Dentin shear strength: effect of distance from the pulp

Objective: Dentin structure varies with orientation and location. Ultimate shear strength (USS) has also been found in previous studies to vary with location. The present study further explores this relationship between USS and various locations in coronal dentin as well as distance from the pulp. Methods: Stick specimens were prepared from coronal dentin located in the center or under cusps of human molar teeth. These were tested in the shear mode at various distances from the pulp. Results: Median values ranged from 52.7 (range 29.0–73.1) MPa near the pulp to 76.7 (range 53.9–104.0) MPa near the dentino–enamel junction. No differences were found among the buccal, central or lingual locations, however, the USS near the pulp was found to be significantly lower. Significance: The properties of coronal dentin vary with distance from the pulp, which may affect adhesion and other aspects of restorative dentistry.