Abstract
OBJECTIVE: To assess the short-term adjunctive effect of systemic antibiotics on non-surgical periodontal therapy and to identify predictors of treatment response in the patients with stages Ⅲ/Ⅳ periodontitis, providing ideas for precise clinical medication. METHODS: A retrospective study was conducted on the patients who received non-surgical periodontal treatment in the Department of Periodontology, Peking University School and Hospital of Stomatology from November 2007 to February 2015. A total of 521 patients with stages Ⅲ/Ⅳ periodontitis were included. Participants were divided into two groups: those who received systemic antibiotic therapy adjunctive to scaling and root planing (SRP) (antibiotic group, n=204) and those who underwent SRP only (non-antibiotic group, n=317). The timing of systemic antibiotic use is divided into before SRP, during SRP, and after SRP. The primary outcome was defined as the relative change in the percentage of sites with probing depth (PD) ≥5 mm. Univariable linear regression was used to identify the association between each variable and treatment efficacy, and multivariable linear regression was utilized to adjust for confounding factors and to determine the relationships of antibiotic therapy, age of the antibiotic group, and timing of antibiotic administration with the treatment efficacy. Furthermore, smooth curve fitting and piecewise linear regression model were employed to assess the potential nonlinear relationship and threshold effect between age and treatment response in the anti-biotic group. The threshold was identified by evaluating a series of potential turning points within predefined intervals and selecting the point with the maximum model likelihood. RESULTS: Both treatment groups exhibited significant improvements in all periodontal parameters following therapy (P < 0.001). After adjustment for potential confounders, multivariable analysis revealed a significantly greater reduction in the percentage of sites with PD≥5 mm in the antibiotic group versus the non-antibiotic group (β=16.33, 95% CI: 13.40－19.27, P < 0.001). Within the antibiotic group, we identified a nonlinear association between age and therapeutic efficacy, with an inflection point at 38 years. The patients aged ≤38 years responded significantly better than those older than 38 years (P=0.022). Furthermore, the timing of antibiotic administration was a significant determinant of outcome. The most pronounced efficacy was achieved when antibiotics were administered concurrently with SRP, surpassing both pre- and post-SRP administration. CONCLUSION: Our findings suggest that the use of systemic antibiotics as an adjunct to SRP is associated with enhanced short-term clinical outcomes in stages Ⅲ and Ⅳ periodontitis. During SRP, treating younger patients (≤38 years old) with systemic antibiotics as an adjunct may yield better therapeutic effects.