Occlusal finishing, functional occlusion, and elastodontic ... · PDF fileThe lateral movement from centric occlusion to maximal intercuspation must not exceed 0.3 mm, the con-dylar-fossa

Address for correspondence:

D. DEROZE,76 rue Henri Tomasi,La Trigance, 13009 Marseille,[email protected]

DOI: 10.1051/odfen/2011207 J Dentofacial Anom Orthod 2011;14:208� RODF / EDP Sciences

1

Conflicts of interest: noneReceived: October 2010.

Accepted: February 2011.

* Danielle Deroze and Jean Lacout are members of the AGORA group, responsible for the development of theelastodontic concept.

Occlusal finishing, functionalocclusion, and elastodonticconcept.How? And why?A look at one case

Danielle DEROZE, Jean LACOUT*

ABSTRACT

The last stage of orthodontic treatment is occlusal finishing. This complex andsubtle treatment period demands careful reflection by orthodontists in order forthem to achieve an optimal occlusion.

Elastodontic concept is a straightforward therapeutic tactic, whose essence is aconsidered and individualised approach to treatment within a well-structured plan.

Elastodontic concept enables orthodontists to construct of a functionalocclusion which satisfies the three fundamental criteria of function of themasticatory apparatus: effectiveness, harmony, and economy.

An illustrated case study will give the reader an understanding of the designand unique action of this type of appliance.

KEYWORDS

Occlusal functions

Elastodontic concept

Centring

Guidance

Occlusion

Stability.

Article available at http://www.jdao-journal.org or http://dx.doi.org/10.1051/odfen/2011207

http://www.jdao-journal.org

http://dx.doi.org/10.1051/odfen/2011207

INTRODUCTION

Can the variability of human biology,the particular structure of each dentalarcade, and the individuality of dentalmorphology be reconciled duringorthodontic treatment?

In the present era of relative (andunfortunate?) standardization of tech-niques, this daily challenge of ortho-dontic practice can become tedious,especially during the final stage oftreatment.

Final refinement of the occlusion isa difficult, even crucial, treatmentstep: patients are weary and longclinical sessions are necessary toachieve the objectives of the finalstage of treatment. To make matters

worse, an improvement in the cos-metic appearance of the teeth hasquite often occurred by this point,making it difficult for the conscien-tious practitioner to convince thepatient to continue with treatmentuntil a satisfactory occlusion has beenattained.

Our goal is to attempt to show,firstly, the value of a simple andintelligently individualized concept:elastodontic; and, secondly, as partof this global concept, the use of twohigh-quality appliances, the Elasto-Aligner and the Elasto-Finisher, tobring about treatment finalizationquickly and easily.

THE IMPORTANCE OF OCCLUSAL FINISHING

It would be extremely presump-tious, in this era of evidence-basedmedicine and professional regulation,to state categorically that refinementof occlusal finishing at the end oforthodontic treatment is necessary forTMJ comfort or case stability, if thepatient is satisfied with the appear-ance of his or her teeth:– The relationship between malocclu-

sion and temporo-mandibular dys-function (TMD) is controversial andnon-demonstrable because of itsmultifactorial nature: systemic phy-sical factors, psychosocial factorsand others are intertwined and it isdifficult to consider each in isolationin randomised trials.The literature abounds with con-tradictory studies of variable qual-ity1-6.

– In 2003, the ANAES1 (now theHAS, the French public body re-sponsible for accreditation and eva-luation in health care) quoted theconclusion of a literature reviewaimed at defining guidelines formanagement of an ideal functionalocclusion: "no workable definitionof the ideal occlusion can be con-clusively established"3.A year earlier, however, it recom-

mended2 treatment for anomalies atrisk of causing:– the arrest or maldevelopment of

facial growth or the dental arcades,or of altering their appearance;

– problems with oral or nasal func-tion;

– risk of dental trauma.Circumstances that might give rise

to caries, periodontal diseases or joint

DANIELLE DEROZE, JEAN LACOUT

2 Deroze D, Lacout J. Occlusal finishing,functional occlusion, and elastodontic concept. How? And why? A case study

problems should also be consideredfor treatment.

What should we conclude from thissometimes contradictory guidance?– The mechanical element of occlusal

problems is difficult to demonstrateobjectively though the clinical intui-tion that it is important is a dailyexperience.

– Inductive reasoning (plausibilityincreased by accumulation of factsin favour of a hypothesis and lack ofopposing examples), held dear in thebioprogressive approach, makesan occlusion-comfort or TMJ-discomfort interaction plausible.If we immerse ourselves in the

issues of the final stages of orthodon-tic treatment, and use some commonsense, some simple notions can bedefined5:– Orthodontic treatment is very often

a major disruption to occlusion;– The dental alignment required for

cosmesis is necessary, but notsufficient;

– The notion of the "ideal occlusion"should be abandoned, and replacedby the notion of the "optimisation of

the occlusion" which is both morerealistic and more clinically relevant;

– even if an adaptation is possible (forexample though growth or model-ling), it is not individually significant,and it is preferable not to rely on ittoo heavily, particularly in adults orwhere a surgical approach is re-quired;

– Finally, above all, biology is gov-erned by two elementary principles:the conservation of tissue, and theconservation of energy.As Ricketts recognised in 19698,

when applied to general dental prac-tice and to orthodontics, these notionsfavour the optimal reconstruction ofthe occlusion according to the princi-ples of simplicity and economy,within a holistic approach to thepatient’s health.

Dawson4 explains it thus: "The teethand the TMJ are components whichmust be integrated in a global ap-proach to the masticatory apparatuswhose disequilibrium results fromanatomical or functional disharmonyof its different constituent parts."

MANAGEMENT OF THE FINAL STAGES OF ORTHODONTIC TREATMENT

The criteria for judging the outcomeof orthodontic treatment7 are centricocclusion, occlusal stops, and occlusalguidance.

• Mandibular centring

In this position of the mandible, thecondyles are centred in the glenoidcavity, with the disc at the level of thetemporal eminence.

The movement from centric occlu-sion towards maximal intercuspationis slight (around 1 mm) and is only inthe sagittal plane.

The mandible is held slightly forward,providing anterior guidance withoutlocking. At the central position, occlusalcontacts are symmetrical with a cleanand precise guidance from the palatalcusp of the first maxillary premolar,preventing posterior movement.

OCCLUSAL FINISHING, FUNCTIONAL OCCLUSION, AND ELASTODONTIC CONCEPT. HOW? AND WHY? A LOOK AT ONE CASE

J Dentofacial Anom Orthod 2011;14:208 3

The lateral movement from centricocclusion to maximal intercuspationmust not exceed 0.3 mm, the con-dylar-fossa position allowing only alittle play of the condyles.

It is necessary to integrate only theessential relations of mandibular cen-tring, a sign of symmetrical andharmonious play of the mandibularcondyles, whether compatible or notwith the alignment of the occlusivespaces.

• The occlusion

The mandible is stabilised by theopposition of 4 or 5 pairs of opposedpluricuspidate teeth, each one in con-tact with its two antagonists, in thesagittal plane.

In the labial-lingual plane, there aremultiple harmonious stops, on boththe labial and lingual aspects of theteeth.

• Guidance

During mandibular movement, pos-terior disocclusion must occur during

propulsive and lateral movements.Guidance must be symmetrical with-out posterior interference or anteriorlocking.

The overjet, the overbite and theangulation of the canines are indis-pensible parameters of measurementof guidance.

The overall functional schema isarranged in a curvilinear system: thecurve of Spee in the sagittal plane, andthe curve of Wilson in the frontalplane.

Objective diagnostic analysis ofthese different parameters is essentialduring the last phases of occlusalfinishing. A set-up on an articulatorcan assist in the interpretation of"occlusal lacunae," but it is not com-pulsory; accurate clinical assessmentmay suffice.

However, if a set-up on an articu-lator is done in order to designelastodontic appliances, other residualproblems of the occlusion can also bevisualised, clarifying the lingual cusp/fossa relationships, and aiding in theirresolution. (fig. 1 a and 1 b).

THE VALUE OF ELASTODONTIC CONCEPT

After reflection on the individualcase, elastodontic concept can bethe judicious choice, providing astraightforward therapeutic technique.

The concept is not a panacea forocclusal problems: it cannot restorethe gross occlusal disharmony causedby problems such as excessive over-jet, overbite, palatal cusps that are toohigh, or abnormal canine angulation.

However, as part of a consideredstrategy in the last stages, it enables ahigher level of refinement to theocclusal finishing, while respectingthe occlusal function of the individualpatient.

It allows the individual dental anat-omy of each patient to be taken intoaccount, thereby permitting optimisa-tion of cusp/fossa relations, and of the



anterior and canine guidances, bypersonalisation of the palatine facesof the upper incisors and canines.

CONSTRUCTION AND MATERIALS

The case is set-up on an articulator.We prefer the SAM articulator withthe Axio Split system. The SAM basesare calibrated in the laboratory. It issufficient to send the model, mountedon a magnetic base (France Elasto-dontie� laboratory), along with referraldetails, cephalometry results, and clin-ical photographs.

The referral that must be completedby the referring orthodontist has 27criteria, including:– Administrative details: patient iden-

tification data, appliance requested;– construction criteria: overcorrection

required? retainer type, desiredpropulsion

– the occlusal criteria of the finalstages of treatment: position ofthe mandibular incisors, dental

axes, intercuspidation, the valuesof compensatory curves.This document is necessary for the

coherent and accurate design of thetherapeutic set-up.

The quality of the set-up model

will determine the eventual quality

of the response of the occlusion to

treatment, integrating the essentialelements of the occlusal finishing foreach case.– the data for repositioning the denti-

tion in centric occlusion– the position of the condyles in the

reference position,– mandibular kinematics,– the anterior and posterior determi-

nants of occlusion,– the compensatory sagittal and fron-

tal curves.

Figures 1 a and bSet-up on the SAM articulator.

The set-up allows both assessment of the occlusion and design of the elastopostioningappliance, in conjunction with the information provided by the referring clinician.



Each set-up is unique for each

patient.Polyvinyl silicon is used to construct

the appliance. This material is malle-able, strong, and well tolerated, en-abling precise control of even thesmallest dental movement.

The individual action on each tooth,unique in orthodontic therapy, is the

key to restoring occlusal harmony withelastodontic concept.

Every aspect of the relation of eachtooth to the appliance can be consid-ered, avoiding the torque errors tointercuspidation which may resultfrom fitting elastic bands to a multiplyattached orthodontic system.

APPLIANCE RANGE

There are several types of elasto-dontic appliance.

In the context of occlusal finishing,only two need to be particularlyconsidered:– The Elasto-Finisseur (Elasto-Fin-

isher) which uses some or all ofthe screws already placed for at-tachment of an anterior orthodonticarch

– The Elasto-Aligneur (Elasto-Aligner)which requires judicious placementof screws in order to achieve itsdesired action on the occlusion.Both devices share the same mode

of action.

• Requirements

The success of the elastodonticphase of treatment depends on theprevious treatment stages:– the functional envelope must be

balanced with the requirements forbreathing and swallowing. Errors oftechnique here will result in a poorlytolerated appliance, even if breath-ing holes are cut to permit oralventilation;

– The dentition must not be locked inany of its three axes of movement.The purpose of the elastodonticdevice is not to compensate forinadequate earlier treatment, butrather to assure fine control of thefinal stages.

ELASTODONTIC CASE STUDY

A 30 year old woman was referredby her general dental practitioner.

She complained of dental instabilityand jaw and neck pains severe en-ough to interfere with both sleep andher daily activity.

The history-taking revealed a habitof mouth breathing and problems withswallowing.

There was no clicking or painrelated to the TMJ.



The condition of the teeth andperiodontium was completely satis-factory.

• Diagnosis

The work-up included recordingbaseline clinical details, photography,a dental impression, an orthopanto-mogram, facial and lateral X-ray views,and cephalometry. The face wasaesthetically balanced with a mesofa-cial pattern (fig. 2 a to 2 c) (fig. 4).

The molar occlusion was class I.The maxillary aspect suggests defi-

ciency of the alveolar ridge, notably atthe canines and premolars, and there isa slight negative overbite (fig. 3 a to 3 d).

The set-up on the articulator at theoutset of treatment confirms the im-portance of the occlusal deficit on

both the labial and palatal aspects(fig. 5 a to 5 d and 6 a to 6 c).

• Treatment plan

An orthodontic treatment plan isestablished and discussed with thepatient.

Its objective is to restore a satisfac-tory equilibrium to the occlusion, withguidance and centring of the mandibleto enable symmetrical and efficientmastication:– A quad helix to restore transverse

compatibility between the arcades,– behavioural therapy for the pro-

blems of ventilation and swallow-ing,

– a diagnostic re-evaluation for finish-ing that corresponds to the envi-saged objectives for the occlusion.

Figures 2 a to cFacial views before treatment.



• Treatment

The quad helix is fitted, and thepatient undergoes behavioural therapyfor the problems of ventilation andswallowing (fig. 7).

After several months, the requiredtransverse dimension is obtained, andthe quad helix is removed.

Nasal ventilation and physiologicaldeglutition are re-established by thepatient without difficulty, there beingno respiratory pathology.

The second set-up on the articula-tor, the key to diagnostic re-evalua-tion, is performed (fig. 8 a to 8 e).

A good proportion of the occlusalcontacts have been re-established on

both labial and palatal aspects, notablybetween the premolars and molars,although the molar torque may havebeen altered by the action of the quadhelix.

However, there is still an unaccep-table occlusal deficit which must becorrected.

So what would be the best meansof orthodontic treatment to optimisethis occlusion?

• The end of treatment

Further adjustment of the occlusionby treatment with an orthodontic archappliance that uses elastic bands to

Figures 3 a to dLateral, frontal and occlusal views before treatment.



Figures 4 a to dRadiographs and cephalometric tracing before treatment.

Figures 5 a to cPre-treatment set-up on the articulator showing occlusal deficit from labial aspect.



Figures 6 a and bPre-treatment set-up on the articulator showing occlusal deficit in palatal aspect.

Figure 7Quad helix in position.

Figures 8 a to eSet-up on the SAM articulator for diagnostic re-evaluation. The labial and palatal views show the beginningsof interlocking of the premolar and molar cusps and fossae. The occlusion remains inadequate.



improve intercuspation would be onepossible solution.

Even if the psychological difficultiesengendered by wearing this kind ofappliance can be overcome by thepatient, this is far from straightfor-ward. Controlling torque will be diffi-cult, especially that of the lingualcusps, and there is also the risk thatthe dental axes may be compromised,leading to torque from the elasticbands. All this can make for a lengthytreatment.

When there is a need, as here, forsubtle adjustments to the occlusion,elastodontic ticks all the boxes in thetherapeutic checklist:– acting on each individual tooth ;– completely personalized for each

case ;– precise adjustment of occlusal in-

terlocking in all three axes ;– highly discreet appliance ;– worn at night ;– The form of the appliance favours

normal functional re-education.An Elasto-Aligneur is suggested,

with placement of temporary retainersbetween the canine and first premolarteeth.

This will assure perfect centring andeasy fitting of the appliance the firsttime it is worn.

The set-up is sent to the laboratorywith the photos, cephalometry, andconstruction instructions outlining therequired final occlusion. Mandibularcentring, guidance, symmetrical den-tal calage and restitution of the com-pensatory curves are all specified for

each individual patient.

In this case, a slight transverseovercorrection and an enhancementto the overbite have been requested.

The therapeutic set-up and theappliance are made according to theseinstructions by the France Elastodon-tie� laboratory (fig. 9 a to 9 e and 10 aand 10 b).

The appliance is mainly worn atnight.

Results are obtained very rapidly,and the temporary retainers can beremoved at the first follow-up ap-pointment at six weeks. (fig. 11 a to11 c).

At the next follow-up appointmentthe inferior incisors have come intoalignment without any direct pressurefrom the appliance. This has beenmade possible by three concomitantelements: the larger transverse max-illary dimension, the intelligent andindividualised design of the therapeu-tic set-up model for adjusting incisorocclusion, and finally, the qualities ofthe elastomeric material (fig. 12 a to12 d).

A final set-up is performed toassess the occlusal results obtained,particularly at the level of engage-ment of the palatal cusps (fig. 13 ato 13 c).

The cusp engagement has been re-established on both the labial andpalatine aspects of the teeth.

The patient no longer complains ofmuscular pains, reports that her teethare stable and comfortable, and issmiling once more.

Radiography and cephalometry atthe end of treatment demonstrate thatthe anterior guidance has been re-established, with an appropriate curveof Spee, and good control of theincisor axes (fig. 14 a to 14 c).



Figures 10 a to bElasto-Aligner in place. The appliance is clipped to the retainers, ensuring a stable fit duringinitial use.

Figures 9 a to eThe therapeutic set-up model. The individual specification for each occlusion must be respected. A slight transversemaxillary overcorrection and an enhancement to the overbite have been prescribed.

Figures 11 a to cAfter 6 weeks of use of the Elasto-Aligner, the retainers can be removed.



Figures 12 a to eFollow-up at 4 months. The new shape of the maxillary arch allows the upper incisors to come into alignment.

Figures 13 a to cSet-up on the articulator at the conclusion of treatment. The quality of the palatal cuspengagement bears testimony to the precise and targeted action of the Elasto-Aligner.



CONCLUSION

Orthodontics should be consideredan integral part of general dental careand can make an important contribu-tion to the overall health of the patient.

A good cosmetic result is but onecriterion in determining the conclusionof treatment; a satisfactory functionalocclusion must also be obtained.Individual assessment of the occlu-sion must always be the final choice inany treatment, because the natural

variability makes standardisation oftreatment difficult.

One can look at occlusal finishing inorthodontics from a new angle, open-ing up technique and meeting thecriteria of a functional occlusion.

Elastodontic appliances, thanks tothe quality of their design, permit us toembark on the last phase of orthodon-tic treatment in a calm and intelligentmanner.

Figures 14 a to cRadiography, cephalometry and smile at the conclusion of treatment.



Using cosmetic criteria as a guidefor the completion of treatment isnecessary, but not in itself sufficient.The reasoned use of the elastodontic

concept completes the necessaryocclusal function.

REFERENCES

1. ANAES. Recommandations pour la pratique clinique : les criteres d’aboutissement dutraitement d’orthopedie dento-faciale. 2003:17.

2. ANAES. Indications de i’orthopedie dento-faciale et dento-maxillo-faciale chez I’enfantet I’adolescent. 2002:10.

3. Clark J, Evans R. Fonctionnal occlusion, a review. J Orthod 2001 ;28(1):76-81.4. Dawson P. L’occlusion clinique, evaluation, diagnostic et traitement, Paris : CDP,

seconde edition, 1992:XV.5. Orthlieb JD, Deroze D, Lacout J, Maniere-Ezvan A. Occlusion pathogene et occlusion

fonctionnelle : definitions des finitions. Orthod Fr 2006;77:451-9.6. Orthlieb J.D., Giraudeau A., Laplanche O. Occlusion et dysfonction : le paradoxe de

I’orthopedie dentofaciale. Orthod Fr 1998;69:69-78.7. Orthlieb JD, Brocard D, Schittly J, Maniere-Ezvan A. Occlusodontie pratique. Paris :

CDP, 2000.8. Ricketts R. Occlusion, the medium of dentistry. J Prosthet Dent 1969;21(1):39-60.



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Occlusal finishing, functional occlusion, and elastodontic ... · PDF fileThe lateral movement from centric occlusion to maximal intercuspation must not exceed 0.3 mm, the con-dylar-fossa