A comparative study of three dental adhesives

The shear bond strengths of three dental adhesives to dentine and a NiCrBe alloy were determined. Forty human third permanent molar teeth were ground to expose superficial dentine, to 20 of which P50 composite was bonded, using All-Bond 2 (n = 10) or Scotchbond 2 (n = 10). Alloy discs were bonded to the remaining 20 specimens, using either All-Bond 2 (n = 10) or Panavia Ex (n = 10). All specimens were stored at 37 degrees C. 100% RH, for 24 h. Testing was carried out using a shear jig at a cross-head speed of 1 mm min-1, following which a 0.5 mm increment was removed to expose middle dentine for further bond tests (n = 10 for each adhesive). Removal of a further 0.5 mm increment exposed 'deep' dentine for final dentine bond strength tests. Results were then aggregated for each substrate/adhesive combination (n = 30). Alloy/alloy bond strengths were determined after bonding alloy discs together using Panavia Ex (n = 30) or All-Bond 2 (n = 30). Results were analysed using ANOVA and Weibull analysis. All-Bond 2 produced significantly greater and more reliable bond strengths to dentine than did either Scotchbond 2 or Panavia Ex. The bond strength of Scotchbond 2 and Panavia Ex to dentine was dependent upon the dentine depth whereas the bond strength of All-Bond 2 to dentine was independent of dentine depth. Alloy/alloy bond strengths were significantly greater when using Panavia Ex compared with All-Bond 2.