The purposes of this study were to evaluate the microtensile bond strength of one-step adhesives according to various dentin surface treatments and to observe the interface between resin(Z-100™) and dentin under SEM.

In this study forty-five non-caries extracted human molars and three adhesive systems were used; All-Bond 2(AB), One-Up Bond F(OU), AQ-Bond(AQ).; In Group 1, 2, 3, AB was used and tooth surfaces were treated by smearing(S), ultrasonic cleansing(US), etching(E) respectively. In Group 4, 5, 6, One-Up Bond F was used and tooth surfaces were also treated as the same way above. In Groups 7, 8, 9, AQ Bond was used and tooth surfaces were treated as the same way. Each specimen was prepared for microtensile bond testing, and were stored for 24hrs in 37℃ distilled water. After that, microtensile bond strength for each specimen was measured. Specimens were fabricated to examine the failure patterns of interface between resin and dentin and observed under the SEM.

The results were as follows;

1. The results(mean±SD) of microtensile test were group 1, 25.69±4.31MPa; group 2, 40.93±10.94MPa; group 3, 47.65±8.85MPa; group 4, 36.98±9.14MPa; group 5, 39.66±8.45MPa; group 6, 43.26±13.01MPa; group 7, 25.07±4.2MPa; group 8, 30.4±4.74MPa; group 9, 33.61±7.88MPa.

2. One-Up Bond F was showed the highest value of 36.98±9.14MPa in dentin surface treatment with smearing, and there were significant differences to the other groups(p<0.05).

3. All-Bond 2 was showed the highest value of 40.93±10.94MPa in dentin surface treatment with ultrasonic cleansing, but was no significant difference to One-Up Bond F(p>0.05).

4. All-Bond 2 was showed the highest value of 47.65±8.85MPa in dentin surface treatment with etching(10%phosphoric acid), and there were significant differences to the other groups(p<0.05).

5. All-Bond 2 was showed the highest value of 47.65±8.85MPa in dentin surface treatment according to manufacture's directions, but was no significant difference to One-Up Bond F(p>0.05).

6. AQ Bond was showed the lowest microtensile bond strength with various dentin surface treatment, and the were significant differences to the other groups(p<0.05).