title: Non-destructive clinical assessment of occlusal caries lesions using near-IR imaging methods.
abstract: OBJECTIVE
  Enamel is highly transparent in the near-IR (NIR) at wavelengths near 1,300 nm, and stains are not visible. The purpose of this study was to use NIR transillumination and optical coherence tomography (OCT) to estimate the severity of caries lesions on occlusal surfaces both in vivo and on extracted teeth.
  
  
  METHODS
  Extracted molars with suspected occlusal lesions were examined with OCT and polarization sensitive OCT (PS-OCT), and subsequently sectioned and examined with polarized light microscopy (PLM) and transverse microradiography (TMR). Teeth in test subjects with occlusal caries lesions that were not cavitated or visible on radiographs were examined using NIR transillumination at 1,310 nm using a custom built probe attached to an indium gallium arsenide (InGaAs) camera and a linear OCT scanner. After imaging, cavities were prepared using dye staining to guide caries removal and physical impressions of the cavities were taken.
  
  
  RESULTS
  The lesion severity determined from OCT and PS-OCT scans in vitro correlated with the depth determined using PLM and TMR. Occlusal caries lesions appeared in NIR images with high contrast in vivo. OCT scans showed that most of the lesions penetrated to dentin and spread laterally below the sound enamel.
  
  
  CONCLUSIONS
  This study demonstrates that both NIR transillumination and OCT are promising new methods for the clinical diagnosis of occlusal caries.
authors: Department of Preventive and Restorative Dental Sciences, University of California, San Francisco 94143-0758, USA.
authors: Michal
authors: M
authors: Staninec
authors: Shane M
authors: SM
authors: Douglas
authors: Cynthia L
authors: CL
authors: Darling
authors: Kenneth
authors: K
authors: Chan
authors: Hobin
authors: H
authors: Kang
authors: Robert C
authors: RC
authors: Lee
authors: Daniel
authors: D
authors: Fried
mesh_terms: D003731:Dental Caries / Q000175:diagnosis* / Q000473:pathology; D003743:Dental Enamel / Q000473:pathology; D003804:Dentin / Q000473:pathology; D006801:Humans; D008852:Microradiography; D008859:Microscopy, Polarization; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000379:methods*