Functional Functional appliancesappliances

BackgroundBackground

Functional appliances are conceptually Functional appliances are conceptually based on Moss’ functional matrix theorybased on Moss’ functional matrix theory

Functional matrix theory proposes that Functional matrix theory proposes that functional matrices, tissues like muscles functional matrices, tissues like muscles and glands influence skeletal units such and glands influence skeletal units such as jaw bones and ultimately control their as jaw bones and ultimately control their growth growth

Form follows functionForm follows function

Functional appliance Functional appliance typestypes

Orthodontic functional appliances may be Orthodontic functional appliances may be active or passive:active or passive: Active appliances reposition the mandible so Active appliances reposition the mandible so

that the condyle is forced out of the glenoid that the condyle is forced out of the glenoid fossa and this in turn is thought to stimulate fossa and this in turn is thought to stimulate the posterior/superior growth of the condylethe posterior/superior growth of the condyle

Passive appliances act by repositioning the Passive appliances act by repositioning the musculature associated with the mandible so musculature associated with the mandible so that the jaw bone itself responds by growing that the jaw bone itself responds by growing to the new equilibrium positionto the new equilibrium position

Passive functional Passive functional appliancesappliances

FrankelFrankel

Active functional Active functional appliancesappliances

Fixed active functional appliancesFixed active functional appliances Herbst Herbst

Active functional Active functional appliancesappliances

Removable active functional Removable active functional appliancesappliances BionatorBionator

Active functional Active functional appliancesappliances

Removable active functional Removable active functional appliancesappliances Woodside activatorWoodside activator

Active functional Active functional appliancesappliances

Removable active functional Removable active functional appliancesappliances Twin-block applianceTwin-block appliance

Duration and timing of Duration and timing of wearwear

Functional appliance treatment should be Functional appliance treatment should be started before the pubertal growth spurtstarted before the pubertal growth spurt

This is the time when the mandible may This is the time when the mandible may exhibit increased growth which may be exhibit increased growth which may be influencedinfluenced

Functional appliances should be worn for Functional appliances should be worn for at least 10-12 hours a dayat least 10-12 hours a day

These appliances should be worn at These appliances should be worn at nighttime as this is when growth takes nighttime as this is when growth takes placeplace

Evidence of clinical Evidence of clinical effectivenesseffectiveness

A Cochrane review, published in 2008, A Cochrane review, published in 2008, studied orthodontic treatment for studied orthodontic treatment for prominent upper teeth in childrenprominent upper teeth in children The study concentrated on primary outcomes The study concentrated on primary outcomes

including the prominence of upper front teeth including the prominence of upper front teeth and the relationship between upper and lower and the relationship between upper and lower jawsjaws

The secondary outcomes compared included The secondary outcomes compared included self-esteem, injury to teeth, joint problems, self-esteem, injury to teeth, joint problems, patient satisfaction and the number of patient satisfaction and the number of appointments during active treatmentappointments during active treatment

Evidence of clinical Evidence of clinical effectivenesseffectiveness

It has been shown that when front teeth stick It has been shown that when front teeth stick out by more than 3mm, they are twice as likely out by more than 3mm, they are twice as likely to be injuredto be injured

The Cochrane review included eight clinical The Cochrane review included eight clinical trials, based on data from 592 patients with trials, based on data from 592 patients with Class II Division 1Class II Division 1

Three trials, evaluating 432 patients, compared Three trials, evaluating 432 patients, compared early treatment (before the age of 10) with a early treatment (before the age of 10) with a functional appliance compared to no treatmentfunctional appliance compared to no treatment

It was found that functional appliance It was found that functional appliance treatment resulted in significant decreases in treatment resulted in significant decreases in overjet and the ANB angleoverjet and the ANB angle

Evidence of clinical Evidence of clinical effectivenesseffectiveness

When the same patients received the When the same patients received the second phase of treatment (full fixed second phase of treatment (full fixed treatment) and when they were compared treatment) and when they were compared to patients who only received one phase of to patients who only received one phase of treatment in adolescence, it was found that treatment in adolescence, it was found that there were no significant differencesthere were no significant differences

Other reviews have also found that Other reviews have also found that although the overall effect of early although the overall effect of early treatment was not significant, the patients treatment was not significant, the patients did have a milder malocclusion at the start did have a milder malocclusion at the start of full fixed treatmentof full fixed treatment

Evidence of clinical Evidence of clinical effectivenesseffectiveness

A systematic review by Cozza et.al. A systematic review by Cozza et.al. included 18 retrospective longitudinal included 18 retrospective longitudinal controlled clinical trialscontrolled clinical trials

It was found that functional appliances It was found that functional appliances did result in a significant elongation of did result in a significant elongation of mandibular length (>2mm)mandibular length (>2mm)

It was concluded that the effect of growth It was concluded that the effect of growth modification is the greatest during the modification is the greatest during the pubertal growth peakpubertal growth peak

What does this mean?What does this mean?

According to the evidence one should not According to the evidence one should not use functional appliances as they are not use functional appliances as they are not necessarily more efficient than one phase necessarily more efficient than one phase treatmenttreatment

Should we rely only on evidence in Should we rely only on evidence in guiding our clinical decisions?guiding our clinical decisions?

I would argue that although sound I would argue that although sound scientific evidence is the most important scientific evidence is the most important aspect of clinical practice, it is not the aspect of clinical practice, it is not the only factor to consideronly factor to consider

What does all this mean?What does all this mean?

Indeed, care for our patients extends Indeed, care for our patients extends beyond all the evidence availablebeyond all the evidence available

True care also includes:True care also includes: HonestyHonesty EmpathyEmpathy Being genuineBeing genuine Patient centered approach Patient centered approach

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2007/08/maxyawns.jpg2007/08/maxyawns.jpg http://imagecache2.allposters.com/images/146/PP0195.jpghttp://imagecache2.allposters.com/images/146/PP0195.jpg http://www.nimrodental.co.uk/appliances/media/http://www.nimrodental.co.uk/appliances/media/

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References References Harrison JE, O’Brien KD, Worthington HV. Orthodontic treatment for Harrison JE, O’Brien KD, Worthington HV. Orthodontic treatment for

prominent upper front teeth in children (review). The Cochrane prominent upper front teeth in children (review). The Cochrane Collaboration. John Wiley & Sons, 2008.Collaboration. John Wiley & Sons, 2008.

Nguyen QV, Bezemer PD, Habets L, Prahl-Andersen B. A systematic Nguyen QV, Bezemer PD, Habets L, Prahl-Andersen B. A systematic review of the relationship between overjet size and traumatic dental review of the relationship between overjet size and traumatic dental injuries. European Journal of Orthodontics 1999;21(5):503-515.injuries. European Journal of Orthodontics 1999;21(5):503-515.

Pavlow SS, McGorray SP, Taylor MG, Dolce C, King GJ, Wheeler TT. Pavlow SS, McGorray SP, Taylor MG, Dolce C, King GJ, Wheeler TT. Effect of early treatment on stability of occlusion in patients with Effect of early treatment on stability of occlusion in patients with Class II malocclusion. American Journal of Orthodontics and Class II malocclusion. American Journal of Orthodontics and Dentofacial Orthopedics 2008;133:235-244.Dentofacial Orthopedics 2008;133:235-244.

Dolce C, McGorray SP, Brazeau L, King GJ, Wheeler TT. American Dolce C, McGorray SP, Brazeau L, King GJ, Wheeler TT. American Journal of Orthodontics and Dentofacial Orthopedics 2007;132:481-Journal of Orthodontics and Dentofacial Orthopedics 2007;132:481-489.489.

Cozza P, Baccetti T, Franchi L, De Toffol L, McNamara JA. Mandibular Cozza P, Baccetti T, Franchi L, De Toffol L, McNamara JA. Mandibular changes produced by functional appliances in Class II malocclusion: a changes produced by functional appliances in Class II malocclusion: a systematic review. American Journal of Orthodontics and Dentofacial systematic review. American Journal of Orthodontics and Dentofacial Orthopedics 2006;129:599.e1-599.e12.Orthopedics 2006;129:599.e1-599.e12.