[Influence of time on shear strength using resin cements].
OBJECTIVE
To compare the shear bond strength of different composite resin cement systems at different time intervals.


METHODS
48 healthy non-carious human molars were selected in the study. The samples were divided into two groups, 24 in each group. (1) RelyX unicem was used on bonding, (2) Variolink 2 was used on bonding. All specimens were stored in water at 37 degrees C for 2 hours, 24 hours and 1 week. 8 specimens in each group were stressed in shear until failure. Statistical analysis was performed with SPSS11.0 software package. Debonged surface was examined under light microscope.


RESULTS
Shear bond strengths of two resin cements showed a significant increase as time went (P<0.05). The failure involved the adhesive/dentin interfaces.


CONCLUSIONS
Time can influence the shear bond strength using different composite resin cement systems. Supported by Shanghai Leading Academic Discipline Project (Grant No.T0202).
Weng
Wei-min
WM
Department of Prosthodontics, College of Stomatology, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, China.
Zhang
Xiu-yin
XY
Zhang
Fu-qiang
FQ
D002681:China; D001840:Dental Bonding; D003738:Dental Cements; D003804:Dentin; D017220:Dentin-Bonding Agents; D005899:Glass Ionomer Cements; D019279:Resin Cements; D033081:Shear Strength
D003738:Dental Cements; D017220:Dentin-Bonding Agents; D005899:Glass Ionomer Cements; D019279:Resin Cements; C103502:Variolink