Effect of bur type on bond strengths of adhesive systems to dentin

  Objectives:  The development of self-etching primers (SEP) and one-step self-etching adhesives (SEA) introduced new alternatives for bonding; however, concern remains about their efficacy on dentin prepared with different high-speed burs.  The purpose of this study was to compare the microtensile bond strength (mTBS) of three adhesives to human dentin prepared with 600-grit SiC paper (SiC), diamond stone (DS), or carbide bur (CB).

  Methods:  Human molars (n=27) were randomly divided into three treatment groups and bonded using a total-etch adhesive (Single Bond, 3M ESPE),  SEA (One-Up Bond F, Tokuyama) or SEP (SE Bond, Kuraray).  A 4-mm composite crown was built over the bonded surfaces and stored in water for 1 day at 37°C.  Specimens were sectioned into 0.7-mm thick slabs, trimmed to a cross-sectional area of 1 mm², and loaded to failure at crosshead speed of 1 mm/min using a table top tester (EZ-Test).  Data were analyzed using ANOVA and Fisher’s PLSD test (p<0.05).

  Results:  Values are expressed as mean ± SD (in MPa) and same superscripts indicate no statistical significant difference (p>0.05).

  Conclusions:  All adhesives had significantly higher mTBS to dentin prepared with carbide than with diamond or SiC.  SEP and SEA had mTBS higher than or similar to the total etch system.  Clinicians should be aware that different bur types commonly used for cavity preparations might affect the performance of adhesives on dentin.

  Acknowledgements:  The authors would like to thank J. Morita and Kuraray Inc.