The present study evaluated the influence of 2% chlorhexidine and 2.5% sodium hypochlorite on the resin sealer/dentin interface bond strength of AH Plus/gutta-percha and Epiphany/Resilon. Seventy-two extracted bovine incisors were randomly distributed into 6 groups according to irrigant and sealers: G_S+AH=physiologic saline solution+AH Plus/gutta-percha; G_S+Ep=physiologic saline solution+Epiphany/Resilon; G_H+AH=2.5% sodium hypochlorite (NaOCl)+AH Plus/gutta-percha; G_H+Ep=2.5% NaOCl+Epiphany/Resilon; G_C+AH=2% chlorhexidine (CHX)+AH Plus/gutta-percha; and G_C+Ep=2% CHX+Epiphany/Resilon. After 7 days at 37°C and 100% humidity, the roots were cut transversally on the long axis of the tooth in 0.8 mm (±0.09)-thick slices; these slices were then subjected to the push-out test. Data were analyzed using a 2-way ANOVA and Tukey tests at 5% significance. The AH Plus/gutta-percha groups showed significantly higher bond strength than the Epiphany/Resilon groups, regardless of the irrigant used (p<0.001). Sodium hypochlorite adversely affected bond strength in the AH Plus group, whereas chlorhexidine did not influence the push-out bond strength of either sealer (p<0.05). Two percent chlorhexidine did not adversely affect the bond strength of the sealers, whereas 2.5% sodium hypochlorite solution damaged AH Plus/gutta-percha bond strength.

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Against a background of a rapidly aging society, the number of patients with oral cancers in Japan is increasing yearly. The number of double-cancers with oral cancer as the first malignancy is also reportedly on the rise. Esophageal and gastric cancers are the most common second malignancies. At our institution, our policy is to proactively perform upper gastrointestinal (GI) fiberscopy (GIF) in patients with oral cancer. In anticipation of a probable further increase in the number of patients with double-cancers consisting of oral and GI tract malignancies, we retrospectively analyzed the occurrence of upper GI tract cancers in patients with oral squamous cell carcinoma (OSCC). The cohort consisted of 171 patients in whom OSCC had been diagnosed and who had undergone upper GIF between March 1996 and August 2008. Multivariate analysis was performed. Upper GIF identified 8 patients (7 men, 1 woman, totaling 4.7% of 171 patients) with double-cancer in the upper GI tract. One patient had a triple malignancy consisting of oral, esophageal and gastric cancers. Seven patients had esophageal cancer, while two had gastric cancer. An age of over 65 years was significantly higher in patients with double-cancers including esophageal cancer than in patients without esophageal cancer (OR=10.454, 95% CI=1.143-95.621). None of the other analyzed patient factors (sex, smoking habit, drinking habit, site of OSCC, TNM classification, staging results) showed a significant difference. These results indicate that, when treating elderly patients with oral cancers, physicians need to devise suitable treatment plans which take into account the possibility of upper GI tract cancer, particularly esophageal cancer, as a double-cancer.

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Lymphoepithelial cyst of the oral cavity is a rare cystic lesion that presents as an asymptomatic, well-circumscribed, yellowish small submucosal nodule covered by normal overlying mucosa, usually located in the floor of the mouth or in the ventral or posterolateral surface of the tongue. Histopathological examination reveals a cyst lined by a stratified squamous epithelium surrounded by lymphoid tissue. In this paper, we report two cases of oral lymphoepithelial cyst, one on the anterior floor of the mouth and another on the posterior lateral tongue. In both cases, the patients were women aged approximately 50 years and the lesions were treated by local surgical excision, with no evidence of recurrence after 2 years of follow-up.

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We report a case of apical fenestration misdiagnosed as persistent apical periodontitis. The patient was a 55-year-old woman who presented with persistent tooth pain at the right maxillary canine, despite repeated root canal treatment by a general practitioner. When the patient visited Tokyo Dental College Suidobashi Hospital, a CT examination was performed and apical fenestration diagnosed. The patient received an apicoectomy after which the symptoms disappeared. This suggests that dentists should consider the possibility of apical fenestration when examining patients with persistent tooth pain after repeated root canal treatment.

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Recently, optical microscopes have been used in endodontic treatment, as they offer advantages in terms of magnification, illumination, and documentation. Documentation is particularly important in presenting images to patients, and can take the form of both still images and motion video. Although high-quality still images can be obtained using a 35-mm film or CCD camera, the quality of still images produced by a video camera is significantly lower. The purpose of this study was to determine the potential of RegiStax in obtaining high-quality still images from a continuous video stream from an optical microscope. Video was captured continuously and sections with the highest luminosity chosen for frame alignment and stacking using the RegiStax program. The resulting stacked images were subjected to wavelet transformation. The results indicate that high-quality images with a large depth of field could be obtained using this method.

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Osteoblasts play a major role in bone formation. Osteoblasts employ intracellular Ca²⁺ as a second messenger modulating hormonal responses and a cofactor for bone mineralization. Voltage-dependent Ca²⁺ channels (VDCCs) are most commonly present in excitable cell membranes. They are also present at lower levels even in most nonexcitable cells too. In both types of cell, they mediate the influx of Ca²⁺ in response to membrane depolarization. Prepulse facilitation is a phenomenon in which a long and strong depolarizing pulse induces a form of VDCC that exhibits an increased opening probability. We believe this to be the first study to demonstrate that strong depolarization prepulses both increase and decrease VDCCs in osteoblasts.

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The aim of this study was to determine the percentage of participants in each of the six Eichner Index groups by number of present teeth (PT). The data were obtained from a periodontal disease examination carried out under a health promotion law in a city located northeast of Tokyo, Japan, in 2005. Data from a total of 1,549 (524 male and 1,025 female) 60-year-old participants were analyzed in this study. Number of occlusal supports was counted by analyzing dental charts. The Eichner Index was used to group the participants into six groups based on distribution of occlusal support teeth. The percentage of patients in Group A with 24 PT was 31.4%; none in Group A had fewer than 19 PT. The percentage in Groups A, B1, and B2 with between 20 and 28 PT was above 50%; the number of participants in these groups with fewer than 20 PT decreased rapidly. Those with fewer than 16 PT were almost found in Groups B3, B4 and C. Only a few patients in Group C had between 10 and 14 PT; those with fewer than 9 PT were only found in Groups B4 or C. Based on these results, the Eichner Index category of a given participant can be estimated from number of PT.

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