The Effect Of Different Preparation Designs & Cement Type On The Marginal Adaptation Of All-Ceramic Cantilever Anterior Fixed Partial Dentures

Abstract

This study was designed to evaluate the effect of different preparation designs and two types of cements on the marginal adaptation of anterior cantilevered fixed partial dentures. Three identical maxillary right canine acrylic teeth were selected from the refill teeth of the typodont. Each tooth was prepared to receive a different all ceramic retainer design; a full coverage, three quarter and a modified three quarter all ceramic retainer with labial extension. A total of 30 all ceramic zirconia cantilever bridges were constructed and divided according to retainer design into three main groups (10 bridges each). Impressions of the master dies were made with a silicone duplicating material. The impressions of the master dies were poured using a non-shrink epoxy resin material for the measurement of the marginal gap. Each group was divided into 2 sub-groups according to the type of cement. Sub group (A) cemented with resin cement while sub-group (B) cemented with glass ionomercement. Sandblasting was performed for all dies . Then,in case of resin cement, 37%phosphoric acid etching gel was applied to the epoxy resin dies for 20 seconds then rinsed for 10 seconds and air dried for 10 seconds. The cements were mixed according to manufacturer’s instruction then used for cementation of the bridges. Calculation of the marginal using stereo-microscope. Three-Way ANOVA test was used to examine the effect the different preparation designs and two cements on the marginal adaptaion of anterior cantilevered fixed partial denture. The results revealed that it was found that the cementation procedure caused statistically significant increase in the marginal adaptation of the restorations after the cementation procedure, with statistically a non-significant higher marginal gap toward Glass ionomercement. Also, it was found that the partial coverage and modified partial coverage restorations showed less increase in marginal adaptation in comparison to full coverage restorations after the cementation procedure due to more free ways for escapement of the cement. Conclusion: Within the limitations of the present study the following conclusions could be drawn:- • All bridges of different preparation designs and type of cement used were within the clinically acceptable marginal adaptation range. • Preparation design had affected the marginal adaptation measurements before the cementation procedure. • Preparation design had no effect on the marginal adaptation measurements after the cementation procedure. • The type of luting cement used had no effect on the marginal adaptation measurements . Clinical Recommendations : The type of luting cement used does not affect the marginal gap .