title: Development of polarization dental imaging modality and evaluation of its clinical feasibility.
abstract: OBJECTIVE
  In the evaluation of tooth color, the specular reflection caused by roughness or saliva on the tooth surface may cause artefacts in image analysis. In this study, a polarization dental imaging modality (PDIM) was developed to obtain cross-polarized images and, therefore, to address the problem of specular reflection. Its clinical validity was evaluated by performing 3 studies of shade tab selection for implant, plaque distribution detection, and evaluation of tooth whitening.
  
  
  METHODS
  In vivo human tooth and shade guide color images were obtained, and the minimum color difference between them was calculated for the best color matching shade tab selection. A dental plaque disclosing agent was used to differentiate plaque regions on teeth, and plaque distribution was detected by applying the K-means algorithm. In vivo human teeth were treated with a commercial tooth whitening gel, and tooth whitening was quantitatively evaluated using the PDIM images.
  
  
  RESULTS
  The PDIM produced repeatable glare-free tooth color images by effectively removing the specular reflection from the tooth surface. The cross-polarized tooth images were successfully utilized for shade guide selection, plaque detection, and tooth whitening by minimizing artefacts in the quantitative image analysis. The PDIM could simultaneously provide both qualitative and quantitative assessment of the tooth condition in clinical diagnosis.
  
  
  CONCLUSIONS
  The clinical feasibility of the PDIM was successfully verified in 3 clinical studies by showing its clinical efficacy as a new imaging modality.
authors.affiliation: Department of Biomedical Engineering, Yonsei University, Wonju, Republic of Korea.
authors.forename: Eunji
authors.initials: E
authors.lastname: Kim
authors.forename: Taeyoon
authors.initials: T
authors.lastname: Son
authors.forename: Yoon
authors.initials: Y
authors.lastname: Lee
authors.forename: Byungjo
authors.initials: B
authors.lastname: Jung
mesh_terms: D016477:Artifacts; D003116:Color / Q000592:standards*; D003773:Dental Plaque / Q000175:diagnosis; D005240:Feasibility Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D055620:Optical Phenomena; D015203:Reproducibility of Results; D014070:Tooth / Q000033:anatomy & histology*; D014073:Tooth Bleaching / Q000592:standards*; D014075:Tooth Discoloration / Q000175:diagnosis