The effect of postsurgical antibiotics and a bioabsorbable membrane on regenerative healing in class II furcation defects

Background: The purpose of this randomized, controlled, blinded, clinical i nvestigation was to determine the effect of postsurgical antibiotics on oss eous healing in Class II furcation defects. Methods: Twenty-four Class II furcation defects in 24 patients were treated with either a polylactide bioabsorbable membrane, demineralized freeze-dri ed bone allograft (DFDBA) plus antibiotics (GBA or test group) or with a po lylactide membrane and DFDBA alone (GB or control group). Twelve patients w ere included in each group. The antibiotic regimen consisted of ciprofloxac in 250 mg twice daily and metronidazole 250 mg tid for 1 week followed by a 7-week regimen of doxycycline hyclate 50 mg daily. Treatment was performed on either mandibular buccal or lingual, or maxillary buccal Class II furca tion defects. Defects were randomly selected by a coin toss for treatment a nd all open and closed measurements were performed by a blinded examiner. F inal open and closed measures from a stent were repeated at the 9-month sec ond stage surgery. Power analysis to determine superiority of antibiotic tr eatment showed that a 12 per group sample size would yield 93% power to det ect a 1.5 mm difference and 64% power to detect a 1 mm difference. Results: Mean open horizontal probing depth reductions at 9 months were gre ater for the GBA group than for the GB group (2.92 +/- 1.78 versus 2.50 +/- 1.62 mm); however, these differences were not statistically significant. S even of 12 furcations (58%) in the GBA group demonstrated >50% vertical def ect fill at 9 months compared to 8 of 12 furcations (67%) in the GB group. There were no significant differences in mean open horizontal probing depth reduction between smokers and non-smokers in either the GBA or GB groups. Membrane exposure did not appear to affect regenerative healing in either t he GBA or GB groups. Conclusions: The administration of postsurgical antibiotics did not produce statistically superior osseous healing of Class II furcation defects. This result may be attributable to membrane design which facilitates connective tissue ingrowth, thereby preventing bacterial downgrowth and contamination of the newly regenerated tissues.