The ultimate goals andresponsibility of theorthodontic therapist isto treat all three compo-

nents of the stomatognathic systemto create an environment for syner-gistic function of the teeth,temporomandibular joints andneuromuscular system. A balancedcranio-mandibular cervical relation-ship must exist in order to establishacceptable dento-facial beauty,balanced masticatory muscle forceson the teeth (intra and extra oral)that are positioned within a neutral-izing zone of muscle forces that willsupport long term occlusal stabilityand good periodontal health.

Soft tissue facial changes in adultsand children with Class I or mild tomoderate Class II malocclusion, treatedwith removable orthopedic applianceshave been shown to improve facialprofiles. In addition, up to a 30 percentrelative increase in the mid-palatalregion with shape changes consistentwith improved dental facial alignment inmaxillary transverse directions hasbeen shown to occur. (See Figure 1-7)

FORMFOLLOWSFUNCTION

FORMFOLLOWSFUNCTION

Keys to Facial Beauty &Expression Involve MaxillaryArch Form and Development

By Clayton A. Chan, D.D.S.

"The origin, development and maintenance of all skeletal unitsare secondary, compensatory and mechanically obligatoryresponses to temporally and operationally prior demands ofrelated functional matrices."

Functional Matrix Hypothesis – Melvin Moss

Figure 1: Note the subtle resulting facial changes that occurs around the eyes andlower one third the face of this TMD paining patient (age 36) face after wearing aneuromuscular mandibular orthosis.

Figure 5: Once solid occlusal terminal contacts are established the second molar pads areremoved to allow final stages of verticalization to neuromuscular position.

Figure 4: Mandibular posterior teeth are beginning to contact holding mandible andcondyles in stable functional position.

Figure 3: Upper straight wire arch anchorage unit developed with a lower tripodizingappliance (anterior region and second molars) to hold the mandible in the neuromuscularposition. 3/16 inch 6 oz. triangulating elastics are used to verticalize the bicuspids and firstmolars to the neuromuscular position.

Figure 2: Mandibular orthosis worn 11.5 months for cranio-mandibular stabilization prior toorthodontic/orthopedic treatment.

Figure 6: Blue marks indicate terminal contacts at the neuromuscular position (myocentric).

Figure 7: Finished bite. Patient no longer is experiencing TMD pain.

Figure 8: Note the hyperplastic change in the condylar neck (bend) resulting from chronic posterior hypo-occlusion. During habitual resting modes the mandible and condyles seek a more down and forward homeostaticposition within the glenoid fossa before any treatment. Stabilization of the mandible to a neuromuscular positionwill assist in triggering cellular stimulation, growth and regeneration of the joint complex.

TEETHTOGETHER

RESTPOSITION

A 10 percent increase was localizedin the nasomaxillary region and this alsoresulted in improved nasal, zygomaticand perio-orbital structures.3 Thus wecan consider it possible to remodel thefunctional matrix and establish suturalhomeostasis of our dental patients withsimplicity and ease.

It is commonly stated within ourdental profession that dentist’s should-n’t change bites, bones don't move,palates and dental arches can'texpand (develop or remodel), andcondyles don't remodel, especially inmore mature adult stages of life. Tomake these claims disregards thedynamics of the human living systemas an entity that constantly undergoescellular changes throughout its life-time. Science, technology and radio-graphic records of facial developmentand an understanding of the dynamicsof mandibular positioning and stabi-lization have shown differently.

It is surprising that many dentistscontinue to believe that adult bones ofthe stomatognathic system no longercan change (see Figure 8). Neuro andphysiologic science is clearly provingthese past myths are unfounded andnot true. Craniofacial development isclearly evident in many cases thathave been treated neuromuscularly,especially when working within thefunctional matrix of the jaw bones.The communication of genes and theirsignaling by transmitted informationinto the boney cells will naturallyproduce facial expressions of pheno-types of nature’s genetic potential ineach human being. Genes can beturned on through mechanical trans-mission with proper stimulation ofcells that can trigger responses togrowth and development within theneuromuscular occlusal system.

"The human body is an extremelycomplex mechanism composed ofmany self maintaining, self regulating,and autonomous systems. The motorsystem allows movement and iscomprised of three interrelated anatom-ical systems: the skeletal system, whichprovides the bony levers which gener-ate motion; the muscular system, whichsupplies the power to move the levers;and the central nervous system, whichdirects and regulates the activity of themuscles. The central nervous systemcontrols and operates this systemthrough neural control of muscletension. This complex system obeys thelaws of mechanics, including bothstatic and dynamic relationships."1Static relationships relate to bodies atrest and forces of equilibrium. Dynamicrelationships relate to bodies in

motion. The static functioning ofmuscle maintains equilibrium of thesupporting bones and teeth, while thedynamic functioning results in visiblemotion of these entities.

The Dynamics of Mandibular Posture

Posture represents the spatial rela-tionships of the skeletal structures toone another.1 There exists a particularspatial relationship of each cervicalneck bone as they relate to the occiput.A spatial relationship exists in multipledimensions of each condyle within theglenoid fossae as the mandible is at restand in dynamic function. When at rest,the mandible is in a state of static equi-librium maintained by a delicatebalance of muscle forces pulling fromabove by the tonus of muscles of masti-

cation and from below by both thehyoid bone musculature and gravity.The clinician should consider the spatialrelationship that exists between theupper and lower arch of teeth. Stillfurther, the clinician should recognizeeach skeletal occlusal joint articulatesfrom a resting state of equilibrium tothe dynamic articulated state of a termi-nal contact position during mandibularfunction back to its resting position.Figure 9 and 10 shows the effects ofproper mandibular positioning vianeuromuscular orthosis therapy and itsimpact on cervical neck postural align-ment without other adjunctive interven-tions. This is clear evidence that theocclusion and its impact on proper jawpositioning can improve cervical neckmusculature and the accompanyingcervical bone alignment.

Figure 9: Lateral cervical spine radiographs showing cervical bone alignment after two daywearing a lower neuromuscularly positioned orthosis. This 51 year old female TMD patient,who presented with severe head and neck pain, no longer complains of TMD pain.

Figure 10: Submental vertex radiograph view of the atlas (C-1) of the samefemale patient. Note the alignment of the atlas after two days wearing theneuromuscular orthosis.

Teeth and Skeletal ComponentsThe teeth are in essence an articulat-

ing extension of the bony skeletal struc-tures. Bone is a living tissue composedof a protein matrix with mineral saltssuch as calcium, phosphorus, magne-sium, sodium, and potassium, but eventhough it is one of the hardest bodytissues, bone is nonetheless highly plas-tic and sensitive to the functionaldemands placed upon it. The internalstructure of bone adjusts to modificationfrom mechanical stresses; a fundamentalprinciple of bone physiology is that formconforms to function. The mandible andmaxillofacial bones obey the laws of bio-physiology and are amenable to changeduring growth and development.

During the growth period of themandible, bone is deposited upon theouter cortical layer of compact bone, andsimultaneously the inner structure ismodified. The adult bone particularly thealveolar bone is maintained in a healthynormal state by stimulation from teeth infunction. Alveolar bone remains healthyand dense when intermittent moderatestimuli are transmitted by the teeth in aphysiologic occlusion.

Ruf and Pancherz, 1999, reported ina prospective longitudinal magnetic reso-nance imaging and cephalometric radio-graphic study, signs of condylar remodel-ing in the postero-superior border in 48of 50 adolescent condyles and in 26 ofthe 28 young adult condyles. Bilateralremodeling of the mandibular ramuscould be detected in 1 adolescent and 2young adult patients. Signs of glenoidfossa remodeling at the anterior surfaceof the post glenoid spine were also notedin 36 adolescent and 22 young adulttemporomandibular joints. Effectivetemporomandibular joint changes duringtreatment were more horizontallydirected and larger in both adolescentsand young adult patients after Herbstappliance therapy than in an untreatedgroup of subjects with ideal occlusion(Bolton standards).4

Temporomandibular JointChanges With Removable and Fixed Appliances

Dr. Gary Wolford, a noted oralmaxillo-facial surgeon in 2004, reportedbilateral radiographic condylar adaptivejoint changes over a thirteen year periodof an adult Caucasian male, age 45. Thepatient demonstrated an audible recipri-col click of the left joint with accompany-ing musculoskeletal occlusal signs andsymptomology of the head and neckregion before treatment. When treatedwith three months orthosis therapy andlater a full mouth reconstruction at themyocentric position, condylar regenera-

Figure 11: 13 YEAR TOMOGRAPHIC STUDYAdult Male – Condylar Adaptive Changes

Note the visible hyperplastic bony changes (bend in the condylar neck) of both left andright joints over a thirteen year period. For comparative purposes the tomographicfilms are the same corrected cut views thirteen years apart.

Figure 12: 3 YEARs After Nuromuscular Treatment with Mandibular Anatomica Orthosis – Condylar Remodeling (Regeneration)

Note the visible reversal of condylar neck changes (less bend in the condylar neck) ofboth left and right joints over a three year period due to decompression of the joints.Remodeling of both condyles occurred after the mandible was stabilized at themyocentric position with an orthosis and later full mouth reconstruction.

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tive/remodeling changes were noted onboth left and right joints over a three yearperiod. The patient was subsequentlyrestored to that proven and comfortableposition with no resulting clicking and orpopping joints. (See Figure 11 and 12).5

The mandibular condyle plays a signif-icant role in giving indispensable latitudefor adaptive growth; it provides a meansfor endochondral bone growth in a situa-tion in which ordinary periostealintramembranous growth would not bepossible. It is also all too frequentlyinvolved in TMJ (temporomandibularjoint) pathology and distress. Not only isthe condyle able to undergo growth andadaptive changes, but the whole ramus isalso involved.

Enlow stated that mandibular growthcan be stimulated when a force isapplied to the mandible, causing boneremodeling on the condyle and glenoidfossa <6>. If this is valid, this secondarygrowth can preserve the condyle relation-

ship within the glenoid fossa while thevisco-elasticity of muscle tonicity alongwith gravitational forces on the mandiblepositions the mandible in a down andforward direction (see Figure 13). Clini-cians have been radiographically confirm-ing the fact that condyles undergo adap-tive changes and are able to regeneratewhen compressive forces are removedand a homeostatic environment is estab-lished via stable neuromuscular occlu-sion (Figures 11 and 12).

Pancherez and Ruf and others 7, 8, 9,

10, 11 state that growth adaptation treat-ment with removable appliances is onlysuccessful during the main growth periodaround puberty. Whereas, fixed appli-ances can change mandibular growth toa clinical degree and make significantdental alveolar changes post-pubertal.These studies have shown that Class IImalocclusion can be corrected with fixedappliances during growth period of theyoung and in adults. Temporomandibular

joints reveal condylar and glenoid fossaremodeling and do not result in temporo-mandibular dysfunction on a long termbasis. These results are now proving tobe an alternative to orthognathic surgery.

Figure 13: As the mandible moves downand forward, joint decompression allowshomeostasis to occur within the glenoidfossa, resulting in an isotonic environmentfor condylar remodeling to occur..

A 15 year old female presented withunfinished orthodontic treatment withaccompanying head, neck and shoulderpain. A comprehensive examination wascompleted which included medical anddental history, intra/extra oral evalua-tion, orthopedic/TMJ musculoskeletalevaluation, radiographs which included:full mouth series (FMX), panoramic,

lateral and AP cephalograms, submentalvertex films, corrected cut tomograms(centric occlusion, rest, maximum open-ing), AP coronal views, lateral and APcervical spine and paranasal views(Figure 16 and 17). A neuromuscularanalysis included diagnostic study casts,computerized mandibular scanning(CMS – Scan 2, 3, 6, 13), electromyo-

graphic anaylsis (EMG before and afterlow frequency TENS – Scans 9, 10, 11)and electro-sonographic analysis (ESG –Scan 15, 16), and a computerizedmyocentric bite registration – Scan 4/5with simultaneous EMGs (Figure 15)taken in a sitting up postural positionwithout manual manipulation.13 Diag-nostic casts were mounted at Myocen-

Figure 14: (a) Habitual occlusion before treatment, (b) start of orthodontics after mandibular stabilization with neuromuscularpositioned orthotic, (c) bicuspids and first molars verticalized to the myocentric/neuromuscular position, and (d) finished orthodonticorthopedics to myocentric position.

Figure 15:ComputerizedMandibularScanning andelectromyographywas used to assistin identifying aphysiologic biteposition prior toorthodontic/orthopedic movement ofthe teeth to thefinishing myocentricposition (MyotronicsKineseograph, K7,Tukwila, WA)

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tric to fabricate a lower orthosis.Photographs were taken both extra oraland intra orally. Orthotic therapy wasimplemented for three months to estab-lished patient comfort and confirm astable physiologic starting positionbefore fixed mechanics were imple-mented (see figure 14).

Straight wire mechanics were usedand the lower arch dentition wassequentially transitioned with vertical-izing triangulating elastics via theorthotic position. The mandible wasmaintained throughout the treatmentto the neuromuscular position bytripoding the mandible with first molar

composite bonded blocks and ananterior night time removable acrylicoverlay to the neuromuscular position.As the first and second bicupids wereverticalized into occlusal contacts andthe second molars self erupted intoposition, the first molar blocks werethan removed. The lower anteriorbrackets were placed and bonded anda light round arch wire was ligated intoposition to assist in anteriorly vertical-izing the cuspids and incisors to thefinal neuromuscular position. A seriesof straight wire finishing mechanicswere implemented to complete thebite and occlusion.

Finishing records were taken whichincluded radiographs, models, comput-erized mandibular scanning data(before and after TENS), electromyo-graphic and electro-sonography andintra/extra oral photographs to confirmthe treatment goals and objectives.

The patient reported that she nolonger experiences any headaches,neck aches, shoulder aches, no jointnoise, improved muscle function andis pleased with her bite. Total treat-ment was 22 months using both theremovable orthotic therapy and finaliz-ing the bite using both fixed straightwire mechanics established at themyocentric position.

Future OutlookToday, one of the many keys to

facial beauty and expression is maxil-lary arch form and development. Formfollows function. Under-developedarches as well as malrelated mandiblesto the cranium naturally leads tomusculoskeletal compromises in bothocclusal and postural stability. Thedentist should recognize "abnormalposterior jaw closure patterns" thatcontribute to forward head postures,headaches, neck aches, shoulderaches and airway breathing compro-mises due to abnormal tongueposture.Narrow arch forms with V-shaped arches and vaulted palatesresult in many of the intra oral occlusalsigns of wear, facets, crowding ofteeth, lingual inclination of lower teeth,teeth chipping and cusp breakage withaccompanying dry mouth syndromeand asymmetric faces. These problemsif unrecognized and untreated will leadto unstable bites and lack of long termretention after orthodontic therapy.Orthodontic/orthopedic concepts arechanging with the dental professiondue to numerous clinical results andlong term treatment outcomes thatmany general orthodontic practitionersand orthodontic specialists are experi-encing in their clinical care.

Figure 16: Lateral cephalograms (above) and lateral cervical spine films (below) of a 15year old female orthodontic patient. Note the improved lateral soft tissue profile andcervical alignment (improved lordosis) after neuromuscular orthodontic/orthopedicscompared to before treatment (hyper-lordosis/forward head posture. As the mandiblemoves posteriorly, the cervical neck aligns (kyophotic). As the mandible moves anteriorthe cervical neck aligns (lordotic).

Figure 17: Note cranial and mandibular bone alignment as well as growth anddevelopment over a 22 months period of orthodontic/orthopedic treatment of thesame 15 year old female patient.

The tongue needs proper oralvolume for optimal function and oralpharyngeal patentcy. Sleep apnea,snoring, retrusive mandibles duringsleep, disruptive sleep and breath-ing will result in less than optimaloxygenation to the human system."The most significant principle tounderstand is that teeth seek aneutral position within a system offorces acting on them. The forcesystem changes constantly duringgrowth, and teeth move in responseto stimuli in their environment. Clin-ical observation can, with experi-ence, enable a dentist to assess theforce system in a child or adult anddetermine whether the position ofthe teeth may improve or deterio-rate when balance between thedentition and force system has beenestablished."12

Bibliography:1. Moss, M.L: 1997 The functional matrix

hypothesis revisited, 4. The epigeneticantithesis and the resolving synthesis.Am J Orthodo Dentofacial Orthop.112: 410-7, 1997.

2. Jankelson, R.R.: Neuromuscular DentalDiagnosis and Treatment, IshiyakuEuroAmerica, Inc. Publishers, 1990.

3. Singh, G.D. et al.: Facial ChangesFollowing Treatment With a RemovableOrthodontic Appliance in Adults. TheFunctional Orthodontist, Vol. 21, No. 3July/august/September 2004.

4. Ruf S, Pancherz H.: Temporomandibu-lar joint remodeling in adolescents andyoung adults during Herbst treatment:A prospective longitudinal magneticresonance imaging and cephalometricradiographic investigation. Am JOrthod Dentofacial Orthop. 1999Dec;116(6):16A-9A.

5. Wolford, G., Temporomandibular JointRemodeling in an adult male, TMDLecture program, Las Vegas Institutefor Advanced Dental Studies, LasVegas, Nevada, 2004.

6. Enlow, Donald H., Handbook of facialgrowth, W.B. Saunders, 1982.

7. Pancherez, H, Ruf, S. Thomalske-Faubert, C., Mandibular articular diskposition changes during Herbst treat-ment: A prospective longitudinial MRIstudy, American Journal of Orthodon-tics and Dentofacial Orthopedics 1999;119:207-14.

8. Ruf, S. Pancherz, H., Long-term TMJeffects of Herbst treatment: A clinicaland MRI study, American Journal ofOrthodontics and Dentofacial Orthope-dics: 1998;114: 475-83.

9. Ruf, S. Pancherz, H., Dentoskeletaleffects and facial profile changes inyoung adults treated with the Herbstappliance, angle Orthodontics1999;69:239-46.

10. Ruf, S. Pancherz, H., Does Bite-Jump-ing damage the TMJ? A ProspectiveLongitudinal Clinical and MRI study ofHerbst Patients, Angle Orthodontics2000;70:183-99.

11. McNamara, J.A., Jr. and Brudon, W.L.,Orthodontic and Orthopedic Treatmentin the Mixed Dentition, Needham Press1995.

12. Garry, J.F.: Upper Airway Obstruction,Occlusion I program lecture given atthe Las Vegas Institute, Las Vegas,Nevada, 2003.

13. Myotronics-Noromed, Inc., Kineseo-graph K7 and J5 Myomonitor TENS,Tukwila, WA.

Dr. Clayton A. Chan, D.D.S.Dr. Chan is a general dentist who practices neuromuscular dentistry in Las Vegas, Nevada wherehe is the Director of the Neuromuscular Dental Center at the Las Vegas Institute for AdvancedDental Studies. He lectures extensively on neuromuscular occlusion and bio-instrumentation inthe United States and abroad. Dr. Chan has focused his care in the areas of dental orthodontic/orthopedic rehabilitation involving musculoskeletal occlusal disorders of the head, neck, face andfull mouth reconstruction problems. Dr. Chan is also a trained gnathologist, a master inneuromuscular occlusion and holds Mastership status in the International College ofCraniomandibular Orthopedics. He can be contacted via email at: clayton@drclaytonchan.com.