Effects of root canal enlargement on unprepared areas and coronal dentine thickness of three-rooted maxillary first premolars with different root configurations: A stepwise micro-CT study.

Aim: To evaluate the effects of progressive root canal enlargements on the unprepared surface area and remaining dentine thickness of three-rooted maxillary first premolars with different root configurations.

Methodology: Thirty three-rooted maxillary first premolars with three root configurations (n = 10) were selected and scanned in a micro-CT device. The root canals were sequentially enlarged with rotary instruments sizes 30.