Avaliação morfológica da cicatrização de defeitos ósseos de tamanho crítico em calvária de ratos usando sulfato de cálcio como substituto ósseo

Abstract

The dental implant is a bone-level dependent treatment that requires, among other factors, an adequate amount of bone tissue. In case of insufficient bone, grafts could be utilized to preserve/restore this bone using different materials. Among them, it is possible to highlight the bone substitutes, such as calcium sulfate (CS). The objective of this paper was to evaluate the CS material in critical-size bone defects in calvarial bone of rats. Forty Wistar rats (180 to 200 g), male, were divided into 2 groups. Each group was subdivided into 4 other based on the period of healing (15, 30, 45 and 60 days). In each animal a circular defect with 8 mm in diameter was made and filled with CS (test) or Bio-Oss® (control). In all animals the defect filled with the respective material was covered by resorbable collagen membrane. After the healing period, the animals were killed, samples were collected, fixed, decalcified and were embedding in paraffin. The sections were stained with hematoxylin and eosin stain. The defects filled with CS developed nucleation centers at 15 days of observation, showed no significant inflammatory response and they did not develop fibrosis. CS was quickly resorbed and none of the defects showed complete regeneration after 60 days of observation. The defects filled with Bio-Oss® showed bone formation at 15 days on collagen membrane. The granules of Bio-Oss® induced osteoconduction and after 60 days some defects presented bone replacement. We conclude that the CS had worse results in comparison with Bio-Oss® material in terms of new bone formation in all observation periods.