Potential Benefits of Photon-Counting CT in Dental Imaging: A Narrative Review

Abstract

Background/Objectives: Advancements in oral imaging technology are continually shaping the landscape of dental diagnosis and treatment planning. Among these, photon-counting computed tomography (PCCT), introduced in 2021, has emerged as a promising, high-quality oral technology. Dental imaging typically requires a resolution beyond the standard CT systems achievable with the specialized cone-beam CT. PCCT can offer up to 100 µm resolution, improve soft-tissue contrast, and provide faster scanning times, which are crucial for detailed dental diagnosis and treatment planning. Using semiconductor detectors, PCCT produces sharper images and can potentially reduce the number of scans required, thereby decreasing patient radiation exposure. This review aimed to explore the potential benefits of PCCT in dental imaging. Methods: This review analyzed the literature on PCCT in dental imaging from January 2010 to February 2024, sourced from PubMed, Scopus, and Web of Science databases, focusing on high-resolution, patient safety, and diagnostic efficiency in dental structure assessment. We included English-language articles, case studies, letters, observational studies, and randomized controlled trials while excluding duplicates and studies unrelated to PCCT's application in dental imaging. Results: Studies have highlighted the superiority of PCCT in reducing artifacts, which are often problematic, compared to conventional CBCT and traditional CT scans, due to metallic dental implants, particularly when used with virtual monoenergetic imaging and iterative metal artifact reduction, thereby improving implant imaging. This review acknowledges limitations, such as the potential for overlooking other advanced imaging technologies, a narrow study timeframe, the lack of real-world clinical application data in this field, and costs. Conclusions: PCCT represents a promising advancement in dental imaging, offering high-resolution visuals, enhanced contrast, and rapid scanning with reduced radiation exposure.

Keywords: cone-beam computed tomography; dental imaging; endodontic imaging; image artifacts; iterative metal artifact reduction; photon-counting computed tomography; radiation exposure; virtual monoenergetic imaging.

Figure 1

(A) A 3D cinematic rendering of the occlusal view of the lower jaw, where the crowns of molars and premolars are visible. (B) Longitudinal MPR and axial cross-section of upper and lower jaws. (C) The region of a single tooth and root structure in relation to the jawbone. The scan was performed on a commercial whole-body Dual Source Photon Counting CT scanner (NAEOTOM Alpha, Siemens Healthineers, Erlangen, Germany); 0.2 mm slice thickness, 0.1 mm reconstruction increment, FOV 140 mm, spiral acquisition with tube current modulation; resolution matrix of 1024 × 1024 pixels on the source axial reconstructions with a kernel filtering of Bv72; maximum intensity of Quantum Iterative Reconstruction (QIR 4). The actual displayed resolution is 0.1 mm (100 microns). Abbreviations: 3D, three-dimensional; MPR, multiplanar reconstruction; FOV, field-of-view.

Figure 2

(A) The curved MPR of the upper and lower jaws, the roots of the teeth, and the surrounding bone structure, which is commonly used to assess overall dental health, including bone levels and root configurations, and to check for any abnormalities such as impacted teeth or pathologies in the jawbone. (B) Front-view 3D cinematic rendering of the jaws and teeth, which shows the relative positions of the teeth in both the upper and lower jaws. This type of visualization helps to assess the bite, spacing, and alignment of the teeth, as well as the relationship between the upper and lower dental arches. The scan was performed on a commercial whole-body Dual Source Photon Counting CT scanner (NAEOTOM Alpha, Siemens Healthineers); 0.2 mm slice thickness, 0.1 mm reconstruction increment, FOV 140 mm, spiral acquisition with tube current modulation; resolution matrix of 1024 × 1024 pixels on the source axial reconstructions with a kernel filtering of Bv72; maximum intensity of Quantum Iterative Reconstruction (QIR 4). The actual displayed resolution is 0.1 mm (100 microns). Abbreviations: 3D, three-dimensional; MPR, multiplanar reconstruction; FOV, field-of-view.

Figure 3

(A) A longitudinal MPR (A) and panoramic view of the upper and lower jaws, displaying a metallic dental prosthesis. Unlike conventional CT, there are no metal artifacts. (B) A curved MPR image of a portion of the jaws, highlighting a detailed view of several teeth and their respective roots. (C) The 3D cinematic rendering, providing a realistic perspective of the teeth’s condition and alignment, including the dental implant. The scan was performed on a commercial whole-body Dual Source Photon Counting CT scanner (NAEOTOM Alpha, Siemens Healthineers); 0.2 mm slice thickness, 0.1 mm reconstruction increment, FOV 140 mm, spiral acquisition with tube current modulation; resolution matrix of 1024 × 1024 pixels on the source axial reconstructions VIM at 190 KeV. The actual displayed resolution is 0.1 mm (100 microns). Abbreviations: 3D, Three-Dimensional; VMI = Virtual Monoenergetic Imaging; FOV = Field of View.

Figure 4

(A) A 3D cinematic rendering that displays the detailed structure of a jaw with teeth, emphasizing their three-dimensional form and alignment. (B) The longitudinal MPR showing the teeth, fillings, and jawbone with high contrast, which is useful for evaluating dental health and anatomy. The scan was performed on a commercial whole-body Dual Source Photon Counting CT scanner (NAEOTOM Alpha, Siemens Healthineers); 0.2 mm slice thickness, 0.1 mm reconstruction increment, FOV 140 mm, spiral acquisition with tube current modulation; resolution matrix of 1024 × 1024 pixels on the source axial reconstructions with a kernel filtering of Bv72; maximum intensity of Quantum Iterative Reconstruction (QIR 4). The actual displayed resolution is 0.1 mm (100 microns). Abbreviations: 3D, three-dimensional; MPR, multiplanar reconstruction; FOV, field-of-view.

Figure 5

(A) The figure shows a 3D cinematic rendering of dental implants. This type of visualization helps to ensure that the implants are properly positioned for the best functional and aesthetic outcomes. (B) The 2D cross-sectional image of a single dental implant in the jawbone. This type of image is useful for evaluating the quality and density of the bone surrounding the implant and ensuring that the implant is properly placed. (C) This is another cross-sectional study, which also shows the detailed interaction between the implants and the bone, ensuring that the implants are not encroaching upon any anatomical structures, such as nerves or sinuses, and that there is enough bone around the implants for a stable fit. The scan was performed on a commercial whole-body Dual Source Photon Counting CT scanner (NAEOTOM Alpha, Siemens Healthineers); 0.2 mm slice thickness, 0.1 mm reconstruction increment, FOV 140 mm, spiral acquisition with tube current modulation; resolution matrix of 1024 × 1024 pixels on the source axial reconstructions VIM at 190 KeV. The actual displayed resolution is 0.1 mm (100 microns). Abbreviations: 3D, Three-Dimensional; VMI = Virtual Monoenergetic Imaging; FOV = Field of View.