The microbiology of ligature-induced periodontitis in the cynomolgus monkey.

The cultivable subgingival microflora in the cynomolgus monkey, Macaca fascicularis, was monitored during the ligature-induced progression of naturally occurring gingivitis to periodontitis. Clinical and microbiological observations were divided into four stages. Stage I, prior to ligature placement, was characterized clinically by chronic generalized gingivitis and microbiologically by Gram-positive cocci and rods with B. melaninogenicus ss. intermedius the dominant Gram-negative organism. Stage III, 1 to 3 weeks following ligature placement, exhibited slightly greater gingival inflammation but no clinical evidence of attachment loss. The subgingival flora showed a significant increase in motile and surface translocating Gram-negative rods, primarily Capnocytophaga species and Campylobacter sputorum. Stage III, 4 to 7 weeks following ligature placement, revealed increased pocket depth and radiographic evidence of alveolar bone loss. This stage was characterized by a Gram-negative anaerobic flora with B. asaccharolyticus as the dominant cultivable organism. Stage IV encompassed the remainder of the experimental period, 8 to 17 weeks, during which time no further change in the clinical parameters occurred and levels of B. asaccharolyticus decreased. The subgingival microflora of ligature induced periodontitis in Macaca fascicularis closely resembled that reported for human periodontal disease and the episodic clinical pattern of attachment loss was associated with levels of Gram-negative anaerobes, primarily B. asaccharolyticus.