Effect of chemical surface treatment on bond strength of a heat-cured acrylic resin denture base and a reline resin
PURPOSE : This study evaluated the influence of chemical surface treatment of a heat-cured acrylic resin denture base on bond strength of a hard reline resin (Tokuyama Rebase II).
Materials and methods : Heat-cured acrylic resin disks (n=120), 16±1 mm in diameter and 15±1 mm thick, were fabricated and divided into 8 groups (n=15) with different surface treatments:
1) no treatment (control)
2) adhesive of Tokuyama Rebase II
3) monomer of Unifast Trad
4) monomer of Unifast Trad + adhesive
5) monomer of Tokuyama Rebase II
6) monomer of Tokuyama Rebase II + adhesive
7) solution of methyl formate and methyl acetate
8) solution of methyl formate and methyl acetate + adhesive.
After chemical treatment, the reline resin was applied to the bonding area (5 mm diameter) and polymerized at 37±1°C for 8 minutes. Bonded specimens were immersed in distilled water for 24 hours before testing. Shear bond strength tests were performed using a Universal testing machine. Data were statistically analyzed using one-way ANOVA and Tukey’s HSD test at 0.05 significance level.
Results : The mean shear bond strengths of the groups without adhesive were not significantly different. (p>0.05) The surface treatment with solution of methyl formate and methyl acetate and the adhesive had significantly greater bond strength than those of the others (p<0.05).
Conclusion : The adhesive is needed to treat surface of the denture base before relining with Tokuyama Rebase II. The use of solution of methyl formate and methyl acetate combined with the adhesive could help increase the bond strength.Keyword: Surface treatment, Bond strength, Reline, Denture base