[Antibiotic use in periodontics. Results from a research study]

The sensitivity of the subgingival plaque for amoxicillin, doxycycline, ofloxacin and clindamycin was estimated by agar diffusion disks and Etest in 22 periodontal patients. The sensitivity of the subgingival plaque varied per patient. Resistance of the subgingival plaque for amoxicillin was observed in 50% of the patients and was significantly related to the use of antibiotics in the previous 6 months. The resistance to clindamycin was 68% and to doxycycline 82%. The resistance of the subgingival plaque to these antibiotics could not be related to the previous use. A decision-tree was constructed including a step wise use of a microscopical spirochete test and an antibiotic sensitivity test of the subgingival microflora for the above mentioned antibiotics. The clinical implications of the observed long lasting antibiotic resistance and the practical use of a decision-tree including a spirochete test and antibiotic sensitivity tests need further investigation.