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Ortho Flashcards

1
Q

What EO assessments are made for ortho?

A

Skeletal

  • anteroposterior
  • vertical
  • transverse

Soft Tissue

  • lip competence
  • incisal display
  • lip protrusion
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2
Q

Discuss AP ortho measurements

A

From side on, pt in natural head position/Frankfort plane parallel, bipalpation of deepest curve of maxilla + mandible

Skeletal

  • 1: normal; chin on/up to 2mm behind zero meridian line
  • 2: retrusive; chin behind line
  • 3: protrusive; chin in front of line
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3
Q

Discuss vertical ortho measurements

A 
Two methods
Linear: Lower Ant. Facial Height
- using ruler for numerical value
- lower 1/3 should = middle 1/3
— glabella-> subnasale -> soft tissue gnathion

Angular: Frankfort Mandibular Plane Angle

  • high/obtuse: lines meet before occiput; inc. LAFH
  • av.: lines meet @ occiput
  • low/acute: lines meet behind occiput; red. LAFH
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4
Q

Discuss transverse ortho measurements

A

Measured above + behind and in front of pt
Facial centreline: mid-eyebrow, tip of nose, U lip philtre, chin point

Facial asymmetry: usually mandibular

  • true: X-bite + mandibular displacement
  • common: molar 3, inc. LAFH
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5
Q

Discuss lip assessment for ortho

A

Morphology: thin, normal, full

Competency:

  • competent: meet @ rest w/o muscular effort
  • potentially: separated only by proclined UIs (Class 2/1)
  • incompetent: don’t meet @ rest; Skeletal 2, inc. LAFH

Coverage: L lip cover 1/3 UIs

Length: alar base to vermillion border; 22-24mm

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6
Q

Discuss intro-arch dental features for ortho assessment

A

Crowding: dento-alveolar discrepancy

  • mild: <4mm
  • mod.: 4-8mm
  • severe: >8mm

Spacing: dento-alveolar discrepancy

  • not usually measured
  • qualify where present
  • maxillary median diastema: gap b/w U1s

Rotations

  • describe direction from side w/ largest contact point displacement
  • i.e. MB, DP

Angulation: mesio-distal tip

Inclination: bucco-lingual
- lat. ceph
— U1s: 109d to maxillary plane
— L1s: 93d to mandibular plane

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7
Q

What inter-arch dental features are in ortho assessment?

A 
Incisor relationship 
Overjet
Overbite 
Centrelines 
Molar relationship 
Crossbites + Displacements
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8
Q

Discuss incisal relationship

A

1: incisal edge LIs occludes on cingulum plateau UIs
2: incisal edge LIs occludes post. cingulum plateau UIs
- 1: inc. overjet; UIs proclined or normal
- 2: retroclined
3: incisal edge LIs occludes ant. cingulum plateau UIs

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9
Q

Discuss overjet + overbite

A

Overjet: horizontal distance b/w incisal edge UIs + labial aspect LIs

  • av.: 2-4mm
  • Class 2/1: >
  • Class 3: <

Overbite: vertical overlap of LIs by UIs

  • av.: 2-4mm (1/3-1/2)
  • complete: contact b/w teeth + teeth/palate
  • incomplete: no contact
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10
Q

Discuss dental midlines

A 
U midline (dental) coincident w/ facial midline 
U+L midlines coincident w/ each other 
L midline coincident w/ chin point
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11
Q

Discuss molar relationship

A

1: MB cusp U6 occludes in midbuccal groove L6
2: U6 occludes M
3: U6 occludes D

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12
Q

Discuss crossbites + displacements

A

Crossbites

  • U teeth should occlude B to L; if occlude P = X-bite
  • ant. or post.
  • unilateral or bilateral

Displacement: mandibular deviation b/w centric relation + centric occlusion

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13
Q

Discuss growth control theories for bone, cartilage and soft tissue matrix

A

Bone

  • no innate growth potential; no growth when transplanted
  • growth @ sutures responds to outside stimuli; pulled apart

Cartilage

  • nasomaxillary: some innate growth
  • mandibular condyle: less growth when transplanted, considered growth site

Soft Tissue Matrix: bone + cartilage react to growth of soft tissue

  • cranial vault: size of brain
  • nasal + oral cavities: functional need
  • mandible: impaired by TMJ ankylosis
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14
Q

Discuss theories of growth modulation

A

Genetic: homeobox control generic blueprint of growth

Epigenetic
- Functional Matrix Theory
— capsular matrix: indirectly by altering vol. of capsule
— periosteal matrix: directly on skeleton
- Updated functional Matrix Theory

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15
Q

General features of craniofacial growth

A

Follows somatic growth pattern

Rate inc. pre-/@ puberty
F earlier
Red. facial convexity (class 2); mandible frowns 18+
Continues throughout life

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16
Q

Discuss structures of cranial vault + growth

A 
Comprises
- flat bones
— frontal
— occipital 
— parietal 
— squamous part of temporal
- sutures + fontanelles

Intramembranous ossification

  • apposition: sutures + exterior
  • resorption: interior
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17
Q

Structures of cranial base + growth

A

Comprises

  • basioccipital
  • ethmoid
  • sphenoid
  • petrous part of temporal

Endochondrial ossification
Spheno-occipital synchondrosis: affects AP
Surface remodelling

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18
Q

5 mechanisms of maxillary growth

A 
Sutural
Surface remodelling
Displacement/Myofibroblasts
Nasal Septum
Functional Matrix
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19
Q

Discuss sutural growth of maxilla

A

Sutures

  • frontomaxillary
  • zygomaticomaxillary
  • pterygomaxillary
  • midline
  • zygomatico-frontal (directly)
  • zygomatico-temporal (indirectly)

Intramembranous ossification; apposition @ sutures grows forwards + downwards

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20
Q

Discuss displacement growth of maxilla

A

From 7-15y up to 1/3 forward movement due to passive displacement
Associated w/ sutural growth
Rotational component masked by periosteal remodelling

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21
Q

Discuss nasal septum growth

A

Cartilaginous growth
1 of 1ry mechanisms of nasomaxillary complex growth
- apposition @ sutures
- surface remodelling: down + forward, widening palatal vault
Considerably affects growth of U face

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22
Q

Discuss growth of mandible

A 
Intramembranous 
Endochondral @ condyle
- elongation 
- ant. + downward 
Surface remodelling (majority)
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23
Q

Discuss growth rotations of mandible

A

Determined by

  • post. face height: condyles, synchondroses
  • ant. face height: tooth eruption, soft tissue growth

Backward (clockwise)

  • IO: red. overbite, ant. openbite
  • EO: inc. FMPA + LAFH

Forward (anti-clockwise): class 2/2

  • IO: inc, overbite
  • EO: red. FMPA + LAFH
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24
Q

Discuss predicting of facial growth

A

Numerous methods

  • 2ry sexual characteristics
  • standing height
  • age
  • skeletal maturity
  • dental age

No strong evidence for any of these; no real way to predict max. growth

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25
Q

Ortho relevance of growth + Tx implications

A 
Relevance
- Tx quicker in presence of growth 
- favourable in XLA cases (spontaneous closure)
- facilitate
— overbite red.
— space closure
— settling
— functional appliance + rapid maxillary expansion

Implications

  • orthognathic: timing + stability
  • timing implant placement
  • stability
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26
Q

Reasons for early loss of teeth

A

Local

  • caries
  • trauma
  • ectopic eruptions

Systemic

  • gingival hyperplasia, poor OH
  • cerebral palsy: red. mobility = poor OH
  • syndromes/disorders
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27
Q

Define balancing and compensating extractions

A

Balancing
- tooth from opposite side of same arch; min. centreline shift

Compensating

  • tooth from opposing quadrant
  • min. occlusal interference by allowing teeth to maintain occlusal relationship as drift forward
  • more difficult to justify
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28
Q

Reasons for early loss A&Bs + management options

A

Reasons

  • retained + effecting eruption UIs
  • XLA as wider Tx: mesiodens, expose + bond UE U1
  • traumatised + poor prognosis + not avulsed
  • carious

Management

  • balancing/compensating not req.
  • space maintainer: aesthetic (URA + pontic) or crowding concern
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29
Q

Reasons for early loss Cs

A 
Aid eruptions 3s
- provide space B 3s
- improve position ectopic 3s
Interceptive: unilateral loss UC causing centreline shift when other C lost
Carious
Trauma
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30
Q

Reasons for early loss D&Es

A

Allow eruption of 4/5s
Aid improvement position ectopic 4/5s
Utilise leeway space to relieve crowding
Carious

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31
Q

Management options for early loss of C&Ds

A

Balancing: may be req. crowded arch
Compensating: not req.

Unbalanced XLA result

  • no centreline shift; don’t balance
  • shift w/ complete space closure; don’t balance until sought ortho exam
  • shift w/ space remaining M to XLA; monitor to see if movement occurring, if yes seek ortho exam
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32
Q

Management options for early loss Es

A

Balancing not req.: no appreciable effect on midline
May allow serious tilting + drifting of adjacent 6
Consider space maintainer

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33
Q

General effect of early loss of teeth

A

Red. arch length =

  • crowding
  • ectopic eruption
  • impaction
  • rotation
  • centreline shift
  • unfavourable molar relationship
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34
Q

Functions of space maintainers

A 
Maintain: arch length, width of leeway space
Prevent OE opposing tooth
Improve aesthetic (ant.)
Aid breaking habits; digit sucking
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35
Q

Ideal space maintainer

A

Simple
Durable, strong, stable
Passive
Cleansable; no inc. risk caries

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36
Q

When to use space maintainers + considerations

A

When

  • presence of permanent successor
  • successor covered by alveolar bone

Consider

  • specific tooth
  • T since tooth lost
  • occlusion
  • pt age; cooperation
  • OH
  • space; already lost? Overcrowding?
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37
Q

Types of space maintainers

A

Unilateral

  • crown/band and loop
  • distal shoe
Bilateral
- fixed
— lingual arch
— transpalatal arch
— nance palatal arch
- removable: URA
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38
Q

Compare indications for lingual arch and transpalatal arch + nance palatal arch

A

Lingual arch

  • lost several post. + L6 erupted
  • maintain length + arch
  • prevent loss Leeway Space

Transpalatal Arch + Nance Palatal Arch

  • lost several post. + U6 erupted
  • maintain length + width
  • prevent Leeway Space loss by prevent M drift 6
  • modify: habit breaker for digit sucking
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39
Q

Indications for URA

A 
A+Bs lost: can + teeth to URA
Habit breaker
Maintain U6 + Leeway Space
Poor OH
Unable to bond enamel
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40
Q

Why are teeth XLA’d for ortho?

A

Create space for alignment
Orthodontically correct malocclusions
Aid dental development through removal 1ry/2ry teeth

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41
Q

Why is space making required?

A 
Relieve crowding
Incisor AP movement to obtain normal OJ
Change incisor angulation/proclination
Levelling occlusal curves
Arch contraction 
Tooth enlargement or replacement
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42
Q

How can space be created?

A 
Leeway Space: 2.5mm/Q L; 1.5mm/Q U
D movement UMs
Expansion of U teeth
Incisor proclination
Enamel stripping
XLA
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43
Q

Discuss ortho XLA of incisors

A

U

  • rare: poor aesthetics
  • poor prognosis due to severe trauma
  • root resorption: ectopic 3
  • development malformation: dens in dente, dilaceration, fusion, macrodont

L

  • easily relieve crowding where M Class 1 + I crowding
  • adult: class 3 + retract LLS
  • disadv: crowding reappears; red. intercanine width + inc. OB+J
  • req. bonded retainer
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44
Q

Discuss ortho XLA 4s and 5s

A

4s
- provide 8-9mm space
- mod-severe crowding + aid ant./post. crowding
- impacted 3s where crowding caused shortage of space
— U4 XLA as erupt pre-3
- 40-60% XLA space available if anchorage not reinforced

5s

  • mild-mod crowding: provide 3-8mm
  • P/L ectopic: early loss U/LE
  • fixed appliances req. contact b/w 4+6
  • 25-50% XLA space available if anchorage not reinforced
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45
Q

Common reasons for poor prognosis 6s

A

Caries
Molar-incisor hypominerlisation
Enamel hypoplasia

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46
Q

Possible effects of early loss of 6s

A

Localised spacing
OE opposing
Tipping of adjacent

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47
Q

Factors to consider before XLA 6s

A 
Age: dental development
Crowding
Malocclusion
DH: hypoplasia
Presence/absence of other teeth: 5s, 8s
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48
Q

Discuss effect of age on 6 XLA

A 
U: spaces close faster spontaneously 
L
- spontaneous closure if T correctly 
— calcification of bifurcation 7s
- early: 5s drift + ectopic 
- late: 7s erupted + req. ortho for space closure in pt not ideal candidate
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49
Q

Discuss effect of crowding on XLA 6

A 
U: potential for rapid space loss
L
- spaced: still spaced
- aligned: min. spaces
- crowded: best results
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50
Q

Are balancing or compensating XLAs req. for 6s?

A

Compensating

  • U6: no
  • L6: often yes

Balancing: only if severely crowded premolars

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51
Q

Compare XLA 6s for Class 1 w/ mild crowding to Class 1 w/ mod-severe crowding

A

Mild

  • XLA @ optimum T for 7s
  • don’t balance unilateral 6 w/ healthy 6s
  • L6: compensate UNLESS L7 erupted + O contact w/ U6
  • U6: don’t compensate if L6 healthy

Mod-severe
- XLA @ optimal T for 7 + relieve premolar crowding
- bilateral B crowding: balance; relief + maintain centreline
- L6: compensate to prevent OE + relieve premolar crowding
- labial crowding: little spontaneous relief w/ XLA 6
— delay until 7s erupt + use space for alignment w/ fixed
- OR XLA @ optimal T + Tx once in permanent dentition

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52
Q

Discuss XLA 6s for Class 2 and Class 3 malocclusions

A

Class 2
- req. space to correct incisor relationship
- L6: @ ideal T for 7s + control 5
- U6
— immediate XLA req.: functional/headgear to correct B segment + fixed (if pt suitable)
— temporise + wait until 7s then reassess
— consider XLA if risk OE or complication of malocclusion

Class 3
- try avoid loss 6s

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53
Q

Discuss ortho XLA 7s and 8s

A

7s

  • rare: so post.
  • aid D movement U buccal segment
  • relieve mild L premolar crowding
  • additional space prevent impacting 8s: no guarantee

8s
- no evidence for XLA to prevent LI crowding

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54
Q

Define class 2/1 malocclusion

A

Lower incisor edge lies post. to cingulum plateau of UIs
Always inc. overjet
UIs: proclined or av. inclination

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55
Q

Skeletal aetiology of Class 2/1

A

Usually skeletal 2
- skeletal 1 possible
Mainly w/ retrognathic mandible (80%)

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56
Q

Dental aetiology of Class 2/1

A

Crowding; push U1s labially

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57
Q

Soft tissue aetiology of class 2/1

A

Teeth erupt in zone of equilibrium w/ soft tissues thus important

L lip: incompetent lips w/ lip trap (push U1s labially)
Lip muscular tone
- inc. mentalis activity = retrocline L1s (normal resting lower lip line)

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58
Q

Habit aetiology of class 2/1

A

Digit sucking

  • proclined UIs
  • retroclined LIs
  • inc. overjet
  • ant. open bite; usually asymmetric
  • narrow U arch w/ or w/o unilateral post. X-bite
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59
Q

Dental features of class 2/1

A 
Inc. overjet
M Class 2
Crowding/spacing
Overbite
- inc. + deep OR
- red./incomplete

If Skeletal 1

  • UIs proclined
  • LIs retroclined
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60
Q

Rationale for Tx class 2/1

A

Aesthetics
Risk of trauma
Psychological well-being

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61
Q

Discuss risk of trauma associated w/ Class 2/1

A

Overjet

  • 5mm 22% trauma incidence
  • 9mm 24%
  • > 9mm 44% (IOTN 5a)

No lip protection

Overbite

  • pain
  • gingival stripping -> PD
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62
Q

5 management options for class 2/1

A 
Accept
Growth modification 
Headgear
Camouflage 
Orthognathic surgery
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63
Q

Define functional appliances

A

Ortho devices that utilise forces generated by stretched MoM, facial expression + periodontium to change position of teeth and/or jaw relationships in actively growing pt

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64
Q

Discuss accepting class 2/1

A

Aesthetics acceptable
Pt not concerned
OH not good enough for appliances

Must

  • explain risk to pt
  • provide mouth guard; red. trauma risk
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65
Q

Classification of functional appliances

A

Mode

  • myotonic: passive muscle stretching
  • myo-dynamic: muscular stretching during function

Retention
- tooth: passive (bionator), active (twin block)
— easy, tolerable, adjustable
- soft tissue: Functional Regulator (Frankel)
— complex, poorly tolerated
— changes zone of equilibrium

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66
Q

Contra/indications for growth modifications for class 2/1

A

Indications

  • motivated
  • actively growing
  • mod-severe AP discrepancy
  • inc. overjet
  • inc. overbite
  • red./av FMPA + LAFH
  • lip trap
  • proclined UIs, retroclined LIs
Contraindications
- poor OH
- non-growing
- mild AP discrepancy 
- inc. FMPA w/ red. overbite
— overbite red. in Tx
- retroclined UIs, proclined LIs
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67
Q

Dental and skeletal effects of growth modification of class 2/1

A

Dental: 70%

  • UIs retrocline
  • LIs procline
  • LMs erupt M
  • UMs drift D

Skeletal: 30%

  • mandibular growth @ condyles (1-2mm)
  • v little restriction of maxilla (0.7mm)
  • glenoid fossa remodel ant.
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68
Q

Discuss headgear, camouflage + orthognathic surgery in Tx of class 2/1

A

Headgear

  • generate force to maxilla restrict AP growth
  • allow catch up of mandible
  • can direct force to in/extrude Ms = control VD
  • compliance: wear 14h/d force 500g/side
Camouflage
- fixed appliances 
- mild-mod. Skeletal 2
- non/XLA
— U4s: easier move teeth back
— L5s: preferable w/o

Orthognathic

  • surgery + fixed
  • adults; growth complete
  • severe skeletal AP or VD discrepancy
  • poor facial appearance
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69
Q

Define class 2/2

A

LIs edge lie post. to cingulum plateau UIs
UIs retroclined
Overjet usually min./dec. can be inc.

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70
Q

Skeletal aetiology of class 2/2

A

AP

  • mild-mod skeletal 2
  • skeletal 1 + mild 3 (rare) possible

Vertical

  • red. VD
  • red. FMPA
  • associated w/ forward growth rotation of mandible
  • progenia: prominent chin
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71
Q

Soft tissue aetiology of class 2/2

A

Influence of skeletal pattern

If LAFH red.

  • lower lip line effectively higher on crowns UIs
  • high resting lower lip line = retroclined UIs

Muscle activity + tone: inc. mentalis activity = high lower lip line

If lower lip line high (not v higher) U2s escape effect = av. inclination whilst U1s retroclined
- if lower lip line v higher = all UIs retroclined

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72
Q

Dental aetiology of class 2/2

A

Acute crown-root angle (crowns flatter)
Thin labial-palatal thickness
Retrusive maxillary + mandibular dento-alveolar process

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73
Q

Dental features of class 2/2

A

Retroclined U1s

U2s

  • crowded
  • M-L rotated
  • normal or proclined (depending on lip line)

Crowding: exacerbated by retroclination U1s (red. arch length)

Inc. overbite
- retroclination UIs = inc. inter-incisal angle
- red. VD + skeletal 2 = no occlusal stop to LIs = OE
— occlude w/ UIs or P mucosa
— severe = trauma P mucosa or L gingiva LIs

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74
Q

Tx rationale for class 2/2

A

Aesthetic concerns
Dental health
- traumatic overbite (IOTN 4f)
- crowding

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75
Q

Tx options for class 2/2

A

Accept
Growth modification
Camouflage
Orthognathic surgery

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76
Q

Discuss accepting class 2/2

A 
Aesthetics acceptable 
Pt
- not concerned
- not suitable (OH)
Overbite: not significant clinically or aesthetically
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77
Q

Discuss growth modification Tx for class 2/2

A

Indications

  • growing pt
  • mild-mod skeletal 2

Functional appliance to convert to Class 2/1
- procline UIs
- inc. overjet
Finish w/ fixed to create class 1

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78
Q

Discuss functional appliances used for Tx class 2/2

A

Procline UIs by

  • URA: Expansion + Labial Segment Alignment Appliance
  • Twin block w/ proclining spring
  • sectional fixed appliance
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79
Q

Discuss camouflage + orthognathic Tx of class 2/2

A

Camouflage

  • fixed appliances
  • mild-mod skeletal 2
  • non/XLA: U4s, L5s (depends on tooth condition)
  • none: generate space by proclining all Is
Orthognathic
- surgery + fixed
- suitable
— adults: growth complete
— severe skeletal AP or VD
— poor facial appearance
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80
Q

What is stability of class 2/2 Tx dependent on?

A

Red. overbite + inter-incisal angle

If IIA not corrected OB will relapse as no occlusal stop to LIs

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81
Q

Define class 3

A

LIs edge lie ant. to cingulum plateau UIs
Skeletal 3
Molar Class 3

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82
Q

Skeletal aetiology of class 3

A 
Maxillary hypoplasia (retrusion)
Mandibular prognathism (protrusion)
Combination
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83
Q

Dental aetiology of class 3

A 
Maxillary hypodontia
Narrow U arch, broad L arch
Pseudo class 3: posturing forward to comfortable bite
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84
Q

Soft tissue aetiology of class 3

A

Not important part of class 3

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85
Q

Other etiological factors of class 3

A

Genetics: Hapsburg royal family
- narrow U arch

Craniofacial anomalies

  • cleft lip + palate
  • Binders syndrome
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86
Q

Indications for Tx of class 3

A

X-bite + displacement
Predicted pattern of future growth (mandible grows more)
Aesthetics
Functional problems

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87
Q

Management options for class 3

A 
Accept: do nothing or wait 
Interceptive
- URA
- functional
- face mask/reverse head gear
Camouflage
Orthognathic
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88
Q

Define early, intermediate and late in terms of ortho Tx

A

Early

  • mixed dentition
  • <10yo

Intermediate

  • permanent dentition
  • growing
  • 10-16

Late

  • permanent dentition
  • non-growing
  • > 16yo
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89
Q

Discuss early interceptive Tx of class 3

A

If do nothing undesirable changes to malocclusion occur
Improvable components @ this stage; not severe
- ant. X-bite
- post. X-bite + displacement
- risk of trauma/dehiscence
Problems: compliance, stability, growth

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90
Q

Intermediate interceptive Tx options for class 3

A

Growth modifications

Camouflage

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91
Q

Discuss growth modification for class 3

A

Functional appliance or reverse headgear

Indications
- cooperative, understand pt
- mild-mod
— severe; Tx not beneficial at this stage

Tx not guaranteed
Has to be worn whole T maxilla growing = long Tx T + potentially poor results

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92
Q

Discuss camouflage of class 3

A

Indications

  • mild-mod skeletal 3
  • pt happy w/ facial profile
  • proclination UIs + retroclining LIs possible
  • good overbite

Method

  • fixed w/o XLA; procline U, retrocline L
  • fixed w/ XLA; U5s, L4s (need more space ant.)

May req. U arch expansion to correct X-bite

  • URA
  • tri/quad helix
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93
Q

Problems associated w/ intermediate Tx of class 3

A

Unfavourable growth (unpredictable)
Late presentation of non-growing pt
Pt unhappy w/ facial profile

94
Q

Discuss late Tx of class 3

A

Orthognathic surgery + fixed

Pt must have stopped growing before commencing
- growth modification not possible
If facial profile not a concern = camouflage

95
Q

Why is it important pt chooses camouflage or orthognathic?

A

As cannot do both

First stage of orthognathic is decompensation which would reverse camouflage = extended Tx time, cost, compliance

96
Q

Reasons for IOTN

A 
Uniformity of ‘need’
Prioritise need
Risk:benefit for pt
Monitor standards of care
Audit + research
Education + teaching
97
Q

Define MOCDO

A

Missing: 5i/h, 4t/h

  • congenital absence
  • traumatic loss
  • ectopic/impacted

Overjet: 5a/m, 4a/b/m
- reverse: all Is lingual

Crossbite: 4c/l
- + displacement

contact-point Displacement (crowding): 4d
- measure b/w anatomical contact points w/ ruler

Overbite: 4e/f

  • deep/complete/traumatic
  • Openbite: 4e, 3e
98
Q

IOTN Grade 5

A

i: impacted
h: extensive hypodontia (>1 tooth/Q) w/ restorative complication
a: overjet >9mm
m: reverse overjet >3.5mm w/ masticatory + speech difficulty
p: cleft lip/palate + craniofacial anomalies
s: submerged deciduous tooth

99
Q

IOTN Grade 4

A

h: less extensive hypodontia
a: overjet >6<9mm
b: reverse overjet >3.5mm w/o masticatory + speech difficulty
m: reverse overjet >1<3.5mm w/ masticatory + speech difficulty
c: ant./post. X-bite w/ >2mm discrepancy
l: post. lingual X-bite w/o functional occlusal contact
d: severe crowding >4mm
e: ant./lat. open bite >6mm
f: inc. + complete overbite w/ gingival/palatal trauma
t: PE
x: supernumerary

100
Q

IOTN Grade 3

A

a: overjet >3.5<6mm w/ incompetent lips
b: reverse overjet >1<3.5mm
c: ant./post. X-bite w/ >1<2mm discrepancy
d: crowding >2<4mm
e: ant./lat. open bite >2<4mm
f: complete overbite w/o gingival/palatal trauma

101
Q

IOTN Grade 2 + 1

A

Grade 2

  • a: overjet >3.5<6mm w/ competent lips
  • b: reverse overjet >0<1mm
  • c: ant./post. X-bite w/ <1mm discrepancy
  • d: crowding >1<2mm
  • e: ant./post. open bite >1<2mm
  • f: overbite >3.5mm w/o trauma
  • g: pre/post-normal occlusion w/o other anomaly

Grade 1: no Tx need
- d: crowding <1mm

102
Q

Aesthetic component of IOTN

A

Used when 3d recorded
10 photographs of inc. unpleasant aesthetics
Subjective assessment by dentist

103
Q

Limitations of IOTN

A 
Lacks skeletal/soft tissue factors 
- only dental factors 
No account for growth potential 
Not index of Tx complexity 
Doesn’t account for pt demands/concerns
Doesn’t account psychosocial effects of malocclusion 
Generalised spacing not recorded
104
Q

What is early ortho?

A

Any ortho assessment or Tx during mixed dentition stage

105
Q

Why is early assessment important?

A

Most malocclusions Tx’d in permanent dentition
Small min. req. Tx early
- red. complexity
- may eliminate need for future ortho Tx

106
Q

What triggers further Ix during early ortho assessment?

A 
Delayed eruption (i)
Crowding (d)
Inc. OJ (a)
X-bite (c)
Submergence (i)
Palpation of UE U3s >10y (i)

Caries
Deep/open bite (e)

107
Q

Aetiology of ectopic 3s

A 
Tooth tissue disproportion/crowding (d)
Long eruption path
2: absence/abnormality 
c: prolonged retention 
Ankylosis 
Pathology
Clefts
108
Q

Discuss clinical + radiographic diagnosis of UE 3s

A

Clinical

  • bone contour: B/P bulge
  • adjacent teeth: position, vitality, mobility, colour
  • contralateral 3 erupted
Radiographic
Morphology 
- apex
- root resorption of adjacent tooth
- size of follicle of 3 (cystic change)
Localisation
- B-P position
- height of crown in relation to O plane
- obliquity of long axis
- proximity to midline
109
Q

Tx options for UE 3

A

Interceptive: XLA C

  • if close to line of arch
  • normalisation in 78% cases

Later Tx

  • no Tx
  • XLA 3
  • XLA + ortho
  • exposure of 3 + ortho
  • autotransplantation
110
Q

Tx for UE 1s

A

Make space

  • XLA: As/supernumeraries
  • move 2 D (not all cases)
111
Q

What is a supernumerary and why are they important?

A

Excess/extra tooth cf to normal

Most common cause of late/delayed eruption

112
Q

Classification of supernumeraries

A 
Supplemental: normal form
Conical/peg shaped/early forming
Tuberculate/barrel shaped/late forming
Odontome
- complex
- compound
113
Q

Compare conical and tuberculate supernumeraries

A

Conical

  • most common; mesiodens
  • root formation early or in time w/ permanent I
  • often erupt, may be inverted
  • usually don’t impact eruption
  • Tx: leave unless causing malposition
Tuberculate
- root formation delayed cf permanent I
- usually P
- rarely erupt or inverted 
- usually impact eruption 
- Tx
— XLA ASAP not before 6y
— not causing delayed eruption may req. XLA pre-ortho
114
Q

Why should tuberculate supernumeraries not be XLA’d before 6y?

A

May damage developing permanent I

115
Q

General Tx options for supernumeraries

A

Conservative

  • XLA $ + 1ry, await eruption permanent
  • maintain space
  • review 3-6/12
Exposure of UE
Open
- tooth close to surface
- place apically positioned flap + bracket
Closed
- tooth far away
- bond bracket + Au chain
- pull
116
Q

Why should localised I X-bites be Tx’d immediately?

A 
Eliminate displacement
Prevent
- PD trauma 
- mobility opposing tooth
- excessive tooth wear
117
Q

Aetiology + pathogenesis of infraoccluded teeth

A

Aetiology

  • idiopathic
  • genetic
  • trauma
  • absence of successor

Pathogenesis
- ankylosis during reparative phase of tooth resorption

118
Q

Tx factors + options of infraoccluded teeth

A

Factors

  • permanent successor?
  • degree
  • co-existing malocclusion
  • long term prognosis of 1ry

Options

  • conservative advocated
  • pt not begun growth spurt + 1-2mm infraocclusion = XLA
  • if left too late = complete coverage + req. extensive bone removal
119
Q

Discuss bone resorption mechanism

A

Osteoclasts recruited by external stimuli
Attach to bone @ clear zone to form seal
H+ ions secreted across ruffled border to demineralise bone
Organic matrix removed by lysosomal enzymes, MMP remove osteoid

120
Q

What are lacunae?

A

Pits of bone resorbed osteoclasts

121
Q

How is bone resorption regulated?

A

Osteoclast differentiation and function regulated by osteoblast derived factors
RANKL stim. OC formation and function
Osteoprotegrin inhibits resorption
- acts as decoy receptor for RANKL

122
Q

Discuss cellular response to light ortho force

A

1-2s: PDL fluid expressive
5s: PDL fibres + cells compressed
Mins: blood flow altered; prostaglandins + cytokines released
Hrs: metabolic changes; OB/OC activity
2-3d: frontal resorption, slight OTM
5-14d: lamina dura removed (no OTM w/o removing)
14-30d: OTM again; resorption + deposition

123
Q

Discuss cellular changes seen with heavy ortho force

A 
1-5s: PDL completely compressed
Mins: blood flow ceased
Hrs: ischaemia, necrosis, hyalinisation
2-3d: OB+OC recruited; undermining resorption begins 
14d: hyalinisation zone removed
15-30d: lamina dura removed, OTM
124
Q

What is the ideal force for OTM? What does this result in?

A 
Force just > capillary pressure 
Dec
- risk tissue + cell necrosis
- pulpal damage
- pt discomfort
125
Q

What is the centre of resistance?

A

Point of tooth where single force passed through would result in translation of tooth in direction of force

126
Q

What affects the centre of resistance of a tooth?

A

No./SA of roots
Degree of bone resorption
Degree of root resorption

127
Q

How do root and bone resorption affect the centre of resistance?

A

Greater bone resorption, CoR more apical

Greater root resorption, CoR more coronal

128
Q

What are the general optimal forces for different OTM?

A

Tipping: 30-60gm
Bodily: 100-150gm
Intrusion: 15-25gm
Extrusion: 30-60gm

129
Q

What is ortho anchorage?

A

Resistance to unwanted tooth movement

130
Q

Why is anchorage important?

A

Prevent waste of space gained from XLA not being used to align teeth
Prevent movement of Ms through fixed + removable appliances
Move teeth with higher anchorage value

131
Q

Discuss headgear

A

EO anchorage system
Use Kloehn bow
- attaches to headgear tubes on U6 bands to prevent M movement of Ms (loss of anchorage)
- move Ms D by inc. forces to create space (up to 1/2 class 2)

132
Q

Discuss temporary anchorage decides

A

IO device used for indirect anchorage
Titanium implant screwed into alveolus @ level of attached gingiva
No osseointegration thus easily removed when not req.
Use
- moving teeth in severe hypodontia case
- red. OJ where U6s lost

133
Q

Relationship b/w anchorage value + root SA

A

Direct

Anchorage value proportional to SA of root

134
Q

Predisposing factors for root resorption during ortho

A 
Long Tx T
Class 2 elastics
Roots in cortical plate
Nail biting
Previous trauma 
Atopic pt
Blunt, short pipette roots 
Previous ortho
Previous radiotherapy
FH
135
Q

Mechanism of root resorption

A

Cementum adjacent to hyalinised PDL resorbed by cementoclasts
Progress to dentine destruction
Ortho forces removed
- repair by deposition of cementum in areas of destruction
- dentine not replaced

136
Q

Types of root resorption

A

Slight blunting: minor blunting of apices
Moderate: <1/4 root
Severe: >1/4 root
Localised/generalised

137
Q

Discuss moderate generalised root resorption

A

Most teeth show some resorption
Greater in pt w/ linger Tx T
Shortening of root length; UIs most severe
Clinically insignificant

138
Q

Discuss severe localised and generalised resorption

A

Localised

  • aetiology: excessive force + prolonged Tx T
  • UIs greatest risk
  • v high risk: roots UIs against lingual cortical plate

Generalised

  • aetiology: unknown
  • MH: thyroid deficiency (high risk)
  • atopic pt: inc. levels inflammatory mediations
139
Q

Challenges/limitations of adult orthodontics

A 
Bone turnover: slower; tooth movement slower, more difficult, inc. risk resorption 
Dental + PD condition
- more likely to be worse
- previous Tx
- resorption 
- XLA spaces
- relapse + stability
140
Q

Difference in management of overbites in adults cf adolescents

A

Adolescents

  • post. not occluding thus extrude post. w/o intruding ant.
  • acceptable as still growing; use functional appliance
  • relative intrusion

Adults

  • post. occluding thus intrude ant. w/o movement of post.
  • true intrusion
141
Q

Challenges faced w/ XLAs for ortho in adults and potential alternatives

A

Challenges

  • slow space closure/long Tx T
  • compliance/acceptance of space
  • space recurrence

Alternatives

  • interdental enamel reduction
  • I proclination
  • if XLA: 5s rather than 4s
  • move Ms D
  • expansion
142
Q

Define impacted tooth

A

Tooth that has failed to erupt due to obstruction/barrier to eruption of normally positioned tooth

143
Q

Incidence of UE teeth

A

8s: 25%
5s: 20%
U3s: 2%
6s: 0.75-6%
U1s: 0.13%

144
Q

Aetiology of impaction

A 
Delayed loss of 1ry
Abnormal position of tooth germ
Ectopia
Supernumerary
Cysts
Tumours 
Odontomes
Ankylosis 
Dilaceration: invulsion of 1ry
Trauma
Systemic 
Genetic
145
Q

Risks associated w/ impacted teeth

A

Damage adjacent teeth/structures
- cyst formation
- root resorption
Poor aesthetics

146
Q

Tx need for impacted teeth (IOTN)

A

IOTN 5i

Speech benefits
Occlusal function
Psychological benefits
Min. damage adjacent teeth

147
Q

Req./steps to localisation of UE teeth

A 
Eruption pattern
Dental anatomy
Visual exam
Palpation 
X-ray
148
Q

Why is knowledge of eruption pattern and anatomy important for localisation fo UE teeth?

A

Eruption pattern

  • timing of crown + root formation; how far down should tooth be
  • eruption dates; late = further Ix
  • contralateral tooth erupted

Anatomy

  • differentiate 2ry vs 1ry
  • erupt into path of least resistance; suggests sites for palpation if ectopic
149
Q

Discuss visual exam + palpation of UE teeth

A 
Visual 
- obvious B/P bulges; crown under mucosa 
- angulation 2: UE 3
- colour changes of 1ry
— previous trauma
— resorption from impaction

Palpation

  • carried out all 9-10yo
  • palpate B/L sulcus for crown UE
  • check mobility Cs + 2s
  • palpate P for crown
  • compare contralateral eps. if erupted
150
Q

When is intervention of UE U1s req.?

A

Contralateral erupted >6/12
Both UE’d + L1s erupted >12/12
Deviation from normal eruption pattern; 2s before 1s

151
Q

Aetiology of UE 1s

A

Hereditary

  • supernumerary
  • cleft lip + palate
  • cleidocranial dystosis
  • odontomes
  • abnormal tooth:tissue
  • generalised retarded eruption
  • gingival fibromatosis

Environmental

  • trauma
  • early XLA/loss 1ry
  • retained 1ry
  • cystic formation
  • endocrine abnormalities
  • bone disorders
152
Q

Management of UE U1s

A 
Remove obstruction: 1ry, supernumerary 
Ensure sufficient space
- URA
- sectional fixed appliance
- retained appliance 
Review 3-6/12; 80% erupt unaided
153
Q

Management when eruption of U1 failed at 12/12

A

Exposure indicated
Closed if high, open if superficial
Avoid incisions in free gingiva
Palatal approach where possible

154
Q

Aetiology of UE 3s

A 
Long path of eruption 
Develop before 2s
Small/absent 2s
Guided eruption by 2s
Cs resistant to resorption 
Polygenic inheritance
155
Q

Management strategies for UE 3

A 
No Tx
Interceptive 
Expose + ortho 
Surgical XLA
Transalveolar implant 
Surgical repositioning
156
Q

Discuss no Tx for UE 3

A

Review 6/12 + occasional X-ray
Warn re root resorption 2s + cyst formation

Indications

  • cooperative
  • age
  • appearance of C: colour, shape, root length
  • long term restorative options
  • 3 position
157
Q

Interceptive Tx for UE 3

A

XLA both Cs

  • uncrowded mouth = 78% improvement where space
  • usually within 12/12
  • XLA both to avoid centreline shift
158
Q

Exposure + ortho for UE 3

A 
When interceptive Tx failed
Req. space for 3s
- URA
- distalisation or XLA 4s
Expose + bone (NICE)
159
Q

Surgical XLA of UE 3

A

Indications
- poorly positioned
- curved root
- XLA req. for ortho
In uncrowded mouth req. pros replacement
Benefit: eliminate need for X-ray monitoring

160
Q

Risks associated w/ aligning impacted 3s

A 
Root resorption adjacent teeth
Loss of vitality 
Poor tissue contour
Inc. pocket depths
3 root resorption 
Ankylosis
161
Q

Aetiology + management of impacted 5s

A 
Aetiology: early loss Es
Management
- accept
- XLA/incorporate into ortho Tx
- expose + bone
162
Q

Aetiology + management of UE 6s

A

Aetiology

  • bulbous E
  • crowding
  • M path of eruption
  • 1ry failure of eruption
Management
- observe 
- persist >8yo: interceptive
— XLA E
— disimpact 6
163
Q

Types of ortho appliances

A

Removable
- Active: URA, functional
- Passive: Hawley retained, vacuum formed retainer
Fixed
- Active: pre-adjusted edgewise appliance
- Passive: fixed/bonded retainer

164
Q

Difference b/w URA and functional appliance

A

Both active removable ortho appliances
URA: simple
Functional: postures mandible away from rest position

165
Q

Design features of removable ortho appliances

A

Active components
Retentive complements
Anchorage
Baseplate

166
Q

Discuss active components of ortho appliances

A

Site of force delivery

Springs: T, Z, palatal finger

  • 0.5mm austenitic SS
  • optimal force: 25-40g/root
  • actives 2-3mm, 1mm movement/mnth

Labial Bow: retract Is

  • 0.7mm SS (Hawley bow)
  • acrylic must be trimmed behind Is

Screws: move 1/+ teeth

167
Q

Discuss retentive components of removable ortho appliances

A

Maintain appliance in mouth

Adams clasps

  • 0.7mm SS
  • easy to adjust
  • versatile; can add auxiliary fittings

Southend clasps: UIs
Fitted labial bow
Ball-ended clasps: 0.6mm SS

168
Q

Discuss anchorage features of removable ortho appliances

A

Prevent unwanted tooth movement

IO

  • Simplified: anchor teeth > moving teeth
  • Reciprocal: equal no. teeth moving in opp. directions

EO: headgear

169
Q

Features of removable ortho appliances baseplate

A

Hold components together + provide anchorage

Heat/cold cure acrylic

Incorporate

  • split screw
  • ant. bite plane: red. OB by discluding B segments allowing OE + compensatory development of alveolus (growing pt only)
  • post. bite plane: disclude occlusion allowing correction of ant. X-bite
170
Q

Uses of removable ortho appliances

A 
Interceptive: correct ant. X-bite; space maintainer 
Functional 
Test compliance
Red. OB
D movement U B segments
Post-Tx retainer
171
Q

Dis/advantages of removable ortho appliances

A

Adv

  • effective for tipping teeth over short distances
  • easy to clean
  • self-limiting
  • cheap
  • min. chair side T
  • aesthetic
  • provide anchorage

Disadv

  • compliance
  • limited to tipping movement
  • speech + mastication difficulty
172
Q

Indications for fixed appliances

A

When req. bodily tooth movement

  • crown + root movement
  • in/extrusion
  • de-rotation
  • space closure
173
Q

Dis/advantages of fixed appliances

A

Adv

  • 3D tooth control
  • not compliance dependent
  • act like bite turbos (red. OB)
    • headgear

Disadv

  • difficulty cleaning
  • risks: perio, resorption, decalcification
  • limited anchorage control; may req. adjunctive appliance
174
Q

Components of fixed appliances

A

Brackets
Bands
Archwires
Auxiliaries

175
Q

Types of archwires

A

Round/rectangular

NiTi/SS

176
Q

Discuss difference between initial and late archwires

A

Initial

  • flexible + elastic
  • engaged in multiple displaced teeth
  • round NiTi

Late

  • rigid + strong
  • resist distortion as teeth moved w/ auxiliaries
  • rectangular SS
177
Q

Types of auxiliaries

A

Close/open coils
Intermaxillary elastics
Springs
Hooks

178
Q

What are the functional limitations of fixed appliances?

A

Alveolar bone has limited capacity for remodelling therefore skeletal pattern offers greatest limit to tooth movement

179
Q

What is ortho relapse?

A

Change in
- tooth position (intra-arch)
- arch relationship (inter-arch)
From positions placed @ end of Tx

180
Q

Causes and types of ortho relapse

A

Orthodontic relapse: predictable + avoidable

  • physiological relapse: return to original malocclusion
  • true relapse: poor Tx

Maturational changes: unpredictable
- unfavourable growth

181
Q

Factors affecting ortho stability post-Tx

A 
Soft tissue
Occlusal 
Facial growth 
Soft tissue maturation 
Occlusal maturation 
Supporting tissue
Habits
182
Q

Discuss soft tissue and occlusal impact on ortho stability

A

Soft Tissue

  • pre-Tx: malocclusion stable as in zone of equilibrium w/ soft tissues
  • post-Tx: unstable unless new stability position found
  • must assess soft tissues + consider during Dx + Tx planning
  • Class 2/1: OJ dependent on lower L action on U labial segment

Occlusal

  • ant. X-bite: req. +ve OB
  • post. X-bite: req. good intercuspation
183
Q

Impact of continuing facial growth on ortho stability

A

Facial growth continues post-Tx
Dentoalveolar adaptation usually maintains O relationships even when skeletal relationship change w/ growth

If intercuspation poor/dentoalveolar adaptation @ limit, O change
- class 3, skeletal open-bite
184
Q

Discuss impact of occlusal maturation + soft tissue maturation on ortho stability

A

Occlusal
- continues throughout life; changes from teens to adulthood
— dec.: inter-canine width, arch length
— inc.: LI crowding, OB

Soft Tissue
- lip maturation + tone -> uprighting of labial segments thus crowding

185
Q

Discuss impact of supporting tissues on ortho stability

A

Incl. supporting bone, PDL, supracrestal fibres

Recently deposited bone esp. susceptible to resorption
- must retain tooth movements until supporting tissues fully adapted

Supporting bone + PDL: 6/12
Supracrestal fibres: >12/12

186
Q

Define ortho retention

A

Holding teeth following ortho Tx in Tx position for period req. for maintenance of result

187
Q

Rationale for ortho retention

A

Allow PD + gingival reorganisation
Min. changes from growth
Permit neuromuscular adaptation to correct tooth position
Maintain unstable tooth positions; if req. for compromise or aesthetics

188
Q

Relapse risk factors

A

Pre-Tx

  • rotations
  • median diastema
  • spacing (esp. adults)
  • palatal 3s
  • class 2/2
  • grossly incompetent lips
  • forward tongue posture
  • ant. open bite
  • PD

During Tx

  • expansion
  • I advancement/retraction
  • XLA spaces (adult)
189
Q

Types of ortho retention

A

Help by Tx occlusion

  • Class 2/2 reverse OJ held by +ve OB
  • lip trap: OJ red. complete, prevent L lip becoming caught

Appliances: all are passive

  • removable: vacuum formed, Hawley
  • fixed/bonded
190
Q

Discuss duration of retention

A

Part time

  • removable: nocturnal wear
  • no evidence for FT wear removable appliance cf PT

Long term

  • relapse potential ongoing
  • maturational changes continue until late adulthood
191
Q

Discuss the Updated Functional Matrix theory of growth

A

Periosteal matrix

  • mechanical loading influence gene expression
  • mechano-sensing enables cells to respond to extrinsic loading through mechano-reception and mechano-transduction

Periosteum

  • bone loaded dynamically (muscle contraction)
  • bone loaded statically (gravity)
192
Q

Explain how updated functional matrix theory may apply to ortho

A

Ortho appliances/muscles deform bone
Mechanoreception: osteoblasts/clasts electrically activated
Mechanotransduction: osteoblasts/clasts respond
Gene expression altered

193
Q

Discuss cheek and nose assessments for ortho

A

Cheeks: paranasal hollowing; skeletal 3, maxillary hypoplasia

Nose
- nasio-labial angle; 90D
— M: 90-95; F: 95-10
— av., acute, obtuse 
- asymmetry
- flaring @ base
194
Q

Define: ant. + post. X-bite and scissor bite

A

Ant.: 1/+ UIs in linguo-occlusion cf L
Post.: B cusp LP/M occludes B to B cusp UP/M
Scissor: B cusp LP/M occlude L to L cusp UP/M

195
Q

What should be incl. in ortho Dx summary?

A

Short description

  • Pt: name, age, CO
  • I relationship
  • skeletal: AP, vertical, transverse

Key dental features

  • presence/absence teeth
  • condition: caries, restorations
  • describe L+U arch
  • O features

Relevant X-ray findings + IOTN

196
Q

What structures are visible on lat. ceph?

A 
Skeletal structures
- calvarium
- cranial base
- facial skeleton; Md, Mx
- cervical spine
Teeth
Soft tissues
197
Q

Ortho uses for lat. ceph

A 
Pre-Tx record
Dx + Tx Planning
- skeletal assessment
- Is: inclination, angulation, position 
- UE teeth
- soft tissue profile assessment
Assess/monitor growth 
During Tx
- end of functional appliance Tx
- monitoring anchorage req. + I inclination (before space closure)
- Tx progress (surgical case)
End of Tx/retention 
Research
198
Q

Ideal features of point on ceph for tracing

A

Valid: represent accurately the structure concerned
Reproducible: repeatably, accurately identifiable

199
Q

What are the sella and naison points on a lat. ceph?

A

Sella: midpoint sella turcica
Naison: most ant. point frontonasal suture

200
Q

What are the orbitale, porion, menton and gonion points on lat. ceph?

A

Orbitale: most ant., inf. point margin of orbit
Porion: uppermost, outermost point EA

Menton: most inf. point of mandibular symphysis in midline
Gonion: most post., inf. point angle of mandible

201
Q

What are ANS, PNS, A, B points on lat. ceph?

A

ANS: tip ant. nasal spine
PNS: tip post. nasal spine

A: most post. point profile maxilla b/w ANS + alveolar crest
B: most post. point profile mandible b/w chin point + alveolar crest

202
Q

What are UIA, UIT, LIA, LIT on lat. ceph?

A

UIA: upper incisor apex
UIT: upper incisor tip

LIA: lower incisor apex
LIT: lower incisor tip

203
Q

Lines drawn on lat. ceph

A

Frankfort: orbitale->porion
Maxillary plane: ANS->PNS
Mandibular: menton->gonion
McNamara: through naison perp. to Frankfort
Functional occlusal plane: through U and L P/Ms

204
Q

Discuss SNA/SNB analysis of lat. ceph and what it means for ortho

A

SNA: sella-naison-A angle; av: 81+3
SNB: sella-naison-B angle; av 78+3

ANB: SNA-SNB

  • Skeletal 1: 2-4
  • Skeletal 2: >4
  • Skeletal 3: <2
205
Q

Discuss dental analysis of lat. ceph

A

Incisal inclination

UI-Mx: angle b/w Mx plane + line through UIA and UIT
- av: 109 +6
LI-Md: angle b/w Md plane + line through LIA and LIT
- av: 93 +6

Inter-incisal angle: b/w UI-Mx and LI-Md
- av: 135 +10

206
Q

Importance of determining aetiology of malocclusion

A

Tx governed by aetiology

- accept/moody skeletal; age? Severity?

207
Q

Differentiate b/w ortho Tx modalities

A

Orthopaedic (Growth Modification)

  • growing pt w/ skeletal discrepancy
  • usually headgear

Ortho Camouflage

  • non/growing pt w/ mild-mod. skeletal discrepancy
  • correct I, accept skeletal

Orthognathic

  • non-growing pt w/ mod.-severe skeletal discrepancy
  • correct I + skeletal
208
Q

Aetiology of Skeletal 2 and 3

A

2

  • Md retrognathia
  • +/- Mx protrusion

3

  • Mx hypoplasia
  • +/- Md prognathism
209
Q

Soft tissue aetiology of class 2 malocclusion

A

Class 2/1

  • low lip line, fail to control UIs -> OJ
  • stability: retract UIs
  • lip trap -> exacerbate OJ

Class 2/2
- high lip line; mentalis hyperactive
— U1s: retroclined due to lip pulling back
— U2s: proclined as shorter so not impacted by high lip line
— LIs: retroclined as lack lip support

210
Q

Effect of strap-like lip on arch

A

L arch has square shape

211
Q

Effect of tongue on malocclusion

A

Size: large

  • procline LIs
  • spacing

Position: forward -> procline LIs + spacing

212
Q

What is dentoalveolar disproportion? What is it’s effect?

A

Discrepancy b/w no and/or size teeth and size of arch/space within arch

Leads to spacing/crowding

213
Q

Aetiology of crowding/spacing

A 
Size of teeth
No. of teeth
Position of teeth
Red. arch size
Insufficient space within arch
- early loss 1ry
- retained 1ry
214
Q

Causes of retained 1ry

A

Successor developmentally absent
Successor ectopic
Local abnormality in alveolar development (infra-occlusion)
Failure of permanent to resorb 1ry

215
Q

Tooth size aetiology of malocclusions

A

Microdont: spacing in normal arch
Macrodont: crowding in normal arch

216
Q

Indications for ortho space creation

A 
Crowding relief 
OB red.
OJ red.
Arch constriction 
Torquing UIs
217
Q

Methods and factors affecting space creation for ortho

A 
Methods
- inc. arch length
— Ms D
— Is forward
- arch expansion 
- interproximal enamel red.
- XLA

Factors

  • dental health
  • degree of crowding
  • total space req.
  • aetiology
218
Q

Mechanism of how habits cause malocclusion

A

Digit sucking alters intrinsic soft tissue pressures

  • > equilibrium b/w teeth + soft tissues lost
  • > teeth move
219
Q

What is the severity of the effect of digit sucking dependent on?

A

Duration; threshold 6h/d
Freq.
Intensity

220
Q

Effects of digit sucking

A 
UIs: proclined
LIs: retroclined 
Inc. OJ
Bi/unilateral X-bite +/- displacement 
Ant. OB; usually asymmetric 
- differential eruption 
Mx constriction 
- lower tongue position 
- inc. buccinator activity
221
Q

When should digit sucking be stopped by?

222
Q

Methods for dissuading digit sucking

A

Explain cause + effect

Conservative: 3-6/12

  • reward
  • reframing
  • bitter nail varnish
  • plaster
  • wearing sock over @ night

Persistent: 6-12/12; fixed/removable appliance

Hypnosis

223
Q

Discuss management of debonded bracket and loose bands

A 
Debonded
- not urgent
- usually still attached by elastic to wire
— moves/spins -> irritation 
- Tx
— wax to stop moving
— ortho appt

Loose
- usually no immediate harm
- left 3-4/52
— swallowing
— enamel demineralisation 
- Tx
— remove if poss.
— ortho appt
224
Q

Management of poking ortho wire

A

Usually handled @ home w/ wax by pt

Cut wire flush to terminal band/bracket w/ D end cutters
Turn wire in at end

Ortho appt

225
Q

Management of lost/loose ortho appliance

A

Urgent: see ortho

Management

  • adjust URA + refit
  • encourage commitment
226
Q

Management of swallowed appliance/brace

A

Infrequent

Small + asymptotic; reassure will pass easily
Airway compromised + symptomatic
- AE chest X-ray
- provide description of inhaled object

227
Q

EO risks of ortho + management

A

Usually headgear/protraction face mask

  • skin trauma: ill fitting
  • skin rash: Ni allergy
  • eye damage -> blindness

Tx

  • allergy: stop, refer to GP
  • ill fitting: stop, don’t refit
  • eye injury: AE
  • urgent ortho appt
228
Q

Importance of Dx UE 3s

A 
3s cornerstone of mouth
Canine guidance
Last tooth to be lost 
IOTN5i
Multidisciplinary care req.
Long Tx T
229
Q

What is ‘late’ eruption for U3s?

A

Normal: 11-12y
Late
- F: 12.3y
- M: >13.1y

230
Q

When should radiographs be used for localisation of UE 3s?

A

> 11y + 3s not palpable or erupted

231
Q

Sequelae following impacted 3

A 
Dentingerous cyst formation 
Internal resorption impacted tooth 
External resorption impacted + neighbouring teeth
Ankylosis 
Infection 
Crowding 2/4 contact + red. arch length
232
Q

How to determine if correct T for XLA 6? (Ortho)

A

Calcification of bifurcation 7: body movement to position of 6
UE5 engaged in roots E: prevent drifting + ectopic
M angulation 7; 15-30°
Follicle 7 contact w/ 6

Additional: presence 5s, 8s?

BDS4 (10 decks)

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