Objective: The objective of this study was to determine if it was possible to retain 2 mm of dentin around the periphery of root-end cavity preparations in maxillary central incisor and maxillary canine teeth.
Study design: Thirty teeth of each type were root filled. Three millimeters of root end was resected and conservative root-end cavities ultrasonically prepared. Root ends were photographed and measured using a computer program. Teeth without 2 mm of peripheral dentin were sectioned for up to 3 further 1-mm increments.
Results: None of the central incisors had 2 mm of dentin remaining at the 3-mm resection level, and none of the canines had 2 mm of dentin remaining even after resecting to 6 mm.
Conclusions: Recommendations to preserve 2 mm of structure around the root-end cavities of these teeth are unrealistic.