3.jaw relation and occ in rpd

GOOD MORNING

JAW RELATION RECORDING AND OCCLUSION IN REMOVABLE

PARTIAL DENTURES

By Dr Zarir Ruttonji

CONTENTS1. Introduction

2. Objectives

3. Vertical jaw relation

4. Horizontal jaw relation

5. Establishing occlusal relationship

6. Selection of an articulator

7. Mounting of cast

8. Selection and Arrangement of prosthetic teeth

9. Preliminary objectives for establishing an occlusal scheme

10. Conclusion

11. References

INTRODUCTION

OBJECTIVES

1.To create an arrangement of the opposing teeth which is in harmony with the mandibular movements.

2. To provide the patient with a masticating mechanism that is at the same time efficient, comfortable and aesthetically pleasing.

3.Need to distribute the functional forces between the remaining natural teeth and the residual ridge to withstand stress

Miller and Grasso, Removable Partial Prosthodontics; 2nd edition, pg215

It may provide information which is difficult to obtain by intraoral examination

Problems such as…..

1. Interarch distance - enlarged maxillary

tuberosity….. -moderate to severe

undercuts….

EVALUATION OF DIAGNOSTIC CAST

Stewarts- Clinical Removable Partial Prosthodontics.

2. Occlusal plane:

- Irregular due to extrusion….

- Several treatment options….


3. Tipped or malposed teeth: - Minor orthodontic corrections…. - Sometimes removal…..


4. Occlusion: - lingual surfaces can be assessed -Selective grinding and coronal reshaping - Interferences…..


Vertical Jaw Relations: Vertical Dimension at rest

Occlusion Vertical Dimension Horizontal Jaw Relations:

Centric RelationCentric OcclusionEccentric Relations

Protrusive relationLt & Rt Lateral relations

JAW RELATION RECORDS

VERTICAL DIMENSION OF OCCLUSION


It is measured between two arbitrary point marked on the face one above the mouth one below the mouth

Two vertical dimension are commonly recognised

1.Vertical dimension at rest2. Vertical dimension at occlusion

ALTERING THE EXISTING OVD

Normally the OVD of a partially edentulouspatient is provided by the opposing natural teeth contact and it should not be changed


ALTERING THE EXISTING OVD cont..

1.Symptoms of diminished OVD exist such as.

tired aching muscles,unexplained pain in the head and neck region, shortened nose-chin distance (appearance of premature aging).

2. Excessive Free way Space or ‘over-closure’ of the jaws.


HOW TO ALTER THE EXISTING OVD

1. Confirm the loss of Vertical dimension by taking history, and the presence of excessive free-way space.

2. Increase the existing OVD temporarily by fabricating an acrylic resin occlusal overlay appliance in maximum intercuspation, ensuring that 4mm of freeway space must

exist.


HORIZONTAL JAW RELATION


It is determined after a correct vertical dimension of occlusion is established

There are two horizontal relationships that are of importance in developing occlusion

1. Centric relation

2. Centric occlusion


What to Record – C.R or C.O

.Centric Occlusion should be recorded whenever a patient requiring a partial denture has cusps on remaining natural teeth that can guide the mandible back to this position,


C.R should be recorded, e.g., for distal extension RPD, or when the opposing arch is edentulous.

ESTABLISHING OCCLUSAL RELATIONSHIP

5 methods can be used for establishing occlusal relationship in removable partial denture fabrication

1.Direct apposition of cast

2. Interocclusal records with posterior teeth remaining

3.Occlusal relation using occlusion rims on record bases

4.Jaw relation made entirely on occlusion rims

5.Functionally generated path

McCracken’s- Removable Partial Prosthodontics.

DIRECT APPOSITION OF CAST

Used when there are sufficient opposing teeth that remain in contact.

This method at the best can perpetuate the existing vertical dimension.


Any existing occlusal discrepancy present between the natural dentition

INTEROCCLUSAL RECORDS WITH POSTERIOR TEETH REMAINING

Used when sufficient natural teeth are remaining but the cast cannot be occluded by hand articulation


Interocclusal records have to be used to records the jaw relation

Usually softened, metal-reinforced wafer of baseplate or set up wax in used

OCCLUSAL RELATION USING OCCLUSION RIMS ON RECORD BASES

Used when on or more distal extension areas are present

Tooth supported edentulous space is large or when opposing teeth do not meet

In this method the missing teeth are replaced by occlusal rims


FUNCTIONALLY GENERATED PATH

Is based on the theory that the patient is the best articulator for developing the occlusion.


Using the removable partial denture frameworkas a base, a dynamic recording of the occlusal patterns is generated in thepatient’s mouth under normal functional conditions.

STEPWISE PROCEDUREDenture base has to be fabricated which is stable and which

will support the wax occlusal rim

A film of hard stick wax is placed on the base before the occlusal rims are adjusted

The wax rim then has to be worn by the patient for the next 24hrs including in the night

The occlusal rim has to be in positive contact with the dentition in all excursion so that the functional path of all the cusp are carved in wax


After 24hrs the occlusal rim is examined, it has to have a continuous gloss, which indicates functional contact of all the cusp.

The completed occlusal registration is now ready for conversion to a occlusal template

The occlusal registration is the boxed with modelling clay after it has been secured on the master cast

Only the wax registration and the vertical stops are left exposed, rest all in poured with dental stone, which

forms the template


SELECTION OF AN ARTICULATOR

Based on adjustability, articulators are

classified as:

Nonadjustable articulators

1. Kennedy class III

2. Functionally generated path

Semi adjustable articulators

1. Kennedy class I II IV

Highly adjustable articulators

1. Used when extensive occlusal rehabilitation is done

Stewarts- Clinical Removable Partial Prosthodontics


MOUNTING THE CAST ON ARTICULATOR

The cast have to be transferred to the articulators

ARBITARY MOUNTING

MOUNTING USING FACE

BOW

ARBITARY MOUNTING OF CAST

The cast are properly related to each other in horizontal and vertical planes

They are secured using stick wax

Then they are mounted in the centre of the articulator, midline of the cast aligns with the incisal pin and occlusal plane parallel to the bench topMiller and Grasso, Removable Partial Prosthodontics; 2nd edition, pg215

FACE BOW TRANSFER

It relates the maxillary cast to the opening and closing axis of the articulator

It also places the maxillary cast in the correct horizontal plane.

Facebow should be compatible with the chosen articulator.


SELECTION OF DENTURE TEETH

Choice of materials

1. Acrylic resin denture teeth

2. Porcelain denture teeth, .In more recent years 1. Glass ceramics and2. Composite materials.

John R. Ivanhoe , Kevin D. Plummer; Removable partial denture occlusion; Dent Clin N Am 48 (2004) 667–683

ACRYLIC RESIN DENTURE TEETH

1. Resilient,

2. Wear-resistant,

3. Natural-sounding in function, and

4. Aesthetic

5. They are easy to adjust, can be recontoured when necessary,

6. Polished with little effort

1. low abrasion resistance

2. Proper function of the occlusal relationships must be checked more frequently when acrylic resin teeth are used

ADVANTAGES DISADVANTAGES


PORCELAIN DENTURE TEETH

1. High abrasion resistance

2. Exhibit minimal wear

3. Highly Aesthetic

4. match the porcelains used for fixed restorations

1. Sound unnatural to the patient

2. Brittle

3. Chip or crack,

4. Difficult to adjust, recontour, and polish

ADVANTAGES DISADVANTAGES


ARRANGMENT OF PROSTHETIC TEETH

ANTERIOR TEETH

1. Should be selected using the manufactures shade guide

2. Should be done as quick as possible

3. Natural light should be used

Shade:-


ARRANGMENT OF PROSTHETIC TEETH cont...

MOLD

Each mold exhibits a different shape and size and also different surface characteristics


Mold selection is based on two important factors:1) The space that has been created by tooth loss. - If single tooth is replaced…. - If multiple anterior teeth are replaced…..

HOUSE technique


2) Overall form or shape of the teeth.


ARRANGMENT OF PROSTHETIC TEETH

POSTERIOR TEETH

1. They should fit into the edentulous spaces

2. But be in harmony with the natural existing occlusion also


POSITION OF NATURAL TEETH

It is desirable to place artificial denture teeth in close proximity to the original position of the natural teeth..

Landmarks for the anterior teeth

1.Incisive papilla

2.Labial vestibule

Arthur R. Roraff, Arranging artificial teeth according to anatomicLandmarks J. Prosthet. Dent. 1977;38,2:120-131

Landmarks for the occlusal plane

3. Commissures of the lips

2. Retromolar pad

1. Parotid papilla

Landmarks for the posterior teeth

1.Maxillary tuberosity

2.Retromolar pads

Arthur R. Roraff, Arranging artificial teeth according to anatomicLandmarks J. Prosthet. Dent. 1977;38,2:120-131

1.If a physiologic state exists, maintain the patient’s maximum intercuspal position.

2.Bilateral simultaneous contacts of the opposing anterior and posterior teeth should be established in restored occlusion

3. Do not alter a patient’s existing occlusal scheme in lateral movement unless such alterations are needed to correct a nonphysiologic condition.


PRELIMINARY OBJECTIVES FOR ESTABLISHING AN OCCLUSAL SCHEME

4. If the restoration must re-establish lateral guidance, canine- protected articulation is preferable when the remaining natural canines are present and not periodontally compromised.

5.Establish group function or a unilateral balanced articulation for patients with missing canines being replaced by a removable prosthesis or periodontally compromised canines that will be maintained


6.Do not establish nonworking contacts on remaining natural teeth unless these teeth are opposed by a complete denture for which bilateral balanced articulation is desirable

7.When there are healthy remaining natural anterior teeth, posterior tooth contact during the protrusive movement is not desirable


DETERMINING THE OCCLUSAL SCHEME

The number and positions of the remaining natural teeth in both the arch in which a removable partial denture is being fabricated and the opposing arch determine the necessary occlusal scheme.


Class III removable partial denture

If the existing occlusion is physiologically healthy, the patient is restored to the existing occlusal scheme

A group function articulation is recommended if the patient’s natural canine is missing or periodontally compromised

A balanced articulation is recommended if the restoration is to oppose a complete denture


Class II removable partial denture

Group function articulation should be avoided when there are no remaining premolars.

Except when opposing a complete denture, a balanced articulation should be avoided to prevent nonworking contacts on natural teeth.


Balanced articulation is recommended for patients for whom canine-protected articulation is not possible to provide bilateral occlusal contacts for increased denture stability.

Class I removable partial denture


Class IV removable partial denture

During excursive movements the anterior artificial teeth should either disocclude or have passive occlusal contact.


A balanced articulation is recommended if the restoration is to oppose a complete denture

CONCLUSION

References

1. Stewarts- Clinical Removable Partial Posthodontics.

2. McCrackens- Removable Partial Posthodontics

3. Miller and Grasso, Removable Partial Prosthodontics; 2nd edition,

4. Louis S. Block. Preparing and conditioning the patient for intermaxillary relations, JPD 1952: 2 ;599-603

5. Davis Henderson. Occlusion in removable partial prosthodontics , JPD 1972: 27; 151-159

6. John R. Ivanhoe , Kevin D. Plummer; Removable partial denture occlusion; Dent Clin N Am 48 (2004) 667–683

7. Arthur R. Roraff, Arranging artificial teeth according to anatomic Landmarks J. Prosthet. Dent. 1977;38,2:120-131

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3.jaw relation and occ in rpd