Influence of Adjacent Teeth Absence or Extraction on the Outcome of Non-Surgical Periodontal Therapy.

: Extraction of periodontally compromised or strategically non-important teeth is often an integral part of non-surgical periodontal treatment (NSPT). This study evaluated the association between the status of adjacent teeth and the outcome of NSPT on molars. : Charting data of patients with generalized chronic periodontitis receiving NSPT in 2012-2014 were included. The association between initial clinical parameters and significant clinical improvement, including the reductions of probing pocket depth (PPD) and clinical attachment loss (CAL), in molar teeth with severe periodontitis after NSPT was assessed by a generalized linear model and logistic regression. : ≥7 mm PPD and <2 mm gingival recession (REC) at the tooth level, and ≥7 mm PPD, ≥7 mm CAL and <2 mm REC at the site level, were associated with significant clinical improvement. Absence or extraction of an adjacent tooth achieved an additional 0.22-0.23 mm and 0.60-0.83 mm clinical improvement. Among the interproximal sites, ≥7 mm PPD, <2 mm REC, ≥7 mm CAL, <Degree II furcation involvement, and absence of an adjacent tooth were associated with significant clinical improvement. : Absence or extraction of teeth during NSPT significantly improves the PPD and CAL of the adjacent periodontal sites of molars.