Quantitative analysis of optical coherence tomography images for early natural enamel caries / 国际生物医学工程杂志

Objective Quantitative analysis of optical coherence tomography (OCT) images of naturally occurred early enamel caries was performed to find quantitative parameter indicator for detecting early caries by OCT.Methods Three human premolars with enamel natural caries in D0,D1,and D2 stages were selected respectively and scanned by OCT.The ratios of the average gray value of the caries region (object region) and sound region (background region),namely,the object-background contrast (OBC) were calculated in OCT images and selected as the quantitative parameters to analyze the OBC trend of different degree of enamel caries.Results Within the fixed depth,the OBC value showed a trend of first increase and then decrease with the severity of dental caries,indicating that OBC value increased with the severity of dental caries from normal to D1 stage,and then decreased from D1 to D2 stage.Conclusion The OBC value can be used as a new quantitative indicator for OCT to estimate the severity of naturally occurred early caries.

Experimental estimate of detection efficacy on early enamel demineralization by the dental OCT / 中国组织工程研究

2 mmx3 mm experimental windows were prepared in adamant slippery surfaces of 7 fresh uprooted permanent teeth. The teeth surfaces in the windows area were demineralized to create artificial caries mould of early stage by aciding the experimental teeth surfaces of 0, 12, 24, 48, 72, 96, 120 hours with demineralized liquid (pH 4.5) in vitro. The demineralized changes on the experimental teeth surfaces were detected by dental Optical Coherence Tomography (OCT) system, which were newly developed by our research group recently, and the detecting results were compared with clinical digital photomicrography and scanning electron microscopy on the same tooth sample, to checkout the efficacy and feasibility of dental OCT for early quantification detecting of artificial enamel demineralization in vitro. The dental OCT system can safelydetect early enamel demineralization of micron level and noninvasively obtain fine resolution quantification information both in surfaces view and sectional view; OCT could accurately detect surface demineralization changes on the experimental windows of artificial dental caries as early as after 12 hours aciding treatment, earlier than the visual inspection and clinical digital photomicrography. OCT could obtain both superficial view and sectional view of quantificational demineralization in early enamel caries homeochronously, and had high correlation to the results of ultramicromorphological changes detected by scanning electron microscopy. Dental OCT system developed by our group could accurately detect early artificial dental caries atraumaticly with high sensitivity and safety. Moreover, it can obtain quantification data in micron level without damaging the experimental teeth samples.