Shear bond strengths of three resin cements to dentine over 3 years in vitro.
OBJECTIVE
This study was conducted to evaluate the bond durability of three resin cements bonded to bovine dentine over a period of 3 years.


METHODS
Ten bovine dentine specimens were tested for shear bond strengths with each of the following materials: Panavia 21, BISTITE resin cement, and MASA Bond (experimental resin cement) at 1 day, 6 months, 1 and 3 years after cementation of a composite rod. All specimens were stressed in shear at a crosshead speed of 1mm min(-1) until failure. The means of the bond strengths were compared statistically by two-way ANOVA and Fisher's PLSD test (P<0.05). The mode of failure was classified after fracture of the bonds by SEM observation. Results for the mode of fracture were analyzed using the Mann-Whitney U-test.


RESULTS
The shear bond strengths (MPa+/-SD) for different times (1 day, 6 months, 1 and 3 years) were: Panavia 21 (15.2+/-3.6, 9.3+/-3.2, 8.5+/-2.1, 6.8+/-2.4), BISTITE (15.6+/-2.8, 11.0+/-1.4, 10.4+/-2.2, 9.0+/-2.7) and MASA Bond (29.6+/-9.5, 17.5+/-4.6, 19.6+/-4.5, 16.1+/-5.4). Panavia 21 and BISTITE strengths were significantly lower (P<0.05) at all times compared with MASA Bond, and 1 day strengths for all three materials were significantly higher (P<0.05) than 3 year strengths. Regarding the fracture modes after bond testing, there were statistical differences between the 1 day and the 1 year results for all cements (P<0.05). Although no Panavia 21 specimen showed complete cohesive failure in the demineralized dentine during the experiment, several BISTITE and MASA Bond specimens showed cohesive fracture in the demineralized dentine. For BISTITE, partially or complete demineralized dentine cohesive failures increased over time.


CONCLUSIONS
The type of resin cement seemed to have an influence on the long-term durability of bonding to dentine.
Department of Operative Dentistry, Faculty of Dentistry, Tokyo Medical and Dental University, 5-45 Yushima 1-chome, Bunkyo-ku, 113-8549, Tokyo, Japan. y.kitasako.odnt@dent.tmd.ac.jp
Y
Y
Kitasako
M F
MF
Burrow
N
N
Katahira
T
T
Nikaido
J
J
Tagami
D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D019245:Compressive Strength; D001840:Dental Bonding; D003804:Dentin; D017220:Dentin-Bonding Agents / Q000737:chemistry; D004356:Drug Storage; D019544:Equipment Failure Analysis; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry*; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D013997:Time Factors
D017220:Dentin-Bonding Agents; D019279:Resin Cements