This study compared Ultra Speed Occlusal Film (USOF) and 3 digital systems in determining the radiopacity of 5 different restorative resins in terms of equivalents of aluminum thickness. Whether those digital systems could be used to determine whether radiopacity was in line with International Organization for Standardization (ISO) recommendations was also investigated. Disks of each of 5 restorative resins and an aluminum step wedge were exposed at 65 kVp and 10 mA on USOF and imaged with each digital system. Optical density on the film was measured with a transmission densitometer and the gray values on the digital images using Image J software. Graphs showing gray value/optical density to step wedge thickness were constructed. The aluminum equivalent was then calculated for all the resins using a regression equation. All the resins were more radiopaque than 1 mm of aluminum, and therefore met the ISO 4049 recommendations for restorative resins. Some resins showed statistically higher aluminum equivalents with digital imaging. The use of traditional X-ray films is declining, and digital systems offer many advantages, including an easy, fast, and reliable means of determining the radiopacity of dental materials.

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The purpose of the present study was to investigate the validity of incorporating a para-periodontal ligament in the test mold used in a basic fracture test of a zirconia all-ceramic fixed partial denture (FPD). A simplified three-dimensional finite element analysis model was designed based on the three-unit FPD fracture test. Two types of model, one with and one without a para-periodontal ligament between the abutment and base mold, were fabricated. Microfocus CT of the missing first molar area in a dry human mandible was performed. A three-dimensional model was then fabricated based on the data obtained. A load of 600 N was applied to the center of the pontic and stress distribution observed. The model with the para-periodontal ligament showed stress dispersion to the dental root with rotation of the abutment mold. Stress distribution in the finite element analysis model with a para-periodontal ligament showed greater similarity with that in the mandibular model than with that in the other two models without a para-periodontal ligament.

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Early detection of oral squamous cell carcinoma (OSCC) improves its prognosis and aids in selecting the appropriate treatment, which may also have a positive effect on quality of life. Early detection, therefore, is an important issue in the treatment of this disease. The purpose of this study was to investigate expression of cytokeratin 13 (CK13), CK17, Ki-67 and p53 as potential markers of tongue SCC. Five areas in 12 specimens were examined: the upper and lower layers of normal epithelium; those of dysplastic epithelial tissue surrounding the cancerous lesion; and the lesion itself. Strong expression of each of the following mRNAs and proteins was observed; CK13 in upper layers of normal epithelium; Ki-67 and p53 in lower layers of normal epithelium; CK13 and CK17 in upper layer of epithelial dysplasia; and CK17, Ki-67, and p53 in lower layer of epithelial dysplasia and cancerous lesions. These results indicate that the characteristic pattern of expression of CK13 and CK17 differs between normal and dysplastic oral epithelium. Oral epithelial dysplasia adjacent to OSCC has high malignant potential, and is similar to early-stage OSCC. This suggests that evaluation of these markers could be a useful secondary procedure for improving detection of early-stage OSCC.

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The number of children with Metabolic Syndrome (MetS) has recently been increasing in Japan. Few studies have investigated the relationship between MetS and oral health. The aim of this study was to investigate the association between MetS, lifestyle, and oral health status in school children. Our goal is to utilize these results in health education aimed at preventing the onset of MetS in school children and adults. A total of 689 Japanese children (365 boys and 324 girls) aged between 10 and 13 years were examined and waist circumference (WC), ratio of WC to height, blood pressure, fasting blood sugar (FBS), high density lipoprotein-cholesterol, and triglyceride values determined together with oral health status, including dental caries experience (DMFT). The results revealed that 6.5% of the children fell under the health board recognized “MetS or high risk of MetS” (MetS/HR) classification. A total of 140 (20%) children had a high Streptococcus mutans count. The mean WC, FBS, and DMFT values were significantly greater in children with a high salivary S. mutans count (p<0.05). Multiple logistic regression analysis revealed a statistically significance association between MetS/HR, non-breakfast eaters (odds ratio (OR): 2.70), no regular exercise (OR: 2.60), and a high salivary S. mutans count (≥10⁵ CFU/ml; OR: 2.18; p<0.05). The present results indicate that lifestyle and salivary S. mutans count could be useful in screening children for MetS/HR. These variables may be useful in targeting interventions aimed at preventing MetS in school children.

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This case involved a 30-year-old woman who visited our hospital with the main complaint of protrusion of the maxillary incisors and upper and lower lips. She had difficulty closing her lips, and a chin button was observed when the lips were closed. The skeletal pattern showed maxillary protrusion and mandibular retrusion, and the mandible showed severe high angle. Labial inclination of both the maxillary and mandibular incisors was found, as well as crowding. In addition, the maxillary left second molar showed buccal displacement, and scissor bite was evident in the left second molar region. The bilateral molar relationship was cusp-to-cusp class II malocclusion. Angle class II maxillary protrusion accompanied by crowding and left second molar scissor bite was diagnosed. Surgical orthodontic treatment was judged as the best approach to treat the jaw deformities. However, in line with the wishes of the patient, treatment was undertaken using implant anchors instead. Straight-wire brackets with a 0.022-inch slot were fitted. A lingual arch was placed in the mandible and plate-type implant anchors in the first molar region of the maxilla. Almost no change was observed in skeletal pattern as no surgery was performed. The maxillary incisors moved back 10 mm, however, and the mandibular incisors showed an improvement of 4 mm from L1 to APo. The upper and lower lips consequently moved back 7 mm with respect to the E-line. Active treatment required 3 years and 6 months. Esthetic and functional improvements were achieved.

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When a dental implant migrates to the maxillary sinus it should be extracted immediately as it may cause sinusitis or further migrate to one of the other paranasal sinuses. Although usually detected due to symptoms such as nasal obstruction, nasal discharge, and nasal bleeding, an ectopic tooth in the maxillary sinus can sometimes be revealed incidentally on radiographic examination. Here, we report a case of simultaneous extraction of a dental implant that had migrated to the maxillary sinus and removal of an ectopic tooth that had arisen in the same location. The patient was a 73-year-old man who had received the implant to replace the first left maxillary molar at a local dental office. The implant had subsequently migrated to the left maxillary sinus and the patient was referred to us for its removal. On locating the implant on a CT scan at our hospital, an ectopic tooth was also observed at the base of the maxillary sinus. With patient consent, the decision was made to remove the ectopic tooth and extract the implant simultaneously. Excision of the lateral wall of the maxillary sinus allowed easy extraction of the implant. The ectopic tooth was removed by slightly expanding a fenestration in the sinus wall. Ectopic teeth in the maxillary sinus are sometimes put on follow-up if asymptomatic. Removal should be considered, however, if there is a risk of it becoming infected due to implantation-induced inflammation.

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Merkel cells (MCs), which form part of the MC-neurite complex, making contact with sensory afferents to drive mechanosensory transduction mechanisms, express transient receptor potential (TRP) cation channel subfamily vanilloid (V) members 1, 2, and 4, as well as ankyrin subfamily member 1. While these proteins are involved in sensing plasma membrane stretch, less is known about the functional properties of TRPV subfamily member 3 (TRPV3) during membrane stretch in MCs. The aim of this study was to determine whether TRPV3 channels were involved in mechanosensory activity by measuring intracellular free Ca²⁺ concentrations ([Ca²⁺]_i) in MCs isolated from hamster buccal mucosa. Application of a hypotonic extracellular solution to quinacrine-positive MCs elicited a transient increase in [Ca²⁺]_i. When TRPV3 channel antagonist 2,2-diphenyltetrahydrofuran was added to the hypotonic extracellular solution, however, no effect was observed on hypotonic stimulation-induced increase in [Ca²⁺]_i. These results suggest that TRPV3 channels are not involved in the mechanosensory mechanism during membrane stretch in MCs.

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