A 5-year prospective study on regenerative periodontal therapy of infrabony defects using minimally invasive surgery and a collagen-enriched bovine-derived xenograft

Aim: The primary objective of this study was (1) to evaluate the 5-year clinical outcome of regenerative periodontal therapy (RPT) using minimally invasive surgery and a collagen-enriched bovine-derived xenograft and (2) to identify predictors for clinical attachment level (CAL) gain and vertical radiographic bone (RB) gain.

Materials and methods: Ninety-five non-smoking patients with ≤ 25% full-mouth plaque and bleeding presenting ≥ 6 months after initial periodontal therapy with ≥ 1 isolated interdental infrabony defect were recruited. Minimally invasive surgery (MIST or M-MIST) and a collagen-enriched bovine-derived xenograft were used in all patients. Patients were surgically treated by the same clinician and evaluated up to 5 years of follow-up. Multivariate analyses were used to identify predictors for CAL gain and RB gain.

Results: Before surgery, mean probing depth (PD) was 7.8 mm, CAL was 10.0 mm, and defect depth amounted to 5.2 mm. Seventy-one patients (33 men, 38 women, mean age 52) could be evaluated at 5 years. Mean PD reduction was 3.3 mm (SD 2.2), CAL gain was 3.0 mm (SD 2.1), and RB gain was 57% (SD 38). Forty-five percent showed ≥ 4 mm CAL gain, whereas 24% were considered failures (≤ 1 mm CAL gain). Forty-eight percent showed considerable RB gain (≥ 75%). Regression analyses showed that plaque was a significant predictor for CAL gain (p = 0.001) and RB gain (p = 0.005). Patients' compliance had a significant impact on RB gain (p < 0.001).

Conclusion: Only patients with perfect oral hygiene and excellent compliance should be considered for RPT. Especially, the latter can only be assessed after sufficient follow-up following initial periodontal therapy.

Clinical relevance: RPT failed in 24% of the patients after 5 years. Regression analyses demonstrated a significant impact of plaque and patients' compliance on the long-term outcome. Only patients with perfect oral hygiene and excellent compliance should be considered for RPT. Patients should not be treated too soon following initial therapy, since compliance can only be reliably assessed after sufficient follow-up.