cover 1/2 to 1/3 of lower incisors

97
Q

What is a class 1 molar relationship?

A

MB cusp if upper 6 occludes with buccal groove of lower 6

2- anterior
3- posterior

98
Q

What is class 1 canine relationship?

A

Maxillary canine occludes between mandibular canine and first premolar

2- Anterior
3- Posterior

99
Q

How is crowding measured?

A

Overlap technique

Space available (between mesial of 6s)- space required (width of every tooth from 5-5)
-> done using callipers on models

100
Q

What is mild/moderate/severe crowding ?

A

Mild 0-4mm

Moderate 4-8mm

Severe 8+mm

101
Q

What are the active components used in URAs?

A

0.5 HSSW:
Finger spring and guard- retracting canines
Z spring- fixing anterior crossbites
Flapper spring
T spring

0.5 HSSW w 0.5 ID tubing:
Buccal canine retractor
Roberts retractor- incisor

Midpalatal screw- expanding upper arch

102
Q

What are examples of retentive components?

A

Adams clasp (0.6 if primary)

Southend clasp

Labial bow

ALL 0.7 HSSW

103
Q

What are examples of baseplate modifications?

A

FABP- allows eruption of posteriors to allow for OB correction (OJ +3mm)

PBP- allows posterior disclusion allowing anterior movement/eruption

104
Q

What are the treatment options for impacted molars?

A

Accept/monitor

Extract E to encourage eruption

Use separator

XLA and retain E

Distalise 6 with a URA

105
Q

What are the cause of first molar impaction?

A

Crowding

Hypoplastic maxilla

Mesial path of eruption

106
Q

What feature of normal development should prevent crowding of permanent dentition?

A

Spacing between teeth

Growth of maxilla and mandible

107
Q

What is Leeway space?

A

Extra mesio-distal space occupied by primary molars which are wider than premolar replacements

-> 1.5mm per side in upper
-> 2.5mm per side in lower

BDS Exam style questions (15 decks)

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