Strengths of modified amalgam-to-dentin interphases

Amalgam remains the primary dental restorative for nearly 200,000,000 Indonesians. Ground occlusal dentin surfaces of 140 formaldehyde-treated human molars were used to study shear strengths of different adhesive bonds (40: Syntac/Variolink, 40: Amalgambond Plus (AP), 40: AP+microfibre, and 20: Amalcoden) to a spherical high-copper amalgam (Valiant, Ivoclar NA). After 24 h at 37 degrees C/100 RH, restorations were stored for 7 d under one of four different conditions (all 37 degrees C) : A, 100% RH; B, deionized water; C, 0.9% NaCl solution; D, saliva electrolyte solution. Amalcoden-treated samples were exposed to conditions A and B only. ANOVA and Tukey post hoc analysis (P<0.05) were applied. For any single storage condition, AP+microfibre bond strengths were significantly greater than those for other agents tested. Storage condition was a significant variable only for the AP+microfibre; weaker bond strengths were observed for saline-stored samples. Improvement of restorative-to-dentin interfaces, eliminating pulp sensitivity, can result from aldehyde pre-treatment of teeth, as well as from the use of microfibre-filled Amalgambond Plus. These results illustrate the importance of "stabilization" of the entire interphase.