title: Action of antimicrobial agents on infected odontogenic cysts.
abstract: OBJECTIVE
  The treatment of choice for odontogenic cysts is surgery, and when the cysts are infected, preoperative antibiotic coverage is needed. However, the diffusion of antibiotics is a matter of controversy because of the low vascularization of the cystic epithelium. The aim of the present study was to determine the antimicrobial action of amoxicillin and metronidazole on infected odontogenic cysts.
  
  
  METHODS
  Ten odontogenic root cysts were punctured before and after antibiotic treatment in 2 patient groups. Group 1 consisted of 5 patients treated with 500 mg amoxicillin at 6-hour intervals, and group 2 consisted of 5 patients treated with 400 mg metronidazole at 8-hour intervals, for 7 days. After this period, the patients were submitted to surgery for enucleation. The fluid collected was seeded onto culture media for counts of total bacteria and facultative anaerobic bacteria.
  
  
  RESULTS
  The results showed that the amount of bacteria present in the fluid was significantly higher than the amount isolated after antibiotic treatment. Also, most of the microorganisms present in the fluid collected before antibiotic administration were strict anaerobes.
  
  
  CONCLUSIONS
  Both antibiotics reduced the number of bacteria in the cystic fluid, showing that they did diffuse into the lesions at sufficient concentrations to exert their antimicrobial action.
authors.affiliation: Department of Oral Surgery, Prostheses and Maxillofacia Traumatology, Dental School, University of São Paulo, São Paulo, Brazil.
authors.forename: Andréia Aparecida
authors.initials: AA
authors.lastname: Traina
authors.forename: Maria Cristina Zindel
authors.initials: MC
authors.lastname: Deboni
authors.forename: Maria da Graça
authors.initials: Mda G
authors.lastname: Naclério-Homem
authors.forename: Silvana
authors.initials: S
authors.lastname: Cai
mesh_terms: D000328:Adult; D000658:Amoxicillin / Q000627:therapeutic use*; D000890:Anti-Infective Agents / Q000627:therapeutic use*; D019072:Antibiotic Prophylaxis; D001421:Bacteria, Anaerobic / Q000187:drug effects / Q000302:isolation & purification; D001424:Bacterial Infections / Q000601:surgery*; D015169:Colony Count, Microbial; D020420:Cyst Fluid / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D008336:Mandibular Diseases / Q000382:microbiology / Q000601:surgery; D008439:Maxillary Diseases / Q000382:microbiology / Q000601:surgery; D008795:Metronidazole / Q000627:therapeutic use*; D008875:Middle Aged; D009807:Odontogenic Cysts / Q000382:microbiology* / Q000601:surgery; D011677:Punctures
chemical_list: D000890:Anti-Infective Agents; D008795:Metronidazole; D000658:Amoxicillin