RESUMO
The purpose of this study was to investigate the effect of retaining holes on the denture base, as well as primer application, on the shear bond strength of denture base resin to the denture base. Using Trubyte Biotone artificial teeth, we selected a maxillary first molar and prepared a total of 80 teeth. Each prepared tooth was polished flat using a dental bar. The polished specimens were placed in the center of a silicon mold (diameter 30 mm, height 23 mm) and were embedded with clear acrylic resin (Ortho Jet, Lang Dental, USA). Forty specimens were shaped, using Fisher bar # 701 at the central part of the alveolar surface, to form retention holes. Each denture base resin was transferred to the resin after surface treatment, as instructed by the manufacturer. The highest shear bond strength (36.2 MPa) was achieved by heat-polymerized resin, when the retention hole and the primer were applied to the artificial tooth. The lowest shear bond strength (11.8 MPa) was achieved by auto-polymerized resin, when the primer was applied to the artificial tooth. The combination of heat-polymerized resin and artificial tooth resulted in a complex fracture pattern, whereas auto-polymerized resin and artificial tooth showed an adhesive fracture pattern.