BackgroundSports-related dental injuries, such as tooth fracture, loosening, and avulsion, are a major concern among young athletes because they directly impair oral function. Although the preventive efficacy of mouthguards has been well established, the prevalence of sports-related dental injuries remains high among young athletes. The aim of this study is to identify the variables contributing to the risk of sports-related dental injuries by conducting a survey on large population of young athletes in Miyagi prefecture.MethodsA cross-sectional study was conducted with school-aged athletes (aged 6–15 years, n = 5735) using a self-reported questionnaire. The questionnaire examined general variables, including sex, age, and body mass index; sports-related variables, including sports-type, team level, activity schedule, break time, and verbal/physical abuse by coaches; and lifestyle variables related to free time, including screen-time and sleep duration. Their associations with sports-related dental injuries were examined using multivariate logistic regression models.ResultsThe prevalence of sports-related dental injuries was 13.3% (763 of 5735 young athletes) and was higher in males (14.3%, 592 of 4132) than in females (10.7%, 171 of 1603; adjusted odds ratios [ORs] and 95% confidence intervals [CIs]: 1.48 [1.22–1.79], p < 0.001). After stratification according to sex, significant associations with the prevalence of sports-related dental injuries were evident for three variables—insufficient break time, verbal abuse, and physical punishment—in males (adjusted ORs [95% CI]: 1.35 [1.03–1.77], p = 0.032; 1.31 [1.05–1.62], p = 0.015; and 1.36 [1.06–1.75], p = 0.016, respectively) but not in females (adjusted ORs [95% CI]: 0.88 [0.53–1.47], p = 0.623; 1.29 [0.87–1.91], p = 0.206; and 0.97 [0.57–1.63], p = 0.894, respectively).ConclusionsAlthough our results might be based on the individual athlete’s self-perception to the sports-related variables, our results suggest that insufficient break time, verbal abuse, and physical punishment from coaches are positively associated with the prevalence of sports-related dental injuries in young male athletes.

A new biosynthetic intermediate of ABA, (2Z,4E)-gamma-ionylideneacetaldehyde, was isolated from young mycelia of Cercospora cruenta. Under an (18)O2 atmosphere, an oxygen atom of this endogenous aldehyde was exclusively labeled. Similarly, three (18)O atoms were incorporated into the ABA molecule recovered after prolonged incubation; selectively labeled were one of the carboxyl oxygen atoms and the two on the ring portion of ABA. A feeding experiment with [1-(13)C]glucose proved the exclusive operation of the mevalonate pathway for the formation of both ABA and beta-carotene. These results suggest that (2Z,4E)-gamma-ionylideneacetaldehyde can be a key ABA biosynthetic intermediate formed by the oxidative cleavage of a carotenoid precursor.

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Summary. Root resorption lacunae are principally formed by odontoclasts. While these cells develop from the same origin as osteoclasts, odontoclasts normally have fewer nuclei and a less clear zone compared with osteoclasts. We therefore, hypothesized that odontoclasts possess less differentiation in matrix resorption characteristics than osteoclasts. To test our hypothesis, we compared the TRAP-positive area and the expression patterns of two important proteolytic enzymes, cathepsin K and matrix metalloproteinase-9 (MMP-9), between odontoclasts and osteoclasts. We focused on physiological root resorption in the rat molar, which is a useful experimental model for estimating odontoclasts and osteoclasts. Observations showed the number of nuclei and the TRAP-positive area of odontoclasts to be significantly less compared with osteoclasts. Using in situ hybridization and double labeling fluorescence in situ hybridization showed the majority of odontoclasts to express both cathepsin K and MMP-9, especially 4 and 5 weeks of age, when physiological root resorption occurs actively. Moreover, putative precursor cells of odontoclasts, which typically appeared in the middle of the periodontal ligament at 3 weeks of age, expressed both enzymes. In contrast, the majority of matured osteoclasts expressed only cathepsin K but not MMP-9. We suggest that odontoclasts are comparable to osteoclasts with less differentiation with regard to the expression of proteolytic enzymes.

BackgroundCleft lip and/or palate is among the most prevalent congenital birth defects, and negatively affects maternal psychological status and may consequently result in higher prevalence of child maltreatment. However, the association of childbirths of infants with cleft lip and/or palate with maternal emotional involvement still remains unclear. We examined the association between childbirths of infants with cleft lip and/or palate and mother-to-infant bonding, using data from the Japan Environment and Children’s Study, a nationwide birth cohort study.MethodsA cross-sectional study using the jecs-an-20,180,131 dataset was performed. A total 104,065 fetuses in 15 regional centres in Japan were enrolled after obtaining informed written consent. The Mother-to-Infant Bonding Scale, a self-report scale consisting of 10 items, was used to evaluate maternal bonding at one year after childbirth. Finally, the participants consisted of 79,140 mother-infant pairs, of which 211 mothers of infants with cleft lip and/or palate were included in our analyses. Multivariable logistic regression analysis using multiple imputation for missing data was performed to calculate the odds ratio and 95% confidence interval in the estimation of the association between bonding disorders and childbirths with cleft lip and/or palate.ResultsNo increased risk of bonding disorders was observed among all the mothers of infants with cleft lip and/or palate (odds ratio [95% confidence interval]; 0.97 [0.63–1.48], p = 0.880), however, advanced maternal age or multiple parity may adversely affect the associations between bonding disorders and cleft lip and/or palate, respectively. After stratification with a combination of maternal age and parity, a significant association of cleft lip and/or palate with bonding disorders was found only among advanced-age multiparae (odds ratio [95% confidence interval] = 2.51 [1.17–5.37], p = 0.018), but it was weakened after additional adjustment for maternal depression.ConclusionsChildbirths of infants with cleft lip and/or palate may increase the risk of bonding disorders among advanced-age multiparae, possibly through maternal depression. This finding provides valuable information for the provision of multidisciplinary cleft care.