Flexil Silicone for Retentive Gaskets

Occasionally we are confronted with partials containing only 1- 4 teeth. It is most difficult to obtain stability with either a flexible or metal partial under these circumstances. We circumvent the problem by adding rubber gaskets around the teeth. Acrylic-silicone combinations became the standard procedure of choice. The technique requires the silicone to be attached to acrylic. If the acrylic is too thick it will be too uncomfortable for the patient. It could also be bulbous, unesthetic and the dentist will invariably trim it down to please the patient. In many cases the acrylic fractures. That is why we recommend Flexite MP, a semi flexible, multi-polymer acrylic with elastomer polymers. The adhesion of silicone to Flexite MP is outstanding. It can be thinned down without fracturing.

Case I

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The teeth and mucosa are surveyed. Relief wax is applied allowing moderate undercuts to encircle the tooth near the gingival third. A duplication is made of the model. The waxed up setup is transferred from the master model to the duplicate model. A completed waxup is made and the case is invested in the flask using all stone. We will be injecting Flexite MP into the flask. All stone is recommended for the injection process. After the denture is injected and finished it is fitted to the master model and polished. The inside of the clasps are roughened and a binder is applied. Silicone is then added inside the clasps and pressed into position. Flexil has a two catalyst system that gives you the option of doing a quick cure or a regular cure.

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Partial denture off the model.

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Observe the excellent esthetics with the denture seated on the model.

Note how thin the buccal clasp section is. This cannot be obtained with conventional acrylic.

Case II

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A unique case with only two teeth remaining to support the denture. (#1 and #16)

The patient wished to retain the two molars. The question of suction and retention with two posterior teeth would be a challenge. Using the same procedure we made two gasket clasps around #1 and #16.

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The finished case clicked into place perfectly and held firmly without any movement.

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A view of the case off the model.

This result could not have been attained with metal or flexible dentures. In the future, should the two molars have to be extracted, it would be easy to convert Flexite MP into a complete full denture because acrylic can be added directly to it.

Case III

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Illustustration shows a lower with 4 remaining teeth.

The gaskets would be placed around lower right cuspid and first bicuspid, (#22 And #27) and left cuspid and first bicuspid on the left (#22 and #21). Using the same procedure, the the teeth are surveyed, blocked out in strategic areas and the model is duplicated. The setup is transferred and the case is completed as previously described.

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Anterior view – completed partial.

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Occlusal view – completed partial.

For all intense and purposes, this is a full lower denture. It will be easier for the patient to get used to the denture with the stabilizing gaskets. Depending on the longevity of the teeth, the knowledge that it could easily be converted to a full lower is reassuring to the patient who will not be without the denture for a longer time than is necessary.

Summary

Cases with 1-4 teeth remaining always present retention problems and challenges. By having the retention encompass the entire tooth, stability is achieved by total reciprocation. Conventional clasping usually engage the buccal and lingual surfaces of the tooth and end up inadequate for these type of cases. An alternative method has been presented for these unusual cases.