Micro–computed tomography may have enabled highly accurate digital reconstruction of fragmented teeth, with reconstructed models differing from intact teeth by approximately 0.01 mm to 0.02 mm between two operators.
In a controlled laboratory study, researchers evaluated 32 extracted human anterior teeth and premolars therapeutically extracted from 14 patients treated at hospitals in Paris. The sample included incisors, canines, and premolars without cavitated caries, large restorations, or substantial calculus deposits. Each tooth underwent baseline scanning with micro–computed tomography (CT). The teeth were then mechanically fragmented using controlled compression, rescanned as separate fragments, and digitally reassociated using three-dimensional registration software and an iterative closest point algorithm. The reconstructed meshes were compared with the original intact tooth meshes to assess geometric accuracy, repeatability, and reproducibility.
The mean deviation between the reconstructed and reference meshes measured 0.012 mm for the first operator and 0.017 mm for a second operator. Corresponding root-mean-square distances measured 0.048 mm and 0.060 mm, respectively. Nearly all reconstructed regions fell within the accepted ±0.05 mm deviation threshold used in forensic odontometric and craniometric analyses, supporting the feasibility of micro-CT for forensic dental reconstruction workflows.
The reassociation protocol also demonstrated strong reproducibility. Bland-Altman analyses showed interoperator bias below 0.01 mm, with nearly all measurements remaining within the 95% limits of agreement. The researchers reported no overall effect of sex, tooth class, or the number of fragments on reconstruction precision. The premolars demonstrated slightly higher root-mean-square values compared with incisors and canines, although subgroup differences weren't substantial.
The researchers noted several technical advantages of micro-CT compared with optical surface scanning. In addition to capturing the external morphology of the teeth at high resolution, the imaging method visualized internal structures, including pulp chambers and dentin architecture. The workflow also enabled digital removal of debris during segmentation without physically manipulating the fragmented specimens.
The study was designed as a feasibility experiment under controlled laboratory conditions, and the researchers emphasized several limitations. Most of the teeth were healthy or minimally restored, and fragmentation was produced through compression rather than the thermal or blunt-force trauma often encountered in forensic investigations. The teeth fractured into more than four fragments or exhibiting extensive enamel flaking were excluded. The researchers also noted that beam-hardening artifacts, loss of enamel contrast, and altered dentin-enamel interfaces in damaged forensic specimens could reduce segmentation accuracy. In addition, micro-CT systems remain less accessible compared with conventional forensic imaging platforms because they are typically housed in research facilities rather than operational forensic laboratories.
Overall, the findings supported the use of micro-CT as a potential tool for forensic dental reconstruction, although additional validation in damaged specimens is still needed prior to its broader implementation.
“Micro-CT provides a powerful, nondestructive method for capturing detailed dental morphology and fracture surfaces. Its capacity to generate highly accurate [three-dimensional] data supports its use as a reliable acquisition technique for digital reassociation of tooth fragments,” concluded lead study author Amaury Paring, of Université Paris Cité in Montrouge, France, and colleagues.
The study received no specific external funding, and the study authors reported no conflicts of interest.
Source: Forensic Imaging
