BOND STRENGTH AND MICROLEAKAGE OF CURRENT DENTIN ADHESIVES

Objectives. The purpose of this in vitro study was to evaluate shear b ond strengths and microleakage of seven current generation dentin adhe sive systems. Methods. Standard box-type Class V cavity preparations w ere made at the cemento-enamel junction on the buccal surfaces of eigh ty extracted human molars. These preparations were restored using a mi crofill composite following application of either All-Bond 2 (Bisco), Clearfil Liner Bond (Kuraray), Gluma 2000 (Miles), Imperva Bond (Shofu ), OptiBond (Kerr), Prisma Universal Bond 3 (Caulk), Scotchbond Multi- Purpose (3M), or Scotchbond Dual-Cure (3M) (control). Lingual dentin o f these same teeth was exposed and polished to 600-grit. Adhesives wer e applied and composite was bonded to the dentin using a gelatin capsu le technique. Specimens were thermocycled 500 times. Shear bond streng ths were determined using a universal testing machine, and microleakag e was evaluated using a standard silver nitrate staining technique. Re sults. Clearfil Liner Bond and OptiBond, adhesive systems that include low-viscosity, low-modulus intermediate resins, had the highest shear bond strengths (13.3 +/- 2.3 MPa and 12.9 +/- 1.5 MPa, respectively). Along with Prisma Universal Bond 3, they also had the least microleak age at dentin margins of Class V restorations. Significance. No statis tically significant correlation between shear bond strength and microl eakage was observed in this study. Adhesive systems that include a low -viscosity intermediate resin produced the high bond strengths and low microleakage. Similarly, two materials with bond strengths in the int ermediate range had significantly increased microleakage, and one mate rial with a bond strength in the low end of the spectrum exhibited mic roleakage that was statistically greater. Thus, despite the lack of st atistical correlation, there were observable trends.