title: Colonization of Streptococcus mutans on esthetic brackets: self-ligating vs conventional.
abstract: BACKGROUND
  Self-ligating orthodontic brackets rely on clips, rather than ligatures, to hold the archwire in place. It is unknown whether replacing ligatures with clips affects the adherence of Streptococcus mutans. The aim of this research was to evaluate whether self-ligating brackets have an advantage over conventional brackets as determined by the adherence of S mutans.
  
  
  METHODS
  The sample consisted of 50 esthetic brackets, divided into 3 experimental groups and 2 control groups of 10 brackets each. Two experimental groups were active self-ligating brackets (QuicKlear; Forestadent, Pforzheim, Germany; and In-Ovation C; Dentsply GAC, Bohemia, NY); the other was a passive self-ligating bracket (Damon 3; Ormco, Glendora, Calif). The 2 control groups were conventional brackets (Mystique; Dentsply GAC; and Clarity; 3M Unitek, Monrovia, Calif). The brackets were randomly bonded to the canines, first and second premolars, and first and second molars in the mandibular left hemiarch of 10 male participants. Biofilm was collected from the tooth surfaces before bonding and from the brackets on day 21 and placed in Petri dishes containing Mitis salivarius agar. The brackets were removed on day 28 and examined by using scanning electron microscopy. Statistical analysis, analysis of variance, and the Tukey correction with a P value of 0.05 were used.
  
  
  RESULTS
  The greatest numbers of colonies were found in an active self-ligating bracket group (In-Ovation C), and the fewest colonies were in a conventional bracket group (Clarity). The largest colonies formed on active self-ligating brackets. In the slot, the greatest formation was in a control group (Mystique).
  
  
  CONCLUSIONS
  Self-ligating esthetic brackets do not promote greater or lesser S mutans colonization when compared with conventional brackets. Differences were found to be related to the material composition of the bracket.
authors.affiliation: Department of Orthodontics, School of Dentistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Leonard Euler Andrade Gomes
authors.initials: LE
authors.lastname: do Nascimento
authors.forename: Matheus Melo
authors.initials: MM
authors.lastname: Pithon
authors.forename: Rogério Lacerda
authors.initials: RL
authors.lastname: dos Santos
authors.forename: Amanda Osório Ayres
authors.initials: AO
authors.lastname: Freitas
authors.forename: Daniela Sales
authors.initials: DS
authors.lastname: Alviano
authors.forename: Lincoln Issamu
authors.initials: LI
authors.lastname: Nojima
authors.forename: Matilde Cunha G
authors.initials: MC
authors.lastname: Nojima
authors.forename: Antônio Carlos de O
authors.initials: AC
authors.lastname: Ruellas
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001422:Bacterial Adhesion; D015169:Colony Count, Microbial; D004955:Esthetics, Dental; D006801:Humans; D008297:Male; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets / Q000382:microbiology*; D013295:Streptococcus mutans / Q000502:physiology*