title: Timing affects the clinical outcome of adjunctive systemic antibiotic therapy for generalized aggressive periodontitis.
abstract: BACKGROUND
  Systemic antibiotics improve the outcome of scaling and root planing (SRP) in patients exhibiting severe periodontitis. This study evaluated the influence of timing of adjunctive systemic antibiotics in the sequence of periodontal therapy.
  
  
  METHODS
  Two cohorts of patients with generalized aggressive periodontitis and treated by SRP, adjunctive antibiotics, and supportive periodontal therapy (SPT) were analyzed retrospectively. Cohort A (17 patients; 36 +/- 5 years of age) received systemic amoxicillin/metronidazole immediately after SRP ("immediate"); cohort B (17 patients; 36 +/- 4 years of age) received the same regimen 3 months after SRP, following SPT, including subgingival reinstrumentation ("late"). Clinical parameters, including probing depth (PD), relative attachment level (RAL), bleeding on probing (BOP), and suppuration, were recorded with a pressure-sensitive electronic probe at baseline and 3 and 6 months after SRP.
  
  
  RESULTS
  Significant time*group interactions were found for all clinical parameters except BOP, i.e., timing of antibiotic therapy affected the course of clinical changes over time. Immediate antibiotic therapy produced significantly higher initial changes (0 to 3 months) in PD and RAL. Late antibiotic therapy at 3 months resulted in additional significant improvements in all clinical parameters between 3 and 6 months. In initially deep sites (baseline PD >6 mm), improvements in PD and RAL over 6 months were significantly higher with immediate antibiotic therapy compared to late antibiotic therapy.
  
  
  CONCLUSIONS
  Within the limits of a retrospective analysis, these findings indicate that administration of amoxicillin/metronidazole immediately after initial SRP provides more PD reduction and RAL "gain" in initially deep sites than late administration at SPT with reinstrumentation after 3 months.
authors.affiliation: Institute for Periodontology and Synoptic Dentistry, Charité - Universitätsmedizin Berlin, Berlin, Germany. dogan.kaner@charite.de
authors.forename: Doğan
authors.initials: D
authors.lastname: Kaner
authors.forename: Claudia
authors.initials: C
authors.lastname: Christan
authors.forename: Thomas
authors.initials: T
authors.lastname: Dietrich
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Bernimoulin
authors.forename: Bernd-Michael
authors.initials: BM
authors.lastname: Kleber
authors.forename: Anton
authors.initials: A
authors.lastname: Friedmann
mesh_terms: D000328:Adult; D000658:Amoxicillin / Q000008:administration & dosage*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D003131:Combined Modality Therapy; D012534:Dental Scaling / Q000379:methods*; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008795:Metronidazole / Q000008:administration & dosage*; D010512:Periodontal Index; D010518:Periodontitis / Q000188:drug therapy*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D008795:Metronidazole; D000658:Amoxicillin