Treatment effect of guided tissue regeneration on the horizontal and vertical components of furcation defects: A retrospective study

Background: Identifying factors affecting the treatment outcomes of guided tissue regeneration (GTR) in furcation defects is imperative in order to obtain predictable regeneration outcomes. The aims of this study were to evaluate the clinical outcomes and survival of furcation-involved teeth treated with GTR, and potential factors affecting the results. Methods: Furcation defects treated with GTR using an allogeneic cancellous bone graft and covered by an absorbable membrane with at least 1-year follow-up were selected. All data relative to the clinical outcomes were recorded. Analyses were conducted to evaluate the immediate (1-year post-op) clinical outcomes and the long-term (the last assessment time) survival of the treated teeth. The effect of variables on the 1-year post-op clinical attachment level (CAL) changes and the tooth survival were assessed via multi-level regression analyses and Cox Proportional-Hazards Models. Results: Ninety-eight treated defects were selected. The average follow-up was 5.3 ± 4.3 years. At the 1-year post-surgical recall, 1.23 ± 1.48 mm CAL gain was observed (P < 0.05). The 5- and 10-year survival rates of the treated teeth were 86.5% and 74.3%, respectively. The vertical component of the defect and the location of the furcation were significantly related to the post-surgical 1-year CAL gain, whereas membrane exposure significantly affected tooth survival. Conclusion: Within the limitations of this study, data suggests GTR using allogeneic cancellous bone graft and absorbable collagen membrane to be a viable option for treating furcation-involved teeth if the defect morphology and the location of the defect are favorable.