An automated measurement method for the endodontic working width of lower molars by means of parametric models using cone-beam CT and micro-CT
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Published:August 13, 2021DOI:https://doi.org/10.1016/j.joen.2021.08.004
Abstract
Introduction
A new method for the approximation of the root canal’s cross-sectional shape and its working width using cone-beam computed tomography (CBCT) or micro-computed tomography (μCT) was introduced.
Methods
Scanned data from twenty-nine extracted human mandibular first and second molar’s distal root canals without instrumentation were reconstructed and analyzed with a self-developed measurement algorithm. The three-dimensional volume models were sliced perpendicular to the vertical axis. Using different two-dimensional parametric models, the contour of each root canal slice was approximated and used to determine the canal’s cross-sectional dimensions. The measurements of minor width, major width and root canal’s conicity were statistically analyzed using ANOVA.
Results
The measured minor and major widths of the investigated root canals were significantly higher (probability value p<0.05) when evaluated by CBCT images than the results obtained from μCT data. Both dimensions increased starting from the apical foramen (p<0.01). The narrowest measured canal widths were 0.19 - 0.24 mm for CBCT and 0.09 - 0.21 mm for μCT in the apical part. The maximum values for conicity were between 13% and 17% in the cervical third.
Conclusions
The three-dimensional imaging data from CBCT and μCT enabled a valuable anatomical assessment of root canal’s cross-sectional ‘working width’ along the canal up to the physiological foramen in order to determine an adequate apical diameter as well as the correct measured taper in the cervical and medial part.
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