Abstract

Objective: This study evaluated the impact of traditional, conservative/contracted, and ultraconservative/”ninja” access cavities on root canal shaping using micro-computed tomography (micro-CT).

Methods: Mesial canals from freshly extracted mandibular molars with pulp vitality were scanned in micro- CT for sample selection. Specimens matched by anatomic similarities were distributed into 3 experimental groups according to the endodontic access cavity types (traditional, conservative, and ultraconservative). After canal preparation using R-Motion instruments size 25.06, the specimens were once again scanned to assess diverse shaping parameters.

Results: There were significant differences in the increment rate of root canal volume and area between traditional and ultraconservative access cavities (P < .05). The amount of unprepared canal areas was significantly higher with the ultraconservative access cavity in comparison with the other groups (P < .05). Intergroup analysis did not reveal significant differences in the structure model index, amount of accumulated hard tissue debris, dentin removed, and remaining thickness of pericervical dentin (P > .05).

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