Impacts of non‐impacted third molar removal on the periodontal condition of adjacent second molars

Abstract Objective The aim of this study was to determine how the removal of non‐impacted third molars (N‐M3s) affects the periodontal status of neighboring second molars (M2s). Subjects and Methods The periodontal condition of M2s for which the neighboring N‐M3s were removed (more than 6 months previously) and those with intact N‐M3s was analyzed in a cross‐sectional observation study. In an additional case series, periodontal changes in M2s in response to adjacent N‐M3 removal were observed during a 6‐month follow‐up period. Results A total of 457 patients with 1,301 M2s were enrolled in this cross‐sectional observational study. Compared to M2s with neighboring N‐M3s, M2s without neighboring N‐M3s (teeth removed more than 6 months previously) exhibited a 0.27‐mm reduction in the average pocket depth (PD) ( p < .001) and a 0.38‐fold reduced risk of at least one probing site with PD ≥5 mm (PD5+) ( p < .001). Subsequently, a 41‐case follow‐up study showed that 6 months after neighboring N‐M3 extraction, the PD of the M2s decreased by 0.31 mm ( p < .001), while the incidence of PD5+ decreased by 21.9% when compared to the parameters detected before tooth extraction ( p = .004). Conclusions Removing N‐M3s was associated with an improved periodontal condition in neighboring M2s.