3D superimposition of cone-beam computed tomography and intraoral scan models for forensic identification:...

In the absence of dental treatment, dental morphology analysis is a promising method for human identification. This study aimed to develop and validate a method that superimposes 3D models derived from CBCT (3DCT) and intraoral scans (3DIOS), and to establish reference values for this approach. The evaluation sample comprised sixty corresponding 3DCT-3DIOS model pairs and sixty non-corresponding pairs. The validation sample comprised thirty non-corresponding 3DCT-3DIOS pairs. For each superimposition, the root mean square (RMS), absolute average (Abs Avg), half the interdecile range ((90-10)/2), and percentage of points within tolerance (InTol%) were calculated. Statistical analyses included the Shapiro-Wilk test, Bartlett's test, one-way analysis of variance (ANOVA), the Benjamini, Krieger & Yekutieli (BKY) test, Pearson's correlation test, the unpaired t-test, the intraclass correlation coefficient (ICC), the technical error of measurement (TEM), and receiver operating characteristic (ROC) curve analysis. All mandibular and maxillary variables differed significantly between corresponding and non-corresponding models (p < 0.0001). For corresponding mandibular models, ROC analysis established the following cutoff values: Abs Avg < 0.13, RMS < 0.23, (90-10)/2 < 0.18, and InTol% > 35%. For corresponding maxillary models, the cutoff values were Abs Avg < 0.12, RMS < 0.21, (90-10)/2 < 0.20, and InTol% > 31%. Combined analysis of all metrics distinguished corresponding from non-corresponding cases in the evaluated sample. Tooth-by-tooth superimposition can be applied regardless of tooth movement, growth, or bone fractures, demonstrating that this digital workflow is a robust alternative for human identification.