In the prior report that analyzed the distribution of the occlusal contact area and contact position at centric occlusion in each Hellman dental developmental stage, occlusal contact showed an unstable aspect in IIIB. T-Scan can measure the duration of intercuspation from initial occlusal contact to maximum intercuspal position. We evaluated the stability of occlusion in each developmental stage from the distribution of occlusal force, duration, and movement trace from initial occlusal contact to intercuspal position using the T-Scan. Eight healthy subjects in each Hellman dental developmental stage (IIIB,IIIC and IVA) participated in this study. Outcome parameters were the absolute value of the bilateral difference and the anteroposterior difference in occlusal force in intercuspal position. The time and displaced distance of the center of occlusal force from initial occlusal contact to intercuspal position were calculated. Only the bilateral difference in occlusal force of IIIB showed a significantly greater value than IIIC and IVA. Our results showed that the bias was observed in the occlusal force distribution at intercuspal position in IIIB, but that the occlusal stability was maintained through the Hellman dental developmental stages of IIIB, IIIC and IVA. Shika Igaku (J Osaka Odontol Soc) 2019; Mar; 82(1):1‐5.

Recently, prevention of hospital acquired infections is becoming more important. There are many opportunities for patient‐provider and patient‐patient infections in dental hospitals and clinics. It is desirable, but unrealistic, to perform serological blood screening at most dental hospitals and clinics. Thus, we can only ask patients about their history of infection. In this study, we investigated the prevalence of three nosocomial infectious diseases, hepatitis C, hepatitis B, and syphilis, in patients seeking treatment. We investigated the effectiveness of detecting these diseases using a questionnaire, conversational questioning, and a combination of the two. We conducted a serological blood screening on 1,429 patients prior to hospitalization in the department of dentistry and oral surgery at a hospital in Kyoto prefecture from April 2012 to March 2017. The prevalence of hepatitis C, hepatitis B, and syphilis among the patients respectively, was 2.0% (n=29), 0.6% (n=8) and 0.1% (n=2), for a total prevalence of 2.7%. The questionnaire demonstrated an effectiveness of 46.2% for sensitivity and 100% for specificity. The conversational questioning demonstrated an effectiveness of 47.6% for sensitivity and 100% for specificity. The combination of both methods demonstrated an effectiveness of 71.8% for sensitivity and 100% for specificity. While a significant improvement in detection was made by using both methods, 28.2% of the patients with infectious diseases still went undetected. Above all, it is considered necessary to take standard precautions with all patients. Shika Igaku (J Osaka Odontol Soc) 2019; Mar; 82(1): 6‐11.

Because approximately 1% of all malignant tumors, metastasize to the oral region, it is necessary to be aware of each patient's symptoms and medical history, and to obtain images as necessary. This is a report of image findings and the clinical course of a metastatic colon carcinoma to the mandible under perioperative oral management. A 70‐year‐old man presented with the chief complaint of a swollen and painful left mandible. The patient had a history of an operation for colon carcinoma and post‐operative chemoradiotherapy two years before. Locoregional and lymph node metastasis were suspected by FDG‐PET/CT. No bone destruction of the left mandible was observed on panoramic radiography at the first visit. Bone algorithm computed tomography (CT) revealed a periosteal lesion in the left mandible. The patient was diagnosed as having osteomyelitis of the left mandible. After two months, the swelling and pain had progressed considerably, and a second CT and the first magnetic resonance image (MRI) were performed.　　An axial CT image showed a low‐density area compared with the muscles within the left masseter space. An axial T1‐weighted image revealed a homogeneous mass with intermediate signal intensity, and an axial fat‐suppressed T2‐weighted image revealed a heterogeneous hyperintense mass in the left mandible. A diffusion‐weighted image (DWI) and an apparent diffusion coefficient (ADC) map showed a heterogeneous hypointense mass in the left mandible. When a biopsy was performed under local anesthesia, the mass was diagnosed as an adenocarcinoma and found to be compatible with colon carcinoma metastasis to the mandible. There was no bone destruction or radiolucency of the left mandible on the panoramic radiograph. However, it was difficult to distinguish the mass lesion or abscess in the left mandible based on the CT image alone. Thus, since the patient had a medical history of malignancy with swelling and pain in the oral cavity, performing panoramic radiography not only with a CT image, but also with an MRI, including a DWI and an ADC map, was helpful in obtaining an accurate diagnosis. Shika Igaku (J Osaka Odontol Soc) 2019; Mar; 82(1):12‐18.

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2. Yuka Yasui, Junko Tanaka, Masaki Kakudo and Masahiro Tanaka. Relationship between preference and gaze for modified food in the young and elderly using an eye tracker.

3. Naoki Sugitatsu, Junko Tanaka and Masahiro Tanaka. Reproducibility of occlusal contacts on dental casts with the bite impression for full arch using a prototype tray: Comparison between conventional and bite impression methods.