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CORONOPLASTYPresented by :Shashwati Paul II Yr PG StudentDept. of Periodontology

Contents

IntroductionTrauma from occlusionDefinitionClassificationDiagnosis of trauma from occlusion Dynamics of Equilibrium CoronoplastyGuidelines for occlusion in dental treatmentIndications for coronoplasty in periodontal therapyObjectives of coronoplastyOcclusal adjustmentsTechnique of coronoplastyOutcome of coronoplastyTreatment of increased tooth mobility ConclusionReferences

INTRODUCTION

Occlusal force affect the condition and structure of the periodontium. Periodontal health is not a static state.

It depends upon a balance between an internal systemically controlled milieu that governs periodontal metabolism and external environment of the tooth, of which occlusion is an important component.

To remain structurally and metabolically sound, the periodontal ligament and alveolar bone require the mechanical stimulation of occlusal force

An inherent margin of safety common to all tissue permits some variation in occlusion without the periodontium being adversely affected.

The periodontium has a capacity to withstand slight variations of masticatory forces.

The ability of periodontium to accommodate some amount of extra force is called the physiological adaptive capacity.

If the force exceed the physiological adaptive capacity, injury to the periodontal tissue results.

Periodontal injury thus caused is known as trauma from occlusion

DEFINITIONS

Trauma from occlusion was defined by Stillman ( 1917) as "a condition where injury results to the supporting structures of the teeth by the act of bringing the jaws into a closed position".

WHO in 1978 defined trauma from occlusion as "damage in the periodontium caused by stress on the teeth produced directly or indirectly by teeth of the opposing jaw".

Glossary of Periodontic Terms" (American Academy of Periodontology 1992), Occlusal Trauma was defined as "An injury to the attachment apparatus as a result of excessive occlusal force

Primary occlusal trauma is injury resulting from excessive occlusal forces applied to a tooth or teeth with normal support

Secondary occlusal trauma is injury resulting from normal occlusal forces applied to a tooth or teeth with inadequate periodontal support.

Combined occlusal trauma refers to injury resulting from abnormal occlusal forces applied to a tooth or teeth with inadequate (abnormal) periodontal support. (Bjorndahl O 1958)

Traumatogenic occlusion refers to a cause and is defined as any occlusion that produces forces that cause an injury to the attachment apparatus

Trauma from occlusion is only one of many terms that have been used to describe such alterations in the periodontium.

Other terms often used are; Traumatizing occlusion Occlusal trauma Traumatic occlusion Traumatogenic occlusion Periodontal traumatism Overload , etc.

CLASSIFICATION

DEPENDING UPON THE DURATION OF OCCURANCEAcute TFOChronic TFO

DEPENDING ON THE ETIOLOGYPrimary TFOSecondary TFO

Primary TFOSecondary TFO

Three different situations on which excessive occlusal forces can be superimposed, as follows : a) Normal periodontium with normal height of bone b) Normal periodontium with reduced height of bone c) Marginal periodontitis with reduced height of bone

CLINICAL FEATURES

SYMPTOMS OF TRAUMA FROM OCCLUSION

1. Periodontal pain

In severe trauma from occlusion, there is localized, sharp pain or soreness to the tooth.In chronic long standing trauma from occlusion, there is little or no pain.The symptoms, if present are those of vague regional discomfort

2. Pulpal painSensitivity of the teeth, especially to cold, is commonly found .

3. Food impactionThe plunger cusp effect of occlusal interference may produce a functional opening of contact between the teeth, leading to food impaction.

4. TMJ painThis is always accompanied by an occlusal disharmony.

SIGNS OF TRAUMA FROM OCCLUSION

1. Increased tooth mobility

This is a hallmark of trauma from occlusion

It can be easily measured by blunt ends of two dental instruments which are placed approximately at the buccal and lingual heights of contour of the tooth, and force are applied in the bucco-lingual direction.

MILLERS MOBILITY INDEX (1950)

Mobility 1 First distinguishable sign of movement greater than normal. Mobility 2 Movement of 1 mm from normal position in any direction.Mobility 3 Greater than 1 mm and rotation, or depression.

Fleszar et al (1980) used a modification of Millers scale :

Class 0 Physiologic mobilityClass I Slightly increased mobilityClass II Definite to considerable increase in mobility, but no impairment of functionClass III Extreme mobility faciolingually / mesiodistally combined with vertical displacement

2. Migration of teeth Loss of inter proximal contact and migration of teeth may be seen in traumatic occlusal relation.

3. Atypical pattern of occlusal wearTooth wear which appears to be greater than one might expect in a patient of that age, and which cannot be attributed to any special diet or deficiency in tooth mineralization.

4. Changes in percussion soundOn percussion, the tooth affected by trauma from occlusion, gives a dull sound whereas a normal teeth gives a sharp sound.This difference could be due to altered width and consistency of periodontal membrane, and partial resorption of lamina dura.

5. Hypertonicity of masticatory musclesBruxism and hypertonicity makes the periodontium susceptible to trauma.

6. Periodontal abscessIf the tooth subjected to increased force, have pockets, the bacteria may get pushed into the traumatized tissue and cause abscess formation.

7. Fremitus test

8. Radiographic changesWidening of periodontal space at crest, giving funnel-shaped appearance and angular bone loss.

RADIOGRAPHIC FEATURES OF TRAUMA FROM OCCLUSION

Trauma from occlusion produces radiographicaly detectable changes in the lamina dura, periodontal ligament spaces, morphology of alveolar crest, and density of surrounding bone. These changes include :

Increased width of periodontal space, often with thickening of lamina dura along the lateral aspect of root, in the apical region and in the bifurcation areas.A vertical rather than horizontal destruction of interdental septum.

Widening of periodontal ligament space at the crest, giving a funnel-shaped appearance and angular defects during adaptive remodeling stage.

Root resorption is seen.

Diagnosis

1.HISTORY

An adequate history is of basic importance of any clinical diagnosis.H/O parafunctional habits must be recorded.Patients psychic status must also be recorded.

CLINICAL INDICATOR OF OCCLUSAL TRAUMAIt may include one or more of the following :FremitusMobility (progressive)Occlusal discrepanciesWear facets in the presence of other indicatorsTooth migration Sensitivity

Fremitus test

Test to detect trauma from occlusion.Fremitus is a measurement of the vibratory pattern of the teeth when the teeth are placed in contacting position and movements.To measure fremitus ,a dampened index finger is placed along the buccal and labial surface of the maxillary teeth. The patient is asked to tap the teeth together in the maximum intercuspal position and then grind systematically in the lateral, protrusive, and lateral-protrusive contacting movements and positions.The teeth that are displaced by the patient in these jaw positions are then identified.

The following classification system is used : Class I fremitus Mild vibration or movement detected Class II fremitus Easily palpable vibration but no visible movement Class III fremitus Movement visible with naked eye

Fremitus differs from mobility in that fremitus is tooth displacement created by patients own occlusal force.

Fremitus is a guide to the ability of the patient to displace and traumatize the teeth.

It is the first ever grid-based sensor technology specifically designed for occlusal analysis.

This diagnostic tool was created in response to the needs of dentists seeking an accurate way to dynamically measure occlusion.

It offers instantaneous occlusal data, including timing and force. The 3rd generation system features a consistent sampling speed of 100 Hz and advanced software analysis tools to provide better quality treatment.

T-Scan

It raises the bar for occlusal analysis by employing patented grid-based sensor technology.The ultra-thin, reusable sensor, shaped to fit the dental arch, inserts into the sensor handle, which connects into the USB port of PC. The softwares vivid graphics (2-D, 3-D, force vs. time graph) display tooth contact data instantaneously and accurately, highlighting each tooth and the force level exerted on that tooth during occlusion. With this data, visualizing and achieving the balance of the perfect bite is easy to accomplish.

Primary requirements for successful occlusal therapyComfortable and stable tmjsAnterior teeth in harmony with the envelope of functionNon-interfering posterior teethEven the slightest disharmony causes severe hyperactivity and incoordination of masticatory muscle function. So it is the fourth factor that is affected positively or negatively by how the other three factors work together.Dynamics of Equilibrium

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Coronoplasty

Coronoplasty is the selective reduction of occlusal areas with the primary purpose of influencing the mechanical contact conditions and the neural pattern of sensory input ( Krough Poulsen 1968)

It is a direct and irreversible change of the occlusal scheme.

There is a tendency to think of occlusal adjustment solely as eliminating injurious occlusal forces.

But an equally important purpose is to provide the functional stimulation necessary for the preservation of periodontal health.

Guidelines for occlusion in dental treatment

These guidelines are for (1) pretreatment evaluation of dental occlusion, (2) planning occlusal changes or fabricating dental occlusion in treatment (3) post-treatment evaluation of the dental occlusion.

Based on Occlusal stability in ICPMaxillomandibutar Relationships and Tooth Contact MovementSubjective Response to Occlusion

Guidelines for occlusion in dental treatment

Occlusal stability in ICPJaw closes to a repeatable, single end point.

Simultaneous masseter muscle contraction after forceful clenching in the intercuspal position.

Simultaneous, widely distributed posterior tooth contacts.

Forces of tooth contact directed along the long axis of the teeth

Maxillomandibutar Relationships and Tooth Contact Movement

6. Contact movement from RCP to ICP (mandibular shift) is less than 1 mm (no shift is acceptable).

7. Laterotrusive side guidance primarily on the ipsilateral canine-premolar teeth.

8. Protrusive guidance is symmetric.

Subjective Response to Occlusion

10. Lack of unpleasantness towards the dental occlusion.

11. Acceptable free way space.

12. Acceptable speech articulation.

13. Acceptable chewing ability.

14. Acceptable mandibular position.

Indications for coronoplasty

Existing occlusion and maxillomandibular relationship is altered when it is anticipated that the resulting changes will (I) normalize the trauma from occlusion

(2) result in occlusal stabilization for future restorative or prosthetic procedures

Objectives of coronoplasty

Change in pattern and degree of afferent impulses Reducing the excessive tooth mobilityMultiple simultaneous tooth contact spread over the occlusal scheme to effect occlusal stabilization Beneficial change in the pattern of chewing or swallowingMultidirectional mandibular movement patternsVerticalization of occlusal forces on tooth

Sequencing coronoplasty in treatment planning

Elimination of gingival inflammation and pocket depth

Occlusal analysis

Informed consent

Occlusal analysis

Diagnostic models should be made.

Mounting of casts on an articulator using facebow transfer

Trial adjustment of occlusion on casts

Material used for occlusal analysis

Occlusal registration strips

Occlusal indicator wax

Marking ribbon

Articulating paper

Informed consent

Patients are often concerned about whether coronoplasty will change their appearance, cause tooth decay, or increase tooth sensitivity.

The clinician should explain that the teeth are not going to be ground down, but reshaped so that they will function better.

The reshaping is done in areas where tooth decay rarely occurs. The patient should understand that the teeth and the occlusion change with time and that minor adjustments will be made on subsequent recall, if necessary.

MethodsI) Determing the end point of coronoplastySelection of an intraborder position is logical, as there is little doubt that the ICP (Intercuspal position) is the functional point of the occlusion.

RCP (Retruded cuspal position) adjustment is practical in more complex cases, because RCP adjustment provides an objective method by which to align the mandible.

Ultimately, stability of the occlusion is more important than whether RCP, ICP or the habitual closure position is selected for the occlusal end point

II) Selecting occlusal guidance scheme.

1) Balanced occlusionRefers to the simultaneous contact between the right and left posterior segments of the arch in lateral excursion of the mandible and between the posterior and anterior segments of the arch in protrusive excursion.

The probable benefits include decreased dental loading forces with bilaterally similar cuspal inclines.

2) Canine protected occlusion

Where the maxillary canines act to guide the mandible so that the posterior teeth come into closure will minimal horizontal forces.

In lateral and protrusive excursions, the mandibular canines and first premolars engage the lingual surface of the maxillary canines so as to disclude the incisors, premolars and molars and protect them from undesirable horizontal forces.

3) Group functionIt is the simultaneous gliding contact of teeth on the laterotrusive side during laterotrusion.

In group function, both functional and parafunctional occlusal forces exceed those in canine function, so it is not indicated for periodontally compromised dentitions.

Occlusal adjustmentsClinical goalsTo reduce the supra contacts so as to create unobstructed closure of cusps into fossae and marginal ridges, while at the same time conserving original crown structure

The correction of occlusal supracontacts consists of Groovingspheroiding pointing

Grooving: Done with a tapered cutting tool.Entails restoring the depth of developmental grooves.

Spheroiding:Restores the original tooth contour while reducing the supra contact.Done with a light paint brush stroke.

Pointing:Consists of restoring cusp point contours.

Grooving

Spheroiding

Pointing

Sequence for coronoplasty

STEP 1 Remove retrusive prematurities and eliminate the deflective shift from RCP to ICPSTEP 2 Adjust ICP to achieve stable ,simultaneous multipointed widely distributed contactsSTEP 3 Test for excessive contact (fremitus ) on anterior teethSTEP 4 remove posterior protrusive supra contacts and establish contacts that are bilaterally distributed on the anterior teethSTEP 5 Remove or lessen mediotrusive interferenceSTEP 6 Reduce excessive cusp steepness on laterotrusive contactsSTEP 7 Eliminate gross occlusal disharmoniesSTEP 8 Recheck tooth contact relationshipSTEP 9 Polish all rough tooth surfaces

Remove retrusive prematurities and eliminate the deflective shift from RCP to ICP

The purpose of this step is to reduce supracontacts that interfere with posterior border closure of the mandible to a stable bilateral RCP

When contact is located on the retruded path of closure, supracontacts may cause the mandible to deflect forward and sometimes laterally into the ICP.

This contact movement is termed the shift or slide from RCP to ICP

Retrusive adjustment results in the elimination of the RCP-to-ICP shift

Remove the inclines between RCP and ICP that cause supracontacts when the mandible moves from RCP to ICP, without removing the vertical stop or supporting cusp tip

These inclines, called retrusive prematurties, are usually found on mesial facing inclines of the maxillary teeth and distal facing inclines of the mandibular teeth (MUDL rule)

Preserve marginal ridges, adjust cusp tip as last resort.

The retrusive range adjustment is complete when the following conditions are achieved:The contact pattern is bilateral with multi-pointed contacts; The deflective shift from RCP to ICP has been eliminatedBoth RCP and ICP approach the same vertical dimension of occlusion.The pathway from RCP to ICP, if present, is smooth and gliding.Repeated closure of the teeth together in the hinge position produces a sharp resonant sound.

Adjustment of the ICP

The purpose of this step is to achieve a stable ICP and to refine occlusal anatomic relationships

The main feature of this step is that supracontacts are identified without guidance by the operator's hand

The alteration that commonly are made in conjunction with this step arereduction of cuspal sizealteration of occlusal table width,lessening of plunger cusp height

The incisor tooth should be slightly out of contact or in light contact over the maximum number of teeth.

The mylar strip should just slip through the incisor teeth in ICP.

No fremitus should be detectable.Test for excessive contact on the incisor teeth in ICP

The ICP adjustment is complete when

The contact pattern is bilateral, stable and many pointedEach posterior vertical step holds a Mylar occlusal strip with equal resistanceSharp, resonant sounds are heard when the patient taps his or her teeth together in ICP (with a stethoscope placed over the infraorbital skin areaThe patient responds negatively to the following question: 'Tap on your back teeth, slow and harddo you feel any difference between the two sides?"No fremitus is detected in the anterior teeth.

Remove Posterior Protrusive Supracontacts; Obtain Bilateral Protrusive Contact Movement on the Anterior Teeth

Remove or lessen mediotrusive (Balancing) supracontacts

Reduce supracontacts on the laterotrusive (working) side

Eliminate undesirable gross occlusal features

Recheck the tooth contact relationship

Tooth contact relationships in all positions and movements are rechecked.Polish all rough tooth surfaces.

CRITERIA FOR JUDGING THE OUTCOME OF CORONOPLASTY

Treatment of increasedtooth mobility

Situation IIncreased mobility of a tooth with increased width of the periodontal ligament but normal height of the alveolar bone

Situation IIIncreased mobility of a tooth with increased width of the periodontal ligament and reduced height of the alveolar bone

If the excessive forces are reduced or eliminated by occlusal adjustment, bone apposition to the pretrauma level will occur, the periodontal ligament will regain its normal width and the tooth will become stabilized

Conclusion: situations I and II

Occlusal adjustment is an effective therapy against increased tooth mobility when such mobility is caused by an increased width of the periodontal ligament.

Situation III

Increased mobility of a tooth with reduced height of the alveolar bone and normal width of the periodontal ligament

The increased tooth mobility which is the result of a reduction in height of the alveolar bone without a concomitant increase in width of the periodontal membrane cannot be reduced or eliminated by occlusal adjustment.

In teeth with normal width of the periodontal ligament, no further bone apposition on the walls of the alveoli can occur.

If such an increased tooth mobility does not interfere with the patients chewing function or comfort, no treatment is required.

If the patient experiences the tooth mobility as disturbing, however, the mobility can only be reduced in this situation by splinting, i.e. by joining the mobile tooth/teeth together with other teeth in the jaw into a fixed unit a splint.

Situation IV

Progressive (increasing) mobility of a tooth (teeth) as a result of gradually increasing width of the reduced periodontal ligament

It will only be possible to maintain such teeth by means of a splint. In such cases a fixed splint has two objectives:

(1) to stabilize hypermobile teeth and (2) to replace missing teeth

Splinting is indicated when the periodontal support is so reduced that the mobility of the teeth is progressively increasing, i.e. when a tooth or a group of teeth are exposed to forces during function.

Situation V

Increased bridge mobility despite splinting

An increased mobility of a cross-arch bridge/splint can be accepted provided the mobility does not disturb chewing ability or comfort and the mobility of the splint is not progressively increasing.

Conclusion

Measurement of the outcomes from occlusal therapy usually cannot be readily achieved.In cases where patient is experiencing discomfort from occlusal contact, patient will experience relief from pain when they are relieved from occlusal forces.In most cases , however, the changes can only be measured in terms of decreased mobility and long term results to periodontal therapy.

References

Clinical Periodontology- Carranza 10thh Edition.Clinical Periodontology- Carranza 8th EditionClinical Periodontology & Implant Dentistry Jan Lindhe 4th editionManagement of Temporomandibular Disorders and Occlusion- Jeffrey P. Okeson (4th edition)Functional occlusion Peter E. Dawson 5th editionWalter . B . Hall Critical Decisions In PeriodontologyOcclusal factors as a risk factor for periodontal disease Perio 2000, 2003; vol 32 Occlusal analysis, diagnosis and management in the practice of periodontal disease Perio 2000, 2004; vol 34

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