Rapid Assessment of the Severity of Caries Lesions for SS-OCT

Objective: Several studies have demonstrated that Optical Coherence Tomography (OCT) can be used to nondestructively measure and quantify the severity of demineralization in enamel and dentin. Swept-Source OCT (SS-OCT) allows rapid collection of 3D tomographic images in real time. The purpose of my project was to develop a program that can be used to rapidly assemble 3D tomographic images and analyze the lesion depth and integrated reflectivity to quantify severity.

Method: The program was written in the LabVIEW graphical programming language. The program compiles 2D images into 3D tomographic images for large data sets and subsequently performs background subtraction, cropping, artifact removal, convolution filtering, edge detection and calculation of lesion depth and integrated reflectivity, which can be correlated with mineral loss and lesion severity. This program was used to analyze images from a cross-polarization SS-OCT system with an integrated handheld Microelectromechanical Systems (MEMS) scanner from Santec (Aichi, Japan). Several extracted teeth with suspected secondary caries lesions were scanned and analyzed with this system.

Result: The program allows efficient and rapid analysis of lesion depth and severity for SS-OCT 3D tomographic images. Processed SS-OCT images show excellent imaging depth through resin-based composite restorations and indicate secondary caries lesions and restoration defects.

Conclusion: Caries lesions depth and severity can be evaluated automatically for rapid analysis from 3D tomographic SS-OCT scans. This program will be primarily used for assessing the stage of caries lesion activity and detecting secondary caries lesion around the resin based restorations both in vitro and in vivo.