class II div 1 malocclusion Flashcards
what is the diagnose of class II div 1 malocclusion based off?
> incisor reltionship
what is Class Div 1 malocclusion?
> 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
what is an overjet?
> it is the horizontal relationship between the upper incisors and lower incisors
> normally around 2-4mm
> measured with an autoclavable ruler
what is the overjet in a Class II div 1 case?
> greater than 4mm
what is the incidence of class II Div 1
> 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?)
what is the significance of class II div 1 malocclusion?
> 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
what is IOTN ?
> 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
what are the two grading components of IOTN?
> Dental health component = grade 1-5 (series of criteria)
> Aesthetic component = grade 1-10 (series of photographs)
what is the dental health component of the IOTN grade system?
> 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
how do you know whether a patient is eligible for treatment for free on the IOTN system?
> use the reference guide, disposable rulers
> 1+2 no treatment
3 = borderline - orthodontist judges the aesthetic component
> 4+5 = always treatment
what is the aesthetic component of the IOTN system?
> 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
what is the aetiology of Class II Div 1?
> 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
what are the extra oral features in a mild Class II div 1 skeletal relationship?
> mandible relatively behind the maxilla?
> cephalometric - B point not too far behind A point
what are the extra oral features in a severe class II div 1 skeletal relationship?
> 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
what does MMA Stand for?
> 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
what are the key values to take away form a cephalometric analysis?
> 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
how do you measure ANB?
> (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
what are the intraoral features of Class II div 1
> 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)
why does a Patient need Treatment for class II div 1 malocclusion?
> Improved dentofacial appearance
> Improved self-esteem – reduce teasing
> Improved psychosocial wellbeing
> Reduction in trauma
> Improved function / reduce lip incompetence
> ? improved speech
what are the aims of treatment in Class II div 1 malocclusion?
> 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
what are the treatment options of Class II div 1 malocclusion?
> 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)
what implication does the class II skeletal relationship discrepancies have on Tx?
> 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
what age would you start using functional appliances?
> age 10-13
for what skeletal discrepancy would you use functional appliances?
> mild to moderate
when can you use functional appliance for complete treatment?
> for well aligned arches
what type of treatment is commonly used with functional appliances
> two stage treatment
- functional to reduce overjet
- 2nd stage of fixed appliances +/- extractions
what are the 3 common types of functional appliances?
> Activator (Andresen)
> Bionator
> Twinblock - most common, upper and lower used together
when would you treat a class II div 1 with an URA?
> 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
what is the treatment sequence of URA to manage II/ i
> Sequence = Extract upper 4s > retract canines > Roberts Retractor to retract incisors > Biteplane
why id overbite reduction important in the treatment of Class II div 1 with URAs?
> Overbite reduction is necessary to allow overjet reduction
> Anterior biteplane incorporated into URAs
> Start overbite reduction early (during canine retraction)
describe Palatal finger spring retractors to reduce overjet -
> used to Retract canines or premolars
> Crib 6s
> 0.5mm springs
> activate by 1/2 width of the canine or premolar
describe buccal canine retractors do reduce overjet -
> Retracting canines (to relieve crowding or reduce overjet)
> Crib 6s
> 0.7mm springs
> activate by 1/3 width of the canine
describe the Robert retractors to retrocline upper incisors?
> 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
why and when would you use fixed appliances?
> 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
when would you extract when using fixed appliances?
> 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
when would removable appliance not be suitable?
> 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
what movement does FA use that URA doesn’t?
> BODILY MOVEMENTS
> URA = tipping movement
why do we need anchorage in Class II div 1 treatment?
> Bodily retraction of upper incisors with fixed appliances is anchorage demanding
how do we manage anchorage balance in class II div 1 treatment with fixed appliances?
> 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
when would orthognathic surgery be a treatment option for Class II div 1 Patients?
> 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
what is the sequence of of orthognathic surgery?
- Fixed appliances to align & coordinate
individual arches - madibular advancement - usually corrects class II div 1 skeletal discrepancy
- +/- maxillary procedure
what is iMF
- inter maxillary fixation
what is the risks of mandibular surgery
- IDN damage
- lingual nerve damage
what is a typical class II div 1 case treatment?
> phase 1 - functional appliance - corrects overjet (sajital space)
> phase 2 - fixed appliance - aligns teeth (closes/ opens space, bodily movements, corrects centre lines)
how do you retain treatment of a class 2 div 1 correction?
Ask functional appliance patients to continue wearing removable appliances for a period of time
how do you enhance stability post treatment of class 2 div 1
Stability of overjet reduction is enhanced by lower lip control of upper incisors
what is a rarely stable treatment option of class 2 div 1?
Advancement of the lower incisors in an attempt to reduce the overjet is rarely stable
what is the summer of class 2 div 1?
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
