title: Quantification of root caries using optical coherence tomography and microradiography: a correlational study.
abstract: OBJECTIVE
  The use of transverse microradiography (TMR) to quantify the amount of mineral lost during demineralization of tooth tissue has long been established. In the present study, the use of an en-face Optical Coherence Tomography (OCT) technology to detect and quantitatively monitor the mineral changes in root caries was investigated and correlated with TMR.
  
  
  METHODS
  We used an OCT system, developed initially for retina imaging, and which can collect A-scans, B-scans (longitudinal images) and C-scans (en-face images) to quantitatively assess the development of root caries. The power to the sample was 250 microW, wavelength lambda = 850 nm and the optical source linewidth was 16 microm.
  
  
  RESULTS
  Both the transversal and longitudinal images showed the caries lesion as volumes of reduced reflectivity. Quantitative analysis using the A-scan (reflectivity versus depth curve) showed that the tissue reflectivity decreased with increasing demineralization time. A linear correlation (r = 0.957) was observed between the mineral loss measured by TMR and the percentage reflectivity loss in demineralized tissue measured by OCT.
  
  
  CONCLUSIONS
  We concluded that OCT could be used to detect incipient root caries, and that the reflectivity loss in root tissue during demineralization, measured by OCT, could be related to the amount of mineral lost during the demineralization.
authors.affiliation: Cariology Unit, Department of Community Dentistry, University of Texas Health Science Center at San Antonio, Texas, USA. amaechi@uthscsa.edu
authors.forename: Bennett T
authors.initials: BT
authors.lastname: Amaechi
authors.forename: Adrian Gh
authors.initials: AG
authors.lastname: Podoleanu
authors.forename: Gleb
authors.initials: G
authors.lastname: Komarov
authors.forename: Susan M
authors.initials: SM
authors.lastname: Higham
authors.forename: David A
authors.initials: DA
authors.lastname: Jackson
mesh_terms: D000704:Analysis of Variance; D003732:Dental Caries Activity Tests; D042241:Early Diagnosis; D006801:Humans; D016014:Linear Models; D008852:Microradiography; D018613:Microscopy, Confocal; D008963:Molar; D017213:Root Caries / Q000175:diagnosis*; D018709:Statistics, Nonparametric; D041623:Tomography, Optical Coherence