Effects of residual water on microtensile bond strength of one-bottle dentin adhesive systems with different solvent bases.
BACKGROUND
The wet-bonding technique is recommended for the one-bottle dentin adhesive systems, but the moisture concept varies widely among the instructions of manufacturers as well as among investigators. The aim of this study was to evaluate the effects of different dentin surface moisture on the microtensile bond strength(s) of an ethanol/water-based adhesive system and an acetone-based system to dentin.


METHODS
Forty intact human premolars extracted for orthodontic reasons were used. Superficial occlusal flat dentin surfaces of these premolars were exposed, finished with wet 600-grit silicon carbide paper. Under four wet and dry conditions (overwet, blot dry, one-second dry and desiccated), resin composite was bonded to dentin by using Single Bond (SB) or Prime & Bond NT (PB) according to the manufacturers' instructions. The teeth were longitudinally sectioned in the "x" and "y" directions to obtain bonded beams with a cross-sectional area of 0.81 mm(2) with a slow-speed diamond saw. The bonded specimens were tested in tension at a crosshead speed of 1 mm/min until failure of the bonds. Failure modes were observed with a scanning electron microscope. The mean bond strengths were analyzed by one-way ANOVA and Turkey's test.


RESULTS
The bond strength of the overwet/SB, blot dry/SB, one-second dry/SB and desiccated/SB groups was 10.87 MPa, 22.47 MPa, 24.91 MPa and 12.99 MPa, respectively. The bond strength of the overwet/PB, blot dry/PB, one-second dry/PB and desiccated/PB groups was 10.02 MPa, 20.67 MPa, 21.82 MPa and 10.09 MPa, respectively. For both SB and PB, the blot dry group and one-second dry group revealed significantly higher bond strengths than the overwet and desiccated groups (P < 0.05).


CONCLUSIONS
In order to achieve the highest bond strength to dentin, keeping the dentin surface in an appropriately moist condition is critical for the one-bottle dentin adhesive systems with ethanol/water or acetone solvent.
Zhang
Zhi-xing
ZX
Department of Prosthodontics, School of Stomatology, Wuhan University, Wuhan 430079, China.
Huang
Cui
C
Zheng
Tie-li
TL
Wang
Sa
S
Cheng
Xiang-rong
XR
D000293:Adolescent; D000328:Adult; D001840:Dental Bonding; D017220:Dentin-Bonding Agents / Q000494:pharmacology*; D006801:Humans; D012997:Solvents; D013718:Tensile Strength; D014867:Water
D017220:Dentin-Bonding Agents; D012997:Solvents; D014867:Water