Orthodontics Flashcards

1
Q

What is the best age for functional appliance?

A
  • during puberty spurt
  • males (12-15)
  • females (9-13)
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2
Q

What does an orthodontic assessment include?

A
  1. C/O
    2.MH (allergies, conditions , GP )
  2. DH (brushing , flossing , toothpaste, compliance, trauma?)
  3. SH (any habits , living condition, parents work, diet)
  4. E/O - (skeletal base palpation, vertical , transverse , LAFH , nasolabial angle, Lips , smile line , pathology)
  5. I/O - (teeth present, teeth quality, OH, BPE , crowding, incisor relationship , rotations, molar and canine relationship)
  6. IOTN (dental health and aesthetic component)
  7. summary ( incisor class on a skeletal class base , main issues include .. overbite , overjet, competent lips etc…)
  8. radiographs
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3
Q

What are the two causes of malocclusion?

A
  • skeletal discrepancies
  • local due to teeth (position and number)
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4
Q

What is the difference between unilateral and bilateral cross bites?

A

unilateral
mandibular displacement when cusp to cusp occlusion
**bilateral*
hemimandibular hyperplasia
Class III skeletal base

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5
Q

What are the local causes of malocclusion?

A
  • teeth (number, shape and position)
  • Soft tissue (tongue thhrust , digit habit , lip trap)
  • pathology (cysts, caries, tumours)
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6
Q

What are the types of supernumerary teeth

A
  • odontome
  • conical
  • tuberculate
  • supplemental
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7
Q

What teeth do hypodontia affect the most?

A

upper lateral incisors
second premolars

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8
Q

how is the number of teeth affected in a malocclusion?

A
  • hypodontia
    -supernumerary teeth
  • retained primary (abscent successor, ectopic position , dilacerated)
  • early primary tooth loss
  • loss of permanent teeth
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9
Q

What conditions might affect the shape of the teeth?

A
  • microdontia
  • macrodontia
  • abnormal form (peg shaped , dens in dente , accessory cusps and ridges)
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10
Q

What we call abnormalities in tooth position?

A
  • ectopic
    affects : 8 , 3, 6 , 1
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11
Q

When to extract lower 6’s

A
  • check prognosis around the age of 8–9
  • if extracted too early = distal drift of 5
  • if too late = no space closure
    Ideally extract at time of development of the root bifurcation of the seven
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12
Q

Tooth eruption dates

A
  • 6yrs = 6s , lower central
  • 7yrs = upper centrals , lower laterals
  • 8 yrs = upper laterals
  • 9 yrs = lower canine
  • 10 yrs - 5’s and 4’s
  • 11yrs = upper canines
  • 12yrs - second premolars
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13
Q

What are andrews 6 keys of occlusion?

A
  • tight approximal contacts with no rotations
  • Class I incisors
  • Class I molars
  • Flat occlusal plane
  • Long axis of the teeth have a slight mesial inclination except the lower incisors
  • the crowns of the canines back to the molars have a lingual inclination
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14
Q

What are the effects of nail biting?

A
  • misalignment of teeth (crooking)
  • spacing
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15
Q

What are the effects of tongue thrust on a malocclusion?

A
  • anterior open bite
  • procline uppers
  • relapse after treatment
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16
Q

What are the effects of lower lip sucking

A
  • proclination of upper incisors
  • retroclination of lower incisors
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17
Q

What is the effects of digit sucking?

A
  • procline upper teeth
  • retrocline lower teeth
  • anterior open bite
  • unilateral crossbite
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18
Q

How to assess vertical dimensions of the face?

A
  • FMPA angle
  • border of mandible to Frankfort plane (normal meets at occipit)
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19
Q

What are the contraindications of orthodontic treatment?

A
  • nickle or latex energy
  • epilepsy
  • drugs such as bisphosphonates and cancer treatment, calcium channel blockers
  • People undergoing MRI scans
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20
Q

when should digit sucking habit be stopped and why?

A
  • age of 8-10 because roots are still developing meaning chances of spontanious repositioning is higher
  • this can correct AOB
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21
Q

when to treat a diastema?

A

at the age of 12 , may close spontaneously if below 2.5mm

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22
Q

Treatment options for impacted 6s?

A
  • if less than 7 years = may erupt on its own
  • orthodontic separator
  • Extract E
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23
Q

List the orthodontic guidelines

A
  • british orthodontic society : managing the developing occlusion
  • british orthodontic society : referral guidelines for orthodontic treatment
  • RCS : management of unerupted maxillary incisors
  • RCS : management of palatally ectopic canines
  • BSI incisor classifications
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24
Q

Describe the growth of the upper ectopic canine

A

starts developing very high and palatally , then migrate labially and distal to lateral incisors

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25
Q

When do we palpate for canines?

A
  • at the age of 9-11
  • X ray at 11 years
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26
Q

What are the treatment options for an ectopic canine?

A

XLA of c’s (wait for spontaneous repositioning)
- orthodontic traction with gold chain (open or closed exposure)

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27
Q

What are the risks of no treatment to ectopic canine?

A
  • missing teeth
  • pain
  • it will become more ectopic
  • may cause root resorption of adjacent teeth
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28
Q

How do you structure orthodontic treatment planning?

A
  • plan around lower arch as angulation is most suitable
  • build upper arch around lower
  • aim for class I incisor and canine relationship
  • decide on molar relationship ( can accept class 1 or class 2 )
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29
Q

What are the two theories explaining why teeth move in orthodontics?

A

differential pressure theory
(when force applied , bone laid on tension side and resorbed in pressure side)
** Mechano-chemical theory**
(mechanical loading causes cell shape changes in the osteoblasts this causes the release of signalling chemicals that stimulate bone remodelling

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30
Q

What are the kinds of orthodontic movements

A
  • Tipping
  • Bodily movements
  • intrusion
  • extrusion
  • rotation
  • torque
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31
Q

At what age do functional appliances become useless? and for how long do you wear them for?

A
  • at the age of 14 as the pt stops growing
  • 6-12 months
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32
Q

What is secondary remodelling?

A
  • when pressure is applied to a tooth causes bone deposition on the other side of the alveolar bone
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33
Q

What is dentoalveolar compensation?

A

a system which can attain and maintain a normal relation with varying skeletal patterns through the eruption of teeth when there is skeletal changes

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34
Q

What is the aetiology for skeletal class III?

A
  • genetics (small maxilla or large mandible)
  • Acromegaly
  • cleft lip and palate
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35
Q

What are the growth modification options for class III skeletal ?

A
  • chin up
  • reverse twin block
  • frankel III - soft tissue born version
  • TAD’s
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36
Q

What treatment options for skeletal Class II

A
  • growth modification during growth
  • Camouflage (accept underlying skeletal base)
  • only if mild skeletal discrepancy
  • make teeth in class I relationship
  • extractions - remove from further back in ipper and more mesial in lower
  • Orthognathic surgery
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37
Q

Define Class II div 1 incisor relationship ?

A
  • lower incisal edges occlude posterior to upper cingulum
  • with increased overjet
  • upper incisors can be proclined or of average inclincation
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38
Q

Why treat class II div 1

A
  • asethetics
  • function
  • avoid trauma
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39
Q

What is the aetiology of class II div 1?

A
  • Class II skeletal pattern
  • retrognathic mandible
  • OJ = inclinded uppers and skeletal pattern
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40
Q

What are the soft tissue issues associated with class II div 1 ?

A
  • common to have incompetent lips
  • lip trap
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41
Q

What dental factors are associated with class II div 1?

A
  • increased overjet
  • overbite
  • dry mouth leading to caries and gingivitis
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42
Q

What are the management options for class II div 1 ?

A
  • accept and monitor
  • teeth tipping : URA
  • fixed appliance
  • growth modification (tooth born, twinblock , frankel II)
  • orthognathic surgery
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43
Q

what is the negative effects of early growth modification?

A
  • skeletal effects not maintained long term
  • 2 stages of treatment are required
  • literature shows no difference to waiting until full dentition
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44
Q

What are the benfits of full adult dentition growth?

A
  • better aesthetics
  • lower risks of trauma
  • better compliance
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45
Q

Define class II div 1

A
  • lower incisal edge occlude posterior to cingulum of upper incisors with the retroclined upper incisors
46
Q

What is the aetiology of class II div 2 ?

A
  • skeletal class II
  • soft tissues (lower lip retroclines upper incisors)
  • crowding
  • pathology
47
Q

What are the signs of Class 2 div 2?

A

reduced FMPA

48
Q

Describe the soft tissue aetiology of class II div 2 ?

A
  • linked with reduced FMPA and lower LAFH
  • lower lips acts on upper central incisors as it is positioned higher
  • can procline lateral incisors as they get trapped on the lower lip
  • high smile line
  • marked labiomental fold
  • high masseteric forces
49
Q

What is the standard radiograph for ortho assessment?

A
  • lateral cephalograms
  • eastman analysis is the analysis of cephalogram
  • it views the relationship between the jaws, the jaw and the cranial base, the position of the teeth compared to the jaws the soft tissue profile
  • relationship of the jaw to the base of the skull
50
Q

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

A

SNA - 81 -/+ 3
SNB - 78 -/+ 3
ANB - 3 -/+ 2

51
Q

Severity of skeletal classes based on ANB?

A

Class II
mild = 4-6
moderate = 6-8
severe = >8
Class III
mild = 0-2
moderate = 0- -3
severe = >-3

52
Q

When is the best age to extract 6s?

A

8.5 - 9.5 yrs

53
Q

What is a compensating extraction?

A

extracting same tooth in one side in both arches ( this is to preserve the occlusion and do avoid over eruption of tooth on other arch)

54
Q

What is balancing extraction?

A

removal of the same tooth in the same arch
- this can be to preserve symmetry
- first permanent molar extraction no effect on shifting the midline

55
Q

What may be some advantages that a functional appliance may do ?

A
  • encourage favourable skeletal growth
  • correct molar relationship
  • correct the angulation of the upper incisors
56
Q

What are the extraction factors to think about when extracting a first permanent molar?

A

–stage of dental development
-other missing teeth
-patient and parent motivation
- skeletal pattern
- malocclusion type
- degree of crowding

57
Q

What are the options available for maintaining teeth that are compromised?

A
  • GI until extraction
  • composite restorations
  • preformed crowns - to buy time or to be replaced once in full dentition
  • onlays - gold or composite
58
Q

how can you carry out an extra oral examination?

A
  • Skeletal bases ( A-P, vertical , transverse)
  • check TMJ
  • check lymph nodes
    -look for asymmetry
  • look for lips if competent or no , lip trap?
  • Smile line
  • Nasolabial angle
59
Q

How to carry out an intro oral examination?(ectopic canine )

A
  • palpate for canines (palatal and bucca
  • check mobility of retained C’s and lateral incisors
  • check all soft tissues
  • chart teeth (present, quality )
  • assess OH
  • look for any toothwear
  • check periodontal health
  • look for crowding (mild , moderate or severe)
  • any toothwear
  • check overjet
  • check overbite
60
Q

What radiographic technique do we use to locate ectopic canine position?

A

OPT + occlusal maxilla
using parallax technique and figure out the position of ectopic canines (SLOB - same lingual opposite buccal)

61
Q

What is the incidence of ectopic canines?

A

1.5%

62
Q

What is the aetiology of ectopic canines?

A
  • genetics
  • could be due to long path of eruption -> delayed eruption
  • can be associated with hypodontia or lateral peg shaped incisors
  • crowding resulting in insuffucuent space
63
Q

What to check to assess IOTN?

A

Missing
overjet
crowding
displacement
overbite

64
Q

What are the risks of doing nothing in an ectopic canine case?

A

root resorption of other teeth if canine moves
may make future treatment more difficult
crown may resorp other teeth
Ankylosis of canine
Aesthetics

65
Q

How would you carry out surgical exposure of canine?

A

surgical exposure and orthodontic traction
Expose canine using open or closed exposure technique (depends on canine position) - then apply gold chain orthdodontic traction to align canine within arch

66
Q

What is open exposure?

A
  • a window of tisue around the tooth is removed and pack placed with sutures to prevent healing
67
Q

What is closed exposure?

A

attachment with chain is bonded to canine an flap is sutured back with chain penetrating the mucosa

68
Q

Describe the option of autotransplantation in managing ectopic canines

A
  • not very good for canines
    it requires no ankylosis and at least 3/4 of root development
69
Q

What are the risks associated with autotransplantation?

A
  • need careful surgical technique
  • pain
  • pt compliance
  • infection
  • bleeding
  • needs MDT
70
Q

What are the most commonly teeth affected by hypodontia?

A
  • third molars
  • mandibular second premolar
71
Q

Advantages of accepting space?

A
  • spaced dentition is more likely to maintain long term
  • occlusion is adequate to maintain goof masticatory function
72
Q

Disadvantages of leaving space?

A
  • patient aesthetic dissatisfaction
  • drifting of other teeth may occur making future treatment more difficult
73
Q

What warnings to give patient after consenting for replacing teeth with prosthesis?

A
  • lifelong maintenance of prosthesis
  • potential failure of prosthesis
  • slight increase in caries risk for bridge abutement teeth
  • patient willingness to undergo complicated implant treatment
  • moderately good long term success of bridgework
74
Q

Why not close incisor space?

A
  • very difficult to close large spaces in an area where alveolar bone width is likely to be compromised
  • Smile aesthetics likely to be poor
  • overbite likely to deepen and become traumatic
  • high chance of relapse
75
Q

What risks should patient be warned about in orthodontic treatment?

A
  • increased caries rate (decalcification)
  • root resroption
  • relapse
  • high level of commitment is required for wearing a twinblock
  • Ability to achieve best outcome depends on patient compliance
  • long term maintenance is required
76
Q

What are the survival rates of resin retained bridge

A
  • five year 80.8
  • 10 years 80.4
77
Q

What is the prevalence of hypodontia?

A

7%

78
Q

What does interceptive orthodontic treatment involve?

A
  • the utilisation of tooth eruption to minimise the impact of a developing malocclusion
  • extracting decidious teeth at correct stage to encourage permanent teeth to erupt
79
Q

When is the correct stage for exctracting decidious teeth to encourage permanent tooth eruption

A

when one half to two thirds root development of permanent tooth

80
Q

where do the permanent incisors develop in relation to the primary incisors?

A
  • palatal / lingually
81
Q

additional space is required to accommodate the larger anterior teeth of the permanent dentition, how is this space gained?

A
  • increase in the intercanine width through lateral growth of jaws
  • the leeway space
82
Q

what is the leeway space in upper arch?

A

1-1.5mm

83
Q

What is the leeway space in of the lower arch?

A

2-2.5mm

84
Q

What size of diastema closes on its own?

A

less than 2.5mm

85
Q

How would you treat a patient with imapction of the first permanent molar?

A
  • if patient under 7 , wait 6 months , usually it will erupt spontaneously
  • place orthodontic separator
  • attempt to distalise the first molar
  • Extract E’s
86
Q

What can early loss of deciduous teeth lead to?

A

localised crowding

87
Q

A patient has loss of As and Bs , what is the treatment options?

A
  • little impact
  • do nothing
  • permanents will erpt
88
Q

Patient has early loss of C , what to do?

A

balancing extractions

89
Q

A patient loss of E’s , what is your treatment?

A
  • tend not to balance
  • major space loss
  • consider space maintainer
90
Q

what might early loss of LRe lead to?

A

mesial drift of LR6

91
Q

Types of space maintainers

A

fixed and removable

92
Q

When is extraction of first molars most ideal?

A
  • 7s bifurcation calcification
  • 8s are present
  • class 1 av/reduced OB
  • moderate lower crowding
  • mild to moderate upper crowding
93
Q

if you extract a lower 6 what must you also do?

A

extract upper 6

94
Q

How can a child with digit sucking habit be managed?

A

positive reinforcement
bitter tasting nail varnish
glove on hand, elastoplast
habit breaker appliance

95
Q

How to tell if the patient wears their appliance?

A
  • walk in surgery wearing it
  • they can speak wih it
  • see if they have excess salivation
  • if they can take it out easily
  • any signs of wear on appliance
  • tooth movement
96
Q

At what age should digit habit be stopped?and ehy treat it?

A

<9 yrs , to encourage spontaneous correction of anterior open bite , to prevent worsening the malocclusion with growth (skeletal development)

97
Q

What appliances can be used for digit habits?

A
  • one piece basplate with single goal post
  • Split baseplate with expansion screw and 2x palatal goal posts
  • bluegrass appliaince
98
Q

What is the aetiology of infraoccluding teeth?

A

through ankylosis of primary tooth and the surrounding alveolar bone continues to grow , may be due to trauma or genetics

99
Q

How can infra-occlusion of teeth be diagnosed?

A

percussion
check for mobility
radiographs

100
Q

what to look on radiograph for an infraoccluded tooth?

A

presence or absence of successor
ankylosis of primary tooth
root resorption of primary tooth

101
Q

How should infra-occlusion of a tooth be treated when the permanent successor is present?

A
  • monitor for 6-12 months
  • extract if below interproximal contact
  • consider extraction if root formation of succesor is near completion
  • maintain space when extracting
102
Q

What are the risks of doing nothing to an infraoccluded tooth?

A
  • permanent successor can become more ectopic
  • tipping of adjacent teeth (leads to hard extraction as cannot access infraoccluded tooth)
  • caries and periodontal disease
103
Q

What to do if you cannot palpate canine by the age of 11?

A

take a radiograph

104
Q

How to intercept ectopic teeth?

A

consider extraction of c

105
Q

when will an extraction of the c be a successful treatment option for ectopic teeth?

A
  • patient between 10-13 years
  • canine is distal to midline of upper lateral incisor
  • sufficient space is available
106
Q

What are the risks of doing nothing about an ectopic maxillary canine?

A
  • can become more ectopic
  • fails to erupt
  • risk of root resorption to adjacent teeth
  • risk of root resorption of canine crown
  • risk of cyst
  • risk of ankylosis
107
Q

What interceptive treatment can be done for class III malocclusion?

A

growth modification
- enhance maxillary growth , reduce mandibular growth
- protraction headgear and rapid maxillary expansion
- patient needs to wear it 14 hours a day
- fixed appliance with URA

108
Q

When will growth modification for class III be most successful?

A
  • mild class III
  • maxillary retrusion
  • anterior displacement on closing
  • average or reduced lower face height
    -patient aged from 8-10
109
Q

What are the risks associated with increased overjet?

A
  • risk of trauma
  • appearance
  • more difficult to achieve correction once patient has stopped growing
110
Q

What is IOTN?

A

Index of Orthodontic Treatment Needed (IOTN) is a scale designed to measure the orthodontic need of a patient. It has two components:

The Dental Health Component (DHC)

The Aesthetic Component (AC)

The Dental Health Component (DHC) scale (1 to 5):

1 = no need

2 = little need

3 = borderline need

4 = need

5 = very great need

The Aesthetic Component (AC) scale (1 to 10):

1 to 4 = little or no need

5 to 7 = borderline need

8 to 10 = great need

111
Q

What is an overjet ?

A

It is the extent of horizontal (A-P) overlap of the maxillary central incisors over the mandibular central incisors - average 2-4mm , measured using ruler held parallel to occlusal plane when teeth are in ICP

112
Q

What is an overbite?

A

It is the extent of vertical (superior inferior) overlap of the maxillary central incisors over the mandibular central incisors measured relative to incisal edges - average 1/2 to 1/rd , measured using a ruler held held parallel to occlusal plane and can be classed as average, increased or decreased