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Periodontal Treatment by Local Drug Delivery Using Resorbable Base Material

The effects of local drug delivery to the subgingival plaque flora using resorbable base material were evaluated by the study of microbial composition in periodontal pockets and clinical manifestations of disease. In vitro, the drug used in this study was released within 24 hr from the hydroxypropylcellulose (HPC) strips. In vivo release of the drug from strips was also measured in nine patients who had, contralaterally, deep pockets of more than 5 mm. A tetracycline (TC)-containing HPC strip was inserted in one pocket, and a blank strip without TC was inserted in the other pocket. The amount of TC in the gingival crevicular fluid (GCF) 24 hr after insertion of the strip was significantly higher than that of the control. Ten subjects, who had at least three pockets greater than 4 mm in depth, were selected from 50 volunteers after an initial examination. HPC strips containing TC, chlorhexidine (CH), and control (base material) were inserted into each pocket three times a week. Clinical and microbiological changes ascertained by darkfield microscopy were monitored over three weeks. Reduction of both probing depth and bleeding-on-probing was observed only in the pockets in which TC was administered. Changes of microbial composition of subgingival plaque were, however, found in both TC- and CH-treated pockets. The percentages of spirochetes and motile rods were remarkably reduced in these pockets.