RESUMO
【Objective】 To explore the effect of low levels of calcium on the biological characteristics of ameloblasts. 【Methods】 Rat primary ameloblasts were cultured in standard DMEM medium. After five days they were identified by RT-PCR and immunohistochemistry. Then 0, 0.6 and 1.2 mmoL/L Ca2+ and 100 mL/L fetal bovine serum were added into DMEM medium without calcium. After 48 hours, the cell morphology was observed by inverted microscope. The proliferation and apoptosis of cells were separately examined by MTT and AnnexinV-PI. Real-time quantitative PCR was used to detect the expression levels of amelogenin and KLK4 mRNA. 【Results】 After Five days in standard DMEM medium, the cells were shaped like the paving pattern. RT-PCR showed that both amelogenin and KLK4 were expressed in the cells. Immunohistochemical staining showed that most cells had positive staining for amelogenin. After 48 hours of calcium intervention, some cells in 1.2 mmoL/L Ca2+ group had higher nuclear density and poor light transmittance, and more high columnar cells could be observed in 1.2 mmoL/L Ca2+ group than those in 0 and 0.6 mmoL/L Ca2+ groups. With the decrease in calcium concentration in the medium, MTT showed that the proliferation activity of ameloblasts reduced (P<0.01). Annexin V-PI showed that the percentage of apoptotic cells decreased, and there was a significant difference between 1.2 mmoL/L and 0 mmoL/L Ca2+ groups (P<0.05). Real time-PCR showed that the expressions of amelogenin and KLK4 mRNA reduced (P<0.01). 【Conclusion】 Low-level calcium may inhibit the differentiation of ameloblasts, thereby affecting the formation of enamel mineralization.
RESUMO
Objective:Understand the status of brushing teeth behavior of preschoolers in Shaanxi Province, to provide basis for oral health of preschoolers.Methods:By adopting the methods of multi-stage, stratified, geometric and cluster sampling, 1 370 kindergarten students at the age of 3-5 in Shaanxi Province were sampled as respondents to implement oral health questionnaire.Results:49.2%(674/1 370) children brushed their teeth every day, including only 14.8%(203/1 370) children brushing their teeth twice or above. Therefore, the difference of the brushing frequency (≥ 1 time/day) between urban and rural areas had obvious statistical significance ( χ2 value was 47.588, P<0.01). 98.7%(741/750) children used toothpaste, including only 6.9% (51/741) using toothpaste with fluoride. Therefore, the use of toothpaste between urban and rural areas has no statistical significance. Only 0.5% (4/751) children started to brush their teeth when their first deciduous tooth erupted. Therefore, the age for children starting to brush their teeth between urban and rural areas had obvious statistical significance ( χ2 value was 24.217, P<0.01). 65.2% (490/751)parents never helped their children to brush teeth, parents in rural areas even reached to 72.8% (227/312). Therefore, the brushing frequency for parents helping their children to brush teeth between urban and rural areas had statistical difference ( χ2 value was 16.192, P<0.01). Conclusions:The status of brushing teeth behavior of preschoolers in Shaanxi Province is lower than the national level, and the level in rural areas is obviously lower that in urban areas. The education and cultivation on brushing teeth behavior should be further strengthened in the future propaganda and education, especially, the power of propaganda on children and parents in rural areas should be strengthened.
RESUMO
Extraction of teeth is the most basic and widely used operation of oral and maxillofacial surgery. According to characteristics of extraction of teeth, the author views medical ethics principles which in the diagnoses and treatments process from the aspect of medical ethics, they are,①Doctors must intensify their own quality and self - cultivations and establish the idea of " People First ". ②Doctors must carry on the overall and systematic inspection, make the plan of diagnoses and treatments synthetically toimplement the idea of " People First ". ③Doctors should pay attention to interact with patient, meet different patients' demands and create the harmonious medical environment.