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背景:目前酸蚀与黏结技术已经广泛应用于口腔临床,有资料表明年轻恒牙与成年恒牙的牙体硬组织中的主要无机元素钙和磷的含量有一定的差异。目的:通过分光光度法与EDTA滴定法测量年轻恒牙与成年恒牙的牙釉质与牙本质中主要无机元素(钙、磷)的含量。方法:年轻恒牙与成年恒牙离体牙各20颗,用生石膏和水混合,待近干时,将牙齿垂直铸于其中,使牙面暴露。用syj-200精密切割机将模型切割成切片,然后将切片放入浓硝酸中,通过加热器使之溶解,然后制备成标准溶液,最后采用分光光度法与滴定法分别测量两者硬组织的钙和磷的浓度。结果与结论:结果证实,年轻恒牙的牙体硬组织钙磷含量和钙/磷比值小于成年恒牙(P<0.05),说明有机物含量较成年恒牙多;矿化程度低于成年恒牙(P<0.05),相对于成年恒牙更加耐酸,临床操作可适当延长对年轻恒牙的酸蚀时间,以达到更佳的酸蚀效果。
BACKGROUND: At present, the technique of acid etching and bonding has been widely used in oral clinical practice. Some data show that the contents of calcium and phosphorus, the major inorganic elements in the dental hard tissue of young permanent teeth and adult permanent teeth, are different. Objective: To measure the contents of major inorganic elements (calcium and phosphorus) in enamel and dentin of young permanent and adult permanent teeth by spectrophotometry and EDTA titration. METHODS: Twenty young permanent teeth and 20 adult permanent teeth were mixed with gypsum and water. When the teeth were near dry, the teeth were cast vertically and the teeth were exposed. The model was cut into slices with a syj-200 precision cutting machine, then the slices were placed in concentrated nitric acid, dissolved in a heater, and then prepared into a standard solution. Finally, spectrophotometry and titration were used to measure the hard tissue Calcium and phosphorus concentrations. RESULTS AND CONCLUSION: The results showed that the calcium and phosphorus ratio and the ratio of calcium to phosphorus in young permanent teeth were less than that of adult permanent teeth (P <0.05), indicating that the content of organic matter was more than that of adult permanent teeth. The degree of mineralization was lower than that of adult permanent teeth (P <0.05). Compared with adult permanent teeth, it is more acid-tolerant, and the clinical operation may be appropriate to prolong the acid etching time of young permanent teeth so as to achieve better acid etching effect.