Objectives: The purpose of this study was to evaluate the tensile bond strength (TBS) of resin cement to resin-coated dentin using an in vitro model system.

Methods: Flat dentin surfaces (#180) of 40 bovine teeth were coated with a self-etching adhesive (Brush&Bond, Parkell) as a coating material. The oxygen inhibited layer on the coated surface was removed with an ethanol containing cotton pellet. The coated specimens were stored in 37˚C water for a week, and then an adhesive cement (Totalbond, Parkell) was applied to the surface (4.8 mm diameter) with and without a pretreatment (re-application) of Brush&Bond. Non-coated dentin specimens were used as a control group. The TBS was measured after 24 hours storage in 37˚C water. The data were analyzed by ANOVA (p=0.05, n = 10).

Results: The results (Table below) showed that the TBS of Totalbond to the resin-coated dentin exposed to water was significantly lower than that to the non-coated dentin (p<0.05). The Brush&Bond pretreatment was significantly effective to increase the TBS to resin-coated dentin (p<0.05). The improved TBS value was equivalent to the values to non-coated dentin specimens.

Conclusion: It is concluded that the Brush&Bond pretreatment is essential to improve the bond strength of Totalbond to resin-coated dentin surface.

Table. Results of TBS (mean value ± standard deviation., unit: MPa)

Resin coating	Coated		Non-coated
Pretreatment	None	Brush&Bond	Brush&Bond	10-3 solution
TBS	5.0 ± 2.8 a	12.2 ± 3.1 b	13.2 ± 2.6 b	13.4 ± 1.7 b

                   Values with the same superscripts are not significantly different (p>0.05).