title: Digital analysis of staining properties of clear aesthetic brackets.
abstract: OBJECTIVE
  To analyse the staining properties of clear orthodontic brackets using a digital analysis.
  
  
  METHODS
  In vitro, laboratory study
  
  
  METHODS
  A total of 500 tooth-coloured brackets from 10 brands (five ceramic and five plastic) were investigated. The cumulative discolouring effect of staining agents (tea, coffee, curry and red wine) were analysed at two consumption levels: light and heavy, based on a 6-month period of exposure. Study group brackets were immersed in the agents consecutively at 37°C. The control group was only exposed to artificial saliva. Samples were analysed digitally to obtain L*, a* and b* (lightness, red-green and yellow-blue) colour readings. Using these values, total colour change (ΔE*) at each level was also calculated. Three-way analysis of variance (ANOVA) test was used for statistical comparisons.
  
  
  RESULTS
  L* and b* colour parameters showed significant differences (P<0·001) between different bracket groups, consumption levels and the type of exposure. However, the a* value only differed between bracket groups (P<0·001). According to the ΔE* values, ceramic brackets had less colour change than plastic brackets at the end of phase 1 for both the study and control groups. However, as consumption time increased, the rate of colour change decreased for the plastic brackets. In general, ceramic brackets demonstrated much more resistance to staining agents than plastic brackets.
  
  
  CONCLUSIONS
  Both plastic and ceramic brackets showed changes in colour when exposed to heavy consumption of staining agents, with plastic brackets being the most affected.
authors.affiliation: University of Texas School of Dentistry at Houston, Houston, TX, USA. sercan.akyalcin@uth.tmc.edu
authors.forename: Sercan
authors.initials: S
authors.lastname: Akyalcin
authors.forename: Jared
authors.initials: J
authors.lastname: Rykiss
authors.forename: Wellington J
authors.initials: WJ
authors.lastname: Rody
authors.forename: William A
authors.initials: WA
authors.lastname: Wiltshire
mesh_terms: D000704:Analysis of Variance; D002516:Ceramics; D003069:Coffee; D003116:Color; D003124:Colorimetry; D004955:Esthetics, Dental; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D010969:Plastics; D012464:Saliva, Artificial; D012815:Signal Processing, Computer-Assisted; D017365:Spices; D013662:Tea; D014920:Wine
chemical_list: D003069:Coffee; D010969:Plastics; D012464:Saliva, Artificial; D013662:Tea