Comparison of the antibacterial effects on subgingival microflora of two different resorbable base materials containing doxycycline.

A study was conducted to evaluate the effects of local drug delivery on subgingival plaque flora using hydroxypropylmethylcellulose (HPMC) and methylcellulose (MC) base material containing 40% doxycycline (DOXY). Eleven patients who had at least four pockets exceeding 5 mm in depth associated with a single rooted tooth were selected from volunteers after an initial examination. Two of the pockets were chosen at random for insertion of the HPMC and MC strips twice a week for 6 w. One pocket received no treatment, and the other was debrided and root-planed only. Baseline and follow-up measurements at 0, 1, 3, 6, and 10w included probing depth, gingival shrinkage, bleeding on probing and crevicular fluid flow. Subgingival bacterial samples were also taken for dark-field microscopy. In vitro drug release from the HPMC strips was greater than that from MC. Significant improvements in many clinical parameters occurred in the pockets treated with HPMC or MC strips, or mechanical debridement. There was a marked decrease in the relative proportions of motile organisms during and after treatment.