The purpose of this study was to evaluate the effect of methyl formate-methyl acetate (MF-MA) surface
treatment on flexural strength between denture base and hard reline materials. One hundred heat-cured acrylic
denture base (Meliodent®) specimens were prepared according to ISO 20795-1 (2013) and divided into ten groups.
Groups I-III: relined with Unifast Trad®, Group IV-VI: relined with Kooliner® and Group VII-X: relined with Tokuyama®
Rebase II Fast. Groups I, IV and VII were untreated surface (control groups), Groups II, V and VIII were surface treated
with methyl methacrylate (MMA) for 180 s and Groups III, VI and IX were surface treated with methyl formate-methyl
acetate (MF-MA) solution for 15 s, Group X were surface treated with the provided adhesive per the manufacturer’s
instructions. Flexural strength was measured using a Universal Testing Machine. The data were analyzed using two-way
ANOVA (group I-IX) and one-way ANOVA (group I-X) where significant differences in the groups were found. The group
means were compared using Tukey’s test at a 95 % confidence level. The reline material type and surface treatments
significantly affected on the flexural strength (p<0.05). For each reline material, the flexural strength of the MF-MA
treated group was significantly higher compared with the other groups (p<0.05). For the same surface treatment,
the flexural strength of Unifast Trad® was significantly higher compared with Kooliner® (p<0.05). The flexural strength
of Kooliner® was higher than that of Tokuyama® Rebase II Fast (p<0.05). This study suggests the application of MF-MA
solutions for 15 s before relining procedure can increase the flexural strength between the denture base and hard
reline materials.