# Photon‐Counting CT for Diagnosing Vertical Root Fractures in Teeth With Metal Posts: An Ex Vivo Comparative Analysis With Four CBCT Devices

## TL;DR

The study compares photon-counting CT with four CBCT devices for diagnosing tooth fractures near metal posts, finding photon-counting CT to be highly accurate.

## Contribution

This is the first ex vivo comparative analysis of photon-counting CT for detecting vertical root fractures in teeth with metal posts.

## Key findings

- Photon-counting CT showed high diagnostic accuracy for vertical root fractures comparable to high-resolution CBCT devices.
- NewTom VGi and PCCT had significantly higher AUC values than Veraview X800, regardless of metal post material.
- PCCT devices demonstrated significantly higher sensitivity with both Ni-Cr and Co-Cr metal posts compared to some CBCT devices.

## Abstract

Photon‐counting computed tomography (PCCT) represents a major innovation in X‐ray detection technology, offering improved signal efficiency and reduced electronic noise compared with cone‐beam computed tomography (CBCT), which can enhance image quality. This study aimed to evaluate the diagnostic performance of PCCT in detecting vertical root fractures (VRF), in comparison with four CBCT devices.

Eighteen single‐rooted teeth were endodontically treated, and VRF was induced in eight of them. Each tooth was individually placed into the mandibular first premolar empty socket of an anthropomorphic phantom and scanned under three conditions: without a metal post, with a nickel‐chromium metal post (Ni‐Cr), and with a cobalt‐chromium metal post (Co‐Cr) in five CT devices: the NAEOTOM Alpha PCCT (Siemens Healthineers) device and four CBCT devices (3D Accuitomo 170—Morita, Veraview X800—Morita, NewTom VGi evo—NewTom, and Carestream 9600—Carestream). The highest‐resolution protocol available on each device was used, resulting in a total of 270 scans. Five experienced dentomaxillofacial radiologists independently and blindly evaluated the scans using a five‐point confidence scale. Diagnostic accuracy was assessed by calculating the area under the ROC curve (AUC), sensitivity, and specificity, with results compared by two‐way ANOVA with post hoc Tukey's test (α = 0.05).

NewTom VGi and PCCT devices showed significantly higher AUC values than the Veraview X800, regardless of the metal post material (p < 0.05). CS9600 and PCCT devices exhibited significantly higher sensitivity values in diagnosing with Ni‐Cr posts than the Accuitomo 3D and Veraview X800 devices (p < 0.05). With the Co‐Cr metal post, the NewTom VGi, CS9600, and PCCT devices showed significantly higher sensitivity values compared to the Veraview X800 device (p < 0.05). There were no statistically significant differences in specificity, regardless of the CT device or metal post material (p > 0.05).

The NEAOTOM Alpha PCCT showed high diagnostic accuracy for VRF detection in an ex vivo model, comparable to high‐resolution CBCT devices, highlighting its diagnostic performance under controlled ex vivo conditions.