Objective: To evaluate microleakage of indirect resin composite inlays luted to dentin with three resin cement strategies in MOD Class II restorations after specimens storage in various media and different periods of time.
Materials and Methods: Intact 48 freshly extracted human third molars were collected and disinfected. Then, MOD Class II cavity design was prepared in all selected teeth. These prepared teeth were assigned into three major sets (n=16) regarding to the luting cement (etch-and-rinse, self-etch and self-adhesive), and restored with the indirect composite inlays. Each set was divided (n=8) according to the aging medium into distilled water and lactic acid, only four restored teeth were kept in each aging medium for 24 h, whereas the remaining was immersed for 168 h. All the specimens were covered by double coats of nail varnish till 1 mm away from the margins of restoration and sunken in a 2% methylene blue solution for one day. Each specimen was cut into two halves in mesio-distal direction then examined by Stereomicroscope. Pearson Chi-Square Test was used to analyze the collected scores.

Results: Pearson Chi-Square Test revealed that, there was a significant difference (p < 0.05) between the three resin cement strategies in each storage medium and time. Etch & rinse (All-Bond 2/Choice) resin cement recorded the highest scores of dye penetration and self-etch (Panavia F2.0) resin cement showed the lowest scores.
Conclusions: Resin cement strategy, storage media and times showed a noticeable impact on the bond durability and microscopic gap formation between dentin and luting cement.