[The studies on microtensile bond strength measurements of two dentin adhesives].
OBJECTIVE
The purpose of this study was to investigate the feasibility of a modified microtensile method used to test bond strengths of two current one-bottle dentin bond systems (Prime & Bond NT, PBNT; Prime one Mirage, P-One) with a parallel match design.


METHODS
15 extracted, caries-free human molars were cut to expose occlusal dentin. A 5 mm deep slot was prepared in each crown to divide the crown into nearly equal halves for accepting treatment of the two dentin bond systems, respectively. After 24 h storage in distilled water at 37 degrees C, the bonded teeth were subjected to two treatments: 5 teeth were tested without further treatment and 10 teeth were thermocycled (2400 cycles, between 5 degrees C and 55 degrees C) prior to bond strength testing. Hour-glass shaped specimens with a distance of approximately 1.0 mm at the narrowest portion were cut from each tooth and tested in tensile mode.


RESULTS
Bond strengths (mean MPa) were: for PBNT: 42 & 31, and for P-One 64 & 38 without and with thermocycling, respectively. Two-way ANOVA revealed a significant difference in bond strengths(P < 0.001) between the two systems and when thermocycled. However, a pairwise multiple comparison (Tukey test) showed that after thermocycling the difference between the two systems was not significant (P > 0.05). Regression analysis showed that a correlation existed between the two systems' tensile bond strength values grouped by tooth (correlation coefficient r = 0.575, P < 0.05).


CONCLUSIONS
The modified microtensile method with a parallel match design is feasible and suitable for evaluating two different bonding systems or dentin treatments.
Xie
B
B
Department of Stomatology, Kunming Medical College, Kunming 650031, China.
Dickens
S H
SH
Schumacher
G E
GE
Giuseppetti
A A
AA
D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D008963:Molar / Q000293:injuries; D013718:Tensile Strength
D003738:Dental Cements; D017220:Dentin-Bonding Agents