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OCCUSAL RELATIONSHIPS IN REMOVABLE PARTIAL DENTURE

Prepared by: Reyes S.M.

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INDEX1 Desirable occlusal contact relationship for removable partial denture

2 Method for establishing occlusal relationship

a) Direct apposition of cast.

b) Interocclusal records with posterior teeth remaining on record base.

c) Jaw relations records made entirely on occlusion rims.

d) Occlusal relations using occlusion rims on record base.

e) Establishing occlusion by the recording of occlusal path way.

3 Materials for artificial posterior teeth

- Arranging teeth to an occluding template

4 Establishing jaw relations for a mandibular removable partial denture opposing a maxillary complete denture.

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INTRODUCTION

• The fourth phase in the treatment of patient with removable partial dentures is the establishment of a functional and harmonious occlusion

• Occlusal harmony between a removable partial denture and the remaining natural teeth is a mojar factor in the preservation of the health of their surrounding structure.

• In removable partial dentures because of the attachment of the removable partial denture to the abutment teeth occlusal stress can be transmitted directly to the abutment teeth and other supporting structures.

• These leads to sustained stress that may be more damaging than those transient stress found in complete dentures

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Failure to provide and maintain adequate occlusion on the removable partial denture is primarily result of:

-Lack of support for the denture base

-The fallacying of establishing occlusion to a single static jaw relation record.

- An unacceptable occlusal plane.

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Remaining natural teeth Influences the establisment of occlusion of

a partial denture in such a way that the occlusal forms of the teeth on a denture conform to the already established occlusal pattern

The pattern present at the time the partial denture is made dictates the occlusion of the RPD

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DESIRABLE OCCLUSAL CONTACT RELATIONSHIP FOR REMOVABLE PARTIAL DENTURES

• The following occlusal arrangements are recommended to develop a harmonious occlusal relationship of removable partial dentures and to enhance stability of the removable partial dentures

1. Simultaneously bilateral contacts of opposing posterior teeth must occur in centric occlusion

2. Occlusion for tooth supporetd removable partial denture may be arranged similar to the occlusion in seen in a harmonious natural dentition

- Stability of such removable partial dentures results from the effect of the direct retainers at the both ends of the dentures base

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3.Bilateral balanced occlusion in eccentric position should be formulated when a maxillary complete denture oppose the removable partial denture. This is a complete primarily to promote the stability of the complete denture.

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4. Working side contact should be obtained for the mandibular distal extension denture. This contacts should occur simultaneously with working side contacts of the natural teeth to distribute the stress over the greatest possible area

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5. Simultaneously working and balancing contact should be formulated for the maxillary bilateral distal extension removable partial denture whenever possibe.

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6. Only working contacts need to be formulated for either maxillary or mandibular unilateral distal extension removable partial dentures.

7. In the Kennedy Class IV removable partial denture configuration contact of opposing anterior teeth in the planned intercuspal position is desired to prevent a continous eruption of the opposing natural incisors unless they are otherwise prevented from extrusion by means of a lingual plate, auxillary bar, by splinting.

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8. Balanced contact of opposing posterior teeth in a straight forward protusive relationship and functional excursive position is desired only when an opposing complete denture or bilateral distal extension maxillary removable partial denture is placed.

9. Artificial posterior teeth should not be arranged further distally than the beginning of a sharp upward incline of the mandibular residual ridge or over the retromolar pad.

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METHODS FOR ESTABLISHING OCCLUSSAL RELATIONSHIP

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A) Direct apposition of cast The first method is used when there are sufficient opposing teeth

that remain in contact to make the existing jaw relationship obvious or when only a few teeth are to be replaced on short denture bases and there is no evidence of occlusal abnormalities

METHODS:

Apposing cast may be occlude by hand The occluded cast should be held in apposition with rigid

supports attached with sticky wax to the base so the cast until they are securely mounted in the articultor.

Occlusal analysis and the correction of any existing occlusal disharmony should preceded the acceptance of such jaw relation record.

Such a jaw relation record between the remaining natural teeth.

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b. Interocclusal records with posterior teeth remaining

INDICATION:- When sufficient natural teeth remain to support the removable partial denture but the relation of opposing natural teeth dose not permit the occluding of cast by hand.

• A uniformily softened, metal reinforced wafer of base plate or setup wax is place between the teeth and the patient is guided to close in centric relation.

• Corret closure should have been rehearsed before placement of the wax so that the patient will not hesitate or deviate into closing.

• Wax is then removed and immediately chilled thoroughly in room temperature water.

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It should be replaced a second time to correct the distortion that result from chilling and than again chilled after removal.

All excess wax should now be removed with a sharp knife. A wax record can be further corrected with a freely flowing occlusal

registration material such as metallic oxide paste used as the final recording medium.

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(C) OCCLUSAL RELATION USING OCCLUSION RIMS ON RECORD BASES

INDICATION:-

1. When one or more distal extension areas are present

2. When a tooth supported edentulous space is large

3. When opposing teeth do not meet

• In this instance occlusal rims on accurate jaw relation record base must be used .

METHOD:-

• It is much same as in the second method except that occlusion rims are substituted for missing teeth .

• It is essential that accurate bases be used to help support the occlusal relationship.

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(D) JAW RELATION RECORD MADE ENTIRELY ON OCCLUSION RIMS

INDICATION:-

1. When an opposing maxillary complete denture is to be made concurrently with a mandibular removable partial denture.

2. Used in those rare situation in which the few remaining teeth do not occlude and will not influence eccentric jaw movements.

• Jaw relation records are entirely on occlusal rims

• The occlusion rims must be supported by accurate jaw relation record base

• The choice of method for recording jaw relation is much the same as that or complete denture

• Either some direct inter occlusal method or stylus tracing may be used

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(5) Establishing Occlusion by the recording of occlusal pathway:

The fifth method of establishing occlusion on the removal partial dentures is the registration of occlusal pathway and the use of an occluding template rather than cast of opposing arch.

When a static jaw relation record is used with or without eccentric supplied teeth are arranged to occlude according to a specific concepts of the occlusion.

These movement are made more complicated by the influences of the remaining natural teeth.

According to Thompson “Observing the occlusion with the teeth in static relation and then moving the mandible into various eccentric positions is not sufficient. A dynamic concept is necessary to produce an occlusion that is functional harmony with facial skeleton , the musculature , and the temporomandibular joint”

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Materials for Artificial Posterior Teeth

Improved Acrylic Resin Teeth Preferred over porcelain teeth because they are

more readily modified and thought to more nearly resemble enamel in action againts opposing teeth

Impregnated with abrasive paricles thereby becoming abrasive substance themselves

Acrylic Resin teeth with gold occlusal surf. Used in opposition to natural teeth , restored

natural teeth, and gold occlusal surface Porcelain Teeth

Used in opposition to other porcelain teeth

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ESTABLISHIN JAW RELATION FOR A MANDIBULAR REMOVABLE PARIAL DENTURE OPPOSING A MAXILLARY COMPLETE DENTURE:

Condition: (1) If mandibular removable partial denture occluding with maxillary complete denture-

- If existing denture is satisfactory and occusal plane is oriented to an acceptable anatomic, function and esthetics position than complete denture not need to b replaced and treated as a intact arch.

- A face bow transfer is made of that arch and cast is articulated on the articulator.

- than face bow and complete denture is remover and irreversible hydrocolloid impression of the denture is made.

- A cast is formed from the impression and mount on the articulator.

- Than centric relation recorded and transferred to the articulator.

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(2) When the removable partial denture replaces all posterior teeth and the anterior teeth are no interfering.

A central bearing point tracer is used may be mounted im the plate on maxillary denture.

A centric relation are recorded by means of introral stylus tracing against the stable mandibular base.

When a existing complete denture opposing a arch on which removable partial denture is fabricated. A cast of complete denture is used during the fabrication procedure.

(3) If the mandibular removable partial dentures is tooth supported than mandibular arch resorted first.

In other instance the mandibular arch is restored first and jaw relation are established if they would be a full complement of opposing teeth. Thus the maxillary complete denture is occluded with an intact arch.

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CONCLUSION

The balanced occlusion is the most important factor for the retention of the prosthesis.

The occlusion must be evaluate before the prosthesis fabrication start.

Preprosthetic mouth preparation must be done for better occlusion reproduction.

Proper method to be used for the record of correct occusion. Imbalanced occlusion is the main cause of retention loss of the

prosthesis.