Chronic periodontitis can be successfully simulated in primates by the method employed in this study. Osseous defects can be created with a marked degree of similarity to one another and subsequently rendered into chronic lesions for healing-repair studies. The chronic periodontal ossious defects corrected by the osseous coagulum technique and by curettage in the rhesus monkey in this study were repaired by the regeneration of the architecture of the lost tissue. The use of the osseous coagulum in two- and three-walled periodontal osseous defects led to a more rapid osteogenesis in such defects as compared to correction by curettage alone. This rapid filling of the osseous defects may serve to inhibit the apical migration of the epithelial attachment during the early stages of repair, and thereby inhibit a subsequent recurrence of the defect. Clinically and histologically, no readily apparent distinction could be made in the healing process between the two- and three-walled lesions.