人牙釉质、牙本质矿化成分的晶体特性

目的　对比研究人乳、恒牙牙釉质和牙本质矿化成分 (牙磷灰石 )的晶体特性。方法　应用X射线衍射、红外光谱和电子探针等方法对牙釉质、牙本质磷灰石进行了检测。结果　牙磷灰石不是由单一成分组成 ,而是一种生物混晶 ,其主要物相组成为含有多种微量成分的碳羟磷灰石。与牙本质相比 ,牙釉质的结晶度高且晶体晶胞参数的a轴膨胀。晶体晶胞参数计算显示人恒牙牙釉质磷灰石为 :a =9 4 5 0 ,c =6 890 ;牙本质 :a =9 4 33 ,c =6 890 。人乳牙牙釉质 :a =9 4 6 2 ,c =6 910 ;牙本质 :a =9 4 4 2 ,c =6 910 。成分分析显示 ,牙本质中Mg、CO3 2 -含量均高于牙釉质 ,而牙釉质中Cl含量较高。结论　乳、恒牙牙釉质与牙本质磷灰石在结晶性和晶胞参数等方面的差异可能与Mg、CO3 2 -、Cl等重要微量成分有关

The crystallographic properties of the mineral phases of enamel and dentin in normal deciduous and permanent teeth

Objective To investigate the crystallographic properties of the mineral phases of normal enamel and dentin (dental apatite) in deciduous and permanent teeth. Methods Three kinds of physical methods including X ray diffraction (XRD), infrared absorption spectroscope (IR) and electron probe micro analysis (EPMA) were utilized in this study. Results Dental apatite was not uniphase, but multiphase, which could be described as carbonate substituted hydroxyapatite. Compared to dentin apatite, the higher crystallinity and expanded a axis lattice parameters were found in enamel. Chemical analyses demonstrated that higher concentrations of Mg and CO 3 2 were found in dentin than those of enamel. But enamel had higher Cl content. Conclusions The differences among enamel and dentin, in terms of lattice parameter and crystallinity may be partially attributed to the incorporation of Mg, CO 3 2- and Cl minor elements.