COOS Journal Vol-S Issue-2, September 2013

FUNCTIONAL TREATMENT OBJECTIVE- ROLE INTWO PHASE TREATMENT

Dr. G. Shivaprakash BDS, MDS,Professor & HOD, Dept. of Orthodontics, College of Dental Sciences, Davangere.Email: drshiva64@gmail.com----~--------~

ABSTRACT:A distal occlusion exerts restraining occlusal forces on the mandibular dentition, and the maxillary dental arch isnarrow from distal positioning of the lower dentition. These factors may not allow the mandible to grow to its fullgenetic potentiaL In severe class II .In the hands of an experienced clinician, full time functional appliances are mostefficient in correcting severe class II malocclusion than conventional fixed appliance techniques without mandibularpropulsion. This is especially true when the treatment is timed to coincide with the pubertal growth spurt. A casesuccessfully treated with two phase treatment to meet the functional treatment objective is presented.

KEYWORDS: Functional appliance, Visual DISCUSSIONtreatment objective, Two phase, Twin blockINTRODUCTION: Functional appliances have beencriticized because of an unpredictable response and alack of long term influence on the facial growth.Although it is not possible to grow beyond theindividual genetic potential, environmental factorsplaya major role in perpetuating a severe class IImalocclusion, A distal occlusion exerts restrainingocclusal forces on the mandibular dentition, and themaxillary dental arch is narrow from distal positioningof the lower dentition. These factors may not allow themandible to grow to its full genetic potentiaL In severeclass II malocclusions the tongue is back in the throatbecause it is contained within a retrusive lower dentalarch. This pattern has negative effects on the healthand metabolism of these patients.Expanding the maxilla and advancing the mandibleunlock the malocclusion. In Functional terms,advancing the mandible advances the tongue and, ascephalometric records confirm, increase in the airway.This is fundamental physiological change withbeneficial effects that can be seen clearly within 2 or 3months of commencing treatment. In the hands of anexperienced clinician, full time functional appliancesare most efficient in correcting severe class IImalocclusion than conventional fixed appliancetechniques without mandibular propulsion. This isespecially true when the treatment is timed to coincidewith the pubertal growth spurt, but equally appropriatein early treatment.

Functional Treatment Objective:The goal of functional therapy is to elicit aproprioceptive response in the muscles and ligaments,and as a secondary response, to influence the pattern ofbone growth to support new functional environment forthe developing dentition. The best results are obtainedby combining orthodontic and orthopaedic techniques,and the future of orthodontics lies in advancingorthopaedic techniques towards a holistic approach toreduce skeletal discrepancies and restore normalfunction in promoting normal growth anddevelopment. 1

Two phase orthodontic treatment is a very specializedprocess that encompasses jaw and facial changes, aswell as tooth straightening. The major advantage of twophase treatment is to maximize the opportunity toaccomplish the ideal healthy, functional, aesthetic andcomfortable result that will remain stable. In somecases, interceptive treatment prevents adult toothextractions or major jaw surgery.Interceptive orthodontic care is one of the mostrewarding treatment options that can be offered to thepatients. Interceptive care is exactly that, intercepting aproblem before it gets out of hand. Treatment occurs ata younger age than conventional orthodontic care and isnot typically as long either.The idea is to shift the teeth, manipulate the growth,create space for unerupted teeth, break habits andprevent trauma before it is too late. Children in the agegroup of 8- 11 years are best suited for this sort oftreatment. They are flexible, compliant and theirgrowth potential is still maximum.

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Treatment usually lasts forI4-I8 months after whichthe child is monitored and the decision as to the needfor the second phase is made. Most children willrequire a second, more comprehensive phase oftreatment in order to create a completely stable,functional and aesthetic occlusion. The second phaseusually begins once most of permanent teeth haveerupted. This phase usually requires less than 18months with braces on all the teeth. This follows withretention protocol.

The American Association of Orthodontistsrecommends all children be seen by an orthodontist atage 7. By age 7 the permanent teeth are starting' to comein and we can tell at this point if a patient has adequatespace for the remaining permanent teeth. If there is asignificant problem with crowding, steps can be takento facilitate the eruption of the permanent teeth. Also, aperson's jaw relationship is pretty much established atthis point or is starting to be established. This is a greatopportunity to see if there is an imbalance in the jawrelationship and correct it early before it becomes asignificant problem. In summary, early screening canhelp prevent more complicated treatment later.

~",----~_.AFig.I. A,B -Shows Positive visual treatment objective.

Twin block is fundamentally a pair of upper and lowerplates, which has occlusal bite blocks that interlock themandible in a forward posture and yet permitmandibular movements. It is the most widely acceptedand popular removable functional appliance. Appliancedesigned by William Clark in 1977.According to Clarkthe occlusal inclined planes were the fundamentalfunctional mechanism for the natural dentition. And theinclined planes play an important role in determiningrelationship of the teeth as they erupt. The aim of theinclined planes of the bite blocks in the twin block istomodify these inclined planes and cause more favourablegrowth pattern (Fig .2).One major advantage of twin block is that it could beworn 24 hours, hence the masticatoryforces aretransmitted via the applaince to the dentition fromwhere they are transmitted to the bony trabaculeaccording to Wolf's law, hence influencing the rate ofgrowth and the supporting structure of the supprtingbone.'

Benefits of early class II treatment:In an RCT trial preadolescent children with over jetgreater than 7 mm were randomly assigned toobservation only in cases treated with head gear andfunctional appliances compared with nontreatedcontrol group. The option of orthognathic surgery waspresented more often in the cases of children who didnot undergo early treatment, but surgery was acceptedor was still being considered almost as frequently in theprevious headgear group as in the controls, less often inthe patients previously treated with functionalappliances 2.

What You See Is What You Get:Clinical diagnosis has the advantage of providing anaccurate prediction of the three dimensional change inthe facial contours as a result of mandibularadvancement and is more important than lines andangles drawn on a cephalometric film. This does notnegate or diminish the value of cephalometric analysis,but rather adds a three dimensional view to support andconfirm the diagnosis (Fig 1). Fig.2

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A 10yrs. old female patient reported with the chief compliant of forwardly placed upper front teeth. On clinicalevaluation case was diagnosed as skeletal Class II with normal maxilla and deficient mandible. As the patientshowed all features favourable for functional appliance therapy most compliant appliance Twin block wasgiven. The duration for the treatment with twin block and followed by non-extraction fixed mechanotherapywith straight wire .022 MBT mechanics was 2 years 6 months (Fig.3, 4).

Fig 3.A-C :Pre treatment extraoral, Profile, Smile andPositive visual treatment objective.

D,E : Pre treatment Intra oral Frontal, With Twin Block appliance(Phase I), F: Post functional( Bigining of Phase II).

G, H: Post Treatment intra oral, I, J: Post treatment extra 'Oral.

Fig 4. Silhouette of progress(Pre, Post functional, Post treatment)

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Future direction of functional appliances:Bilological research is making rapid progress midentifying the controlling factors m growthmodification. The landmark article "Functionalappliance therapy accelerates and enhances condylargrowth" is not the optimistic evaluation of anenthusiastic clinician. Rather, it represents arevolution level to examine and define the chemicaland biological factors involved m growthmodification.Replicating mesenchymal cells have been identified inthe condyle and glenoid fossa during mandibularforward positioning'>. Scientific study .confirmsimportance of the genetic control factor. Patients witha high mesenchymal cell count would respond well tofunctional mandibular advancement, whereas a lowcell count would produce a poor mandibular growthresponse.In future, the mesenchymal cell count from the bloodsample may define a patients potential to respond tofunctionalmandibular advancement. Clinicians maybe able to predict the individual patient's response tofunctional therapy with the information from a bloodtest or a salivary smear.

CONCLUSION:The challenge of the functional appliance therapy is tomaximize the genetic potential of the growth of theindividual and guide the growing face and developingdentition towards a pattern of optimal development.REFERENCES:1. Current Therapy in Orthodontics, Ravindra Nanda,Sunil Kapila Mosby 2010, Pg87-102.2. Benefits of early Class II treatment: Progress reportof a two - Phase randamized clinical trial, J.F.CamillaTulloch, Ceil, Philips, William Proffit, Am J OrthodDentofacial Orthop 1998; 113:62-72.3. Twin Block Functional Therapy, by William JClark, Mosby,2002.4. Rabie ABM et al: Functional appliance therapyaccelerates and enhances condylar growth, Am JOrthod Dentofacial Orthop 123:40-48,2003.5. Rabie ABM et al: Replicating mesenchymal cells inthe condyle and the glenoid fossa during mandibularforward posturing, Am J Orthod Dentofacial Orthop123:4-57,2003