Bonding of acrylic denture teeth to resin denture bases

Abstract

Anterior teeth debonding from dentures is a common prob­ lem. This study tested the bond strength of denture teeth to two types of denture res1n, with and without grooving the ridge-lap surface. Bond strength and fracture type of three d1fferent groups were compared: 1 Teeth bonded to heat-cured polymethyl methacrylate (PMMA); 2. Teeth bonded to pour-type PMMA: 3. Grooved teeth bonded to pour-type PMMA. Specimens were manufactured following ISO standard 22112. Force values at failure were analysed using one-way analy­ sis of variance, us1ng the mixed procedure with confidence interval of 95%. Types of failure were Identified as adhes1ve, cohesive or combination. Indescending order, mean failure forces were 418.551\J (Group One), 367.551\J (Group Two) and 290.051\J (Group Three). There was no significant difference between the means of groups 1 and 2 (p=0.0627). Group Three differed from both other groups (p<0.001). Groups One and Two showed pre­ dominantly cohesive fractures within denture teeth (83% and 72% respectively): group Three showed predom1nant1y cohe­ sive fractures withtn the denture PMMA (75%) Wtthout ridge-tap modiftcat1on, the bond strengths of den­ ture teeth to pour-type and heat-cured denture res1n were Similar. Failures were predominantly of cohesive nature with1n the teeth themselves. Grooving the ridge-tap reduced fracture resistance and ted to breakages predominantly in denture PMMA.