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Purpose: To analyze spread of odontogenic infections in the elderly, especially the prevalence and characteristic multidetector computed tomography (MDCT) findings. Materials and methods: Ninety-seven patients with odontogenic infection who underwent 64-row MDCT were evaluated in this study. The study patients comprised 31 elderly patients (≥ 60 years) and 66 adults (< 60 years). Age, gender, location of causal tooth, and spread of odontogenic infections with MDCT were analyzed. Results: The elderly patients (74.2%) had higher ratio with female compared to the adults (57.6%). The buccal space (93.5%) was the most common spread of odontogenic infections for the elderly patients, followed by the masticator space (54.8%) and submandibular space (45.2%), whereas the buccal space (97.0%) was the most common spread of odontogenic infections for the adults, followed by submandibular space (65.2%) and masticator space (51.5%). Logistic multivariate regression analysis for odontogenic infections in the elderly demonstrated that the gender (odds ratio = 3.462, P = .024) and submandibular space (odds ratio = 0.168, P = .013) were significant variable. Conclusions: The study showed the prevalence and characteristic MDCT findings of spread of odontogenic infections in the elderly.

We report a case of impacted tooth in the maxillary sinus. The frequency of ectopic impacted tooth is higher with permanent teeth than with deciduous teeth, and the mandibular third molars are the most commonly impacted teeth. The most common site of ectopic impacted teeth is the maxillary canine area, followed by the mandibular molar area and ramus. However, impaction in the nose or maxillary sinus has rarely been reported. We encountered a patient with an impacted tooth located in the maxillary sinus. This case was coincidentally found on panoramic radiography and computed tomography (CT) for assessment of the alveolar bone with dental implantation. CT showed a marginal highabsorption area with clear and smooth boundaries of the long axis 18 mm in size, located in the floor of the left maxillary sinus. We confirmed the tooth as the second premolar impacted in the maxillary sinus from imaging findings of panoramic radiography and CT.

Parametric radiation-based X-ray (PXR), one of the pioneering modalities using an accelerator, is being studied as a new kind of X-ray source in the Laboratory for ElectronBeam Research and Application Institute of Quantum Science(LEBRA). The purpose of this study was to evaluate the potential of LEBRA-PXR as a new X-ray source for diagnostic imaging. Dog mandibular tissue with malignant melanoma was examined. Simple X-ray images were taken with LEBRA-PXR at several wavelengths(12 keV, 15 keV, 18 keV, 21 keV, 24 keV, 27 keV, 30 keV). An energy subtracted image was generated with the image with the longest wavelength PXR and the image with the shortest wavelength PXR. As a control, an image was taken with conventional X-ray (40 kV, 125 mA, 40 msec; effective energy 21 keV). Simple X-ray images were taken with LEBRA-PXR, and the energy subtracted and conventional X-ray images were compared with the histopathological stained images.Compared to conventional X-ray images, LEBRA-PXR images showed contrast related to different wavelengths, reflecting histological differences between tissues. Compared with the histological findings, malignant tumor images with LEBRA-PXR were clearer than conventional X-ray images.Using LEBRA-PXR, a type of nearly perfectly monochromatic X-ray source imaging, the images of the malignant tumor displayed different contrasts from conventional X-ray images. LEBRA-PXR is a useful diagnostic imaging tool using a new X-ray source.

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