Near-infrared imaging of demineralization under sealants.

Henry Tom,Daniel Fried,Cynthia L Darling,Kenneth H Chan,Jacob C Simon

doi:10.1117/1.jbo.19.7.077003

Abstract

Previous studies have shown that near-infrared (NIR) reflectance and transillumination imaging can be used to acquire high contrast images of early caries lesions and composite restorative materials. The aim of the study was to determine the optimum NIR wavelengths for imaging demineralized areas under dental sealants. Fifteen natural human premolars and molars with occlusal lesions were used in this in vitro study. Images before and after application of sealants were acquired using NIR reflectance and NIR transillumination at wavelengths of 1300, 1460, and 1500 to 1700 nm. Images were also acquired using polarization sensitive optical coherence tomography (OCT) for comparison. The highest contrast for NIR reflectance was at 1460 nm and 1500 to 1700 nm. These NIR wavelengths are coincident with higher water absorption. The clear Delton sealant investigated was not visible in either copolarization or cross-polarization OCT images. The wavelength region between 1500 and 1700 nm yielded the highest contrast of lesions under sealants for NIR reflectance measurements.

Highlights

Near-infrared (NIR) reflectance, NIR transillumination, and optical coherence tomography (OCT) are new imaging techniques that are capable of imaging caries lesions with high contrast in the wavelength region from 1300 to 1700 nm.[1,2,3,4,5,6,7] We have found that 1300 nm yields the highest contrast for transillumination while wavelengths with higher water absorption, 1450 nm and 1500 to 1700 nm, yield the highest contrast for NIR reflectance
A small shallow lesion is located at the base of the central fissure and the dentinal-enamel junction (DEJ) is clearly visible in the initial bscans for both polarizations [Fig. 4(a)]
The primary objective of this study was to determine the influence of clear sealants on the contrast of lesions in tooth occlusal surfaces in NIR reflectance and transillumination images

Summary

Introduction

Near-infrared (NIR) reflectance, NIR transillumination, and optical coherence tomography (OCT) are new imaging techniques that are capable of imaging caries lesions with high contrast in the wavelength region from 1300 to 1700 nm.[1,2,3,4,5,6,7] We have found that 1300 nm yields the highest contrast for transillumination while wavelengths with higher water absorption, 1450 nm and 1500 to 1700 nm, yield the highest contrast for NIR reflectance. The purpose of this paper was to determine the influence of a clear sealant on the contrast of small natural caries lesions in the pits and the fissures of tooth occlusal surfaces measured using NIR reflectance and transillumination. Polarization sensitive optical coherence tomography (PS-OCT) was employed to confirm the severity of the occlusal lesions before application of the sealant and to evaluate the severity of demineralization. Several studies both in vitro and in vivo have shown that PS-OCT can be used to quantify the severity of early demineralization on tooth occlusal surfaces.[17,18,19] The

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Conclusion