Effect of surface treatment on marginal integrity of amalgam restorations (in vitro study)

A total of 80 freshly extracted human molars, free from caries, cracks & decalcifications, were used in this study. Conservative class I cavities were prepared in the occlusal surface. Two types of amalgam alloys were used, high copper (Dispersalloy) & conventional (Velvalloy). The prepared cavities were classified into 5 groups, 16 each carve (C), carve & polish (CP), precarve burnish (BC), past-carve (CB) & pre post carve burnish (BCB). The specimens were thermally stressed using the stress fatigue device. The marginal integrity of the amalgam enamel interface were evaluated using SEM, for the four marginal quantities: 1--excellent margin, 2--open margins, 3--enamel fracture, and 4--amalgam fracture. The results of this study revealed that higher copper amalgam demonstrated superior marginal integrity than the conventional one. The pre-post carve burnish group showed the highest percentage of excellent margin than the other groups.