Monitoring silver diamine fluoride application with optical coherence tomography.

The objective of this study was to investigate the use of optical coherence tomography (OCT) for monitoring changes in the structure of caries lesions overtime after treatment with silver diamine fluoride (SDF). Artificial caries lesions were formed on dentin bovine blocks. Each block was partitioned into 5 windows: one lesion was covered by nail varnish as control (LC), one sound window was covered with nail varnish (SC), one sound window was exposed to SDF (SCT), one lesion received 2 applications of SDF (L2), while the other lesion received one application of SDF (L1). Each window was scanned using OCT before SDF application, and every week subsequently, for 12 weeks after initial SDF treatment. Parameters such as mean intensity and the width of the peak of increased reflectivity located at the sample surface and the intensity at a depth of 180-μm were monitored. High-resolution microscopy was also used to for the analysis of selected samples. Changes in the parameters measured showed significant changes on dentin lesions after SDF application. OCT resolved structural changes after SDF application as well as changes overtime. High resolution microscopy images confirm penetration of SDF into the samples. Such changes can potentially be monitored to determine if and when re-application of SDF is needed.