Differential clinical treatment outcome after systemic metronidazole and amoxicillin in patients harboring Actinobacillus actinomycetemcomitans and/or Porphyromonas gingivalis

J Clin Periodontol. 1998 May;25(5):380-7. doi: 10.1111/j.1600-051x.1998.tb02459.x.


48 adult patients with untreated periodontitis harboring subgingival Actinobacillus actinomycetemcomitans and/or Porphyromonas gingivalis as assessed by PCR were randomly assigned to receive full-mouth scaling alone (control) or scaling with systemic metronidazole plus amoxicillin and supragingival irrigation with chlorhexidine digluconate (test). In patients harboring A. actinomycetemcomitans intraorally at baseline, the adjunctive antimicrobial therapy resulted in a significantly higher incidence of probing attachment level (PAL) gain of 2 mm or more compared to scaling alone over 12 months (p<0.05). In addition, suppression of A. actinomycetemcomitans in subgingival plaque below detectable levels was associated with an increased incidence of PAL gain. In contrast, patients initially harboring P. gingivalis but not A. actinomycetemcomitans in the oral cavity showed a significantly higher incidence of PAL loss following adjunctive antimicrobial therapy compared to scaling alone (p<0.05). When the presence of pathogens at baseline was disregarded in the analysis, adjunctive antimicrobial therapy did not significantly enhance clinical treatment outcome. The results indicated that adults with untreated periodontitis harboring A. actinomycetemcomitans may benefit from the adjunctive antimicrobial therapy for a minimum of 12 months, whereas, the regimen may adversely affect the clinical treatment outcome of patients harboring P. gingivalis but not A. actinomycetemcomitans.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aggregatibacter actinomycetemcomitans / drug effects*
  • Amoxicillin / administration & dosage
  • Amoxicillin / therapeutic use*
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / therapeutic use*
  • Anti-Infective Agents, Local / administration & dosage
  • Anti-Infective Agents, Local / therapeutic use
  • Chlorhexidine / administration & dosage
  • Chlorhexidine / analogs & derivatives
  • Chlorhexidine / therapeutic use
  • Dental Scaling
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Metronidazole / administration & dosage
  • Metronidazole / therapeutic use*
  • Middle Aged
  • Penicillins / administration & dosage
  • Penicillins / therapeutic use*
  • Periodontal Attachment Loss / drug therapy
  • Periodontal Attachment Loss / microbiology
  • Periodontal Attachment Loss / pathology
  • Periodontal Attachment Loss / therapy
  • Periodontitis / drug therapy
  • Periodontitis / microbiology*
  • Periodontitis / pathology
  • Periodontitis / therapy
  • Porphyromonas gingivalis / drug effects*
  • Therapeutic Irrigation
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Anti-Infective Agents, Local
  • Penicillins
  • Metronidazole
  • Amoxicillin
  • chlorhexidine gluconate
  • Chlorhexidine