[Influence of storage methods on microtensile bond strength of dentin adhesive system].
OBJECTIVE
To compare the effects of teeth stored with different methods and different durations of storage on the microtensile bond strength of the dentin adhesive system Single Bond.


METHODS
30 human first premolars were stored immediately after extraction in one of five commonly used methods respectively: 0.02% distilled water and thymol, 10% formalin, 1% chloramine, distilled water at 4 degrees C and were refrigerated at -20 degrees C. After 10 days, 90 days, the dentin adhesive system Single Bond and composite Z250 were applied to superficial occlusal flat dentin according to the manufacturers' instructions and microtensile bond strength measurements were evaluated, freshly extracted teeth being used as control. Stero-microscope and scanning electronic microscope were used to evaluate the fracture modes of the microtensile bond strength specimens. Two-way ANOVA was used for analysis of the microtensile bond strengths among different groups.


RESULTS
The results showed that there was significant difference among five tooth storage methods on the microtensile bond strength of dentin bonding agent (P=0.01). Compared with freshly extracted teeth, two of five storage methods/media, 0.02% distilled water and thymol at 4 degrees C (P=0.008) and distilled water at 4 degrees C (P=0.024), resulted in significantly lower microtensile bond strengths. The duration of teeth storage had no effect on the microtensile bond strength of dentin bonding agent (P=0.279). The interaction of two factors was significant (P=0.000). Stero-microscope and SEM examination indicated that all fracture modes were adhesive failures.


CONCLUSIONS
From this study, it can be concluded that the teeth storage methods/media can influence the microtensile bond strength of Single Bond adhesive system. If sufficient numbers of freshly extracted teeth are not available for bond strength test, the freezing teeth at -20 degrees C and teeth stored in 1% chloramine at 4 degrees C are preferred .
Zheng
Tie-li
TL
Key Lab for Oral Biomedical Engineering of Ministry of Education, Wuhan University, Wuhan 430079, Hubei Province, China.
Huang
Cui
C
Zhang
Zhi-xing
ZX
Wang
Sa
S
Zhang
Guo
G
D001840:Dental Bonding / Q000379:methods*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004356:Drug Storage / Q000379:methods*; D008422:Materials Testing; D019279:Resin Cements; D013718:Tensile Strength
D017220:Dentin-Bonding Agents; D019279:Resin Cements