Effect of surface treatments on shear bond strength of denture teeth to denture base resins

Abstract

Background: Debonding of denture teeth from denture bases is the most common failure in

removable dentures. The purpose of this study was to evaluate the effect of surface treatments on

shear bond strength of denture teeth to heat-polymerized and autopolymerized denture base resins.

Materials and Methods: In this experimental in vitro study, 60 maxillary central incisor acrylic

teeth were divided into two groups. Group M was polymerized with heat-polymerized acrylic resin

(Meliodent) by compression molding technique and group F was processed by autopolymerized

acrylic resin (Futura Gen) by injection molding technique. Within each group, specimens were divided

into three subgroups according to the teeth surface treatments (n = 10): (1) ground surface as the

control group (M1 and F1), (2) ground surface combined with monomer application (M2 and F2),

and (3) airborne particle abrasion by 50 μm Al2O3 (M3 and F3). The shear bond strengths of the

specimens were tested by universal testing machine with crosshead speed of 5 mm/min. Data

were analyzed by two-way analysis of variance (ANOVA) and Tukey’s honestly signifi cant difference

(HSD) tests (P < 0.05).

Results: The mean shear bond strengths of the studied groups were 96.40 ± 14.01, 124.70 ± 15.64,

and 118 ± 16.38 N for M1, M2, and M3 and 87.90 ± 13.48, 117 ± 13.88, and 109.70 ± 13.78 N for F1,

F2, and F3, respectively. The surface treatment of the denture teeth signifi cantly affected their shear

bond strengths to the both the denture base resins (P < 0.001). However, there were no signifi cant

differences between the groups treated by monomer or airborne particle abrasion (P = 0.29). The

highest percentage of failure mode was mixed in Meliodent and adhesive in Futura Gen.

Conclusion: Monomer application and airborne particle abrasion of the ridge lap area of the

denture teeth improved their shear bond strengths to the denture base resins regardless of the

type of polymerization.

Key Words: Acrylic resin, dental bonding, denture bases