Ahmed M, Melaragno LE, Nyirjesy SC, von Windheim N, Fenberg R, Herster R, Sheldon A, Binzel K, Knopp MV, Herderick ED, VanKoevering KK. Higher Computed Tomography (CT) Scan Resolution Improves Accuracy of Patient-specific Mandibular Models When Compared to Cadaveric Gold Standard.
J Oral Maxillofac Surg 2023;
81:1176-1185. [PMID:
37315925 DOI:
10.1016/j.joms.2023.05.014]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 05/26/2023] [Accepted: 05/29/2023] [Indexed: 06/16/2023]
Abstract
BACKGROUND
3D-printed patient-specific anatomical models are becoming an increasingly popular tool for planning reconstructive surgeries to treat oral cancer. Currently there is a lack of information regarding model accuracy, and how the resolution of the computed tomography (CT) scan affects the accuracy of the final model.
PURPOSE
The primary objective of this study was to determine the CT z-axis resolution necessary in creating a patient specific mandibular model with clinically acceptable accuracy for global bony reconstruction. This study also sought to evaluate the effect of the digital sculpting and 3D printing process on model accuracy.
STUDY DESIGN
This was a cross-sectional study using cadaveric heads obtained from the Ohio State University Body Donation Program.
INDEPENDENT VARIABLES
The first independent variable is CT scan slice thickness of either 0.675 , 1.25, 3.00, or 5.00 mm. The second independent variable is the three produced models for analysis (unsculpted, digitally sculpted, 3D printed).
MAIN OUTCOME VARIABLE
The degree of accuracy of a model as defined by the root mean square (RMS) value, a measure of a model's discrepancy from its respective cadaveric anatomy.
ANALYSES
All models were digitally compared to their cadaveric bony anatomy using a metrology surface scan of the dissected mandible. The RMS value of each comparison evaluates the level of discrepancy. One-way ANOVA tests (P < .05) were used to determine statistically significant differences between CT scan resolutions. Two-way ANOVA tests (P < .05) were used to determine statistically significant differences between groups.
RESULTS
CT scans acquired for 8 formalin-fixed cadaver heads were processed and analyzed. The RMS for digitally sculpted models decreased as slice thickness decreased, confirming that higher resolution CT scans resulted in statistically more accurate model production when compared to the cadaveric gold standard. Furthermore, digitally sculpted models were significantly more accurate than unsculpted models (P < .05) at each slice thickness.
CONCLUSIONS
Our study demonstrated that CT scans with slice thicknesses of 3.00 mm or smaller created statistically significantly more accurate models than models created from slice thicknesses of 5.00 mm. The digital sculpting process statistically significantly increased the accuracy of models and no loss of accuracy through the 3D printing process was observed.
Collapse