PURPOSE: To evaluate the influence of using either ultrasonic CVD (Chemical Vapor Deposition) or conventional rotary diamond tips on the adhesive strength of cingulum rest seats made of composite resin over bovine dentin. METHODS: Twenty specimens were produced for each experimental group. For specimens in Group 1, the dentin was exposed with a rotary diamond tip; in Group 2 this procedure was performed using an ultrasonic CVD diamond tip. In both groups a two-step self-etching adhesive system was used, and the shape and size of the rest seats made of composite resin were standardized. The specimens were subjected to a shear assay using a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed by Student's t-test at the significance level of 0.05. RESULTS: There was a statistically significant difference (P=0.028) between the means of the experimental groups: 24 kgf for Group 1 and 31 kgf for Group 2. CONCLUSION: Dental preparation with dentin exposure in the cingulum region by using ultrasonic CVD diamond tip showed the highest bond strength of self-etching adhesive system and composite rest seats for support of removable partial dentures.
Removable partial prosthesis; composite rest seat
