Factors influencing the connection of acrylic teeth with denture plate

Introduction
Patients who use removable dentures often contact dentists about restoration of a separation or fracture of their acrylic teeth. This causes great discomfort for the patient as well as huge labor and time-consuming procedures for dentists and dental technicians.

Objectives: The purpose of this study was to evaluate the adhesion between self-curing acrylic material and teeth in distillate water and denture disinfection agent.

Material and methods
Five types of self-cure acrylic resin samples’ groups were prepared for the study, and were combined with acrylic teeth. First group included teeth samples made without surface modification, second group consisted of teeth samples’ surfaces activated with acetone, while in third group, retention holes were made. In fourth group of samples, their surfaces were increased by retention holes and washed twice with monomer, whereas in fifth group of teeth, cervical layers were grinded with a bur. One plate from each group was stored in distilled water (W) and another in Corega Tabs (CT) solution for 30 days at 37oC. Connection between acrylic resin-acrylic tooth was assessed using tensile strength instrument.

Results
The highest bonding force was achieved between Villacryl SP and Mifam teeth in the group with retention holes made and surface washed twice with monomer (W: 149.86 ± 5.42 N; CT: 146.38 ± 4.39 N), cohesive type. The lowest adhesion values were observed for tooth surfaces with no changed surface (W: 15.15 ± 3.44 N; CT: 13.49 ± 3.80 N), and with samples washed with acetone (W: 15.8 ± 3.22 N; CT: 12.0 ± 1.0 N). In these cases, the connection had adhesive character.

Conclusions
A proper connection between acrylic teeth and surface of denture base is possible to achieve when both chemical and mechanical methods surface are combined, thus increased by retention elements.