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FTIR imaging studies on early dental caries with/without polarization
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X. YAO, J.C. WHITT, P. SPENCER, and Y. WANG, University of Missouri-Kansas City, USA | | The early caries process involves the demineralization of the outer enamel and causes the enamel polarization changes. The state of polarization of a carious lesion is important in detecting a carious lesion and for imaging the structure of lesion. Objective: Use both nonpolarized and polarized FTIR imaging to evaluate changes in chemical properties of enamel white spot lesions. Materials and Methods: Extracted human molars (n=3) with white spot lesions on the buccal or lingual surfaces were collected following extraction under an IRB-approved protocol, and sectioned sagittally through the lesion center using a low-speed diamond saw. FTIR chemical images were collected from areas containing sound enamel and white spot lesions using the Spotlight (Perkin Elmer) with 8cm-1spectral resolution in reflectance mode w/wo polarization. The images were analyzed using multivariate statistical methods. Results: The chemical imaging of enamel with white spots demonstrated decreased mineral intensities at sites of carious lesions as compared to those of sound enamel. FTIR spectra obtained without polarization showed that the n3 PO4 domain was shifted from 1048cm-1 in sound enamel to 1054-1060cm-1 in white spot lesions, and the n2CO3 intensities decreased in white spot lesions. | | n3CO3 / n1 PO4 (1412/960) | n3CO3 / CH2 (1412/1448) | CH2 / n1 PO4 (1448 /960) | Sound enamel | 2.84±0.29 | 1.02±0.07 | 2.78±0.18 | White spot lesion | 1.70±0.49 | 0.72±0.04 | 2.65±0.65 | The spectra of carious lesions were more sensitive to the polarization direction than those of sound enamel, which might be due to demineralization induced alterations of enamel crystallite orientation. Multivariate analyses of both non-polarized and polarized FTIR images further delineated the white spots. Conclusions: Distinct differences in chemical composition were observed in white spot lesions as compared to sound enamel. Polarized FTIR, a nondestructive imaging system, has potential as a new diagnostic tool to detect and characterize early carious lesions. Supported by NIH DE014392, DE015281, DE15735
Seq #67 - Graduate Student Abstracts
2:45 PM-3:45 PM, Thursday, April 3, 2008
Hilton Anatole Hotel Trinity I - Exhibit Hall |
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