Evaluation of 10 Cone-beam Computed Tomographic Devices for Endodontic Assessment of Fine Anatomic Structures

Cone beam computed tomography in dentistry: Clinical recommendations and indication-specific features

OBJECTIVES

To provide a narrative overview of commercially available CBCT devices, highlight the wide range of technical features and their impact on image quality and diagnostic performance, and develop decision support charts to guide clinicians in selecting appropriate CBCT parameters for different dental specialties.

DATA AND SOURCES

Data collection involved reviewing published articles on CBCT devices and accessing manufacturer websites. Additional manufacturers were identified through a literature search and by attending scientific and commercial events held in 2023 and 2024. Information on CBCT features was obtained from websites, manuals, and inquiries until February of 2025. Data were categorized and analyzed descriptively and quantitatively to recommend device requirements for dental specialties. Decision support charts were developed for each specialty based on common indications and technical parameters (e.g., field-of-view, scout need, spatial resolution, X-ray exposure parameters, and post-processing tools).

RESULTS

Eighty-seven commercially available CBCT devices from 34 manufacturers across 11 countries were identified, with information confirmed for only 10 companies. Missing data varied, however FOV and voxel size were commonly reported. Tube voltage ranged from 50-120 kV, and tube current mostly varied between 1-17 mA. Dose considerations varied widely, with dose-product-area ranging from 10 to 5600 mGy.cm2 and typical effective dose estimates from 3 to 500 µSv. Decision support charts were created, outlining necessary image acquisition and reconstruction-related parameters for prosthodontics and implant dentistry, periodontology, oral and maxillofacial surgery, pediatric dentistry and orthodontics, and endodontics.

CONCLUSION

This study provides an overview of the technical features of commercially available CBCT devices, highlighting gaps in reconstruction parameters and dose considerations. Tailored recommendations based on patient-specific needs are essential, with clinicians individualizing CBCT acquisition to optimize diagnostic accuracy and minimize biological risks.

CLINICAL SIGNIFICANCE

This study provides valuable insights into commercially available CBCT devices in terms of their features and provides decision support chart to help clinicians select optimal technical parameters tailored to specific dental specialties.

Progress of Artificial Intelligence-Driven Solutions for Automated Segmentation of Dental Pulp Space on Cone-Beam Computed Tomography Images. A Systematic Review

INTRODUCTION

Automated segmentation of 3-dimensional pulp space on cone-beam computed tomography images presents a significant opportunity for enhancing diagnosis, treatment planning, and clinical education in endodontics. The aim of this systematic review was to investigate the performance of artificial intelligence-driven automated pulp space segmentation on cone-beam computed tomography images.

METHODS

A comprehensive electronic search was performed using PubMed, Web of Science, and Cochrane databases, up until February 2024. Two independent reviewers participated in the selection of studies, data extraction, and evaluation of the included studies. Any disagreements were resolved by a third reviewer. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess the risk of bias.

RESULTS

Thirteen studies that met the eligibility criteria were included. Most studies demonstrated high accuracy in their respective segmentation methods, although there was some variation across different structures (pulp chamber, root canal) and tooth types (single-rooted, multirooted). Automated segmentation showed slightly superior performance for segmenting the pulp chamber compared to the root canal and single-rooted teeth compared to multi-rooted ones. Furthermore, the second mesiobuccal (MB2) canalsegmentation also demonstrated high performance. In terms of time efficiency, the minimum time required for segmentation was 13 seconds.

CONCLUSION

Artificial intelligence-driven models demonstrated outstanding performance in pulp space segmentation. Nevertheless, these findings warrant careful interpretation, and their generalizability is limited due to the potential risk and low evidence level arising from inadequately detailed methodologies and inconsistent assessment techniques. In addition, there is room for further improvement, specifically for root canal segmentation and testing of artificial intelligence performance in artifact-induced images.

Optimization of orofacial cleft imaging protocols using device-specific low-dose cone-beam computed tomography

OBJECTIVE

The aim of this study was to present optimized device-specific low-dose cone-beam computed tomography (CBCT) protocols with sufficient image quality for pre-surgical diagnostics and three-dimensional (3D) modelling of cleft defects.

METHODS

Six paediatric skulls were acquired, and an artificial bony cleft was created. A high-resolution CBCT scan acted as a reference standard (Accuitomo 170, Morita, Kyoto, Japan) for comparing eight low-dose protocols of Newtom VGi-evo (QR Verona, Cefla, Verona, Italy), which included Eco and Regular protocols with different field of views (FOVs). Delineation of lamina dura, cementoenamel junction (CEJ), trabecular bone and bony bridge were assessed. A 3D model of the defect was also evaluated.

RESULT

The dose area product of low-dose protocols ranged from 31 to 254 mGy*cm2. Despite the dose difference of up to eight times between applied protocols, trabecular bone and CEJ exhibited appropriate image quality in all scans. However, Regular small FOV protocols (5 × 5 and 8 × 5 cm2), for both lamina dura and bony bridge, demonstrated a significant improvement in image quality compared to Eco FOV counterparts. Based on 3D defect analysis, no significant difference existed between low-dose protocols and the reference standard.

CONCLUSION

The findings highlight the possibility of achieving a considerable reduction (up to eight times) in the radiation dose using low-dose CBCT protocols while maintaining sufficient image quality for assessing anatomical structures and 3D modelling in cleft cases.

Diagnostic value of cone beam computed tomography for root canal morphology assessment - a micro-CT based comparison

OBJECTIVES

The aim of this study was to assess cone beam computed tomography (CBCT) as a root canal anatomy diagnostic tool by comparison with micro-CT gold-standard.

MATERIALS AND METHODS

216 two-rooted mandibular molars were first scanned in a CBCT device (200 μm voxel size) and posteriorly in a micro-CT scanner (19.61 μm). The volumes were sequentially screened to classify main root canal anatomy according to Vertucci classification, and for the presence of lateral canals and apical deltas, in both mesial and distal roots.

RESULTS

Both methods revealed a higher prevalence of Vertucci Type II and IV in the mesial root, and Vertucci Type I in the distal root. The percentage of agreement for main root canal anatomy classification between CBCT and micro-CT scores was high (85.2%).

CONCLUSION

Sensibility to detect both lateral canals and apical deltas with CBCT was low. These results attest to the fact that minor anatomical changes might be difficult to identify with CBCT imaging, hampering its diagnostic value.

Development and validation of a 3D anthropomorphic phantom for dental CBCT imaging research

BACKGROUND

Optimization of dental cone beam computed tomography (CBCT) imaging is still in a preliminary stage and should be addressed using task-based methods. Dedicated models containing relevant clinical tasks for image quality studies have yet to be developed.

PURPOSE

To present a methodology to develop and validate a virtual adult anthropomorphic voxel phantom for use in task-based image quality optimization studies in dental CBCT imaging research, focusing on root fracture (RF) detection tasks in the presence of metal artefacts.

METHODS

The phantom was developed from a CBCT scan with an isotropic voxel size of 0.2 mm, from which the main dental structures, mandible and maxilla were segmented. The missing large anatomical structures, including the spine, skull and remaining soft tissues, were segmented from a lower resolution full skull scan. Anatomical abnormalities were absent in the areas of interest. Fine detailed dental structures, that could not be segmented due to the limited resolution and noise in the clinical data, were modelled using a-priori anatomical knowledge. Model resolution of the teeth was therefore increased to 0.05 mm. Models of RFs as well as dental restorations to create the artefacts, were developed, and could be inserted in the phantom in any desired configuration. Simulated CBCT images of the models were generated using a newly developed multi-resolution simulation framework that incorporated the geometry, beam quality, noise and spatial resolution characteristics of a real dental CBCT scanner. Ray-tracing and Monte Carlo techniques were used to create the projection images, which were reconstructed using the classical FDK algorithm. Validation of the models was assessed by measurements of different tooth lengths, the pulp volume and the mandible, and comparison with reference values. Additionally, the simulated images were used in a reader study in which two oral radiologists had to score the realism level of the model's normal anatomy, as well as the modelled RFs and restorations.

RESULTS

A model of an adult head, as well as models of RFs and different types of dental restorations were created. Anatomical measurements were consistent with ranges reported in literature. For the tooth length measurements, the deviations from the mean reference values were less than 20%. In 77% of all the measurements, the deviations were within 10.1%. The pulp volumes, and mandible measurements were within one standard deviation of the reference values. Regarding the normal anatomy, both readers considered the realism level of the dental structures to be good. Background structures received a lower realism score due to the lack of detailed enough trabecular bone structure, which was expected but not the focus of this study. All modelled RFs were scored at least adequate by at least one of the readers, both in appearance and position. The realism level of the modelled restorations was considered to be good.

CONCLUSIONS

A methodology was proposed to develop and validate an anthropomorphic voxel phantom for image quality optimization studies in dental CBCT imaging, with a main focus on RF detection tasks. The methodology can be extended further to create more models representative of the clinical population.

Feasibility of photon-counting computed tomography as a novel imaging modality for challenging endodontic diagnostic tasks

Photon-counting computed tomography (PCCT) is an innovative technological advancement in relation to x-ray detectors which offers ultra-high-resolution images. The current study aimed to evaluate the visualization ability of PCCT compared to cone-beam computed tomographic (CBCT) devices for challenging endodontic diagnostic tasks. A reference image of an anthropomorphic phantom was acquired using an industrial micro-CT device. Thereafter, the phantom was scanned with three imaging devices, which included PCCT scanner (NAEOTOM Alpha) and two CBCT devices (3D Accuitomo 170 and NewTom VGi evo) having standard and high-resolution acquisition protocols. The diagnostic tasks involved visualizing fine endodontic structures (apical delta, narrow canal, and isthmus) and root cracks. Three experienced examiners assessed the images and were blinded to the PCCT and CBCT devices. Each image was rated according to a three-grade scale (appropriate, acceptable, or inappropriate) for the diagnostic tasks. In relation to fine endodontic structures grouped together, PCCT showed similar diagnostic performance compared to the reference image (p > 0.05). As for the CBCT devices, an excellent performance was only observed with the 3D Accuitomo 170 device at a high-resolution acquisition mode (p > 0.05). The visualization of root cracks was also better with 3D Accuitomo 170 compared to other devices (p < 0.05). Overall, PCCT and 3D Accuitomo 170 at a high-resolution setting showed similar performance for visualizing fine endodontic structures. In addition, the high-resolution CBCT protocol was superior for visualizing root cracks compared to both PCCT and other standard- and high-resolution CBCT protocols.

Impact of metal artefacts on subjective perception of image quality of 13 CBCT devices

OBJECTIVES

The overall objective of this study was to assess how metal artefacts impact image quality of 13 CBCT devices. As a secondary objective, the influence of scanning protocols and field of view on CBCT image quality with and without metal artefacts was also assessed.

MATERIALS AND METHODS

CBCT images were acquired of a dry human skull phantom considering three clinical simulated conditions: one without metal and two with metallic materials (metallic pin and implant). An industrial micro-CT was used as a reference to register the CBCT images. Afterwards, four observers evaluated 306 representative image slices from 13 devices, ranking them from best to worst. Furthermore, within each device, medium FOV and small FOV standard images were compared. General linear mixed models were used to assess subjective perception of examiners on overall image quality in the absence and presence of metal-related artefacts (p < 0.05).

RESULTS

Image quality perception significantly differed amongst CBCT devices (p < 0.05). Some devices performed significantly better, independently of scanning protocol and clinical condition. In the presence of metal artefacts, medium FOV standard scanning protocols scored significantly better, while in the absence of metal, small FOV standard yielded the highest performance.

CONCLUSIONS

Subjective image quality differs significantly amongst CBCT devices and scanning protocols. Metal-related artefacts may highly impact image quality, with a significant device-dependent variability and only few scanners being more robust against metal artefacts. Often, metal artefact expression may be somewhat reduced by proper protocol selection.

CLINICAL RELEVANCE

Metallic objects may severely impact image quality in several CBCT devices.