Effect of nonsurgical periodontal therapy. III. Single versus repeated instrumentation.

Healing events following nonsurgical periodontal therapy were studied, comparing the effect of a single initial instrumentation to the effect of 3 instrumentations, each separated by 3 months. Incisors, cuspids and premolars with periodontal pockets up to 11 mm deep in 13 patients were treated by plaque control and supra- and subgingival debridement using ultrasonic instruments. A split mouth approach was used to compare the 2 frequencies of instrumentation. The results were evaluated by recording of plaque scores, bleeding on probing, probing pocket depths and probing attachment levels. A gradual and marked improvement of the periodontal conditions took place during the initial 9 months following start of therapy. During the remaining 15 months of the 24-month experimental period no further changes of the recorded parameters were noted. No differences in results could be observed when comparing the effects of a single versus repeated instrumentation. Thus, it appears that deep periodontal pockets in incisors, cuspids and premolars may be successfully treated by plaque control and 1 episode of instrumentation. The results also suggest that recurrence of disease due to subgingival recolonization by microorganisms during the healing phase may not be a major clinical problem.