Answer… Facial Balance Functional Appliances

Vincent E. Mascia, D.D.S. Vincent E. Mascia, D.D.S

Traditional form of treatment Wouldn’t it be nice if we could…

• Influence growth • Had a simple appliance to use • One that is hygienic • Possibly avoid surgery • Influence occlusion • Influence facial esthetics • Economical to use

Problem… Facial Esthetics Functional Appliance

1 Working definition Why treat ?

• Functional Appliance - a device that alters a • Possible pre-disposition to disease patient’s functional environment in an • May lead to jaw dysfunction attempt to influence and permanently (TMD,Speech,Mastication) change the surrounding hard tissue . • Facial esthetics with psychological implications • Single or multiple tooth damage

Percentage of in early History of development of mixed dentitions functional appliances

Study by Keski-Nisula et al Dec 03 • Robin 1902- monobloc • 92.7 % some disharmony present • Andresen 1908- Activator • 67.7% malocclusion • Herbst 1934- Herbst • 52.4% Class ll type • Balters 1960- Bionator • 1.5% Class lll type • Bimler 1964 – Bimler • 30.1% Asymmetrical Bite • Frankel 1967- Frankel • Clark 1977-Twin Block

Historical biases of Europe and Percentage of malocclusions America on functional appliances

Study by U.S.P.H.S. 1970 European • 75% some disharmony present • Functional approach most biocompatible • 40% malocclusion • Mechanical force deemed unbiologic • 20% Class ll type American • 5% Class lll type • European social system excluded extensive fixed • 4% Open Bite appliance therapy • Question of precision of results

2 Potential advantages of functional appliances Bone suspension bridge

• Enlarge transverse width of arches to relieve crowding • Diminish adverse fixed appliance problems (gingival proliferation, TMD, decalcification, extractions-Ismail AJO 2002) • Reduced time with braces? (Profit-AJO, June 2002) • Reduce or eliminate dysfunctional habits • Tx of TMD? (Pancherz AJO Aug 1999)

Growth Hypothesis Role of muscles

• His 1874- Physiology of the plasticity of bone (biologic structures may be altered) Study by McNamara with primates 1975 • Moss 1960,1962,1997- Regional and local factors • Masticatory muscles and appropriate orthopedic play a role in cranio-facial morphogenesis- appliances can modify the rate and amount of Functional Matrix Theory condylar growth • Voudouris 2000- Factors of displacement, • LPM activity may induce condylar deposition viscoelasticity, transduction-Growth Relativity Study by Voudouris- AJO March 2000 • Mao &Nah 2004- Growth and development is the net result of environmental modulation of genetic Growth Relativity Hypothesis- Three factors of inheritance displacement, several direct viscoelastic connections, and transduction of forces

Facial Growth Spurt Role of glenoid fossa

Voudauris 1988 • Beginning of puberty or menstruation • Fossa is altered and brought forward by • Evaluated by age, tooth eruption, height, mandibular advancement ossification of hand/wrist bones on Ruf et al- AJO 1999 x-ray • The increase in mandibular to be a result of condylar and glenoid fossa remodeling Rabie et al –AJO 2002 • Forward mandibular positioning causes significant increases in vascularization and new bone formation in the glenoid fossa

3 Factors influencing maxillary growth Problem of controls

• Maxillary sutures • Varied response of children • Subperiosteal bone deposition • Individual basis • Nasal septum • All factors not predictable • STH (Somatomedin) • Role of “Evidence Based Research” • Ligaments and muscles

Factors influencing mandibular growth Advancement stability

Study with rats • Cranium positioning Functional advancements at different ages and • Condylar cartilage occlusions • Muscles (LPM ?) Stable Results • Treatment continues until growth stops • TMJ disc • Continued growth possible with locked-in • STH (Somatomedin) occlusion • Other factors Unstable Results Continued growth with imprecise occlusion

Extrapolation of studies to Does the mandible actually grow? clinical experience

Sample • Treatment with young patients- correct and • Panchez-changes direction hold • Stutman-yes • Treatment with older growers- establish a • Mills,Janson-no class l in permanent dentition to lock-in • Treatment with non growers-not rec

4 Arch width stability Adult TMD and Bionator

Study by Sillman,Baume,Moorrees • Night time wear • Lower canine most stable • Reduces bruxism and clenching • 2-5 mm change in maxillary molar width • Relaxes LPM during sleep post-eruption • Long term use needed • Premolars vary

Indications for functional Optimum timing appliances

• Increase of STH (Somatomedin) • Well aligned dental arches • Increase of sex hormone • Posterior positioned mandible • High growth rate • Non severe skeletal discrepancy • 8-10 years for removable type • Lingual tipping of mandibular incisors • 11-13 years fixed type • Proper patient selection Note- Most efficient in permanent dentition- Barton- AJO Sept 1997 (Profit, Pancherz AJO 2002)

Types of habits Contraindications

Study by Davidovitch • Class ll skeletal by maxillary prognathism Habits influencing hard tissue when of long • Vertically directed grower duration • Labial tipping of lower incisors • Finger sucking •crowding • Soft tissue rests on teeth • Tongue posturing • Head position

5 Conclusions on efficacy

According to Woodside • Removable functionals do not work well part-time • Large vertical changes in construction bite redirects maxilla • Apical base width change possible with Frankel • Bionator and Frankel work similarly on LPM activity • Glenoid fossa changes stable • Stepwise progression of advancement best

Informed consent Activator facts

• Diagnosis- presented and understood by pt • Original design worn at night • Comprehensive tx plan • Large one piece of acrylic • Overview of reasonable alternatives • Teeth could be redirected during eruption • Discussion of probable sequella of non-tx • Large vertical opening construction bite • Potential risks • Could not speak or eat when worn • Predicted outcome and probability of • Advances mandibular jaw success

Bionator appliance

6 Bionator appliance inserted Frankel facts

• Exoskeleton of metal and acrylic • Restrains muscles and lips •Exerciser • Expands apical base Nikon Scan.exe • Worn day and night • Speaking possible, yet difficult

Bionator facts Herbst appliance

• Prototype of less bulky activator • Worn day and night • Allows more tongue action • Mandibular advancement • Speaking possible, yet difficult

Frankel appliance Herbst appliance

7 Herbst facts Latest Findings- the challenges

• Fixed to teeth • June 2004 AJODO by Tullock et al • Patient compliance not required – 1 phase of fixed is more efficient • Works 24 hours than 2 phases with functional/fixed appliances. • Less airway blockage • September 2003 AJODO by O’Brian et al • Most popular type at present time in U.S. – Fully randomized study demonstrated clinically significant dento-alveolar changes with Twin Block. Effective at /overjet reduction.

Twin Block Latest Findings (con’t)

• July 2003 EJO by Basciftci et al – the activator appliance can produce both skeletal and dental effects in the growing dentofacial complex. • January 2003 AJODO by Laecken et al – Retroactive study suggests that both skeletal and dental changes contribute to Class II treatment with the Herbst appliance with fossa remodeling From Mills et al, AJO 1998

Twin Block facts That’s all folks….thanks

•Removeble • Separate upper/lower plates • Patient compliance required • Less airway blockage • Improved speech • Most popular removable type at present

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