Clinical response to experimental forces and non-surgical therapy of teeth with various alveolar bone loss

Firm lateral force is necessary for the thorough removal of calculus during scaling and root planning (SRP) with hand instruments. However, this firm lateral force should be applied to root surfaces without considering the tooth's loss of supporting tissues. The purpose of the present study was two-fold: firstly, to evaluate the initial pain response of periodontally diseased non-molar teeth with two different levels of alveolar bone loss (ABL) to experimental lateral and vertical pull forces; and secondly, to examine the clinical response of these teeth to non-surgical therapy. Twenty patients with chronic periodontitis were specifically selected in two groups according to the level of ABL at non-molar teeth. Group I consisted of 10 patients who have 141 non-molar teeth with a radiographic evidence of 40-65% ABL. Group II consisted of 10 patients who have 132 non-molar teeth with a radiographic evidence of > or =70% ABL. All patients were systemically healthy, free of pain, and reported no current medication usage. Starting from 0 and gradually increasing an experimental lateral force with digital force gauge, and also an experimental vertical pull force with mechanical force gauge were applied to each tooth and measured. As a result of a single experimental force applied to each non-molar tooth, the initial pain response emerged in the patients was determined by means of electronic bell system used by patients themselves. Each patient was treated with SRP using specific hand instruments under local anesthesia. Plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment level (CAL) and periotest values (PV scores) were compared in both groups at initial and at month 3. A mean experimental lateral force of 24.6 N and a mean experimental vertical pull force of 48.3 N caused initial pain response in group I. Initial pain response occurred with a mean experimental lateral force of 5.3 N and a mean experimental vertical pull force of 19.4 N in group II. Only group I showed statistically significant decrease in PI, GI, PD and a significant attachment gain at month 3 (P < 0.05). There was a decrease of 6 PV in group I at month 3 (P < 0.05), whereas an increase of 4 PV was observed in group II (P > 0.05). This study showed that lateral and vertical forces required for effective SRP do not cause any problem in the group with 40-65% ABL. However, they may cause trauma in the group with approximately 70% ABL. Thus, the results suggest that the degree of healing would be different in the group with > or =70% ABL and in the group with 40-65% ABL.