[Effect of DKK1 on the biological behaviors of dental pulp cells exposed to lipopolysaccharide].

PURPOSE: To detect the effect of DKK1 on biological behaviors of human dental pulp cells exposed to lipopolysaccharide (LPS). METHODS: The dental pulp cells were isolated and cultured by modified enzyme-tissue block method and identified by immunofluorescence staining. The effect of DKK1 on proliferation and migration of human dental pulp cells exposed to LPS were measured by cell counting kit (CCK-8) and Transwell assay. Meanwhile, the effect of DKK1 on differentiation of human dental cells exposed to LPS were studied by alizarin red staining and real-time PCR experiment, statistical analysis was performed using SPSS 20.0 software package. RESULTS: The results of immunofluorescence showed that the cultured cells were in consistent with the mesenchymal stem cells. The result of CCK-8 indicated that DKK1 had no significant effect on proliferation of dental pulp cells exposed to LPS; The result of transwell assay showed that DKK1 significantly promoted the cell migration of dental pulp cells exposed to LPS. The results of Alizarin red staining and real-time PCR revealed that DKK1 could promote cytodifferentiation of dental pulp cells exposed to LPS. CONCLUSIONS: DKK1 promotes the ability of cell migration and cytodifferentiation of LPS treated dental pulp cells, which may be resulted from inhibition of Wnt/ß-catenin pathway.

China experts' consensus on preventive and interceptive orthodontic treatments of malocclusions of children.

Malocclusion is one of the three most common oral diseases reported by World Health Organization(WHO). In China, its incidence rate is rising. Malocclusion seriously affects the dental and maxillofacial function, facial appearance and growth development of nearly 260 million children in China, and what is more, it affects their physical and mental health development. Malocclusion occurrence is related to genetic and environmental factors. Early treatment of malocclusion can create a good dental and maxillofacial development environment, correct abnormal growth and control the adverse effects of abnormal genetic factors. It can effectively reduce the prevalence of children's malocclusion and enhance their physical and mental health. This is an urgent need from the economic perspective of our society, so it has great practical and social significance. Experts from the project group "standard diagnose and treatment protocols for early orthodontic intervention of malocclusions of children" which initiated by China National Health Institute of Hospital Administration wrote the "China Experts' Consensus on Preventive and Interceptive Orthodontic Treatments of Malocclusions of Children", which aims to guide and popularize the clinical practice, improve the clinical theory and practice level, and accelerate the disciplinary development of early treatment of children's malocclusion in China. The consensus elaborates the harmfulness of malocclusion and the necessity of early treatment, and brings up the principles and fundamental contents. Based on the law of dental and maxillofacial development, this paper puts forward the guiding suggestions of preventive and interceptive treatments in different stages of dental development ranging from fetus to early permanent dentition. It is a systematic project to promote and standardize the early treatment of malocclusion. Through scientific and comprehensive stratified clinical practice and professional training, the clinical system of early treatment of malocclusion in China will eventually be perfected, so as to comprehensively care for children's dental and maxillofacial health, and improve their oral and physical health in China.

Expression, localisation and synthesis of versican by the enamel organ of developing mouse molar tooth germ: an in vivo and in vitro study.

OBJECTIVE: Versican is a large, aggregating chondroitin sulphate proteoglycan. In dental tissue, versican expression occurs primarily in mesenchymal tissue but rarely in epithelial tissue. We investigated the expression, localisation and synthesis of versican in the enamel organ of the developing tooth germ. DESIGN: To elucidate versican localisation in vivo, in situ hybridisation and immunohistochemistry were conducted in foetal ICR mice at E11.5-E18.5. Epithelium and mesenchyme from the lower first molars at E16.0 were enzymatically separated and versican mRNA expression was investigated by semi-quantitative RT-PCR. Organ culture of the separated samples combined with metabolic labelling with [(35)S], followed by gel filtration, was performed to analyse secreted proteoglycans. RESULTS: Versican mRNA was first expressed in the thickened dental epithelium at E12.0 and continued to be expressed in the enamel organ until the bell stage. Versican immunostaining was detected in the stellate reticulum areas from the bud stage to the apposition stage. The enamel organ at E16.0 expressed versican mRNA at a level comparable to that in dental mesenchyme. Furthermore, when compared to dental mesenchyme, about 1/2-3/4 of the [(35)S]-labelled versican-like large proteoglycan was synthesised and released into tissue explants by the enamel organ. CONCLUSIONS: The dental epithelium of developing tooth germ is able to synthesise significant amounts of versican.