Optical coherence tomography evaluation of deep dentin crack removal techniques

This in vitro study used optical coherence tomography for noninvasive evaluation of the effectiveness of current clinical techniques to remove deep coronal dentin cracks.

Standard dentin cracks were induced on the pulpal floor of 40 decoronated, extracted, sound human posterior teeth using a diamond disk, resembling cracks extending from marginal ridges. The specimens were randomly assigned to 1 of 5 treatment groups for crack removal using airborne-particle abrasion or a bur (fissure, small round, medium round, or tapered fine diamond). Optical coherence tomographic scans were obtained before and after the crack removal. Three-dimensional image registration analyzed the amount of dentin removed and the dimensions of cracks initiated or propagated in each treatment group.

Particle abrasion resulted in the smallest crack propagation in each dimension, which was significantly different from all bur groups (Mann-Whitney, P < .01). Removed dentin depth and width differed among burs (P < .05). All burs resulted in a degree of crack formation, and there was no difference in crack dimensions among bur groups (P > .05). The amount of removed dentin during crack treatment was the largest in the particle abrasion group, which was significantly different from those of the bur groups (Mann-Whitney, P < .005).

Dental burs used with the purpose of removing pulpal floor dentin cracks induced new small cracks and extended existing cracks, and the volume of removed dentin depended on the shape and size of the bur. Air particle abrasion induced the fewest new cracks despite removing larger dentin volume.