Functional ApplianceFunctional ApplianceMejMej (B) Dr Akbar S (B) Dr Akbar S HussinHussinBDS (Malaya), Grad Dip BDS (Malaya), Grad Dip ClinClin Dent (Adelaide)Dent (Adelaide)D D ClinClin Dent (Dent (Orthodontics)(AdelaideOrthodontics)(Adelaide), ), MOrthMOrth RCS (Edinburgh)RCS (Edinburgh)

Functional ApplianceFunctional Appliance

A variety of fixed or removable A variety of fixed or removable appliancesappliancesDesigned to ‘reposition’ the mandibleDesigned to ‘reposition’ the mandibleLeading to muscle stretching Leading to muscle stretching Forces transmitted to dentition and Forces transmitted to dentition and basal bonebasal bone

Functional ApplianceFunctional Appliance

Muscular forces generated by altering Muscular forces generated by altering the the mandibularmandibular position position sagitallysagitally & & verticallyverticallyResulting in orthodontic & Resulting in orthodontic & orthopaedicorthopaedicchangeschangesMost effective skeletal Most effective skeletal ClCl II II txtx((retrognathiaretrognathia))Most effective during active growthMost effective during active growth

Bishara, 1989

Functional ApplianceFunctional Appliance

Growth modification involving Growth modification involving functional appliances have the functional appliances have the objectives of acting as a therapeutic objectives of acting as a therapeutic biomechanical interference to cause biomechanical interference to cause clinically significant morphological clinically significant morphological alterations in a growing child’s alterations in a growing child’s dentition and craniofacial skeletondentition and craniofacial skeleton

Vig & Vig, 1986

The The First First Functional Functional ApplianceAppliance

BreastfeedingBreastfeeding

Places beneficial Places beneficial orthopaedicorthopaedic forces on forces on the jawsthe jawsHelps to develop airways (pacifier Helps to develop airways (pacifier suckling deforms airways)suckling deforms airways)Cultivates positive down & forward Cultivates positive down & forward growing forces required by both upper growing forces required by both upper & lower jaws& lower jaws

Page, 2001

BreastfeedingBreastfeeding

Suckling forces generally act to form Suckling forces generally act to form wide dental archeswide dental archesSuckling also promotes good swallow Suckling also promotes good swallow muscle tone which assists proper jaw muscle tone which assists proper jaw and airway developmentand airway development

Page, 2001

Functional AppliancesFunctional Appliances

AndreasenAndreasen ActivatorActivatorBionatorBionatorFrankleFrankle Functional Regulator FR2Functional Regulator FR2HarvoldHarvold ActivatorActivatorTeuscherTeuscher ApplianceApplianceClark Twin BlocksClark Twin BlocksHerbstHerbst ApplianceAppliance

Frankel appliance

Clark Twin Blocks

Herbst Appliance

Timing of TxTiming of Tx

Effective during active growthEffective during active growthThe faster the growth, the faster the The faster the growth, the faster the response, the shorter the response, the shorter the txtx timetimeMost common time for Most common time for txtx –– pubertal pubertal growth spurtgrowth spurtEarly Early txtx -- 99--10 yrs10 yrsDefinitive Definitive txtx -- 1212--13yrs13yrs

Early Early txtx

To intercept a developing problemTo intercept a developing problem–– Improve aestheticsImprove aesthetics–– Decreased trauma risk to anterior teethDecreased trauma risk to anterior teeth–– Early correction of deleterious habitEarly correction of deleterious habit–– Improve eventual prognosisImprove eventual prognosis–– Decrease length of definitive Decrease length of definitive txtx

Twelftree, 1998

Early Early txtx

Ideal Ideal txtx time time –– when four upper when four upper incisors have eruptedincisors have eruptedMost common Most common –– correction of large OJ correction of large OJ caused by caused by retrognathicretrognathic mandiblemandibleTx Tx -- Reposition mandible forwardReposition mandible forwardTx discontinued once correction Tx discontinued once correction achievedachievedSome relapse will occurSome relapse will occur

Definitive Definitive txtx

During pubertal growth spurtDuring pubertal growth spurtUsually all permanent teeth have Usually all permanent teeth have eruptederuptedCorrection of maxCorrection of max--mandmand discrepancy discrepancy usually followed by fixed appliance usually followed by fixed appliance txtxFunctional appliance may also be used Functional appliance may also be used during fixed appliance during fixed appliance txtx

Effects of TxEffects of Tx

SkeletalSkeletal–– CondylarCondylar growthgrowth

Increased Increased condylarcondylar remodellingremodellingIncreased Increased glenoidglenoid fossafossa remodellingremodelling

–– Increased lower face heightIncreased lower face height

Ruf et al., 2002

Effects of TxEffects of Tx

DentoalveolarDentoalveolar–– RetroclinationRetroclination of upper incisorsof upper incisors–– ProclinationProclination of lower incisorsof lower incisors–– MesialMesial eruption of lower posterior teeth eruption of lower posterior teeth

Mode of Action of Mode of Action of Functional AppliancesFunctional Appliances

DentoalveolarDentoalveolar changeschangesRestriction of forward growth of maxillaRestriction of forward growth of maxillaStimulation of Stimulation of mandibularmandibular growth beyond growth beyond what is normally seen in growing childrenwhat is normally seen in growing childrenRedirection of Redirection of condylarcondylar growth from upward growth from upward and forward directed growth to posterior and forward directed growth to posterior direction direction

Mode of Action of Mode of Action of Functional AppliancesFunctional Appliances

Changes in neuromuscular anatomy Changes in neuromuscular anatomy and function that would induce bone and function that would induce bone remodellingremodellingAdaptive changes to Adaptive changes to glenoidglenoid fossafossalocation to a more anterior and vertical location to a more anterior and vertical directiondirection

DentoDento--Alveolar EffectsAlveolar Effects

DentoDento--alveolar changes alveolar changes –– 6060--70%70%–– Inhibition of downward and forward Inhibition of downward and forward

eruption of maxillary teetheruption of maxillary teeth–– RetroclinationRetroclination upper incisorsupper incisors–– ProclinationProclination of lower incisorsof lower incisors

OrthopaedicOrthopaedic EffectsEffects

OrthopaedicOrthopaedic changes changes –– 3030--40% 40% –– CondylarCondylar growthgrowth

Increased Increased condylarcondylar remodellingremodellingIncreased Increased glenoidglenoid fossafossa remodellingremodelling

–– Increased lower facial heightIncreased lower facial height

Clark Twin BlocksClark Twin Blocks

Consists of separate upper & lower Consists of separate upper & lower appliances appliances More comfortable & aestheticMore comfortable & aestheticPt able to eat & speak without Pt able to eat & speak without restriction of tongue, lip & mandible restriction of tongue, lip & mandible movements movements Pt able to cooperate to wear appliance Pt able to cooperate to wear appliance 24hrs 24hrs

Fricker, 1998

Clark Twin Blocks

Clark Twin BlocksClark Twin Blocks

Constructed to a protrusive biteConstructed to a protrusive biteWith appliances in mouth, pt not able With appliances in mouth, pt not able to occlude in former distal positionto occlude in former distal positionMandible forced to adopt protrusive Mandible forced to adopt protrusive bitebite

Clark Twin BlocksClark Twin Blocks

Block ~ 5Block ~ 5--6mm thick between molars 6mm thick between molars (mouth open beyond freeway space) (mouth open beyond freeway space) so that pt cannot return to former so that pt cannot return to former distal occlusiondistal occlusion

Orthodontics and DentofacialOrthopaedics:

A Comprehensive Textbook

CTB designCTB design

BaseplateBaseplate–– Upper Upper –– up to 6sup to 6s–– Lower Lower –– up to ½ cusps of 5sup to ½ cusps of 5s

Expansion screwExpansion screw–– Necessary only when compensatory Necessary only when compensatory

expansion needed to accommodate lower expansion needed to accommodate lower arch as the mandible translates forwardarch as the mandible translates forward

CTB designCTB design

RetentionRetention–– Upper Upper

Adams clasps at upper 6s, 4sAdams clasps at upper 6s, 4s

–– Lower Lower Adams clasps at lower 4sAdams clasps at lower 4sBall clasps at lower anterior teethBall clasps at lower anterior teeth

CTB designCTB design

Occlusal blocks Occlusal blocks –– Upper Upper

From 6s up to From 6s up to mesialmesial of 5sof 5s

–– Lower Lower From midFrom mid--cusp of lower 5s to cusp of lower 5s to mesialmesial of lower 4of lower 4

–– Occlusal inclined plane Occlusal inclined plane –– 7070oo

Orthodontics and DentofacialOrthopaedics:

A Comprehensive Textbook

Orthodontics and DentofacialOrthopaedics:

A Comprehensive Textbook

Appliances for Cl II div 2

Bite RegistrationBite Registration

Boxing wax

Wooden spatula

Hot water

Pt bites with incisors edge to edge.

~ 6mm separation of molars

Fold wax lengthwise twice to 1/3 size

Do not flatten

Turn folded wax lengthwise and fold once with spatula in between

Crimp lower edge against spatula

Do not flatten

Pt bites with incisor edge to edge

Stages of TxStages of Tx

11stst stagestage–– To correct To correct anteroposterioranteroposterior relationship from relationship from

skeletal skeletal ClCl II to II to ClCl I I

22ndnd stagestage–– Settling of posterior teeth into occlusion from Settling of posterior teeth into occlusion from ClCl

II molar relationship to II molar relationship to ClCl II–– Upper bite blocks trimmed to allow eruption of Upper bite blocks trimmed to allow eruption of

lower posterior teethlower posterior teeth–– Lower bite blocks trimmed to level Lower bite blocks trimmed to level occlusalocclusal plane plane

Orthodontics and DentofacialOrthopaedics:

A Comprehensive Textbook

Stages of TxStages of Tx

In deep bite cases, trim blocksIn deep bite cases, trim blocksIn reduced or open bite cases, do not In reduced or open bite cases, do not trim blockstrim blocks

Tx ProtocolTx Protocol

FullFull--time wear for first 6 monthstime wear for first 6 months–– Worn at all times including eating and Worn at all times including eating and

sleepingsleeping–– Removed only for brushing of teethRemoved only for brushing of teeth–– Not to be worn during sporting activitiesNot to be worn during sporting activitiesNightNight--time wear for next 6time wear for next 6--9 months9 monthsFinishing may be undertaken with Finishing may be undertaken with fixed appliancesfixed appliances

Before

After

Pre CTB

Post CTB

Advantages of CTB TxAdvantages of CTB Tx

Comfortable Comfortable –– pt able to eat, speakpt able to eat, speakAesthetic Aesthetic –– appliance not obviousappliance not obviousMandible able to move freelyMandible able to move freelyCompliance Compliance –– can be removable or can be removable or temporarily cementedtemporarily cementedImproved facial appearanceImproved facial appearanceNormal speechNormal speech

Advantages of CTB TxAdvantages of CTB Tx

Easy to manage clinicallyEasy to manage clinicallyNot easily breakableNot easily breakableAllows independent arch developmentAllows independent arch developmentImprovement of vertical heightImprovement of vertical heightAllows for asymmetrical correctionAllows for asymmetrical correctionRapid & efficient correction of skeletal Rapid & efficient correction of skeletal discrepancy & malocclusion discrepancy & malocclusion

Advantages of CTB TxAdvantages of CTB Tx

Tx can be undertaken from childhood Tx can be undertaken from childhood to early adulthoodto early adulthoodMay be integrated with fixed May be integrated with fixed appliancesappliancesTx of TMJ dysfunction Tx of TMJ dysfunction –– splint allows splint allows displaced disc to be recaptureddisplaced disc to be recapturedTx of sleep Tx of sleep apnoeaapnoea –– increases airway increases airway spacespace

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