THE EFFECT OF CAVITY WALL TAPER ON FRACTURE-RESISTANCE OF TEETH RESTORED WITH RESIN COMPOSITE INLAYS

The effect of a range of cavity wall tapers on fracture resistance of teeth restored with an indirect composite restoration (ICR) system has been investigated, using two methods of application of the fracturing force. The fracture load data are similar in both cases, and in neith er cass does ANOVA suggest a statistically significant difference in p erformance with cavity taper. However, the mean values are lower for t he 6-degrees taper specimens, and linear regression suggests a signifi cant decrease, which is confirmed by the mode data for the bar loading condition, which indicates a greater incidence of severe fractures fo r the 6-degrees taper. Since technical difficulties were encountered i n the construction of inlays for the 2-degrees taper preparations, the most appropriate taper of the range assessed would appear to be 4-deg rees, at least when considered with regard to fracture resistance.