Effects of antibiotic treatment on clinical conditions with guided tissue regeneration: one-year results.

The one-year results of a regenerative procedure in patients treated with or without antibiotics are presented. Expanded polytetrafluoroethylene (ePTFE) was placed over mandibular molar Class II furcation invasions and retained for four weeks. The patients in group 1 received no antibiotics; patients in group 2 received amoxicillin/clavulanate potassium during the first 10 post-operative days. The initial differences in tested microorganisms and post-surgical inflammation indicated that the use of the antibiotic might enhance the long-term outcome. After one year, the reduction in mean probing depth of the furcation invasions was 2.0 +/- 1.2 mm for group 1 and 1.8 +/- 1.1 mm for group 2. An overall gain of 0.8 mm of clinical attachment was found. Twenty-two of the 24 sites were re-entered. Wide individual variations were found but the changes between pre-treatment and one-year data for any of 6 linear measurements of hard tissue landmarks did not differ between groups or between pre-treatment and re-entry. A combination of an overall loss of 0.4 mm alveolar bone at the crest and 0.3 mm gain of bone at the bottom of the furcation defects was found. Volumetric analysis indicated an average 32% bone fill for both groups, ranging from a decrease in defect volume by 84% (gain) to an increase of the size of the furcation invasion by 66% (loss). A decrease in defect volume > 30% was found at 7 sites from each group. The antibiotic may have controlled initial inflammation, but 12 months later it had no direct effect on bone regeneration or soft tissue attachment.

RCT Entities:   Population Interventions Outcomes