Use of Optical Clearing Agents for Imaging Root Surfaces With Optical Coherence Tomography

The diagnosis of root caries and root fractures is of increasing importance due to our aging population. The objective of this study is to show that optical clearing agents can be used to increase the visibility of subsurface structures in tooth roots to aid in the diagnosis of root caries depth and extension and to differentiate from subsurface defects. Previous studies have shown that high refractive index fluids can increase the depth penetration of optical coherence tomography (OCT) for imaging caries lesions on tooth enamel. Extracted teeth with suspected root caries were imaged with (OCT) with and without the addition of water (W), glycerol (G), and propylene glycol (PG). The reflectance was monitored in sound and demineralized areas before and after application of W, G, and PG. The visibility of subsurface root canals was also measured before and after application of the respective fluids. In addition, shrinkage in lesion areas was measured after lesion dehydration to aid in the assessment of lesion activity. This study shows that optical clearing agents can be used to increase the performance of OCT for the diagnosis of root caries and other defects on root surfaces.