MBT FAMILLY

andem Archwires •014 + 014

•014 + 016

•018 + 012

•014 + 014

•014 + 016 – Alignment phase •018ss + 012 NiTi – Auxillary mechanics

Premolar tubes •Reduced friction •Offset to prevent debond •Hook to allow traction –Seating –Short elastics •But! –Can be difficult to position –If very rotated difficult to thread wire –Difficult to place auxillary wire –Difficult to place rigid wires

Class II cases - II div 1 •Upper arch torque resists retroclination during overjet reduction and elastic use

•Increase to 22 degrees?

•Non extraction lower

–Resists excessive proclination •Watch out when extractions in lower arch –Particularly low angle and deep bite

–-6 degrees incisors can run away! (se duc in fata incisivii inf)

Class II cases - II div 2 •Perfect prescription

•Extra upper torque to correct retroclination

•Non extraction lower –-6 resists excessive proclination

Class II cases – Functional appliances •Prescription counteracts deleterious effects of functional –Upper buccal root torque Vs expansion

–Upper labial torque Vs retroclination

–Lower Labial torque Vs proclination

–Upper reduced tip Vs distal tipping

What about surgical Class II? •Same again

•Upper torque –brings upper labial segment forwards •Lower torque –Holds back the lower labial segment

UI-Max 88ºUI-Max 114º

Class II div 1 •Typical extraction patterns are opposite to camouflage

•More likely to extract further forward in the lower arch unless crowding is minimal

•If you extract in the upper arch extract further back to prevent loss of overjet

•Or aim for Class III molar finish with lower extractions only

Class III Camouflage - Prescription •-6° lower incisor brackets –helps tip lowers back •Swap right and left lower canines to provide 3 degrees of distal tip

•Increased upper palatal root torque

•But surgery could be a problem?

2. Class II Malocclusions Treatment Decisions and Borderline Cases

Borderline Patients •One of the most difficult decisions facing the clinician is whether the patient with a borderline skeletal discrepancy can be treated by orthodontics alone

•The decision must be made from the very beginning, however, because the orthodontic preparation for surgery differs from the orthodontic treatment for camouflage

•Ill-advised attempts to camouflage problems that are too severe extend treatment time and compromise the final result, on the other hand , unnecessary surgery should be avoided •The problem facing clinicians therefore, is how to decide which patients have the potential to be successfully camouflaged, and which are better surgical candidates

Factors Helpful In Making The Decision In Borderline Cases •General Factors

•Factors specific to the malocclusion

General Factors •The patient’s health status: Are they a good risk for surgery and a general anaesthetic from a health point of view?

•The patients view on the acceptability of surgery

•The specific nature of the patient’s complaint – is it related to the appearance of the dentition or the face?

Factors Specific To The Malocclusion •The vertical skeletal pattern

•Facial aesthetics

•The anteroposterior discrepancy

•Space requirements

•The transverse discrepancy

The vertical skeletal pattern:- In a borderline case one would be more likely to attempt camouflage in a low angle case rather than a high angle case •This is because any molar extrusion as a result of mechanotherapy would be helpful in a low angle case •In a high angle case at the limits of orthodontic treatment any molar extrusion would rotate the mandible downwards and backwards and make both the vertical and anteroposterior discrepancy worse

High Angle Cases •It is worth noting that a lot of these patients have got an increased vertical dimension as they have already experienced vertical growth with posterior rotation of the mandible

•This is likely to continue during treatment in most high angle cases

Facial Aesthetics Consider the prominence of the nose and the nasolabial angle

•The clinician needs to ask the question :-will retraction of the upper incisors achieve a good dental occlusion at the expense of facial aesthetics?

The Size Of The Anteroposterior Discrepancy •Will it be possible to displace the teeth sufficiently on the skeletal bases to disguise the skeletal discrepancy? •Will it be possible to retract the upper incisors into a secure relationship with the lower incisors?

•Would it be appropriate to consider advancement of the lower incisal edges to help this correction?

Space Requirements •Will crowding of the teeth take up all the extraction spaces, including the space needed to reduce the overjet?

•If so then camouflage may be difficult and surgery may be more appropriate

The Transverse Discrepancy •If surgery is needed for treatment of a co-existing transverse discrepancy or skeletal asymmetry then it would probably be easier to tackle the anteroposterior discrepancy during the surgery as well.

Orthodontic Camouflage For Skeletal Malocclusion In Borderline Cases

Acceptable Result When Following Factors Are Present •Average or low maxillary mandibular plane angle with average or reduced face height •Mild anteroposterior skeletal discrepancy •Crowding of less than 4-6mm per arch •Normal soft tissue features – nose lips and chin •No transverse skeletal problem

Poor Result Likely If Patient Has The Following Factors•Long vertical facial pattern with high maxillary mandibular plane angle and increased lower face height •Moderate or severe anteroposterior discrepancy •Crowding greater than 4-6 mm per arch •Exaggerated facial features with prominent nose or chin or obtuse nasolabial angle •If there is a transverse skeletal component to the overall malocclusion

Borderline Cases

In borderline cases if satisfactory aesthetics and functional occlusion can be achieved by either camouflage or surgery then each approach must be carefully explained so that an informed decision can be reached by the patient

Returning to a discussion of the patient’s concerns in the form of a prioritised list often helps to clarify the treatment expectations and suggest the appropriate treatment choice

Extractions For Camouflage And Surgery •The importance of deciding on surgery or camouflage from the outset is further illustrated by the difference in extraction patterns needed in the two approaches

Camouflage for the Class II Patients

•Both upper first premolars are removed to allow retraction of the maxillary anterior teeth •Extraction of the teeth in the lower arch is planned to create space for levelling and alignment •If lower extractions are necessary generally lower second premolars are chosen in an effort to avoid retroclining the lower labial segment and working against the orthodontic camouflage •Class II elastics are helpful

The Surgical Management Of Class II Patient

The extraction pattern for the same patient would be quite different if mandibular advancement was being planned

•The extraction of lower first premolars to align the lower arch and decompensate for proclination of the lower incisors is often necessary

The upper arch is often treated non-extraction, or by the extraction of upper second premolars to avoid retraction of the upper labial segment

•Class III elastics are useful in decompensation Class III treatment and borderline cases

What am I going to cover? •Characteristics

•The early patient –Brief overview of treatment possibilities

•The adolescent patient –Treat now or wait

•Adult patient –Surgical treatment

–Camouflage

Incidence •4% referred Ortho population –Foster and Day 1974 •1-4 % White Caucasians and Swedish population –Ishii et al 1987 •Increased in oriental populations –14% Japanese •48% Of Ortho population (Takada)

Class III Characteristics •Skeletal –Guyer et al 1986 • 56% Maxillary Retrusion

•41% Increased lower face height –Shorter cranial base length and angle

–Ant position of the glenoid fossa

–Straight or concave profile

–Genetic

Skeletal III - Genetic predisposition •Polygenic - Interaction between susceptibility genes and environmental factors –Family pedigrees show monogenic dominant phenotype

–Genes code for growth factors or signalling molecules linked to condylar growth under mechanical strain

–Examples IGF-1, IHH (Indian hedgehog homolg)

–Chromosomes 1p36, 12q23, 12q13, 14q24 •Han Chinese - Li Q et al 2011 –Matrilin- 1 gene in Koreans • Jang et al 2010

Class III Characteristics

Displacement Pseudo Class III, really Class I •Worsens mild Class III tendency •Particularly with overclosure

Soft tissue•Thinner upper lip •Everted lower lip

Dental •Proclined upper incisors •Retroclined lower incisors •Displacement/deviation •Edge to edge/reverse overjet •Cross-bites •Crowded upper arch •Well aligned lower arch •Crowded as retroclines •Upper trapped as erupts into crossbite

Why do patients seek treatment for Class III? •Crooked top teeth

•Bite wrong way

•Prominant chin –Male Vs Female complaints •Problems eating/speaking

•TMD

•Rarely crowded lower teeth

•Parental pressure

What about facial aesthetics? •It is important to consider the facial aesthetics and complaints of the patient

•Most Class III facial complaints cannot be dealt with by braces alone

Why treat early? •Traumatic occlusion –Perio ant displacement of lower incisor

–Tooth mobility

–Direct attrition of crowns •Avoid later treatment?

•Facial appearance/teasing

•Parental pressure

Options for early treatment

•URA

•Chin cup

–Extra oral force directed to the mandible •Functional appliances –FR-3

–Twin block •Traction to TADs and bone anchors

•Simple fixed

•Face mask +/- Expansion……..RMEGrowth Modification

•Functionals not common in the UK –99% Class II div 1

–16% Class III •Frankel FR-3

•Reverse Twin block

•Face mask and EOT

•Chin cup/headgear to the mandible

Frankel FR-3 Ulgen and Firlati 1994 and 1996 •RCT FR-3 Vs Untreated controls

•Dentoalveolar effects –Lower incisors tipped back

–Upper arch expansion •Downward and backward rotation of the mandible

Reverse Twin block •Giles Kidner 14 cases BJO 2003 –Lower labial bow –Bite at maximal retrusion –6 months treatment –Procline ULS retrocline LLS –Same effects as longer FR-3 treatment –Ideal age about 8 years

Simple fixed appliance •Upper 2 by 4 mechanics –Addition of lower 2 by 4 mechanics

–Bonds/band 6’s

–Bond 2-2 •Free occlusion

•Need good OB

•Scope to procline upper & retrocline lower

•Problem principally dentoalveolar

Protraction Headgear

Kim et al., 1999 meta-analysis –Best age 4-14 years!!

–Less effective after 10 years age

–Early better in short term but ? more relapse

–7-8 years optimum

–Without RME longer and more proclination

–+ RME extra 1mm protraction (Baik 1995)

Poor responders Stensland et al., 1988 •Bigger MM (more divergent profile)

•Bigger chin prominence

•Shorter cranial base

•More forward position of the mandible

Changes to Class IIIStensland et al., 1988 •Without exception •Procline ULS/Retrocline LLS •Increase lower face height •Downward and backward rotation of mandible

Most suitable cases Most suitable cases •Deep overbites •A-P and vertical maxillary deficiency •Normal-mild mandibular prognathism •8 years •+ RME •Good Co-operation

Most recent evidence Mandall et al, 2010

•Randomised controlled clinical trial •73 patients –35 facemask (2 lost to follow-up) –38 control (2 lost to follow-up) •3-4 incisors in crossbite •7-9 years old •15 months data taken (even if treatment finished before this) •Bonded RME if posterior crossbite •No retention

Protraction group •SNA protracted 1.4°

•B point moved backwards by 0.7° –Overall difference between groups of 2.6 degrees •Lower labial segment more retroclined –4.9° versus 1.2 ° •Mean overjet improvement of 4.4mm (CG 0.3mm)

The future? – Class III skeletal tractionDentofacial effects of bone-anchored maxillary protraction: A controlled study of consecutively treated Class III patients DeClerck, AJODO 2010 •21 consecutive Class III cases treated pre puberty 18 untreated controls •Showed significant advancement of –maxilla –orbitale –pterygomaxillare. •Restriction of mandibular growth was significant •Significant soft tissue changes reflected skeletal changes

DeClerck - 2010 •Significant improvements in –Overjet 3.8mm (Mandell 4mm)

–Molar relationship 4.8mm –Proclination 1.7˚of the lower incisors •Treated group had 4mm greater advancement of maxillary structures and >2mm favourable mandibular changes compared to untreated controls.

Adolescent Class III Which way to go? Options •Definitive fixed ortho –Ext/Non-Ext •Align the upper arch only •Nothing •Discuss surgery •Review growth

Can we predict growth? •We can predict the predictable

•Male or female

•Age

•Vertical grower

•Family history

•Assume continuation of current pattern

All the other factors! •Severity of the Skeletal Pattern –Incisor compensation •Molar relationship >¼ Unit III

•Family history

•Growth to come

•Amount of overbite

Is there any published guidance? •Kerr et al 1992

•Liverpool study 2003

•Burns et al 2010

Kerr, Miller and Dawber 1992 •Class III – Surgery or orthodontics?

•Retrospective study

•40 subjects

•20 successful camouflage

•20 allocated to surgical treatment

•Pre treat cephs

Kerr, Miller and Dawber 1992 •Greater negative ANB •Smaller ratio of maxillary to mandibular length –shorter maxilla +/- longer mandible •Lower Incisors more retroclined •Smaller Holdaway angle

Thresholds for orthodontic camouflage

ANB -4° Holdaway angle 3.5° Lower Incisors 83° Max:Mand 0.78 +

Clinical and ceph variables to determine camouflage or surgery •Kong 2003 - Retrospective study of 42 cases Liverpool University Dental Hospital –21 surgical

–21 camouflage •Outcome measures –Pre treat cephs, sm’s,

–pt preferences

Camouflage Vs surgery •Results Significant differences P<0.05

–Age

–Non dental complaints

–Overjet

–Inclination of the LLS (80°)

–Angle ANB (-1)

–Holdaway angle (4.5°)

–Ratio of length of maxilla to mandible (0.95)

•Logistic regression showed 83% of the treatment planning decision predicted by –Non dental complaints

–Angle ANB

–Inclination of the LLS

Class III camouflage treatment: What are the limits? Burns et al, 2010 AJODO •Retrospective study •30 non-extraction treated Class III pts (12.4 + 1 yrs) compared to untreated controls •Looked at Skeletal, dental and ST changes assessed using cephs. • Quality assessed using PAR •Changes in gingival attachment level during tx assessed using SM’s

•Wits Txd Grp 1.2 mm + 0.1mm, CG -0.5mm +0.3mm. •PAR improved from 33.5 to 4.1. •Ging att level: No sig diff between txd and CG.

•ANB angle did not improve with camouflage tx. •Upper and lower limits for incisal movement to compensate were –Uppers 120° to SN line

–Lower 80° to the mandibular plane.

•Align upper accept lower – or delay starting the lower arch •Maintain OJ •Centreline •Retain++ •Avoid lower arch extractions

Class III Camouflage - mechanics •Extraction pattern –Upper 5’s lower 4’s –Four first premolars –Non-Extraction •-6° lower incisor brackets •Swap right and left lower canines to allow distal tip •Upper rectangular lower round wire

Extraction of a lower incisor •Not ideal for adolescent patients

•Bolton discrepancy

•Centre line problems

•Buccal segment fit

•Permanent retention required

The typical surgical case Later presentation •Growth has finished •Significant dental and skeletal Class III •C/O –prominent chin –Teeth bite the wrong way round –Crooked teeth –Difficulty eating/TMD •Very compensated incisors

Class III surgical preparation •Decompensation –Joint planning and decide how much movement –It is not moving the incisors to normal angles –Incisors are positioned to facilitate surgery –Small movement 1 jaw, small reverse overjet •Limit decompensation –Bimax large reverse overjet •maximal decompenation

•Maintain upper incisor torque for radial fit –Proclined & Moderate to severe crowding upper extractions •Lower incisor torque –can hamper decompensation in non crowded arch

–If de-crowding already tendency for incisors to come forwards

–-6 degrees easily taken out by adding torque

–Invert brackets if lower spacing

–Consider lower extractions only if want to limit surgical movement

Surgical Class III… MBT’s achilles heel? •Arch expansion –Consider SARPE for bilateral crossbites

–can be difficult to gain arch co-ordination –Upper additional buccal root torque –Lower reduced lingual crown torque •Using zero torque canines helps develop upper arch width

In summary Treat or not…? •Early –A short burst of treatment only –Good evidence of some useful effect of face mask –Don’t burn out co-op –Retain with an overbite

Adolescent –Mild III •With favourable features •Pseudo Class III

–Moderate/Severe + Growth •Delay •Align upper only •Don’t extract in the lower

Adult –Definitive options without worry of growth –Surgery if complaint includes facial aesthetics –Camouflage •Consider lower incisor as extraction option –Align only with permanent retention

Take home messages

•Lip retracts and NLA increases when incisors retracted –Lip retraction approx 2mm when 4’s extracted

–NLA increase approx 1.5-2 degrees per mm of incisor retraction

•Lips >3mm retrusive E-Plane less attractive

•Thin lips effected more than thicker lips

•Significant individual variation

•Includes the effects of growth

Usual brackets MBT lower incisors •-6 degree labial crown torque •Great to resist forward movement in non-extraction cases •Lingually placed lower incisors brings root forwards

Problems with -6° •Extraction cases –Lower incisors can dump back into space during space closure

–Deepen OB –Worsen overjet –Offers poor anchorage when trying to resist lingual movement •Hypodontia/microdontia •Lower first molar extraction cases –Lots of space to close in a lower arch

Problems with -6 incisors •Class III surgical cases –Decompensation when lower arch space •Gingival dehiscence –Encourages mid and apical portion of roots forwards and potentially out of the bone •Lower incisor extraction cases

–3 incisors fill less space and make fit with upper arch difficult

How overcome? Need to reinforce lower labial segment anchorage •Place labial crown torque •Use of Class II elastics •Lower anterior TADs •Tip edge breaks

Invert the lower incisors to give +6 degrees torque

Effect •Begins only when in rectangular wire •Need to figure of 8 tie to overcome 10 degrees slop in torque •Less uprighting •Tent pegs the lower incisors forwards

Cases at greatest risk of ‘dishing in’

•Anatomy –Lips already 3mm or more retrusive to E-plane

–Low angle, nose chin prominence

–High angle, lack of chin projection

–Obtuse Nasolabial angle

–Thin soft tissues (Merz Scale)

Cases at greatest risk of ‘dishing in’•Treatment –Extraction of first premolars

–Large spaces to close

–Leaving the upper incisors undertorqued •Heavy forces overpowering the prescription

•Low torque upper brackets

•Undersized archwires, particualrly round wires