title: Short-term effect of removal of fixed orthodontic appliances on gingival health and subgingival microbiota: a prospective cohort study.
abstract: OBJECTIVE
  The aim of this prospective longitudinal study was to assess and compare the microbiological and clinical parameters of patients wearing a fixed orthodontic appliance, as opposed to 10 days after the bracket had been removed following treatment.
  
  
  METHODS
  In total, 122 patients participated in this study; 61 of the subjects were assessed at baseline (wearing a fixed orthodontic appliance: T1) and 10 days after bracket removal (T2). The other 61 individuals had never worn an orthodontic appliance before and these subjects served as controls (CT). Subgingival plaque samples were assessed for bleeding on probing (GBI) and plaque index (VPI). PCR of 16s rDNA, followed by reverse species-specific hybridization for Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia and Treponema denticola were performed. A descriptive analysis was conducted; chi-squared, Student's matched and unmatched t-tests, the point biserial correlation coefficient and the McNemar test were used to test for differences between groups (p < 0.05).
  
  
  RESULTS
  The GBI and VPI clinical parameters showed statistical differences (p < 0.05) between T1-T2, T1-CT and T2-CT. The prevalence of T. denticola had significantly decreased (p = 0.039) 10 days after appliance removal. At T2, a significant positive correlation was found between GBI and A. actinomycetemcomitans (p < 0.01) and between clinical parameters and P. intermedia. In patients without a fixed orthodontic appliance (T2 and CT), there was a significant positive correlation between T. forsythia and VPI.
  
  
  CONCLUSIONS
  Local factors associated with the wearing of a fixed orthodontic appliance influence changes in subgingival plaque that leads to more inflammation and bleeding.
authors: Department of Orthodontics, School of Dentistry, University of Seville , Seville , Spain.
authors: Rosa-María
authors: RM
authors: Yáñez-Vico
authors: Alejandro
authors: A
authors: Iglesias-Linares
authors: Sofía
authors: S
authors: Ballesta-Mudarra
authors: Estefanía
authors: E
authors: Ortiz-Ariza
authors: Enrique
authors: E
authors: Solano-Reina
authors: Evelio-José
authors: EJ
authors: Perea
mesh_terms: D000293:Adolescent; D000328:Adult; D016976:Aggregatibacter actinomycetemcomitans / Q000302:isolation & purification; D001439:Bacteroides / Q000302:isolation & purification; D015331:Cohort Studies; D003773:Dental Plaque / Q000382:microbiology; D003774:Dental Plaque Index; D005260:Female; D005881:Gingiva / Q000382:microbiology*; D005891:Gingivitis / Q000382:microbiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D016910:Orthodontic Brackets / Q000382:microbiology*; D010512:Periodontal Index; D016966:Porphyromonas gingivalis / Q000302:isolation & purification; D011446:Prospective Studies; D048373:Treponema denticola / Q000302:isolation & purification; D055815:Young Adult
keywords: Periodontopathogens; gingivitis; microbiology; orthodontics