[Influence of time on shear strength using resin cements].

Purpose: 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).