The effect of chemical surface treatments
on the flexural strength of repaired acrylic
denture base resin material 
- Nonglax Thunyakitpisal D.D.S.
- Chairat Wiwatwarapan B.Sc., M.S. (Polymer Science)
Abstract :
Objective To evaluate the effect of the selected chemical surface treatment agents on flexural strength
of heat-cured acrylic resin after repairing with auto-polymerized acrylic resin.
Materials and methods Sixty heat-cured acrylic resin specimens were prepared according to ISO
1567 and divided into six groups; positive control (group 1), negative control (group 2) and four
experimental groups (group 3-6). Group 2 and all experimental groups were cut in the middle and
beveled at 45 degree. Group 2 was untreated. Group 3 and 4 were treated with liquid part of Unifast
triad® for 5 and 180 seconds, respectively. Group 5 and 6 were treated with methyl acetate and methyl
formate for 15 seconds, respectively. All the specimens in group 2-6 were then repaired with
auto-polymerized acrylic resin. A three-point loading test was performed using universal testing
machine (Instron Corp, USA). Statistically analysis was done by one-way ANOVA and post hoc
Tukey's analysis at p < 0.05. Failure analysis was also categorized as adhesive or cohesive failure for
each specimen.
Results The flexural strength of group 1 and 3-6 were significantly greater than that of the group 2
(p < 0.05) and the flexural strength of group 5 and 6 were significantly greater than that of the
group 3 (p < 0.05). All fractured specimens in group 5 and 6 showed only cohesive failure.
Conclusion From this study, surface treatment with methyl acetate and methyl formate showed
high flexural strength when repairing denture base resin.
(CU Dent J. 2010;33:89-98)
Keywords :
acrylic resin; flexural strength; methyl acetate; methyl formate; repair