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Aim: The aim of the present study is to make a histologic analysis the effects of a human demineralized bone matrix and a polyurethane resin derived from the Ricinus communis, on bone regeneration process., Materials and Methods: For this, 24 rabbits were submitted to two surgical calvaria bone defects, one on the right and another on the left side of the parietal suture. The animals were divided in two groups. In group I the experimental defect (right side) was treated with a human demineralized bone matrix, while in group II the experimental cavity was treated with the polyurethane resin derived from Ricinus communis. The control defects were filled with the animals own blood. The animals were slaughtered after subsequent periods of 04, 07 and 15 weeks., Results: The histological analysis revealed that all groups (control and experiment), presented increased bone regeneration with time, but this repair was faster in the control group, even showing important decrease in defect thickness., Conclusion: Both materials proved to be biologically compatible, however polyurethane was more slowly resorbed presented considerable better results when compared with demineralized bone matrix.

Purpose: The purpose of this pilot study was to evaluate the histologic and mechanical healing process in dental implants under the action of pulsed electromagnetic field (PEMF)., Materials and Methods: Forty-eight commercially pure implant fixtures were implanted in tibiae metaphysis of 12 New Zealand white rabbits divided into experimental (PEMF) and control groups. A PEMF with pulse width of 85 microseconds and a pulse frequency of 20 Mc was applied for 30 minutes per day. The animals were killed 21 and 42 days after implantation. The mechanical tests were performed in all animals and bone biopsies were prepared for decalcified sections analysis., Results: Mechanical tests did not show significant differences between the groups (P > 0.05); however, statistically significant differences were observed over time (P < 0.0001). Similar histologic features were achieved for both groups., Conclusions: These results suggest that PEMF stimulation does not improve the bone-healing process around commercially pure dental implants.