Effectiveness of nonsurgical re‐instrumentation: Tooth‐related factors

The present study aimed to investigate the influence of tooth-related factors on the outcome of repeated nonsurgical therapy of periodontitis. Therefore, 480 patients (10,807 teeth) presenting with clinical symptoms of persistent periodontitis after initial therapy were administered repeated nonsurgical therapy and retrospectively analyzed. Therapy outcomes were associated with tooth-related factors, namely tooth type, tooth location (maxilla/mandible), number of roots, involvement of the root furcation area in multi-rooted teeth, pulp vitality, mobility, restoration, presence of plaque and bleeding upon periodontal probing, using mixed-effects models. The results revealed that repeated nonsurgical therapy was effective in reducing inflammation and clinical signs of disease, with moderate residual periodontal defects responding better than deep defects. Healing of deep defects after repeated nonsurgical therapy; however, was significantly influenced by the factors: tooth type, location, number of roots, and bleeding on probing. Considering these factors, particularly in deep residual defects which are commonly suggested to be treated surgically, may allow less invasiveness and thus a more tailored re-intervention.