Long-term outcomes of regenerative periodontal therapy and orthodontic treatment: 20-year results from a prospective study.

Objectives To evaluate the 20-year clinical outcomes of periodontal regenerative and orthodontic treatment for severely periodontally compromised teeth.Methods In this prospective study, 48 patients with Stage IV periodontitis, each with at least one non-molar tooth (n=48 test teeth) exhibiting pathologic migration and an associated intrabony defect characterized by probing depth (PD) of ≥ 7 mm, were consecutively included. The treatment protocol comprised: 1) supra/sub-gingival instrumentation (Step Ⅰ-Ⅱ); 2) periodontal regenerative surgery using enamel matrix derivative (EMD) alone or combined with a bone graft and membrane (Step Ⅲ); 3) orthodontic treatment initiated 8-12 months post-surgery to correct malposition (Step R); and 4) tailored supportive periodontal care (SPC) (Step Ⅳ). Clinical parameters were recorded at baseline (T0), 10-year (T10), and 20-year (T20) follow-up visits.Results Thirty-three patients (drop-out rate: 31.2%; n=29 test teeth) completed the 20-year follow-up. The T20 estimated tooth survival was 89.1% (CI: 79.4-99.9%), while complication-free probability was 86.3% (CI: 75.7-98.3%). Overall, five test teeth experienced complications (1 pulp necrosis, 2 root fractures, 2 periodontal disease recurrence) and four were extracted during the 20-year period. All periodontal parameters significantly improved from T0 to T20: full-mouth plaque scores decreased from 48.8% to 14.6% (34.2 ± 19.3%; 95% CI: 27.3, 41.0; p < 0.001), and full-mouth bleeding scores dropped from 55.5% to 10.2% (45.4 ± 18.5%; 95% CI: 38.8, 51.9; p < 0.001). The number of sites with PD ≥ 7 mm was reduced from 25.8 to 0.9 (24.9 ± 17.0; 95% CI: 18.9, 30.9; p < 0.001). At the test tooth level, mean PD decreased from 6.3 mm to 3.0 mm (3.1±1.4 mm; 95% CI: 2.6, 3.7; p < 0.001). Treatment success (i.e., tooth survival + PD ≤ 4 mm) was observed in 81.8 % of cases.Conclusions The 20-year results demonstrate that orthodontic treatment subsequent to periodontal regeneration is a predictable strategy for long-term tooth preservation, provided it is integrated into a stringent and tailored supportive care program. This interdisciplinary approach does not compromise the benefits of regeneration and offers a viable alternative to tooth extraction.Clinical Significance This study revealed that the combination of peridoontal regeneration and orthodontic therapy can successfully preserve natural teeth in severe periodontitis cases over two decades, highlighting the critical role of a tailored SPC program.