We investigated factors influencing chewing ability in 136 children, including fifth-year municipal primary school students and first- to third-year middle school students. Two chewing instruction sessions were conducted with a 3-week interval, after which a questionnaire survey was conducted.Chewing ability was evaluated using color-changeable chewing gum that each participant chewed for2 minutes, during which the a* value was determined using a differential colorimeter. The results indicated a significant difference in chewing ability after the first and second instruction sessions, with a* scores for chewing ability higher after the second session (＋2.286±6.454).Using hierarchical regression analysis, first, second, third, and fourth factor scores were inputted to investigate factors that influenced variations in a* value. The results demonstrated that the first factor,termed ‘proactive actions,' the third factor, termed ‘energy,' and the rate of decayed, missing, filled(DMF) teeth were correlated with chewing ability (a* value variations). Next, a simple main effect test was conducted to investigate between-group interactions. Our results showed that as the DMF tooth rate increased, the decrease in a* value variations was greater in subjects with high first factor scores than in those with low first factor scores. The present findings suggest that proactive actions by children and factors that can cause tooth loss, including DMF rate, which comprehensively represents dental disease, number of untreated teeth, and oral hygiene, are combined factors that affect chewing ability.

View full abstract

Mesenchymal stem cells (MSCs) are clinically utilized for tissue engineering and regenerative medicine. Dental tissue has received attention as an easily accessible source of high quality stem cells. In this study, we compared the characteristics of dental pulp stem cells from deciduous teeth(DDPSCs) to those from permanent teeth (PDPSCs). Teeth were obtained from 2 patients in each group, then cells were isolated from dental pulp and used for comparative analysis of DDPSCs and PDPSCs. Colony-forming ability, proliferation rate, and expression levels of cell surface antigens were similar in both groups. However, DDPSCs showed greater levels of osteogenic differentiation as compared to PDPSCs. We consider that pulp cells from both deciduous and permanent teeth are valuable sources of MSCs and useful for stem cell research and future therapeutic applications, while DDPSCs are more suitable for clinical applications of bone regeneration.

View full abstract

Glucose, an essential source of energy for determination of size and form during tooth development, is transported across the cell membrane by glucose transporters (GLUTs), while epigenetic alterations are crucial events for tissue development and histone acetylation is a major epigenetic event that is regulated by histone deacetylases (HDACs). Although epigenetic events may occur in the process of tooth development, the involvement of epigenetic modifications remains unclear. We investigated immunohistochemical localization of GLUTs and HDACs during tooth development in mice to determine their effects on tooth development. Dental germ tissues were subjected to immunohistochemical staining with anti-GLUTs and anti-HDACs, and PAS staining was also performed. HDAC3 and GLUT 1 were found to be co-localized in the enamel organ and mesenchymal tissue surrounding the tooth germ in the cap stage. In addition, localized HDAC5, GLUT3, and PAS staining was seen in the dental lamina, mesenchymal tissue surrounding the enamel organ, and dental papilla in the cap stage. In the early bell stage, HDAC3 and GLUT1 were co-localized in the stellate reticulum, dental papilla, and mesenchymal tissue, while HDAC5, GLUT3, and PAS staining was observed in the dental lamina and mesenchymal tissue. No expression of HDAC5 was seen in the bell stage. Our results suggest that GLUT and HDAC expressions, and their cooperation play critical roles in tooth development.

View full abstract

It is essential for guardians to help children with tooth brushing at home for prevention of dental caries, while assisting autistic children with tooth brushing presents various challenges. We conducted a questionnaire survey of guardians of preschool children aged 4 to 5 years and compared 40 autistic children with 56 normally developing children in regard to tooth brushing habits and uncooperative behavior during help with brushing. The following results were obtained All autistic children surveyed received help with tooth brushing from their guardians. For analysis, 45% of those with autism were categorized into the behaviorally difficult group, which was a significantly greater percentage as compared to those among normally developing children (p＜0.01). During help with tooth brushing,95% of autistic children exhibited more than 1 type of uncooperative behavior as compared with44.7% of normally developing children, which was a significant difference (p＜0.01). As compared with normally developing children, autistic children exhibited a significantly higher proportion of uncooperative behaviors such as “biting the toothbrush,” “refusing to put the toothbrush into the mouth,” and “resisting the toothbrush with crying and struggling” (p＜0.01). As compared with autistic children in the behaviorally easy-to-handle group, those in the behaviorally difficult group exhibited a significantly higher proportion of “resisting the toothbrush with crying and struggling” during help with tooth brushing (p＜0.01).

View full abstract

Dandy-Walker malformation and Dandy-Walker variant are congenital cerebellar malformations characterized by cystic dilation of the fourth ventricle and enlarged posterior fossa associated with hypoplasia of the vermis. In Dandy-Walker variant, there is no substantial enlargement of the posterior fossa because of a relatively small cystic dilation of the fourth ventricle. We report a 10-year-6-month-old boy with Dandy-Walker variant complicated by hypoplasia in several of his permanent teeth. The patient was referred to the Pediatric and Special Needs Dental Clinic at Kyushu University Hospital for diagnosis and treatment of an unusual infected right mandibular lesion, which was possibly caused by a periapical infection of the right mandibular first molar. Due to severe mental retardation associated with Dandy-Walker variant, he was unable to cooperate for a further dental examination. In order to perform comprehensive dental assessment and treatment, intra-oral and dental X-ray examinations, and treatment were performed under general anesthesia. X-ray findings revealed a thin root or wide pulp chamber in many of the erupted permanent teeth, including the right mandibular first molar and permanent tooth germs. Also in the right mandibular first molar, a periapical cystic radiolucent lesion was noted without pulp exposure. These findings were most suggestive of general tooth hypoplasia along with fragile enamel or dentin. The periapical lesion in the right mandibular first molar was considered likely to be caused by a continuous bacterial infection in the root canals through fragile crowns. Amelogenesis imperfecta, dentinogenesis imperfecta, and odontodysplasia were also considered as possible existing conditions. However, none could be definitively diagnosed because no discoloration, attrition, enamel fracture, or severe dental caries were apparent in any of the erupted teeth. Further examinations are required to establish an accurate diagnosis. For treatment of the right mandibular first molar, mechanical root canal preparation, filling, and restoration with a steel crown were performed, followed by periapical curettage to remove pathologic tissue, and the postoperative course was satisfactory and uncomplicated. After 2 months, a periapical infectious lesion was found in the left mandibular first molar without any pulp exposure, which was very similar to the previous right mandible condition. We performed the same treatment under general anesthesia. In addition, prophylactic steel crowns were placed on the maxillary first molars, because general tooth hypoplasia with fragile crowns was strongly suggested. We found that long-term follow-up examinations were essential for early diagnosis and management of pulp infection without pulp exposure in other affected teeth.

View full abstract

A hemangioma frequently occurs on the tongue, lip, buccal mucosa, and gingiva in the oral region,though it relatively rarely seen on the palate. We report a case of capillary hemangioma found on the palate of a 2-year-10-month-old boy. He was referred to our department with the chief complaint of a tumor on the palate and a hemangioma was noted on the palatal side of the upper deciduous incisors.We performed surgical resection and the mass was extirpated. The postoperative course was uneventful. Although there was no evidence of recurrence at 6 months after surgery, careful follow-up examinations will be necessary until the upper permanent incisors erupt.

View full abstract