Initial antimicrobial effect of controlled-release doxycycline in subgingival sites

To determine the ability of a 10% doxycycline hyclate controlled-release polymer (Atridox) to suppress periodontopathic bacteria when placed subgingivally following scaling and root planing (Sc/Rp).

Eight males and seven females, mean age 48 years, with moderate to advanced periodontitis participated in the study. In each patient, bilateral periodontal pockets probing 6-7 mm were randomly assigned to treatment by Sc/Rp + doxycycline polymer or by Sc/Rp alone. Subgingival placement of doxycycline polymer was carried out according to the manufacturer's instructions. Sc/Rp was performed with hand instruments for at least 10 min in each study tooth. Subgingival samples were collected by paper-points at baseline, at 2 weeks and at 4 weeks post-treatment. Culture methodology was used to isolate and identify putative periodontal pathogens, including Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Dialister pneumosintes, Tannerella forsythia, Prevotella intermedia/Prevotella nigrescens, Campylobacter species, Eubacterium species, Fusobacterium species, Peptostreptococcus micros, Eikenella corrodens, Staphylococcus species, enteric gram-negative rods, beta-hemolytic streptococci and yeasts. The microbiologic examination was carried out blindly. Microbiological data were analyzed using a General Linear Model Analysis of Variance for within and between group effects.

Sites receiving Sc/Rp + doxycycline polymer and sites receiving Sc/Rp alone exhibited similar levels of periodontal pathogens at baseline and did not differ significantly in total viable counts and proportional recovery of periodontopathic bacteria post-treatment.

Controlled-release doxycycline placed in moderate to deep periodontal pockets caused no significant additional reduction in the subgingival pathogenic microbiota compared to thorough Sc/Rp alone. Since controlled-release doxycycline may not significantly suppress several subgingival pathogenic microorganisms and seems to possess no distinct advantage over broad-spectra, safe and inexpensive antiseptics, the rationale for its employment in periodontal therapy remains unclear.