Dentin Bond Strength of Bonding Agents to Moist and Dry Dentin

Self-etching bonding agents promise simpler application especially being able to bond to dry or moist dentin.  Objective: This study measured and compared the dentin shear bond strength of 3 self-etching bonding agents bonded to dry and moist dentin and 1 three-bottle adhesive (Optibond Solo Plus).  Methods:  Forty extracted teeth were ground on a polisher grinder to create a superficial dentin bonding area. The dentin was finished with a series of abrasive disks ending with 320 grit.  The bonding agent was applied following each manufacturers’ directions.  The self-etching bonding agent was applied to air-dried dentin or to moist dentin (dentin dried with a tissue).  After the bonding agents were light cured with a Caulk Spectrum curing light with output > 600 mW/cm², Z-250 composite resin (shade A2) was placed into a Teflon tube and inserted over the cured adhesive.  The Z-250 was light cured from three directions for a total of 60 seconds. The specimens were stored in tap water at room temperature for 24 hours.  After storage, the specimens were placed into an Instron testing machine model 4411 and loaded in shear at a 5 mm per minute crosshead speed until failure.  Data were analyzed with ANOVA and Tukey B. (n=10).  Bond strength = MPa. Results:       

Wet and dry shear bond strength for self-etching adhesives were not significantly different (p>.05). Bond decreased to dry dentin with Optibond Solo (p=.05). Conclusions:  Moisture tolerance of self-etching adhesives is good and eliminates an important variable in bonding.