title: Molecular detection of Aggregatibacter actinomycetemcomitans on metallic brackets by the checkerboard DNA-DNA hybridization technique.
abstract: BACKGROUND
  The purpose of this randomized clinical study was to evaluate the presence of the periodontal pathogen Aggregatibacter actinomycetemcomitans on metallic brackets and the effectiveness of a 0.12% chlorhexidine digluconate mouthwash in inhibiting this microorganism.
  
  
  METHODS
  The study involved 35 patients of both sexes having orthodontic treatment with fixed appliances between the ages of 14 and 22 years, randomized into 2 groups: experimental (n = 17) and control (n = 18). Two new metallic brackets were placed on the patients' premolars, and the subjects rinsed with a solution of 0.12% chlorhexidine digluconate or a placebo solution twice a week for 30 days. After that, the brackets were removed and underwent microbiologic analysis with the checkerboard DNA-DNA hybridization technique. Data were analyzed by using the Student t, Fisher exact, and Mann-Whitney tests at the significance level of 5%.
  
  
  RESULTS
  The results showed that A actinomycetemcomitans was present in all brackets from the subjects in the control group vs 83% of the subjects who rinsed with chlorhexidine digluconate (P <0.0001). There were also significantly lower levels of this species in the chlorhexidine digluconate group compared with the control group (P = 0.0003).
  
  
  CONCLUSIONS
  We concluded that 0.12% chlorhexidine digluconate rinsing, twice a week for 30 days during orthodontic treatment, is effective in reducing the presence and levels of A actinomycetemcomitans on metallic brackets.
authors.affiliation: Department of Pediatric Clinics, Preventive and Social Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Brazil. nelson@forp.usp.br
authors.forename: Paulo
authors.initials: P
authors.lastname: Nelson-Filho
authors.forename: Karla Orfelina
authors.initials: KO
authors.lastname: Carpio-Horta
authors.forename: Marcela Cristina Damião
authors.initials: MC
authors.lastname: Andrucioli
authors.forename: Magda
authors.initials: M
authors.lastname: Feres
authors.forename: Raquel Assed
authors.initials: RA
authors.lastname: Bezerra da Silva
authors.forename: Francisco Wanderley
authors.initials: FW
authors.lastname: Garcia Paula-Silva
authors.forename: Fábio Lourenço
authors.initials: FL
authors.lastname: Romano
mesh_terms: D000293:Adolescent; D016976:Aggregatibacter actinomycetemcomitans / Q000187:drug effects / Q000302:isolation & purification*; D000891:Anti-Infective Agents, Local / Q000627:therapeutic use; D058491:Bacterial Load; D001641:Bicuspid / Q000382:microbiology; D018441:Biofilms / Q000187:drug effects; D002327:Cariostatic Agents / Q000627:therapeutic use; D002710:Chlorhexidine / Q000031:analogs & derivatives / Q000627:therapeutic use; D004269:DNA, Bacterial / Q000032:analysis; D003722:Dental Alloys; D003773:Dental Plaque / Q000517:prevention & control; D003774:Dental Plaque Index; D003802:Dentifrices / Q000627:therapeutic use; D005260:Female; D005459:Fluorides / Q000627:therapeutic use; D006801:Humans; D008297:Male; D009067:Mouthwashes / Q000627:therapeutic use; D009693:Nucleic Acid Hybridization / Q000379:methods; D016910:Orthodontic Brackets / Q000382:microbiology*; D010865:Pilot Projects; D010919:Placebos; D016037:Single-Blind Method; D014099:Toothbrushing / Q000295:instrumentation; D055815:Young Adult
chemical_list: D000891:Anti-Infective Agents, Local; D002327:Cariostatic Agents; D004269:DNA, Bacterial; D003722:Dental Alloys; D003802:Dentifrices; D009067:Mouthwashes; D010919:Placebos; C010882:chlorhexidine gluconate; D005459:Fluorides; D002710:Chlorhexidine