As part of development of a component vaccine against dental caries, the catalytic region (CAT) and glucan-binding domain (GBD) of glucosyltransferase B (GtfB) from Streptococcus mutans have been employed as target antigens, because they theoretically include epitopes associated with enzyme function. However, their antigenicity has not been fully evaluated. Although there are many reports of successful vaccinations performed with these components, the principle has not yet to be put into practical use. Thus, we have come to doubt their antigenicity and reevaluated the antigenic region of GtfB using in silico analyses in experiments conducted in vitro and in vivo. Our results suggest that the variable region (VR) in the N-terminus of GtfB is immunodominant and S. mutans and/or GtfB specific, while it is not conserved in other streptococcal Gtfs and has an unknown function. Successful immunization with an adenovirus-vector borne DNA vaccine confirmed that VR is a useful epitope that shows promise for development of a caries vaccine.

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In the field of pediatric dentistry, management of occlusion change from primary to permanent dentition is important for prevention and early treatment of malocclusion. Mandibular growth and tooth inclination are important phenomena related to human facial growth. Presently, when dental casts are used to analyze the dental arch form and all teeth in a 3-dimensional manner, those casts and the cranio-mandibular skeleton are separately measured and analyzed. However, since 3-dimensional changes in dental and craniomandibular form occur together during growth, it is desirable to analyze them using a single integrated coordinate system.In the present study, landmark points were marked on lateral cephalograms and dental casts of examined subjects. The landmark coordinates of each subject were integrated and transformed to a standardized plane, and used to clarify the characteristics of permanent and primary tooth-crown inclinations. The maxillary tooth-crown inclination in most of the subjects showed significant age-related differences, while only the second premolar and primary second molar significantly differed in the mandible. Furthermore, the maxillary molars were parallel to the corresponding mandibular molars and correlated, whereas the primary molars were not. Our results suggest that similarities and differences among the inclinations of primary and permanent teeth are related to changes in craniomandibular form that occur during growth.

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Root canal filling materials used for deciduous teeth must have superb biocompatibility and be simultaneously absorbed along with the root. Among the components of those materials, octacalcium phosphate (OCP) is considered to be a precursor of biological apatite crystals.Our previous results showed that a new CPC setting material composed of OCP and α-TCP (OCPmediated cement) had physical properties favorable for use in clinical settings. The purpose of this study was to evaluate OCP-mediated cement as a root canal filling material for deciduous teeth.We evaluated phase transformation and evaluated temporal change in apical sealing ability of OCPmediated cement when used as a root canal filling material, along with its subsequent transformation into apatite. We found that this cement transformed into dentin-like carbonated hydroxyapatite, while sealing ability improved along with apatite formation.We also evaluated the resorption potential of human osteoclasts cultured on OCP-mediated cement disks in vitro and observed that activated human osteoclasts were formed on those disks. Our results indicate that OCP-mediated cement is useful as a root canal filling material for deciduous teeth.

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The quality of occlusal contact during chewing is thought to be critical for effective breakdown of food and numerous studies have used a variety of methods to determine that. Although those methods are relatively easy to apply and evaluate in a clinical setting, those contacts were measured in previous studies only in the maximum intercuspal position (ICP) rather than during masticatory function. Most clinicians consider that the maximum closing position (MCP) during chewing coincides with ICP, though that has not been tested, since it would be necessary to record occlusal contacts at all mandibular positions during mastication. In the present study, we examined the differences in mandibular position and occlusal contact area (OCA) between the MCP and ICP during chewing with use of a measurement system that combines 3-D tracking of mandibular movements with 3-D digitization of tooth shapes.We enrolled female children and adult subjects. The three-dimensional distance between the ICP and MCP at the incisor position in children was significantly larger than that in adults. At the MCP,the OCA in children was less than 77% of the contact area seen at the ICP. Also, the timing of maximum OCA in children was shifted more towards the opening stroke as compared with adults and the OCA remained greater during opening in children. Occurrence of MCP was less stable in children than in adults, both between and within the subjects. We concluded that both the amount of OCA and pattern of occlusal contacts during the occlusal phase of chewing are significantly different between children and adult females.

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We aimed to evaluate the caries-preventive effects of a fissure sealant containing surface reactiontype pre-reacted glass ionomer (S-PRG) filler as compared to those of 2 conventional resin-based sealants. In the sealant containing S-PRG filler, significantly higher amounts of Sr and B ions were detected relative to those in the other sealants, while a considerable amount of fluoride was also released after recharge with a high fluoride concentration. On the other hand, the conventional resinbased sealants bonded by acid etching, which caused surface defects on the enamel as subsurface lesions and showed significantly increased lesion depth, indicative of enamel demineralization. In contrast, the sealant containing S-PRG filler, which bonded by means of a self-etching primer, maintained the enamel surface integrity and inhibited enamel demineralization. There was no difference in regard to bond strength for both untreated enamel and enamel subsurface lesions among the sealants. These findings suggest that sealants containing S-PRG filler have enhanced enamel demineralization inhibiting and remineralization promoting effects in long-term dental care.

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Infective endocarditis (IE) is initiated by formation of vegetation composed of pathogenic bacteria,platelets and fibrin on impaired endothelium of the heart, which causes various clinical signs and symptoms. Replacement of the infected valve may be required in some cases with development of the disease, which is fatal in severe cases. Therefore, antibiotics prophylaxis is usually performed for patients with heart diseases at risk for IE undergoing dental treatments, such as tooth extraction known to be related to the disease, with oral amoxicillin (AMPC) widely selected by general dentists. In some cases of IE, the affected patients received antibiotics prophylaxis prior to dental treatments. However, there is a limited number of studies regarding the distribution of AMPC-resistant strains in dental plaque of Japanese subjects. In the present study, we investigated the distribution of strains highly resistant to AMPC in dental plaque specimens obtained from Japanese children, adolescents,and adults. Approximately 5% of the subjects possessed such strains, which were also shown to be resistant to other antibiotics. We plan to perform a large-scale study to investigate the distribution of these strains in subjects considered to be at risk for IE and will also attempt to elucidate their properties using molecular biological techniques.

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Recently, outcomes of treatments for childhood cancer have improved, with a greater than 70% survival rate currently noted for affected individuals. On the other hand, late effects of antineoplastic treatment (i.e., dental disturbances such as microdontia, atypical root formation, and tooth aplasia) are frequently observed in these patients. Cyclophosphamide (Cy) is a cytostatic drug often present in chemotherapeutic cocktails commonly used for cancer treatment in children. However, to the best of our knowledge, no studies have reported the effects of cancer chemotherapy on cells that initiate growth of the tooth root. Here, we aimed to evaluate the effects of Cy on dental development in mice.We treated 12-day-old ICR mice with Cy (100 mg/kg, i.p.) and control mice with saline, then dissected the mandibles of mice in both groups at 14, 16, 20, 24, and 27 days of age. The mandibular right molars were scanned using micro-computed tomography and the distal root length of the first molar was measured, while the other side mandibular molars were fixed, then demineralized, dehydrated, and embedded in wax. Serial sagittal sections were prepared from the first molars and histomorphological (hematoxylin and eosin staining) and immunohistochemical (cytokeratin) examinations were performed.At 27 days, the root length in the experimental group was approximately 60% of that in the control group. Although all roots continued to develop after Cy injection, microscopic examinations showed that the roots of the first molars of mice in the experimental group developed more slowly and were shorter than those seen in the control group. Furthermore, Hertwig's epithelial root sheath (HERS) in the experimental group disappeared from 20 days of age and periodontal ligament fibers became more sparse than those observed in the control group. In the experimental group, a lower volume of alveolar bone was formed in the interalveolar septa and the first molars tended to show slower eruption.Our results indicate that Cy can induce defects in and alter the function of HERS. Since HERS plays an important role in tooth root formation, disruption of the epithelial sheath inhibits proliferation and root formation. Furthermore, Cy also affects periodontal tissue modeling. Our results suggest that Cy administration may cause delayed eruption of teeth.

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Suckling behavior during infancy is considered to affect development of masticatory function and growth of masticatory organs. Evaluation of suckling movement is considered necessary to support successful breastfeeding, which promotes subsequent healthy development of masticatory function and jaw growth. Noninvasive sucking evaluation methods that do not require special equipment are necessary in clinical situations, and visual analysis of suckling movements using obtained images may be useful for evaluating suckling behavior and providing support. In this study, the characteristics of suckling patterns during breastfeeding were clarified using recorded video images. The subjects were 13 healthy breastfed term infants without complications such as asphyxia or anomalies. Suckling movements during routine breastfeeding were video recorded within 1 week and then 1, 3, and 5 months after birth (total 4 sessions). Next, kinetic analysis of the recorded mandibular movements was performed using 2-dimensional motor analysis software. The following findings were noted.1.As for suckling rhythm, alterations between a continuous suckling period (burst) and suspension of suckling (pause) disappeared with age.2.Mandibular shift during suckling movements increased with age.3.During suckling movements, mouth-closing speed was faster than mouth-opening speed, though both increased with age.4.The time period of a single suckling cycle did not significantly change with age. At the age of 3 months, individual differences were minimal and stable suckling behavior was observed in all of the subjects.5.As a basic technique to establish a noninvasive method to observe and establish infant suckling movements, the present method of video recording and use of motion analysis software with the same infants over time was useful to clarify changes in suckling pattern with growth.

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This report describes results of a survey of 129 pregnant women who attended a prenatal class lecture. Those at the beginning to middle term of their pregnancy responded to a questionnaire about consciousness of personal oral health and that of their unborn babies, and the responses were compared with those obtained in a previous report.We found no differences in answers to questions regarding age, birthing history, smoking experience, anxiety about oral health of the child, intentions about breast-feeding, or recognition of the relationship among periodontitis, smoking, alcohol consumption, and premature and low birth-weight infants as compared with the prior responses. A present poor condition and present difficulties with tooth brushing showed a greater number of responses than in the first report, while responses noting having a family dentist and understands mother-to-child transmission of cariogenic bacteria were fewer than in the first report.Poor condition and mental instability caused by morning sickness were evident at an average of 16.5 weeks of pregnancy. Our results imply that these differences were influenced by increased consciousness of personal health as a result of pregnancy. Furthermore, it seems that pregnant women have inadequate knowledge regarding dentistry and its relationship to health after childbirth. Thus, advice about oral health from the beginning of pregnancy by a community medical organization is considered important improve the health consciousness of pregnant women.

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Mouth rinsing is an effective means of fluoride application for prevention of dental caries. It has been reported that autistic preschool children have delays in acquisition of mouth rinsing ability. The aim of the present study was to clarify the readiness for mouth rinsing in autistic children. Fifty-eight autistic children between 3 and 6 years old were investigated in regard to chronological age, developmental age, and mouth rinsing ability. Cut-off points for developmental age in each domain were examined to discriminate mouth rinsing ability and the following results obtained.1.Forty-three (74.1%) of the subjects were able to perform mouth rinsing.2.There was no relationship between chronological age and mouth rinsing ability in all domains.3.Developmental age was significantly older in the group of subjects able to perform mouth rinsing in all domains.4.As for developmental age in each domain, the cut-off points obtained were as follows : speech, 1 year 4 months ; fundamental habits, 2 years 4.5 months ; hand movements, 2 years 3 months ;language understanding 1 year 5 months ; personal relationships, 1 year 7.5 months ; and locomotion, 3 years, each of which was correlated with the age of mouth rinsing ability acquisition.5.The most significant correlation with mouth rinsing ability acquisition was seen in the speech domain. The predictive value and odds ratio were 75.9% and 9.1, respectively.Our results indicate that mouth rinsing instruction will be more effective for autistic preschool children when language development at a constant rate is balanced with individual development.

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Prader-Willi syndrome is caused by an abnormality in chromosome 15 and characterized by hypotonia in infancy, poor weight gain due to suckling disorder, overeating and obesity that becomes prominent from early childhood, ambiguous external genitalia, almond-like palpebral fissures, a fishlike triangular mouth, and mental retardation. Although affected individuals have a friendly personality, they have difficulty in suppressing their emotions, and problems with their surroundings frequently occur due to character disorders and abnormal behavior. In particular, the character disorders become more difficult to manage with age.As for oral manifestations, enamel hypoplasia, saliva with high viscosity, and dry mouth along with other are generally observed, with tooth decay prone to occur from overeating and poor oral hygiene. We have been conducting oral management of several Prader-Willi syndrome patients since early childhood. However, they gradually became non-cooperative when reaching school age and treatment becomes difficult after adolescence. Even though behavior modification was attempted in these cases,cooperation could not be obtained and dental treatment was conducted under general anesthesia.In our experience, Prader-Willi syndrome patients may first seem compliant, leading practitioners to conclude that they will cooperate with various management techniques. However, these patients often do not understand the explanations or results provided by the practitioner. In order to solve these problems, we think it important to perform treatment according to individual circumstances by keeping intravenous sedation and general anesthesia in mind as possible options, so as not to cause discomfort and/or stress to patients, as well as in cooperation with other medical departments to fully understand the current physical and mental state of the patient.

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We perform individualized training sessions and provide oral myofunctional therapy (MFT) for patients with oral dysfunctions at our clinic. Here, we report successful outcome of MFT in a pediatric patient who underwent tongue muscle training after a frenuloplasty procedure. A 7-year-7-month-old boy could not elevate the tongue or close the lips completely following a lingual frenuloplasty, and exhibited tongue thrust both at rest and when using the tongue, as well as linguoclination of the upper anterior teeth. We started MFT in the early postoperative stage to restore a normal oral myofunctional state. Linguoclination of the upper anterior teeth was improved early and normal oral functions, such as tongue elevation and lip sealing, were recovered after 1.5 years. We considered that MFT was successful in this case because intervention was started early, though a long period was required to complete the training. Thus, for early recovery of oral functions, it may be necessary to start MFT even prior to surgery. In addition, follow-up observations are needed to ensure that improved oral function is maintained, and growth-related changes in regard tooth alignment and occlusion are detected early.

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