Bulletin of Tokyo Dental College

Noriyuki Seta

The Bulletin of Tokyo Dental College

Role of Circulating Monocytes and Periodontopathic Bacteria in Pathophysiology of Rheumatoid Arthritis

循环单核细胞和牙周致病菌在类风湿性关节炎病理生理学中的作用

A range of experimental designs have been used in destructive testing of composite resin CAD/CAM crowns. Various materials have been adopted for the abutment in such tests, including human or bovine dentin, stainless steel, PMMA, and composite resin, the selection of which is made in accordance with study objective or preference of the researcher. The purpose of this study was to determine how the material selected for the abutment material affected fracture load and maximum displacement. Destructive tests were conducted on composite resin crowns of the same design. Three types of material were used for the abutments together with 2 types of adhesive material. Images of each sample were acquired before destruction using a microfocus X-ray CT scanner to confirm the feasibility of a non-destructive test.

Syuntaro Nomoto

Tomotoshi Masuda

Toru Sato

Mariko Yumoto

Gen Kuroishi

Yosuke Maeda

Mizuho Hirano

Hideshi Sekine

Influence of Tooth Mold Materials in Composite Resin CAD/CAM Crown Destructive Test

复合树脂CAD/CAM冠破坏性试验中牙模材料的影响

Mucoepidermoid carcinomas in the minor salivary glands usually originate in the palatine gland, and their occurrence in the retromolar region is rare. We report a rare case of mucoepidermoid carcinoma with clear cell components occurring in the retromolar region. The patient was a 63-year-old woman referred to our hospital with the chief complaint of a painless mass in the right retromolar region initially found during treatment at a local dental clinic. The 20×10-mm mass was well-defined, elastic, and flexible. The surface of the mucosa was healthy. The mass was clinically diagnosed as a gingival benign tumor in the right retromolar region. There were no significant findings in the patient's medical history. The tumor was resected under local anesthesia. Histopathology revealed that squamoid cells, undifferentiated intermediate cells, and clear cells were dominant, with mucus-producing cells in some areas. A mucoepidermoid carcinoma with clear cell components was diagnosed. There were no signs of recurrence or metastasis at 15 months postoperatively and the patient's progress has been satisfactory. Because the tumor was a painless, slow-growing mass, it was clinically diagnosed as a benign tumor of the gingiva, and resection was performed under local anesthesia without performing a biopsy. However, even if a mass in the retromolar region is clinically diagnosed as a benign tumor, the course of treatment should be decided after performing fine-needle aspiration cytology, taking into consideration the possibility of mucoepidermoid carcinoma.

Nobuharu Yamamoto

Yukio Watabe

Masashi Iwamoto

Kenichi Matsuzaka

Takahiko Shibahara

A Case of Mucoepidermoid Carcinoma with Clear Cell Components Occurring in Retromolar Region

磨牙后区伴透明细胞成分的粘液表皮样癌一例

The objective of this study was to verify whether loss of posterior occlusal support induced displacement of the mandibular condyles from a physiological point of view. Stabilization-type splints were fabricated for 12 healthy dentulous individuals. Each splint was designed to cover the bilateral maxillary teeth up to the second molars. To reproduce loss of posterior occlusal support, the extent of the splint was reduced one tooth at a time, bilaterally, starting from the back and moving forward sequentially. Tapping movement and lateral excursions were performed with each splint and a jaw movement tracking device with 6-degrees of freedom used to observe condylar displacement. Evaluation of 3-dimensional (3-D) displacement of the kinematic axis of the condyle during experimental jaw movement was performed under each occlusal condition with occlusal contact on all teeth, including the maxillary second molars. The habitual closing position was used as the reference. An increase was observed in 3-D displacement of the kinematic axis at the terminal point of the tapping movement with loss of occlusal support, and significant differences were observed in both condyles. An increase was also observed in 3-D displacement of the kinematic axis on the working side during lateral excursion with loss of occlusal support, and a statistically significant difference was observed in the left condyle. A small increase was observed in 3-D displacement of the kinematic axis on the non-working side during lateral excursion with loss of occlusal support. The results of this study suggest that loss of posterior occlusal support induces displacement of the mandibular condyles, suggesting that occlusal support in the molar region is an important factor in stabilization of the condylar position.

Ryo Sakai

Shuichiro Yamashita

Influence of Simulated Loss of Posterior Occlusal Support on Three-dimensional Condylar Displacement

模拟后牙咬合支持丧失对髁突三维位移的影响

The primary aim of this study was to determine the prevalence of dental caries and its association with infant feeding and oral health-related behavior in Japanese children between the ages of 18 months and 3 years. A total of 387 infants were initially examined at the age of 18 months (or 19 months in some cases) and then again at 3 years (or at 3 years 1 month in some cases). The primary objective was to identify factors contributing to the prevalence of caries in children aged 18 months. The secondary objective was to follow up children with no caries at the age of 18 months to seek potential correlations between background factors and the increment of caries by the age of 3 years. In an adjusted multivariate logistic regression model, children who continued breastfeeding were approximately 7 times more likely to have dental caries at 18 months of age than those who did not. Infants brought in for an oral examination and consultation at around 12 months of age were less likely to develop dental caries at 18 months of age than those who were not. Multivariate logistic regression analysis revealed that infants who did not receive a dental check-up at 12 months of age showed a significantly higher incidence of dental caries at 3 years of age. The present results suggest that prolonged breastfeeding is a risk factor for early childhood caries at 18 months of age, and that infants in whom a regular oral care program is implemented from the age of 12 months are less likely to develop early childhood caries at 18 months or 3 years.

Ayako Tashiro

Takuro Yonezu

Kaido Kumazawa

Atsuo Sakurai

Seikou Shintani

Caries and Its Association with Infant Feeding and Oral Health-related Behavior in 18-month and 3-year-old Japanese Children

龋齿及其与18个月和3岁日本儿童喂养方式和口腔健康相关行为的关联

Cardiac ischemia, such as angina pectoris or myocardial infarction, is associated with pain in the oral cavity, lower jaw, head, or neck, or spanning from the left upper arm to the shoulder. When presenting to a dentist, however, appropriate treatment for such patients is often delayed, as dental problems are usually the first to be suspected when the chief complaint is orofacial pain. This report describes a case of a 70-year-old woman who was aware of pain and a burning sensation in the oral cavity upon exertion for a year prior to presenting at our clinic. She had been examined by her family physician, an otolaryngologist, and another dentist, none of whom found any abnormalities other than suspected periodontal disease and caries, for which she was treated. An examination at our clinic revealed no abnormal dental findings that would have been consistent with the mandibular pain, however. Although no chest symptoms were reported, pain was elicited on exertion, suggesting cardiogenic toothache. An immediate referral to a cardiologist was therefore made on the same day. The patient visited the cardiology department of the University Hospital of Tokyo Dental College 6 days later. The increased frequency of symptoms on exertion suggested unstable angina, and the patient was admitted to the emergency department on the same day. Emergency coronary angiography showed that right coronary artery #1 was 99% stenosed proximally (highly calcified plaque). The diagnosis was unstable angina pectoris, with the right coronary artery #1 as the responsible lesion, and percutaneous coronary angioplasty was performed on the same day. Subsequently, all the orofacial pain disappeared, confirming unstable angina as the cause. The pain characteristics in this case were consistent with pain associated with cardiac ischemia, which led to the immediate referral to the cardiology department. In cases of toothache associated with cardia ischemia, it is essential to seek cardiological care as soon as possible.

Jun Kawaguchi

Tatsuya Ichinohe

A Case Report on Unstable Angina Pectoris Manifesting as Orofacial Pain

不稳定型心绞痛表现为口面痛的病例报告

Although the working environment may play a role in dental acid erosion, few studies have been conducted on this in Japanese workers in recent years. The purpose of this study was to investigate oral health status, including dental erosion, in workers who may have been exposed to an acidic environment. The study participants were recruited by an online research company. Oral examinations and questionnaire surveys were conducted on this cohort in January 2023. A total of 144 participants were finally included. Workers exposed to an acidic environment showed more use of protective equipment and underwent more dental examinations at the workplace (p<0.001). Possible dental erosion was observed in only 3 out of the total of 144 participants (2.1%), however. No significant difference was observed in the number of teeth, caries experience, or dental erosion according to the number of years of acid exposure in the workplace. The results of this study suggest that acid exposure exerts a relatively small effect on the oral health status of workers in Japan.

Seitaro Suzuki

Koichi Yoshino

Atsushi Takayanagi

Yuki Onose

Atsushi Ohyama

Tomoaki Shibuya

Ryouichi Satou

Takako Eguchi

Hideyuki Kamijo

Naoki Sugihara

Oral Health Status of Workers in Acid Exposure Environments in Japan: A Cross-sectional Study

日本酸暴露环境下工人的口腔健康状况：一项横断面研究

This case report describes a 19-year-old woman with skeletal Class I crowding and an unsalvageable maxillary right central incisor. She visited our clinic with the chief complaint of mobility of the maxillary right central incisor due to a traffic accident. After extraction of the maxillary right central incisor, the space was closed orthodontically. All the maxillary right teeth were moved mesially with an elastic chain attached to a palatal lever arm which was connected to palatal temporary anchorage devices (TADs). After orthodontic treatment had been completed, the maxillary right lateral incisor and peg-shaped left lateral incisor were restored with a porcelain laminate veneer. The maxillary right canine was morphologically reshaped and built up with composite resin. Consequently, esthetically ideal occlusion and functional lateral guidance with uncontacted molars were obtained. These results show that mesial movement of the entire dental arch with TADs is a useful orthodontic treatment option in patients in whom the maxillary central incisor has been extracted.

Noriko Sano

Ryota Sano

Junji Ohtani

Saiji Shimoe

Hiroki Nikawa

Takeshi Murayama

Masato Kaku

Entire Dental Arch Mesial Movement after Extraction of Maxillary Right Central Incisor due to Root Fracture Treated with Temporary Anchorage Devices

上颌右侧中切牙根折拔除后全牙弓近中移动的临时支抗装置治疗

The present study investigated the cyclic fatigue properties of titanium alloys (Ti-6Al-4V and Ti-6Al-7Nb) as implant materials and compared their properties with those of commercially pure titanium. Ti-6Al-4V and Ti-6Al-7Nb cylinders with diameters of 3.0 mm were examined. The surfaces of the cylinders were roughened by sand blasting with alumina particles and acid etching. Static and cyclic tests were performed according to ISO 14801:2016. The yield force in the static test (YS) was measured in 5 specimens of each alloy using a universal testing machine. The yield force in a cyclic test (YC) was measured in 20 specimens of each alloy using the staircase method, which involved applying a cyclic load at a frequency of 10 Hz for 106 cycles. After the cyclic loading tests, cross-sections of the specimens were examined under an optical microscope. The YS values for Ti-6Al-4V and Ti-6Al-7Nb were 1463 N±93 N and 1405 N±79 N, respectively, and the YC values were 870 N±58 N and 853 N±202 N, respectively. Microscopic observation revealed cracks on the tensile side of some of the specimens, including run outs and failures. The results of this study suggest that the YC values for Ti-6Al-4V and Ti-6Al-7Nb were 40% less than those for YS. The yield force of Grade-4 Cp-Ti significantly decreased after cyclic loading. The YC values for Ti-6Al-4V and Ti-6Al-7Nb were approximately 900 N, which was markedly greater than that for commercially pure, Grade-4 titanium (700 N).

短名	Bull. Tokyo Dent. Coll.
Journal Impact	0.67
国际分区	DENTISTRY, ORAL SURGERY & MEDICINE(Q4)

ISSN	0040-8891
h-index	26

涉及主题	医学生物牙科内科学口腔正畸科化学病理遗传学地质学古生物学外科生物化学解剖物理心理学材料科学
出版信息	出版商: Tokyo Dental College Society，出版周期: ，期刊类型: journal，开源期刊: 否
基本数据	创刊年份: 1965，原创研究文献占比: 100.00%，自引率:0.00%， Gold OA占比: 100.00%

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Role of Circulating Monocytes and Periodontopathic Bacteria in Pathophysiology of Rheumatoid Arthritis

Influence of Tooth Mold Materials in Composite Resin CAD/CAM Crown Destructive Test

A Case of Mucoepidermoid Carcinoma with Clear Cell Components Occurring in Retromolar Region

Influence of Simulated Loss of Posterior Occlusal Support on Three-dimensional Condylar Displacement

Caries and Its Association with Infant Feeding and Oral Health-related Behavior in 18-month and 3-year-old Japanese Children

Role of Circulating Monocytes and Periodontopathic Bacteria in Pathophysiology of Rheumatoid Arthritis

A Case Report on Unstable Angina Pectoris Manifesting as Orofacial Pain

Oral Health Status of Workers in Acid Exposure Environments in Japan: A Cross-sectional Study

Entire Dental Arch Mesial Movement after Extraction of Maxillary Right Central Incisor due to Root Fracture Treated with Temporary Anchorage Devices

Cyclic Fatigue Properties of Titanium Alloys for Application in Dental Implants