Diabetes as a prognostic factor in periodontitis

Background + Aims

• Periodontal disease, affecting hundreds of millions adults globally, is a leading cause of tooth loss and negatively impacts oral health-related quality of life.
• Guided tissue regeneration (GTR) therapy is a recognised regenerative treatment for deep intra-bony defects, enabling periodontal ligament, cementum, and alveolar bone regeneration through cell-occlusive membranes.
• Despite its efficacy, GTR outcomes vary due to patient, defect, and surgical factors, and it remains a complex, cost-intensive procedure.
• This study revisits three randomised clinical trials (RCTs) conducted between 1992 and 1996 to evaluate tooth survival and long-term outcomes up to 26 years after GTR, irrespective of membrane type.

Materials + Methods

• This study is a long-term follow-up of 3 RCTS with split-mouth clinical design evaluating GTR in deep intra-bony defects.
• Originally, 74 patients were treated between 1992 and 1996 using various resorbable and non-resorbable barrier membranes. They were recruited from University Hospital Regensburg, Germany, and had deep intra-bony defects (≥6 mm probing pocket depth and ≥4 mm angular bone loss). Eligible patients had no furcation involvement and completed pre-surgical scaling, root planing, and one-year follow-up.
• Due to patient dropouts, this follow-up focused on tooth survival and attachment gain, independent of membrane type.
• A single experienced surgeon performed all procedures, including mucoperiosteal flap elevation, defect debridement, and barrier membrane placement. For non-resorbable membranes, a second surgery was conducted for removal. Post-operative care included systemic antibiotics, chlorhexidine rinses, and strict supportive periodontal therapy (SPT) with follow-ups every 2–3 months during the first year.
• Blinded examiners assessed oral hygiene (plaque and bleeding indices), gingival recession, probing pocket depth (PPD), clinical attachment level (CAL), and vertical attachment gain. Tooth survival, medical history (e.g., smoking, diabetes), and SPT adherence were also recorded.
• Statistical analyses included chi-square tests, Mann–Whitney tests, Kaplan–Meier survival analysis, and log-rank tests, with a significance threshold of α = 0.05.

Results

• The follow-up study included 50 patients (102 surgical sites), with 34 undergoing clinical examination and 16 participating via telephone.
• Tooth survival analysis showed that:
  • 9% of teeth were still in situ up to 26 years post-GTR therapy.
  • 1% of teeth were extracted.
  • Median survival duration was 23.4 years for retained teeth and 13.8 years for extracted teeth.
  • Tooth loss was associated with:
    • Molar teeth type
    • Deeper defects (≥12 mm CAL)
    • Poor one-year outcomes (≥7 mm CAL).
  • Patients with diabetes or ≥10 pack-years smoking history experienced significantly more tooth loss.
  • Regular SPT was not statistically linked to improved survival, though 53.9% of sites received SPT twice yearly.
• Clinical parameters showed:
  • Significant improvements after one year, including median PPD reduction from 8.0 mm to 4.0 mm for in situ teeth and 9.0 mm to 5.0 mm for extracted teeth.
  • Median CAL improved by 3.0 mm for both groups at one year, with stable outcomes up to 26 years for retained teeth.
• GTR-treated teeth were associated with better oral health, as evidenced by a higher median number of residual teeth (25) compared to sites where GTR-treated teeth were lost (12).

Limitations