Genome-wide association scan for childhood caries implicates novel genes

Dental caries is the most common chronic disease in children and a major public health concern due to its increasing incidence, serious health and social co-morbidities, and socio-demographic disparities in disease burden. We performed the first genome-wide association scan for dental caries to identify associated genetic loci and nominate candidate genes affecting tooth decay in 1305 US children ages 3-12 yrs. Affection status was defined as 1 or more primary teeth with evidence of decay based on intra-oral examination. No associations met strict criteria for genome-wide significance (p < 10E-7); however, several loci (ACTN2, MTR, and EDARADD, MPPED2, and LPO) with plausible biological roles in dental caries exhibited suggestive evidence for association. Analyses stratified by home fluoride level yielded additional suggestive loci, including TFIP11 in the low-fluoride group, and EPHA7 and ZMPSTE24 in the sufficient-fluoride group. Suggestive loci were tested but not significantly replicated in an independent sample (N = 1695, ages 2-7 yrs) after adjustment for multiple comparisons. This study reinforces the complexity of dental caries, suggesting that numerous loci, mostly having small effects, are involved in cariogenesis. Verification/replication of suggestive loci may highlight biological mechanisms and/or pathways leading to a fuller understanding of the genetic risks for dental caries.     

Is there any difference between the British and Japanese de?nitions of the mandibular cortical index (MCI) on panoramic radiographs? A pilot study

Objectives To assess the reproducibility of the mandibular cortical index (MCI) on panoramic radiographs among British and Japanese observers, and to investigate the difference between the British and Japanese observers in the definition of MCI.Methods Three observers, a Japanese oral radiologist, a British oral radiologist, and a British prosthodontist, classified the inferior cortex of the mandible on a set of 100 duplicated films of randomly selected panoramic radiographs twice, 2 weeks apart, using the MCI. The kappa index for intra- and interobserver agreement was calculated for the three observers.Results The kappa index for intraobserver agreement was moderate (0.56) to perfect (0.86) for the three observers. Interobserver agreement between the Japanese and the British oral radiologists was moderate at the first reading (kappa, 0.59) and substantial at the second (0.61). Interobserver agreement between the prosthodontist on the one hand and each of the oral radiologists on the other was fair (0.35, 0.38) at the first reading, but moderate (0.43, 0.60) at the second reading. The prosthodontist tended to overestimate the MCI compared with either of the oral radiologists.Conclusion Our results suggest that the definition of MCI used by Japanese observers is basically similar to that used by British observers, although some improvements in the definition of MCI would be necessary for clinical dental practice.     

A catalogue of anomalies and traits of the primary dentition of southern Chinese

Variation in size, form and morphology of the teeth result in anomalies such as macrodontia, microdontia, hyperdontia, hypodontia, double tooth, taurodontism and dens in dente. While traits that may occur more commonly in certain ethnic groups may be considered to be specific to that population. The characteristics of these anomalies and traits are presented along with the prevalence figures for their occurrence in primary dentition of southern Chinese.