Ligature-induced peri-implant infection in cynomolgus monkeys. I. Clinical and radiographic findings.

The purpose of this study was to compare the effect of plaque accumulation in conjunction with or without placement of plaque-retaining ligatures on peri-implant and periodontal tissues. Four cynomolgus monkeys received 2 ITI (Type F) dental implants in edentulous areas of each side of the mandible. Following a healing period of 2 months with regular prophylaxis procedures twice per week, plaque was allowed to accumulate. After 1 month (day 0), silk ligatures were placed around 1 of the 2 implants. The third molars served as controls and were ligated as well. Clinical examinations comprising Plaque Index (PlI), Gingival Index (GI), probing depth (PD) and loss of attachment (LA) were performed at the test and control sites before and 1, 2, 3, 4, 5, 6, 7 and 8 months after ligature placement. Sixty and 30 days prior to ligation and at 2, 5, 6 and 8 months following ligation, standardized radiographs were obtained and subtracted from a baseline radiograph obtained at the time of ligation. PlI and GI scores increased significantly following the elimination of prophylaxis procedures. After ligation, these indices continued to increase and reached values significantly higher in ligated implant (LI) and ligated teeth (LT) sites than in non-ligated teeth (NLI) sites. PD also increased after plawue accumulation and ligature placement. Significantly greater PD values were noted in LI and LT sites than in NLI sites.(ABSTRACT TRUNCATED AT 250 WORDS)