Orthodontics past papers Flashcards

1
Q

Q1 A child presents with the upper left permanent centra incisor in crossbite - a) when is the ideal time to treat this type of malocclusion?

A

As soon as the problem has been detected

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2
Q

A child presents with the upper left permanent central incisor in crossbite - b) list three features of this particular malocclusion that would make it favourable for treatment with a removable appliance

A
  • tooth in cross bite being palatally tipped
    -correct cross bite (bodily movement not required)
  • a significant/good overbite to aid stability post treatment
  • adequate space to move teeth into line of arch
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3
Q

Q1 A child presents with the upper left permanent central incisor in crossbite - c) thinking about removable appliance design for the above clinical situation, please provide the correct details for each of the following (wire sizes and description of component necessary for full mark)

A

Aim - please construct a URA to correct an anterior crossbite on the 21

A - Active component: 21 z-spring; 0.5mm HSSW
R - Retention: Adams clasp on 54 + 64; 0.6mm HSSW and 16 + 26; 0.7mm HSSW
A - Anchorage: achieved as only moving one tooth
B - Self cure PMMA and posterior bite plane

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4
Q

Q1 A child presents with the upper left permanent central incisor in cross bite - d) give an alternative active component to one you gave before

A

Flapper spring

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5
Q

Q2 A 12 year old girl presents to you with developmentally absent upper lateral incisors, second premolars and third molars -

a) what clinical term describes this condition

A

Hypodontia

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6
Q

Q2 A 12 year old girl presents to you with developmentally absent upper lateral incisors, second premolars and third molars -

b) the girl is very concerned about the aesthetics of her upper anterior teeth. Outline two potential treatment options

A
  • Accept and monitor
  • Restorative alone - composite bonding, veneers
  • Orthodontics alone
  • Orthodontics and restorative: space closure and restorative to alter tooth shape
  • space opening and bridge, implant, fixed or removable pros or autotransplantation
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7
Q

Q2 A 12 year old girl presents to you with developmentally absent upper lateral incisors, second premolars and third molars -

c) list two syndromes associated with missing teeth (2 marks)

A
  • ectodermal dysplasia
  • cleft lip palate
  • down’s syndrome
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8
Q

Q2 A 12 year old girl presents to you with developmentally absent upper lateral incisors, second premolars and third molars -

d) you decide to refer the girl to the multidisciplinary team. List three of the specialties that should ideally be represented on the team

A
  • Orthodontist
  • Restorative dentist
  • Paediatric dentist
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9
Q

Q2 A 12 year old girl presents to you with developmentally absent upper lateral incisors, second premolars and third molars -

Fill in the blanks to complete the following sentence

With regard to developmentally absent teeth in the general population; less than 1% have missing (blank) teeth and less than 6% have missing (blank) teeth

A
  • deciduous
  • permanent
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10
Q

Q3 - what is a supernumerary tooth

A

a tooth or tooth-like entity which is additional to the normal series

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11
Q

Q3 - in which part of the mouth do most supernumerary teeth occur?

A

most common in anterior maxilla

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12
Q

Q3 - supernumerary teeth can be classified according to their position and/or shape. Please list and describe four different morphological types of supernumerary teeth you know of

A

Conical - small peg shaped teeth close to midline. They tend not to prevent eruption but may displace adjacent teeth

Tuberculate - paired, barrel shaped that tend not to erupt. They are one of the main causes of failure of eruption of permanent upper incisors

Supplemental - extra tooth/teeth of normal morphology, often an upper lateral incisor or lower incisor but can be third premolars or fourth molars

odontome - can be compound (discreet denticles) or complex (disorganised mass of dentine, pulp and enamel)

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13
Q

Q3- What effects can supernumerary teeth have upon the permanent dentition

A
  • failure of eruption
  • displacement - midline diastemas
  • crowding
  • cyst formation
  • root resorption of surrounding teeth
  • occasionally (usually conical) can have no effect on dentition
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14
Q

Q4 - A 9 year old presents and you discover that they have a persistent thumb sucking habit - what occlusal changes might you see

A
  • proclined upper incisors
  • retroclined lower incisors
  • localised anterior open bite or incomplete open bite
  • narrow upper arch with or without unilateral posterior crossbite
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15
Q

Q4 - A 9 year old presents and you discover that they have a persistent thumb sucking habit - what is the british shandards institute (BSI) definition of a Class II div 1 incisor relationship

A

The lower incisor edges lie posterior to the cingulum plateau of the upper incisors. The upper incisors are proclined or of average inclination and there is an increase in overjet

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16
Q

Q4 - A 9 year old presents and you discover that they have a persistent thumb sucking habit - a patient wears a twin-block appliance for 9 months and their overjet is reduced from 10mm to 2mm. List 6 possible changed that functional appliances can produce to allow this

A
  • Distal movement of maxillary dentition
  • mesial movement of mandibular dentition
  • retroclination of upper incisors
  • proclination of lower incisors
  • minor skeletal changes of 1-2mm by mandibular growth and maxillary constraint
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17
Q

Q5 List two ways that a skeletal base relationship may be assessed clinically in the anteroposterior plane

A
  • visualisation
  • palpate skeletal base (hard tissues)
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18
Q

Q5 what description below best fits a class 1 skeletal base
- the mandible is retruded to the maxilla
- the mandible is 2-3mm posterior to the maxilla
- the mandible is protruded relative to the maxilla
- the mandible is 2-3mm anterior to the maxilla

A
  • the mandible is 2-3mm posterior to the maxilla in class I
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19
Q

Q5 Cephalometric analysis reveals that a patient has an ANB angle of 8 degrees. What does this suggest about their skeletal pattern?

A
  • Class II skeletal pattern
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20
Q

Q5 - List two ways that the skeletal pattern can be assessed clinically in the vertical plane

A
  • FMPA (Frankfort mandibular plane angle)
  • anterior face height proportion (LAFH/TAFH)
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21
Q

Q5 What is meant by a class III incisor relationship?

A

the lower incisor edges lie anterior to the cingulum plateau of the upper incisors. The overjet is reduced or reversed

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22
Q

Q5 what is a balancing extraction and why might you consider a balancing extraction

A
  • the extraction of a tooth from the opposite quadrant of the same arch with the aim to minimise midline shift
  • early unilateral loss of deciduous canine in a crowded arch or loss of permanent first molar in a lower crowded arch
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23
Q

Q6 - A Patient is 30 years old and is worried about his class III incisor relationship - how would you assess the patients skeletal anterior-posterior

A
  • visualisation
  • palpate hard tissues of skeletal base
  • Lateral cephalometry analysis (SNA-SNB = ANB)
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24
Q

Q6 - A Patient is 30 years old and is worried about his class III incisor relationship - what are the classes of AP relationship

A

> Class I - the maxilla is 2-3mm anterior to the mandible and has an ANB of 2-4 degrees
Class II - the maxilla is more than 2-3mm anterior to the mandible and the ANB is greater than 4 degrees
Class III - the maxilla is less than 2 degrees anterior to mandible (or mandible is anterior to maxilla) and the ANB is less than 2 degrees

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25
Q

Q6 - A Patient is 30 years old and is worried about his class III incisor relationship - name four special investigations an orthodontist would do

A
  • Radiograph - OPT, lateral ceph
  • clinical photographs
  • study models
  • sensibility testing
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26
Q

Q6 - A Patient is 30 years old and is worried about his class III incisor relationship - describe a class III incisor relationship

A

the lower incisor edge occludes anterior to the cingulum plateau of the upper anterior incisors and there is a reduced or reversed overjet

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27
Q

Q6 - A Patient is 30 years old and is worried about his class III incisor relationship - name 4 intra-oral features that this patient may have

A
  • maxilla is often crowded with mandible being aligned or spaced
  • class III molar relationship
  • anterior cross bite
  • buccal crossbite
  • proclined upper incisors and retroclined lower incisors
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28
Q

Q6 - A Patient is 30 years old and is worried about his class III incisor relationship - what systemic condition might the patient have if his mandible keeps growing

A
  • Acromegaly
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29
Q

Q6 - A Patient is 30 years old and is worried about his class III incisor relationship - how is a class III malocclusion managed?

A
  1. Accept and monitor in mild cases where pt has no concern and there is no dental health indication
  2. Intercept early with URA - early correction of incisor relationship
  3. Growth modification - functional appliance/head gear/ TAD’s
  4. Camouflage - accept underlying skeletal relationship and correct incisors to class I
  5. Combined orthognathic and orthodontic Tx - functional/masticatory/profile concerns
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30
Q

Q7 Give 3 uses of a URA, other than tipping and tilting teeth

A
  • movements of blocks of teeth
  • Correcting overbites, crossbites and overjet’s
  • Expanding the arch
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31
Q

Q7 - Write a prescription for a URA to reduce a 6mm OJ, 1st premolar have been extracted and previous URA retracted canines and reduced the overbite. Pt is in permanent dentition

A

Aim - please construct a URA to correct the 6mm overjet

On prescription - cross out the first pre molars

A - active component is 22, 21, 11 and 12 Roberts retractor 0.5mm HSSW + 0.5mm ID tubing. Stops - 13 and 23; mesial stops 0.7mm flattened HSSW
R - retention: 16 and 26 adams clasps; 0.7mm HSSW
A -
B - self cure PMMA and flat anterior bite plane (overjet + 3mm)

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32
Q

Q7 - what instructions would you give to a pt on delivery of a URA

A
  1. Appliance will feel big and bulky (this is normal and they should get used to it quickly)
  2. May cause initial excessive salivation (this will pass in 24 hours)
  3. May impinge speech for a short period of time - practice talking and reading a book aloud and this will subside
  4. May cause initial discomfort or ache - this is perfectly normal and indicates that the appliance is working
  5. Must be worn 24/7 including meal times and sleep
  6. Remove after every meal and clean with a soft brush
  7. Remove and store in a protective container when participating in contact or active sports
  8. Avoid hard or sticky foods that may damage the appliance and be cautious with hot food and drinks
  9. Missing appointments and non=compliance will significantly lengthen the treatment time
  10. Provide emergency contact details in case of any problems
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33
Q

Q7 - outline the delivery of a URA

A
  1. Ensure the patient details match the details supplied for the appliance
  2. Check the appliance matches the design specifications
  3. Inspect the appliance and run finger over surfaces, looking for potentially sharp or traumatic areas
  4. Check the integrity of the wirework (damage or work-hardening)
  5. Insert the appliance into the patient’s mouth, immediately looking for areas of blanching or soft tissue trauma
  6. Check posterior retention (Adam’s clasps). Check flyovers then ensure arrowheads are correctly engaging the appropriate undercuts
  7. Apply the same principles to anterior retention
  8. Activate the appliance (1mm movement per month)
  9. Demonstrate to patient the correct procedure for insertion and removal of the appliance (ensure the patient demonstrates this correctly)
  10. Book a review appointment for 4-6 weeks
34
Q

Q7 - what five factors can resist displacement forces of a URA?

A
  • gravity
  • mastication
  • tongue
  • talking/vibrations
  • active components
35
Q

Q8 - A 7 year old child presents with impacted 1st permanent molars and crowded lateral incisors - why might a first molar be impacted?

A
  • morphology of crown of E causes impaction
  • pt has a small maxilla
  • angle of eruption of 6
  • ectopic crypt
36
Q

Q8 - A 7 year old child presents with impacted 1st permanent molars and crowded lateral incisors - what problems are associated with impacted FPM?

A

Pulpitis of E
premature exfoliation of E
Caries
Periodontal disease

37
Q

Q8 - A 7 year old child presents with impacted 1st permanent molars and crowded lateral incisors - give 5 possible treatment options for an impacted FPM?

A
  • Do nothing and monitor for six months
  • XLA of deciduous second molar and treat crowding at a later stage
  • Dis-impact the permanent molar via
    >URA with finger spring on the six
    >Paediatric separators
    >Band E and bracket 6 with open coil
    >Discing of E
38
Q

Q8 - A 7 year old child presents with impacted 1st permanent molars and crowded lateral incisors - his mother mentions his primary teeth were straight, what features of normal development should prevent crowding of the permanent dentition?

A
  • deciduous incisors should erupt upright and spaced which will prevent crowding
  • ideal to have 6mm spacing in deciduous dentition
  • teeth exfoliating at correct time (i.e. avoiding the premature loss of deciduous teeth) will prevent crowding of permanent dentition
39
Q

Q8 - A 7 year old child presents with impacted 1st permanent molars and crowded lateral incisors - what is leeway space?

A

The leeway space is the difference in width of the canine, first and second molars of the primary dentition and the canines and premolars of the permanent dentition. The width of the primary dentition is greater than that of the permanent successors, meaning that if these deciduous buccal segment teeth are retained until their expected exfoliation time there will be adequate room for the permanent canine and premolars
- usually 1.5mm per side on upper and 2.5mm per side on lower

40
Q

Q9 - name 4 components of fixed appliances

A
  • archwire
  • brackets
  • modules
  • bands
41
Q

Q9 - how does tooth movement work?

A
  • The cells of the PDL are responsible for the bone remodelling and so responsible for tooth movement
  • when optimum force is applied to a tooth, bone is laid down where the PDL is under tension and bone is resorbed from areas where the PDL is compressed
  • 3 theories exist for tooth movement - differential pressure theory, piezo-electric and mechano-chemical theory
42
Q

Q9 - how does bodily movement work in fixed appliances?

A
  • Tooth movement is achieved by the interaction of the bracket on the tooth surface and the archwire tied into the bracket
  • bodily movement results from even compressive forces along one side of the PDL and tension on the other side

-

43
Q

Q9 - what is frontal resorption

A

frontal resorption occurs when orthodontic forces do not exceed capillary forces, it is painless bone remodelling of the socket that occurs on the lamina dura adjacent to the affected tooth (pressure side of the tooth experiencing the force)

44
Q

Q9 - Give 4 methods of anchorage

A

-Absolute anchorage using TADs (example would be non osseointegrating mini screw)
- Cortical anchorage using transpalatal arch
- intermaxillary anchorage (e.g. class III elastics)
- Compound anchorage (grouping a couple of teeth together, increasing the surface area against the tooth you’re trying to move)
- reciprocal anchorage (equal force on each tooth, e.g. correcting a diastema)
- baseplate
- nance palatal arch

45
Q

Q10 - what is the incidence of CLP in the UK

A

1 in 700 births
M > F for CLP

46
Q

Q10 - what are the general health implications of CLP?

A
  • aesthetics
  • speech and mastication challenges
  • hearing problems
  • difficult for new born babies to suck to get milk
  • 40% of children with cleft palate will also have a cardiac anomaly
  • children with cleft tent to have other branchial arch discrepancies
47
Q

Q10 - what are the dental features of CLP?

A
  • missing teeth (usually lateral incisor, always the tooth associated with the area that the cleft goes through)
  • impacted teeth
  • crowding
  • growth (tend to be class III)
  • high vaulted and narrow palate
  • increased caries risk
48
Q

Q10 - outline the 5 treatment stages for CLP

A

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

49
Q

Q10 - Name 5 members of the CLP MDT

A
  • cleft nurse
  • maxillofacial surgeon
  • speech therapist
  • Phycologist
  • Geneticist
  • ENT respiratory consultant
  • Dental team > paediatric, dental therapist, orthodontist and therapist, oral surgeon and restorative consultant
50
Q

Q11 what percentage of 6-18 year olds have a diastema

A
  • 98% at age 6
  • 49% at age 11
  • 7% at 12-18
51
Q

Q11 Give 4 reasons for a diastema

A
  • prominent frenum
  • proclination of upper incisors
  • generalised spacing
    -hypodontia of lateral incisors
  • midline supernumerary
52
Q

Q11 how is a diastema managed

A
  • periapical radiograph to exclude presents of midline supernumerary
  • less than 3mm don’t intervene
  • more than 3mm, may consider appliance tx
53
Q

Q11 - how is a posterior crossbite managed

A
54
Q

Q11 - give two ways of expanding the arch

A
  • quadhelix appliance
  • rapid maxillary expansion appliance
55
Q

Q11 what teeth are most commonly infra-occluded

A

lower D most commonly affected (mandible more common than maxilla)

56
Q

Q11 - how will infra occluded teeth appear clinically and radiographically?

A
57
Q

Q11 what factors determine the management of infra-occluded teeth?

A
58
Q

Q11 - what are the treatment options for infra-occluded teeth?

A
59
Q

Q12 - what are the common complications of orthodontics

A
60
Q

Q12 - how is each complication managed

A
61
Q

Q12 give three other linked complications

A
62
Q

Q13 what are the oral signs of thumb sucking

A
63
Q

Q13 what additions can be made to a URA to break the habit

A
64
Q

Q13 explain the effects of prolonged digit sucking on posterior dentition

A
65
Q

Q13 what four methods can be used for stopping NNSH?

A
66
Q

Q14 - A patient has an anterior crossbite and requires fixed appliance treatment. Name four fluoride supplements you would give the patient to prevent decalcification, naming the dose and frequency

A
  • Toothpaste, high risk patients use duraphat 2800ppm or 5000ppm twice daily
  • mouthwash -0.05% fluroide mouthwash 225ppm daily in between meals
  • Fluoride varnish 22600ppm fluoride, 4 times per year
  • fluoride tablets 1mg daily
67
Q

Q14 - A patient has an anterior crossbite and requires fixed appliance treatment. Name other methods to prevent decalcification other than fluoride supplements

A
  • good case selection > only embark on orthodontics with patients who are motivated, with good OH and a low caries risk
  • diet advice > encourage a low cariogenic diet
  • oral hygiene > brush 2x per day and after every meal, and use inter dental brushes
  • regular hygiene appointments at GDP
  • fissure sealants
68
Q

Q14 - A patient has an anterior crossbite and requires fixed appliance treatment. List 8 potential risks of orthodontic treatment other than decalcification?

A

-root resorption
- relapse
- soft tissue trauma
- recession
- loss of periodontal support
- enamel fracture and tooth wear
- loss of vitality
- allergy
- poor or failed treatment
- headgear injuries

69
Q

Q15 -what four factors make early loss of a primary tooth worse

A
70
Q

Q15 - give four reasons for an unerupted 1

A
  • unerupted supernumerary
  • retained primary tooth
  • early loss of a primary tooth
  • trauma to the deciduous tooth leading to dilaceration of the unerupted tooth
  • crowding
  • ectopic position of tooth germ
71
Q

Q15 what are your treatment options for an unerupted central

A
  1. Accept the malocclusion
  2. Bring central incisor into line or arch
  3. Remove the unerupted central incisor
72
Q

Q16 - what is the BSI classification of class II div 1

A

the lower incisor edge lie posterior to the cingulum plateau of the upper incisors and there is an increased overjet with incisors being either proclined or of average inclination

73
Q

Q16 - what are the dental features in class II div 1 patients

A
  • increased overjet
  • upper incisors may be proclined
  • may have an increased overbite
  • if increased vertical proportions, may have anterior open bite
  • can occur in presence of crowding or spacing
74
Q

Q16 - what soft tissue problems are associated with class II div 1 malocclusion?

A
  • if lips are incompetent then there is an increased risk of trauma
75
Q

Q16 - what are the 6 features of a twin block appliance?

A

-two separate bite blocks
- expansion screw to widen maxilla
- bow on the anterior region
- adams clasps for retention
- deterrent rake can be added to prevent non nutritional sucking habit

76
Q

Q16 - what makes a class II div 1 malocclusion amendable to correction via removable appliance therapy?

A

URA’s have a limited role in the treatment of increased overjets but can be used in
- mild class II or class I cases
- when overjet is due to proclined and spaced incisors
- when there is a favourable overbite (aids stability)

77
Q

Q16 - what are the treatment options for class II div I

A
  • URA to retrocline the upper anterior incisors
  • growth modification with functional appliance
  • orthodontic camouflage
  • orthognathic surgery
78
Q

Q17 - what is dentoalveolar compensation

A

dentoalveolar compensation is when the teeth within the alveolar arches adapt to ensure occlusion despite an underlying skeletal discrepancy. In class III this tends to result in retroclination of lower incisors and proclination of upper incisors - this can occur in class III because frequently an anterior oral seal can be achieved

79
Q

Q17 - what is the BSI of class III

A

edge of lower incisor occludes anteriorly to the cingulum plataeu of the upper incisor and there is a reduced or reversed overjet

80
Q

Q17 - what are tx options for class III

A

1 - accept the incisor relationship - in mild class III with minimal overbite it may be preferable to accept

2 - intercept early with a URA - correct anterior crossbite with z spring
3 - growth modification - reverse twin block or protraction headgear with RME
4 - orthodontic camouflage - possible if little dentoalveolar compensation prior to tx
5 - orthognathic surgery + orthodontics