Effects of Different Treatment Sequences on the Efficacy of Combined Periodontal-Endodontic Lesions: A Systematic Review and Meta-Analysis.

OBJECTIVE

This study aimed to evaluate systematically the clinical efficacy of different treatment sequences (root canal therapy first, periodontal therapy first or periodontal therapy only) in periodontal-endodontic lesions (PELs; also termed EPL in some literature).

METHODS

Comprehensive searches were conducted in English databases (MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Web of Science, Scopus), Chinese databases (Chinese National Knowledge Infrastructure, Wanfang, Weipu) and grey literature sources from inception to May 2025. Studies were included in randomised controlled trials (RCTs), non-randomised controlled studies (nRCTs) and comparative observational studies that reported the probing depth (PD), clinical attachment level (CAL) and tooth survival/success rate in adult patients with PELs.

RESULTS

A total of 16 studies (10 RCTs, 6 non-RCTs, with a total of 1468 cases) were included. Meta-analysis showed that root canal treatment-first treatment could significantly improve PD shortening rate (pooled mean difference [MD] = -1.07 mm; 95% CI: -1.49 to -0.65; P < .0001), CAL gain (MD = 0.99 mm; 95% CI: 0.61-1.37; P < .0001) and tooth survival/success rate (risk ratio = 1.22; 95% CI: 1.08-1.37; P = .001). The results showed significant heterogeneity (PD: I2 = 98.4%; CAL: I2 = 91.5%). Subgroup analysis showed that region, follow-up time and regenerative materials were important sources of heterogeneity. Chinese studies reported significant improvements in PD (MD = -1.39 mm) and CAL (MD = 1.35 mm), with low internal heterogeneity. Egger's test showed significant publication bias for PD (P = .003) but no significant difference for CAL (P = .733).

CONCLUSION

The endodontic-first approach significantly improved the clinical outcomes of combined PELs compared with periodontal-first or periodontal-only treatment. However, significant heterogeneity across lesion categories and interventions, together with evidence of publication bias, highlights the need for cautious interpretation and underscores the importance of future well-designed, standardised RCTs.