CONSTRUCTING A DENTURE: Technique exercise

Dr S Gonsalkorale

Types of dentures

Complete dentures/full dentures Partial dentures Cobolt-chromium dentures Acrylic dentures

Cobolt chromium dentures

Treatment Sequence History, Exam, Primary impressions MMR, Face bow Treatment plan, design, informed consent Tooth modification, secondary

impressions Casting try-in MMR, shade selection Wax try-in Primary issue Secondary issue Fluoride treatment/ Exam/ Recall

Primary Impressions

Aim: To obtain an accurate models of the patients maxillary and mandibular oral tissues.

Facebow record

Facebow Record Adjustable articulators allow the cast of the

maxillary denture to be located accurately in relation to the mandibular condyles and to a horizontal plane of reference (frankfurt plane). The Facebow records this information clinically and transfers this relationship to an articulator.

The mandible moves along an arc of rotation as it opens and closes. The centre of rotation is in the condyle. The distance from the centre of rotation of the arc to the teeth is relevant in developing the occlusion

MMR: maxillo-mandibular relationship

Aim:– relate the upper cast

to the lower cast in the correct anatomical relationship.

– Relate the upper cast to the condyles in the correct relationship

How do you do this?

Hand articulate If you cannot hand articulate you will

need to use base plates with wax rims.

(The casts are then articulated)

Surveying and denture design

The articulated casts are surveyed before the denture is designed.

Special trays

Once the design has been finalised special trays are constructed.

Tooth modification

Based on the denture design carry out any tooth modification:– Rest seat

preparation– lowering of survey

lines– Guideplanes

Secondary impression

Once the tooth modification has been carried out a new impression is taken using the special tray.

Retake MMR

The new cast needs to be re-articulated against the existing lower cast.

If the casts cannot be hand articulated new baseplates and wax rims will be required.

Set teeth and wax-up

Once the casts have been re-articulated the teeth are set on the baseplate.

The wax contours are finalised. The denture is now ready to

process…...

Process denture

Heat cure acrylic - invest and pack Cold cure acrylic - construct key

Issue

Trim and polish denture carefully to maintain contours and maintain contact.

Polish with pumice and then with dentishine.

The denture is now ready to issue…...

References McGivney GP, Castleberry DJ. McCracken’s

Removable Partial Prosthodontics. 9th Ed. 1995.

Removable partial prosthodontics : a case oriented manual of treatment. Lechner SK, MacGregor AR. St. Louis : Wolfe c1994.

CD: ROM : Interactive Prosthodontics. Learning to design removable partial dentures. Lechner SK, Thomas GA. The University of Sydney.