Lactobacillus fermentum attenuates the alveolar bone loss in ligature‐induced periodontitis in mice

Abstract Objective This study investigated the effects of Lactobacillus fermentum BELF11 on periodontitis in mice (LIP). Methods Sixty mice were randomly assigned to a control group (CTL), LIP/PBS group (LIP and PBS applied), or LIP/BELF11 group (LIP and L. fermentum BELF11 applied). For 14 days, PBS or L. fermentum BELF11 was applied twice daily to the mice in the LIP/PBS or LIP/BELF11 group, respectively. After 14 days, radiographic, histological, and pro‐inflammatory cytokine assessments were conducted. Results The LIP/PBS and LIP/BELF11 groups demonstrated greater alveolar bone loss than the CTL group ( p < 0.05). The LIP/BELF11 group showed significantly reduced alveolar bone loss on the mesial side compared to the LIP/PBS group. Histologically, the LIP/BELF11 group showed consistent patterns of connective tissue fiber arrangement, lower levels of inflammatory infiltration, less alveolar bone loss, and higher alveolar bone density than the LIP/PBS group, despite showing more signs of destruction than the CTL group. The LIP/BELF11 group also exhibited significantly lower levels of pro‐inflammatory cytokines than the LIP/PBS group. Conclusions L. fermentum BELF11 inhibits alveolar bone loss and periodontitis progression by regulating pro‐inflammatory cytokine production. These findings suggest that L. fermentum BELF11 may be a potential adjunctive therapy in periodontal treatment.