Histamine H₃ receptors are autoreceptors that regulate histamine release from histaminergic neuronal terminals. The celebral cortex, including the insular cortex (IC), expresses abundant H₃ receptors; however, the functions and mechanisms of H₃ receptors remain unknown. The aim of this study was to elucidate the functional roles of H₃ receptors in synaptic transmission in the rat IC. Unitary excitatory and inhibitory postsynaptic currents (uEPSCs and uIPSCs) were obtained through paired whole-cell patch-clamp recording in cerebrocortical slice preparations. The H₃ receptor agonist, R-α-methylhistamine (RAMH), reducedthe uEPSCs amplitude. Similarly, RAMH reduced the uIPSC amplitude. JNJ5207852 dihydrochloide or thioperamide, H₃ receptor antagonist, inhibited RAMH-induced suppression of uEPSCs and uIPSCs. Unexpectedly, thioperamide alone increased the uIPSCs amplitude. Miniature EPSC or IPSC recordings support the hypothesis that the activation H₃ receptors suppresses the release of glutamate and GABA from presynaptic terminals. The suppressive regulation of H₃ receptors on synaptic transmission might mediate the regulation of sensory information processes, such as gustation and visceral sensation in the IC.

The prevalence of dental caries in children has recently declined statistically, but there are some children whose oral environment has deteriorated due to a large number of carious teeth. The polarization of children who have almost no dental caries has become a problem. Since the environment surrounding children is becoming more complicated due to the diversification of family structures, it is considered that dental caries in deciduous dentition is greatly affected by the environment because of children's difficulty in managing oral hygiene by themselves. Therefore, we investigated the relationship between the living environment of children and dental caries.

We included 475 subjects aged 3 to 5 years (mean age 4 years 4 months) with deciduous dentition, who visited our department for the first time between 2009 and 2016. In the survey on lifestyle, we investigated the living environment of children such as: “snack habits,” “home environment,” and “oral hygiene habits.” In addition, the experience of dental caries (decayed, missing, and filled; dmf tooth rate) was calculated based on the results of the oral examination, dental radiograph, and dental medical record. Furthermore, the relationship with the children's living environment was statistically examined.

As a result, it was revealed that dental caries in children correlated with their “snacking frequency,” “employment situation of their parents,” “order of birth,” “brushing status,” “toothbrushing frequency,” and “experience with topical fluoride application.” On the other hand, there were no significant differences in the prevalence of dental caries with regard to “living with grandparents” and “status of entering kindergarten.”

These results suggested that children's living environment and lifestyle may affect their oral environment.

Introduction

Caries adjacent to primary molars often spreads buccolingually near the dental neck. For thin primary teeth smaller than permanent teeth, based on the concept of minimal intervention, it is necessary to manipulate the side walls in order to protect the teeth, prevent loss of restoration and maintain them long-term. In the past, the literature has recommended inward-opening cavities, but no supporting evidence has been presented.

In this study, in order to help reduce the possibility of marginal fracture of composite resin (CR) and secondary caries in complex cavities extending to adjacent surfaces, we investigated cavity conditions and CR filling conditions while controlling the amount of cutting. We compared CR compressive strengths with respect to the profile of the inward-opening cavity, side wall width and CR type.

Method

1. Six flowable and three paste-type CRs were divided into three groups (GF, BK and UN). Their compressive strength, elastic modulus and indirect tensile strength were measured and compared.

2. Inward-opening cavities were formed using S1, F1 or F2 files and filled with CR. The CR compressive strengths were measured in situ and compared across the CR types and cavity types.

3. After the compressive strength tests, fractured surfaces of the CR-filled cavities were examined using a scanning electron microscope (SEM).

Results

1. As the cavities widened due to file type, the compressive strengths of the flowable types in groups GF and UN significantly increased.

2. The mechanical properties of conventional flowable CR were not as good as those of the paste type but, in this study, in the cavities the flowable CR had higher compressive strength than the paste type. This suggests that the flowable type could have clinical application for laminated fillings comprised of this material alone.

3.Because the compressive strength of the cavity increased in the order F2＞F1＞S1, the thickness of CR in the side wall and the volume of CR are thought to influence the prevention of fractures in the restored crown of deciduous teeth which are smaller than permanent teeth and are thinner.

Conclusions

1. As the cavities widened, the high value of the flowable types in groups GF and UN significantly increased.

2.In each CR group, the fracture load of CR in the cavity showed a tendency to increase as the cavity became larger, suggesting that the CR thickness and volume at the side wall affect fracture prevention in deciduous crown restoration.

3.The results of the indirect tensile tests and the within-cavity compression tests were similar, so selecting a CR with a large indirect tensile strength could help prevent fracture.

Chronological age is how old an individual actually is. However, it does not indicate the degree of development of the mind or body. Physiological age, such as bone age and dental age, indicates the stage of growth of an individual by evaluating the development of each organ, for example, the bones and teeth. By clarifying the mechanism of development of each organ, it is possible to predict an individual's growth accurately.

In this study, the maturation of bones and teeth during the early stage of school age (6 to 8 years old) was evaluated, and the relationships between chronological age, bone age, and dental age were investigated. As a result, the increase in maturation differed depending on each bone and tooth. Both bones and teeth matured in girls more rapidly than in boys. The ulna showed the largest maturation in both girls and boys, and the mandibular second molar showed remarkable maturation in both girls and boys. Furthermore, significant correlations were found between chronological age and bone age, chronological age and dental age, and bone age and dental age.

It is suggested that by evaluating the maturation of teeth, it is possible to predict the growth of individuals accurately.

The Committee on Education (JSPD) conducted a questionnaire survey on the 2018 Guideline for Pediatric Dentistry in the National Dentistry Examination for the pediatric dentistry departments of all dental schools in Japan. The questionnaire covered the category of compulsory basic matters, general dental medicine, and clinical dental medicine in pediatric dentistry.

The results of the survey revealed that there are various problems with the current Guideline. It was shown that clinical dental medicine has a more specific questioning standard than the compulsory basic matters or general dental medicine. Regarding whether it met the criteria of the Guideline related to pediatric dentistry in the National Dentistry Examination, there were many categories including subcategories and further subcategories for which less than 50% of respondents answered “Applicable”.

Oral myofunctional therapy (MFT) before and after lingual frenectomy is indispensable for improving tongue function and preventing relapse due to scarring after resection. We report the cases of three siblings with ankyloglossia [Case 1: Brother 10 years 11 months, Cases 2 and 3: Twin brothers (A, B), 8 years 6 months]. After resection and preoperative and postoperative MFT, we performed ankyloglossia training.

In all three cases, the range of tongue movement and the amount of tongue zonule extension were good. In cases 2 and 3 in which the tongue protrusion habit was remarkable, reduction of the habit during swallowing and pronunciation was observed at the end of postoperative MFT. In case 1, the voluntary movement disorder of the tongue was mild and there was a possibility of avoiding lingual frenectomy. We decided to perform the operation, and obtained the thrusting power and control power of the entire back of the tongue by postoperative MFT.

By providing the same training as a group, the number of visits and instruction time were shortened, the training content was simplified, and the burden on parents was reduced. Furthermore, it became possible to maintain motivation by having three cases work on the same training content. However, it was also important to set tasks according to individual personality, tongue zonule morphology, tongue movement, and muscular strength, and to provide individual guidance.