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orthodontics 4th year > class II div 1 malocclusion > Flashcards

class II div 1 malocclusion Flashcards

1
Q

what is the diagnose of class II div 1 malocclusion based off?

A

> incisor reltionship

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2
Q

what is Class Div 1 malocclusion?

A

> Lower incisor edges are palatal to the cingulum plateau of the upper incisors

> and the upper incisors are proclined or of average inclination, with an increased overjet

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3
Q

what is an overjet?

A

> it is the horizontal relationship between the upper incisors and lower incisors

> normally around 2-4mm

> measured with an autoclavable ruler

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4
Q

what is the overjet in a Class II div 1 case?

A

> greater than 4mm

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5
Q

what is the incidence of class II Div 1

A

> Class II Div 1 is a common malocclusion

> 20-30% of all malocclusions (UK)

> 3/4 have skeletal II base (if skeletal I base present think … possible habit?)

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6
Q

what is the significance of class II div 1 malocclusion?

A

> Poor dental appearance

> Facial profile often poor

> Increased risk of upper incisor trauma – over 40% risk with overjets 9mm+ Roberts Harry & Sandy BDJ series 2003

> often associated with deep overbite and possible palatal trauma

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7
Q

what is IOTN ?

A

> INDEX OF ORTHODONTIC TREATMENT NEED

> Used in N.Ireland since 2014 to decide which cases are severe enough to warrant treatment under the NHS
Has been used in rest UK for many years

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8
Q

what are the two grading components of IOTN?

A

> Dental health component = grade 1-5 (series of criteria)

> Aesthetic component = grade 1-10 (series of photographs)

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9
Q

what is the dental health component of the IOTN grade system?

A

> Grade 1 = very mild, no need for tx

> Grade 2 = OJ 4 – 6mm with competent lips
- mild crowding

> Grade 3 = OJ 4 - 6mm with incompetent lips
- moderate crowding

> Grade 4 = OJ >6 – 9mm
- severe crowding
- mild hypodontia or supernumeraries
- deep traumatic OB

> Grade 5 = OJ 9mm +
- impacted teeth
- supernumerary teeth

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10
Q

how do you know whether a patient is eligible for treatment for free on the IOTN system?

A

> use the reference guide, disposable rulers

> 1+2 no treatment
3 = borderline - orthodontist judges the aesthetic component

> 4+5 = always treatment

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11
Q

what is the aesthetic component of the IOTN system?

A

> series of 10 photos

> if patent scores a 3 on DC =
- 1-5 is not treated on the NHS
- 6-10 is treated on the NHS

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12
Q

what is the aetiology of Class II Div 1?

A

> Growth - AP skeletal discrepancy ( > 70% of cases)
Mandibular retrognathia - (mandible is under developed)

> Habits eg. thumb sucking - proclines uppers, retroclines lowers leading to increased overjet

> Soft Tissues - lower lip maintains proclination

> Dental factors – maxillary crowding

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13
Q

what are the extra oral features in a mild Class II div 1 skeletal relationship?

A

> mandible relatively behind the maxilla?

> cephalometric - B point not too far behind A point

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14
Q

what are the extra oral features in a severe class II div 1 skeletal relationship?

A

> severity of discrepancy can be disguised by a prominent chin point

> lower vertical facial proportions often reduced (reduced MMA)

> cephalometric - B point way behind A point , increased overjet, increased overbite

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15
Q

what does MMA Stand for?

A

> maxillary mandibular Plane Angle

> the maxilla plane runs through the maxilla on the line through the anterior on the posterior nasal spine

> the mandibular run line runs through the inferior border of the mandible

> where these two line intersect it give us the measure of the MMA, therefore a measure of the lower face height

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16
Q

what are the key values to take away form a cephalometric analysis?

A

> Upper incisors are proclined = (> 109 degrees)

> ANB angle > 4 degrees = indicate a class II

(ANB = SNA-SNB)
SNA is a measure of maxillary AP position
SNB is a measure of mandibular AP position

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17
Q

how do you measure ANB?

A

> (ANB = SNA-SNB)
SNA is a measure of maxillary AP position
SNB is a measure of mandibular AP position

> A - maxilla point A
B - mandible point B
N - nasion
S - sella

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18
Q

what are the intraoral features of Class II div 1

A

> proclined or average upper incisors (upper incisors may be prominent but not proclined)

> overjet increased (always)

> overbite increased (not always )

> buccal segments usually Class II (but not always)

> crowding often present (but not always)

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19
Q

why does a Patient need Treatment for class II div 1 malocclusion?

A

> Improved dentofacial appearance

> Improved self-esteem – reduce teasing

> Improved psychosocial wellbeing

> Reduction in trauma

> Improved function / reduce lip incompetence

> ? improved speech

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20
Q

what are the aims of treatment in Class II div 1 malocclusion?

A

> Improve facial profile

> Reduce overjet (OJ)

> Reduce overbite (OB)

> Relieve crowding and align arches

> Correct centre-lines

> Deal with impacted / ectopic / supernumerary / missing teeth as appropriate

> Produce a stable result / retain result

21
Q

what are the treatment options of Class II div 1 malocclusion?

A

> FUNCTIONAL APPLIANCES
- Andresen, MOA or most commonly Clarke Twin-Block
+/- FA

> UPPER REMOVABLE APPLIANCES
- normally to facilitate transition between functional and fixed phase
- occasionally as complete Tx (historical)

> FIXED APPLIANCES
- often in conjunction with functional appliances +/- extractions
- Or with class II correctors eg. PowerScope (AO)

> Headgear
(used less and less frequently)

> Orthodontic mini-implants
- to improve anchorage balance – becoming more popular

> Surgical orthodontic treatment
(Non-growing patients)

> New developments
(Invisalign® with class 2 elastics)

22
Q

what implication does the class II skeletal relationship discrepancies have on Tx?

A

> None:
- Fixed appliance only (occasionally URA)

> Mild:
- Functional / Fixed

> Moderate:
- Functional / URA / Fixed

> Severe:
- Surgery + Fixed – possibly try functional aged 12/13 to reduce discrepancy – key is informed consent

23
Q

what age would you start using functional appliances?

A

> age 10-13

24
Q

for what skeletal discrepancy would you use functional appliances?

A

> mild to moderate

25
Q

when can you use functional appliance for complete treatment?

A

> for well aligned arches

26
Q

what type of treatment is commonly used with functional appliances

A

> two stage treatment

  1. functional to reduce overjet
  2. 2nd stage of fixed appliances +/- extractions
27
Q

what are the 3 common types of functional appliances?

A

> Activator (Andresen)

> Bionator

> Twinblock - most common, upper and lower used together

28
Q

when would you treat a class II div 1 with an URA?

A

> Cases with proclined upper incisors and mesially inclined upper canines

> Mild or no skeletal discrepenecys

> acceptable in lower arches

> Sequence = Extract upper 4s > retract canines > Roberts Retractor > Biteplane

29
Q

what is the treatment sequence of URA to manage II/ i

A

> Sequence = Extract upper 4s > retract canines > Roberts Retractor to retract incisors > Biteplane

30
Q

why id overbite reduction important in the treatment of Class II div 1 with URAs?

A

> Overbite reduction is necessary to allow overjet reduction

> Anterior biteplane incorporated into URAs

> Start overbite reduction early (during canine retraction)

31
Q

describe Palatal finger spring retractors to reduce overjet -

A

> used to Retract canines or premolars

> Crib 6s

> 0.5mm springs

> activate by 1/2 width of the canine or premolar

32
Q

describe buccal canine retractors do reduce overjet -

A

> Retracting canines (to relieve crowding or reduce overjet)

> Crib 6s

> 0.7mm springs

> activate by 1/3 width of the canine

33
Q

describe the Robert retractors to retrocline upper incisors?

A

> Retracting incisors (Class II Division 1)

> Crib 6s

> 0.5 mm labial bow supported by SS tube

> should lie just behind incisal edges when passive

34
Q

why and when would you use fixed appliances?

A

> Excellent tooth control, now treatment of choice

> MILD (TO MODERATE) SKELETAL DISCREPANCIES

> CROWDED UPPER / LOWER ARCHES

> May need headgear / orthodontic mini implants

> Commonly used after initial phase of functional

35
Q

when would you extract when using fixed appliances?

A

> Extractions are common =

  • upper premolars to provide space for overjet reduction.
  • If lower crowding then consider upper 4’s & lower 5’s to improve anchorage balance
36
Q

when would removable appliance not be suitable?

A

> when the incisors are retroclined you would be left with an unfavourable inter incisal angel + unstable incisal relationship = deepening over bite

> would be suitable for fixed appliance

37
Q

what movement does FA use that URA doesn’t?

A

> BODILY MOVEMENTS

> URA = tipping movement

38
Q

why do we need anchorage in Class II div 1 treatment?

A

> Bodily retraction of upper incisors with fixed appliances is anchorage demanding

39
Q

how do we manage anchorage balance in class II div 1 treatment with fixed appliances?

A

> Usually extract upper 4s, provide better anchorage balance than upper 5’s*

> consider banding / bonding upper 7’s to improve anchorage balance

> uncommon = Headgear may be required to help anchorage – orthodontic mini implants now also an option

> Carry out initial phase of functional Tx

40
Q

when would orthognathic surgery be a treatment option for Class II div 1 Patients?

A

> Moderate to severe Class II skeletal discrepancies in patients too old for functional appliances

> often patients have has a failed term of treatment when younger

41
Q

what is the sequence of of orthognathic surgery?

A
  1. Fixed appliances to align & coordinate
    individual arches
  2. madibular advancement - usually corrects class II div 1 skeletal discrepancy
  3. +/- maxillary procedure
42
Q

what is iMF

A
  • inter maxillary fixation
43
Q

what is the risks of mandibular surgery

A
  • IDN damage
  • lingual nerve damage
44
Q

what is a typical class II div 1 case treatment?

A

> phase 1 - functional appliance - corrects overjet (sajital space)

> phase 2 - fixed appliance - aligns teeth (closes/ opens space, bodily movements, corrects centre lines)

45
Q

how do you retain treatment of a class 2 div 1 correction?

A

Ask functional appliance patients to continue wearing removable appliances for a period of time

46
Q

how do you enhance stability post treatment of class 2 div 1

A

Stability of overjet reduction is enhanced by lower lip control of upper incisors

47
Q

what is a rarely stable treatment option of class 2 div 1?

A

Advancement of the lower incisors in an attempt to reduce the overjet is rarely stable

48
Q

what is the summer of class 2 div 1?

A

Class II Div 1 is common
Main treatment aim is overjet reduction
Best timing is in late mixed or early permanent dentitions: functional appliances frequently used
Fixed appliances required if crowding present in upper or lower arches
Severe skeletal discrepancies (over jet >10mm) in growing patients - difficult to fully treat with functional appliances
Significant skeletal discrepancies in non-growing patients require surgery

Refer patients with skeletal discrepancies
Refer early (age 10-12)
Clarke Twin Block is default functional of choice
Consider extraction of upper 4s and lower 5’s in crowded Class II division 1 cases
Full overbite reduction important to allow overjet reduction

orthodontics 4th year (12 decks)

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