ORCID

Document Type

Article

Abstract

Background/Objectives: Successful endodontic treatment depends on preserving sufficient radicular dentine to prevent perforations. Mandibular first molars present with complex root morphology and “danger zones,” especially of the mesial root. This study aimed to address the limited South African dentine thickness data. Methods: This cross-sectional study evaluated 77 first mandibular molars obtained from 45 Black South African mandibular micro-CT scans. A novel software program developed for this study was used for the first time to generate automated orthogonal virtual sections and measurements at 0.1 mm intervals along the entire root length adapting to its curved axis. Statistical analyseswere performed to assess variations according to root surface, root level, sex, side, and age. Results: Despite statistically significant effects of co-factors on dentine thickness, variations between left and right molars, sexes, or in relation to age were not significant. In both roots dentine thickness tapered toward the apex. Thinner dentinal walls were noted in the mesial root (on distal aspect 0.98 mm at furcation tapering to 0.28 mm at apex) than the distal. Up to the apical third, buccal and lingual surfaces remained significantly thicker (2.61 and 2.48 mm respectively at furcation tapering to 0.66 and 0.52 mm at the apex) than mesial and distal. Conclusions: Comprehensive three-dimensional data onmandibular first molar dentine thickness in a Black South African sample is provided.Dentine thickness was thinner than reported using micro-CT scans and a novel software program (Unity 2022.3 LTS, Unity Technologies, San Francisco, CA, USA), emphasizing the need for increased clinical caution. Findings should be cautiously applied and experimentally validated.

Publication Date

2026-09-09

Publication Title

Oral

Volume

6

Issue

5

Acceptance Date

2026-08-26

Deposit Date

2026-09-16

Funding

This study was supported by the National Research Foundation (NRF) under the Research Development Grants for New Generation of Academics Program (nGAP) [Grant No: NGAP240205203589] and co-funded by the Department of Higher Education and Training (DHET) through the Staffing South African Universities Framework (SSAUF) and nGAP.

Keywords

danger zone, safety zone, mesial root, distal root, raycasting, surface-to-interface thickness

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

First Page

1

Last Page

20

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