Differential resin-dentin bonds created after caries removal with carbide burs

Objective: To evaluate the bonding efficacy of four different adhesive systems in caries affected dentin excavated with carbide burs. Methods: Resin restorations were performed in sound and caries-affected dentin, after using carbide burs and bonding with four different adhesive (Single Bond -SB-; Clearfil SE Bond -SEB-; FL-Bond II, -FLB-; and Fuji IILC –FUJI-). Microtensile bond strength (MTBS) was measured. Data were analyzed with ANOVA and Student-Newman-Keuls tests. Debonded surfaces were observed by scanning electron microscopy. Bonded interface morphology was examined using light microscopy (Masson's trichrome staining). Results: Mean and standard deviation of MTBS (MPa) is presented in the table. Within the same column, identical letter indicates no differences; for each row, matching numbers indicate no differences (p>0.05). Sound dentin showed major collagen encapsulation than the bonded caries affected dentin interfaces in which non uniform pink and red areas below the adhesive interface, and thicker hybrid layers are observed. Conclusions: Lower MTBS was found for caries-affected dentin (except for FLB). In caries-affected dentin, porous and non-homogeneously infiltrated hybrid layers were observed, when bonding with self-etching agents hybridized complexes could not be clearly detected. Acknowledgements: CICYT/FEDERMAT2008-02347 and MAT2011-24551, JA-P08-CTS-3944 and P07-CTS-2568.