Guided tissue regeneration combined with bone allograft in infrabony defects: Clinical outcomes and assessment of prognostic factors

Background: Clinical data on the outcomes of guided tissue regeneration (GTR) is scarce. The aim of this retrospective cohort study was to evaluate the outcomes after GTR, their stability and the survival of the treated teeth with periodontal infrabony defects. Methods: Infrabony defects treated with GTR using a bioabsorbable membrane and a bone graft substitute with at least 1-year follow-up were included. Survival and regression analyses were conducted to evaluate the outcomes, their stability, and the retention of the teeth. The effect of recorded variables on clinical attachment gain (CAL) and tooth survival were assessed via Cox proportional-hazards models and multivariate generalized linear models. Results: One hundred seventy-five treated defects were selected from a total of 641 charts. The average follow-up was 5.75 ± 4.6 years. At baseline, the mean CAL was 9.56 ± 1.93 mm with a mean pocket depth (PD) of 8.41 ± 1.42 mm. At the 1-year post-surgical recall, 3.55 ± 1.85 mm of CAL gain and 3.87 ± 1.87 mm PD reduction were observed (P < 0.05). The 5- and 10-year survival rates of the treated teeth were 85.0% and 72.7%, respectively. Baseline PD, smoking, and membrane exposure were significantly related to CAL gain, whereas baseline CAL, age, frequency in maintenance visits significantly affected tooth survival. Conclusion: Within the limitations of this study, data suggests GTR is a good option for the treatment of infrabony defects because it can improve both tooth retention rate and overall clinical outcomes.