NEW ADHESIVES IN CLASS-V RESTORATIONS UNDER COMBINED LOAD AND SIMULATED DENTINAL FLUID

Objectives. This study compared the efficacy of three dentinal adhesives using the ''all etch'' technique (All-Bond 2, Bisco; Scotchbond MP, 3M Dental Products Co.; OptiBond, Kerr) with a dentinal adhesive which still uses phosphoric acid to condition enamel and a self-etching primer for dentin (A.R.T.-Bond, Coltene/ Whaledent). Methods. Eight V-shaped mixed Class V restorations were placed per group in extracted human premolars. The restorations were subjected to 1,200,000 mechanical occlusal cycles (max. force 49 N; frequency 1.7 Hz) and 3,000 simultaneous thermal cycles (5-50-5 degrees C). Dentinal fluid was simulated using 1:3 diluted horse serum and fed into the pulp chamber both during restoration and loading. Percentages of ''continuous margin'' were assessed on SEM replicas of enamel and dentinal margins at 200x magnification immediately before and after stressing, respectively. Results. No significant differences were observed before stress between the materials either in enamel or in dentin. After stress, however, OptiBond and A.R.T.-Bond performed significantly better in dentin than the two other adhesives (Kruskal-Wallis, Mann-Whitney; p < 0.05). Although high initial values were observed, All-Bond 2 and Scotchbond MP were not stress-resistant under simulated physiological conditions. Significance. The predicted clinical potential of All-Bond 2 and Scotchbond MP is inferior to that of OptiBond and A.R.T.-Bond.