This study evaluated the influence of application time of self-etching primers on microtensile bond strength (μTBS) to dentin using three self-etching primer adhesive systems.

Dentin surfaces were exposed from forty-eight human molars. They were conditioned with three self-etching primers (Clearfil SE Bond [SE], Unifil Bond [UF], Tyrian SPE + One Step Plus [TY]) and different primining times (10s, 20s, 30s and 40s). Composite resins were bonded to dentin surfaces and specimens were made. μTBS was tested and statistically compared using by one-way ANOVA and Tukey’s Test.

The results of this study presented that priming time for 10s in SE and UF groups and for 30s and 40s in TY group was highly decreased μTBS to dentin.

The purpose of this study was to compare and to evaluate the combination use of 5 kinds of dentin adhesive systems and 5 kinds of composite resins using micro-shear bond test. Five adhesive systems (Prime & Bond NT (PBN), Onecoat bond (OC), Excite (EX), Syntac (SY), Clearfil SE bond (CS)) and five composite resins (Spectrum (SP), Synergy Compact (SC), Tetric Ceram (TC), Clearfil AP-X (CA), Z100 (Z1)) were used for this study (5 × 5 = 25group, n = 14/group). The slices of horizontally sectioned human tooth were bonded with each bonding system and each composite resin, and tested by a micro-shear bond strength test. These results were analyzed statistically. The mean micro-shear bond strength of dentin adhesive systems were in order of CS (22.642 MPa), SY (18.368 MPa), EX (14.599 MPa), OC (13.702 MPa), PBN (12.762 MPa). The mean bond strength of self-etching primer system group (CS, SY) in dentin was higher than that of self-priming adhesive system groups (PBN, EX, OC) significantly (P<0.05). The mean bond strength of composite resins was in order of SP (19.008 MPa), CA (17.532 MPa), SC (15.787 MPa), TC (15.068 MPa), Z1 (14.678 MPa). Micro-shear bond strength of SP was stronger than those of other composite resins significantly (P < 0.05). And those of TC and Z1 were weaker than other composite resins significantly (P < 0.05). No difference was found in micro-shear bond strength of composite resin in self-etching primer adhesive system groups (CS, SY) statistically. However, there was significant difference of micro-shear bond strength of composite resin groups in self-priming adhesive systems group (PBN, EX, OC). The combination of composite resin and dentin adhesive system recommended by manufacturer did not represent positive correlation. It didn’t seem to be a significant factor.