RESUMEN
PURPOSE: To evaluate the treatment outcomes after guided tissue regeneration (GTR) with a bioabsorbable membrane in Class II furcation defects in mandibular molars. The open flap debridement (OFD) was used as the control. METHODS: Nine patients, with two comparable Class II furcation defects were included in the study. After initial preparation, the defects were randomly assigned in each patient to either GTR-group or OFD-group. Clinical parameters and standardized radiographs were obtained at baseline and 6 months after the surgeries. The radiographs were analyzed by subtraction radiography. RESULTS: Comparing baseline to 6-month results, both groups showed statistically significant probing depth reduction (PD), horizontal clinical attachment level (CAL-h) gain, and increase in gingival recession (GR). The vertical clinical attachment level (CAL-v) gain was statistically significant only for the OFD-group. Comparing the two treatments, no statistically significant differences were found in PD reduction (GTR: 1.67 mm; OFD: 2.51 mm, P = 0.26), CAL-v gain (GTR: 0.62 mm; OFD: 1.16 mm, P= 0.37), and GR increase (GTR: 1.04 mm; OFD: 1.24 mm, P = 0.31). GTR provided complete closure of the furcation defect in two sites and superior horizontal clinical attachment level gain (GTR: 2.27 mm; OFD: 1.01 mm, P = 0.05). Subtraction radiography showed significant difference in bone height change between GTR-group and OFD-group (-0.14 mm and 0.86 mm, respectively; P = 0.028) at 6 months.