Digital periapical radiography is widely used in clinical dentistry because the technique is relatively simple and inexpensive. However, the main drawback of periapical radiography is that it represents a three-dimensional object in a two-dimensional film due to its inherent projection technique. The objective of this study was to develop a prototype intraoral computed tomosynthesis system, which can provide quasi-three-dimensional (so-called 2.5D) images. We developed a prototype intraoral computed tomosynthesis machine. Regular digital periapical radiography, computed tomosynthesis scanning, and computed tomography scanning of a human central incisor were performed. Then, reconstruction images obtained using computed tomosynthesis and computed tomography approaches were quantitatively evaluated using the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). From the experimental results, compared with periapical radiographic images, reconstruction images obtained using the computed tomosynthesis approach revealed detailed microstructures in different depth sections. In addition, the SNR and CNR of reconstruction images obtained using the computed tomography approach was better than those of the images obtained using the computed tomosynthesis approach. However, the differences could not be clearly identified by the naked eye. The preliminary experimental results indicate that an intraoral computed tomosynthesis system may be useful for clinical dental diagnosis.

X-ray radiography is currently used in dentistry and can be divided into two categories: two-dimensional (2D) radiographic images (e.g., using periapical film, cephalometric film, and panoramic X-ray) and three-dimensional (3D) radiographic images (e.g., using dental cone-beam computed tomography (CBCT)). Among them, 2D periapical film images are most commonly used. However, 2D periapical film compresses 3D image information into a 2D image, which means that depth cannot be identified from the image. Such compressed images lose a considerable amount of information, reducing their clinical applicability. A 2.5D periapical radiography system prototype was developed by our research team. Our previous study indicated that this prototype could be used to capture images at different depths of an object. However, the prototype was limited by its commercially available intraoral periapical sensor, which had a low temporal resolution and could not capture multiple images in a short period of time. Therefore, the total time required for image capture was too long for practical clinical application. The present study developed a high-frame-rate intraoral periapical sensor with a sensor imaging speed of up to 15 Hz. The primary components of the developed intraoral periapical sensor include a scintillator, complementary metal oxide semiconductor chip, component circuit board, and video processing board. The external dimensions of the sensor are 41×26×6.6 mm3. The performance of the developed high-frame-rate intraoral periapical sensor was verified through qualified and quantified analyses using line pairs. The results showed that the resolution of the developed intraoral periapical sensor could reach 18 lp/mm. The sensor was further installed in our 2.5D periapical radiography system to conduct image capturing. The results indicated that the developed sensor could be used for high-frame-rate imaging to incorporate tomosynthesis to obtain reconstructed slice images of different depths. The developed sensor has the potential for clinical dentistry applications in the future.