GINGIVAL FLUID TETRACYCLINE RELEASE FROM BIOERODIBLE GELS

Intracrevicular antimicrobial therapy is consistent with the site-spec ific nature of periodontitis. Considerable research has focused on the use of nonresorbable fibers. However, a bioerodible system is desirab le. The purpose of this study was to assess tetracycline release and s afety following a single application of a syringable 35% tetracycline hydrochloride in a lactic-glycolic acid gel. 31 generally healthy adul t volunteers (mean age = 59 years) were enrolled in and completed this randomized, double-blind eight day study. 2, 6-10 mm non-adjacent int erproximal pockets that bled on pocket probing were chosen as experime ntal sites in each subject. I experimental site and the surrounding gi ngival crevice received small particle size tetracycline in gel while the other site received larger particle size tetracycline in gel. Ging ival crevicular fluid (GCF) was collected prior to treatment and 15 mi n, 1, 2, 3, 4 and 8 days post-treatment. GCF tetracycline concentratio ns were determined by agar diffusion bioassay and GCF volume measureme nts. 61% and 71% of sites had greater than or equal to 100 mu g/ml tet racycline 3 days following application of large (mean concentration = 430 +/- 92 mu g/ml) and small particle gels (mean concentration = 418 +/- 70 mu g/ml), respectively. 37% and 55% of sites had measurable tet racycline 8 days after placement of large (mean concentration = 86 +/- 31 mu g/ml) and small particle gels (mean concentration = 293 +/- 79 mu g/ml), respectively. The most common adverse event was ''bitter tas te'' (10% of subjects). Based upon the reduction in probing depths and % of sites bleeding on probing at 8 days relative to pretreatment, an d the absence of any serious adverse events, it is concluded that thes e bioerodible gels are safe, and since the bacteriostatic range for mo st putative periodontopathogens is in the 2-10 mu g/ml range, the tetr acycline levels observed al days 3 and 8 likely represent significant antimicrobial efficacy.