title: Prevalence of cariogenic streptococci on incisor brackets detected by polymerase chain reaction.
abstract: BACKGROUND
  Streptococcus mutans and Streptococcus sobrinus are the main causative organisms for enamel demineralization during orthodontic treatment. In this study, we analyzed the prevalence of cariogenic streptococci adhering to incisor brackets.
  
  
  METHODS
  Four incisor brackets from both the maxilla and the mandible were collected from 80 patients at debonding, immediately after the visible plaque index and the gingival bleeding index were measured from the incisors. The genomic DNA of adhered cariogenic streptococci was extracted and amplified by using polymerase chain reaction, and the prevalence of cariogenic streptococci was determined and compared with oral hygiene indexes in the incisor area.
  
  
  RESULTS
  The results showed that the prevalence of S mutans on incisor brackets was higher than that of S sobrinus, and the maxillary incisor brackets were colonized by both cariogenic streptococci to a somewhat higher degree than were the mandibular brackets. The prevalence of S mutans was 50.0% on the maxillary incisor brackets and 33.8% on the mandibular incisor brackets, but that of S sobrinus was 17.5% and 15.0%, respectively. At least 1 species of cariogenic streptococci was detected on the incisor brackets of 51 subjects (63.7%). However, the prevalence of cariogenic streptococci was not significantly associated with the oral hygiene indexes at debonding.
  
  
  CONCLUSIONS
  Cariogenic streptococci can adhere to orthodontic brackets. Careful hygiene control around orthodontic brackets is important.
authors.affiliation: Department of Orthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Korea.
authors.forename: Sug-Joon
authors.initials: SJ
authors.lastname: Ahn
authors.forename: Bum-Soon
authors.initials: BS
authors.lastname: Lim
authors.forename: Shin-Jae
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001422:Bacterial Adhesion; D004269:DNA, Bacterial / Q000032:analysis; D006801:Humans; D007180:Incisor; D008875:Middle Aged; D009911:Oral Hygiene Index; D016910:Orthodontic Brackets / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D013295:Streptococcus mutans / Q000302:isolation & purification; D016986:Streptococcus sobrinus / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial