Measurement of the remaining dentin thickness using optical coherence tomography for crown preparation

This study aimed to investigate the maximum depth imaging and optical properties of the dentin near the pulp by using optical coherence tomography (OCT) and to explore the possibility of measuring the remaining dentin thickness (RDT). Human third molars were used. In experiment 1, the cuspal dentin blocks (0.50-mm to 1.75-mm thickness) were prepared. Each specimen was scanned using OCT. OCT images could be obtained for all specimens with 1.00-mm or less thicknesses. In experiment 2, dentin-pulp complex slices (0.50-mm and 1.00-mm RDT) were prepared. Each specimen was scanned using OCT and micro-computed tomography, and compared. The resulting length change rates of OCT images for the 0.50-mm RDTs were significantly lower than those of the 1.00-mm RDTs. Within the limitations of this study, OCT was effective for measuring the 1.00-mm or less RDT and preventing pulpal injury, while considering the length change rate of OCT image as a variable.