title: Changes in subgingival microflora after placement and removal of fixed orthodontic appliances.
abstract: BACKGROUND
  The placement of fixed orthodontic appliances may lead to increased plaque accumulation and changes in subgingival microflora.
  
  
  OBJECTIVE
  The aim of this study was to examine the changes in frequency of subgingival microflora that occur after placement and removal of fixed orthodontic appliance using polymerase chain reaction (PCR).
  
  
  METHODS
  This study included 33 orthodontic patients, who were divided into two groups. Subgingival plaque samples were collected from the right upper incisor (U1) and right upper first molar (U6). In group A, the samples were taken three times: before placement appliance (T1), after one month (T2), and after 3 months (T3). In group B the samples were also taken three times: before appliance removal (T1), after one month (T2), and after three months (T3). PCR method was used to determine the presence of P. gingivalis, A. actinomycetemcomitans, T. forsythia, and P. intermedia.
  
  
  RESULTS
  In group A the frequency of P. gingivalis showed statistically significant decrease at U1 (p = 0.049) and U6 (p = 0.008), from T1 to T2, and at U1 (p = 0.048) from T1 to T3. In group B only the frequency of T. forsythia showed a statistically significant decrease, at U6 (T1 vs.T2, p = 0.004; T1 vs.T3, p = 0.0003). Regarding other analyzed bacteria, changes in the presence were noticed but no statistical significance was found.
  
  
  CONCLUSIONS
  Placement of fixed appliances may have an impact on subgingival microflora, but in the first months after the placement and removal of the appliance changes were not significant, probably due to good oral hygiene.
authors.forename: Marija Zivković
authors.initials: MZ
authors.lastname: Sandić
authors.forename: Branka
authors.initials: B
authors.lastname: Popović
authors.forename: Jelena
authors.initials: J
authors.lastname: Carkić
authors.forename: Nadja
authors.initials: N
authors.lastname: Nikolić
authors.forename: Branislav
authors.initials: B
authors.lastname: Glisić
mesh_terms: D000293:Adolescent; D000328:Adult; D015373:Bacterial Typing Techniques; D002648:Child; D004269:DNA, Bacterial / Q000032:analysis; D003757:Dental Implantation; D003773:Dental Plaque / Q000382:microbiology; D020878:Device Removal; D005260:Female; D005881:Gingiva / Q000382:microbiology*; D006801:Humans; D008297:Male; D064307:Microbiota / Q000235:genetics; D009967:Orthodontic Appliances / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial