[Effect of two different desensitizers on bond strength of dentin bonding agents].
OBJECTIVE
To evaluate the bond strength of total-etch or self-etch dentin bonding agents after using two different dentin desensitizers on exposed dentin and investigate the bond interface by scanning electron microscope (SEM).


METHODS
Thirty intact and non-carious human third molars were used. The occlusal enamel was removed with the use of a slow-speed saw under water cooling. These teeth were divided into three groups using a table of random numbers with 10 teeth each. These three groups were treated with water (Group C), UltraEZ (Group U) and MI Paste (Group M) respectively. Then 10 teeth from each group were divided into A subgroup (n = 5) bonded with Single Bond 2 adhesive system and B subgroup (n = 5) bonded with Xeno III adhesive system according to manufacturers' instructions. A block of composite resin was build up to 4-5 mm. All the teeth were sectioned occluso-gingivally to obtain bar-shaped specimens with bonded surface area about 0.9 mm x 0.9 mm. The tension of the sample was tested by a microtensile tester at 1 mm/min. The mean values of bond strength were compared using one-way ANOVA. Three samples were chosen randomly from each of six groups for SEM investigation.


RESULTS
There were no significant differences between Group U and Group C both in A and B subgroups. While there were significant differences between Group M and Group C in two bonding-agent subgroups. For SEM, the hybrid layer was thin and dense in six groups. Both total-etch and self-etch bonding systems could get fair resin tag infiltration in Group C and Group U. In Group M, the resin tags were relatively shorter and fewer than the anterior mentioned two groups.


CONCLUSIONS
UltraEZ had no effect on bond strength of both kinds of dentin bonding agents, while MI paste could diminish bond strength.
Yang
Yun-Dong
YD
Department of Prosthodontics, School of Stomatology, Wuhan University, China.
Xiao
Hui-Juan
HJ
Duan
Yin-Ling
YL
Huang
Cui
C
Wang
Yi-Ning
YN
Cheng
Xiang-Rong
XR
D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D003764:Dental Materials; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008964:Molar, Third; D009566:Nitrates / Q000737:chemistry*; D017680:Potassium Compounds / Q000737:chemistry*
D003764:Dental Materials; D017220:Dentin-Bonding Agents; D009566:Nitrates; D017680:Potassium Compounds; C489164:UltraEZ; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate