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Cone-beam CT (CBCT) systems specifically designed for hard-tissue imaging of the maxillofacial region have recently become commercially available. The newly-developed CBCT system, CB Throne ® (Hitachi Medical Corp., Tokyo), is characterized by a number of features such as low dose, sub-millimeter spatial resolution, and a small footprint. This system has been clinically applied at Chiba Hospital, Tokyo Dental College, since April 2005. This article reports the characteristics of this system, and its diagnostic power for maxillofacial lesions and the pre-operative planning dental implants.

The purpose of this study was to investigate the accuracy of distance measurements of implant length based on periapical radiographs compared with that of other modalities. We carried out an experimental trial to compare precision in distance measurement. Dental implant fixtures were buried in the canine and first molar regions. These were then subjected to periapical (PE) radiography, panoramic (PA) radiography, conventional (CV) and medical computed (CT) tomography. The length of the implant fixture on each film was measured by nine observers and degree of precision was statistically analyzed. The precision of both PE radiographs and CT tomograms was closest at the highest level. Standardized PE radiography, in particular, was superior to CT tomography in the first molar region. This suggests that standardized PE radiographs should be utilized as a reliable modality for longitudinal and linear distance measurement, depending on implant length at local implantation site.

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High-resolution PDW- and T2W MR images could be processed by tissue segmentation and 3D-reconstruction procedures, and the resultant images showed the anatomical details in an easily recognizable way. By the simultaneous visualization of both bony surfaces and soft tissues, disc displacement and deformity can be recognized in a 3D context. The additional superposition of the 3D visualization with the original 2D MR slices allows for a combination with conventional diagnostics.

Identification of the relationship of a lesion in the sublingual space to the mylohyoid muscle using MDCT and high-resolution MRI is a key part of the imaging assessment of the oral cavity and upper neck.

Objective An approach of 3D-visualization of the temporomandibular joint (TMJ) with special focus on the articular disc based on magnetic resonance imaging (MRI) was developed for the purpose of diagnosis support. Materials and methods Mandibular condyle and fossa were reconstructed as 3D-surfaces. Articular disc, retrocondylar tissue, and the lateral pterygoid muscle were visualized by means of direct volume rendering. By simultaneous visualization of both, the bony surfaces and the soft tissue, anterior disc displacement could be recognized in 3D-context. Additional superposition of the 3D-visualization with the original 2D-MRI slices allowed for a combination with conventional diagnostics. The method was tested for clinical T1-, T2-, and This paper has been written on behalf of a publication request following Cars proton density weighted MRI data from four independent medical institutions. Results For all cases, the skeletal anatomy could be reproduced. Applied validation approaches showed good results. Anterior disc displacement could be clearly depicted as well as the incidence of reduction of the disc. By several experienced observers, the approach was rated as significant. Conclusion Although partially non-standard in the clinical routine the new method provided promising results for efficient diagnosis support. Its validity in the medical practice, namely, its impact for dislocation/deformity of the mandibular disc will be further analyzed.

The purpose of this study was to clarify the presence of pain and a correlation between pain and characteristics of signal intensity of mandibular bone marrow in temporomandibular joints (TMJ) with osteoarthritis (OA). A total of 196 joints in 98 patients with TMJ disorders were examined using magnetic resonance imaging (MRI). A pain score and signal intensity on mandibular bone marrow were analyzed in the TMJ with OA. TMJ with OA showed a higher degree of pain compared to those without (p<0.05). During opening, the joints in the higher signal intensity group showed a significantly higher degree of pain compared to the joints in the lower signal intensity group in those with OA on proton density weighted images (p<0.05). It was concluded that TMJ with osteoarthritis is related to pain and that a symptomatic osteoarthritic TMJ can accompany bone marrow changes in the condyle, showing an increased signal on proton density weighted images.