title: An in situ caries model to study demineralisation during fixed orthodontics.
abstract: OBJECTIVE
  To investigate de/remineralization of enamel during the early stages of orthodontic treatment using the in situ caries model.
  
  
  METHODS
  A prospective, longitudinal study, using the in situ caries model.
  
  
  METHODS
  The Department of Orthodontics at the University of Liverpool School of Dentistry. Fifteen orthodontic patients undergoing fixed appliance treatment with extraction of premolar teeth.
  
  
  METHODS
  Two enamel samples with pre-formed caries-like lesions were placed bilaterally, in specially constructed holders, on an orthodontic fixed appliance. One sample was bonded with a small bracket base.
  
  
  METHODS
  The parameters of the pre-formed carious lesion, expressed as mineral loss (delta Z), lesion depth (ld), lesion width (lw) and ratio (delta Z/ld) were compared between the bracketed, the non-bracketed and a control sample that had not been placed in the mouth. The difference between brackets place on the dominant (toothbrush hand) side and non-dominant side were also investigated. The correlation between mineral loss and length of time the sample was in the mouth was also analysed.
  
  
  RESULTS
  There was considerable individual variation; however, a one-factor repeated analysis of variance showed a significant difference in ratio values between the three groups (p = 0.006). A pairwise comparison showed a significant reduction in ratio value for the non-bracketed sample compared with the control, but not the bracketed sample. There was no significant difference in mineral loss between the dominant and non-dominant sides. There was no linear correlation between the length of time the sample was in the mouth.
  
  
  CONCLUSIONS
  An enamel sample with a pre-formed carious lesion, when placed in the mouth of an orthodontic patient, showed reduced remineralization in the presence of a simulated orthodontic bracket. Consistently effective preventive regimes to prevent demineralization in patients with fixed orthodontic appliances need to be developed. The technique described will be a valuable tool in this process.
authors.affiliation: Department of Clinical Dental Sciences, University of Liverpool, UK. p.benson@liverpool.ac.uk
authors.forename: P E
authors.initials: PE
authors.lastname: Benson
authors.forename: N
authors.initials: N
authors.lastname: Pender
authors.forename: S M
authors.initials: SM
authors.lastname: Higham
mesh_terms: D000704:Analysis of Variance; D003627:Data Interpretation, Statistical; D003731:Dental Caries / Q000209:etiology; D003743:Dental Enamel / Q000737:chemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008852:Microradiography; D008954:Models, Biological; D016910:Orthodontic Brackets / Q000009:adverse effects*; D011446:Prospective Studies; D015203:Reproducibility of Results; D017001:Tooth Demineralization / Q000209:etiology*; D014089:Tooth Remineralization