title: Non-surgical periodontal therapy with adjunctive topical doxycycline: a double-masked, randomized, controlled multicenter study. II. Microbiological results.
abstract: BACKGROUND
  Topical application of active substances offers an additional option in periodontal therapy. The aim of this study was to examine the influence of the administration of a novel, biodegradable 14% doxycycline gel on microbiological findings, in connection with scaling and root planing.
  
  
  METHODS
  One hundred ten patients in three centers (Frankfurt and Heidelberg, Germany; Nijmegen, The Netherlands) with moderate to advanced periodontitis were evaluated in this randomized, double-masked, split-mouth clinical trial. In each patient, three test teeth were randomly assigned to one of three treatment modalities: 1) scaling and root planing (SRP) alone; 2) SRP with subgingival placebo gel (VEH); or 3) SRP and 14% doxycycline gel (DOX). Subgingival plaque samples were analyzed at baseline and 3 and 6 months after therapy for Actinobacillus actinomycetemcomitans (A.a.), Tannerella forsythensis (T.f.), Porphyromonas gingivalis (P.g.), and Treponema denticola (T.d.) using a RNA probe. Samples from 10 patients were tested for resistance against doxycycline, amoxicillin/clavulanic acid, cefoxitin, clindamycin, and metronidazole using agar diffusion testing.
  
  
  RESULTS
  The largest decrease in pathogens was found after 3 months, with the most pronounced differences between DOX and SRP (P <0.05). At 6 months, pathogens were still reduced markedly in all groups. Treatment results were consolidated for VEH and DOX, with a slight deterioration for SRP (DOX versus SRP: P <0.001). Resistance was observed to amoxycillin/clavulanic acid, cefoxitin, clindamycin, and metronidazole (four isolates) but not to doxycycline.
  
  
  CONCLUSIONS
  The addition of subgingival instillation of a 14% doxycycline gel resulted in pronounced reduction of periodontal pathogens after 3 months and stabilizing results up to 6 months after therapy. Resistance to doxycycline was not induced.
authors.affiliation: Department of Operative Dentistry and Periodontology, School of Dental Medicine, Albert-Ludwigs-University of Freiburg, Freiburg, Germany. ratka@zmk2.ukl.uni-freiburg.de
authors.forename: Petra
authors.initials: P
authors.lastname: Ratka-Krüger
authors.forename: Beate
authors.initials: B
authors.lastname: Schacher
authors.forename: Thomas
authors.initials: T
authors.lastname: Bürklin
authors.forename: Boris
authors.initials: B
authors.lastname: Böddinghaus
authors.forename: Rolf
authors.initials: R
authors.lastname: Holle
authors.forename: Heinz H
authors.initials: HH
authors.lastname: Renggli
authors.forename: Peter
authors.initials: P
authors.lastname: Eickholz
authors.forename: Ti-Sun
authors.initials: TS
authors.lastname: Kim
mesh_terms: D000287:Administration, Topical; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D003773:Dental Plaque / Q000382:microbiology; D012534:Dental Scaling; D004311:Double-Blind Method; D004318:Doxycycline / Q000627:therapeutic use*; D024881:Drug Resistance, Bacterial; D005260:Female; D005782:Gels; D006801:Humans; D008297:Male; D008875:Middle Aged; D010510:Periodontal Diseases / Q000188:drug therapy* / Q000382:microbiology; D016745:Root Planing
chemical_list: D000900:Anti-Bacterial Agents; D005782:Gels; D004318:Doxycycline