电子探针分析乳牙釉质和牙本质钙含量的研究

The study on deciduous teeth enamel and dentin calcium content analyzed by Electron Probe X-ray Microanalysis

目的研究乳牙釉质和牙本质中钙含量及分布,探讨其与龋患状况之间的关系。方法运用电子探针显微分析仪测定40颗离体下颌乳中切牙纵剖面上不同深度的钙含量,并以标本所在个体的龋患状况分组,分别进行统计学分析。结果 40例下颌乳中切牙标本的总计钙含量均值为37.13±1.10(wt%)。其中,牙釉质钙含量均值为38.31±0.94(wt%),牙本质钙含量均值为36.66±1.38(wt%);牙釉质表层下50μm、100μm处钙含量高于250μm处钙含量;牙本质釉牙本质界下50μm、100μm处钙含量分别低于450μm、500μm、550μm、600μm处钙含量。正常乳牙钙含量在无龋组、龋病低危组、龋病高危组间未见统计学差异。正常乳牙钙含量与龋补牙数、龋补牙面、龋蚀指数之间均无相关关系。结论正常乳牙中钙元素分布呈非均质状态。牙釉质钙含量从表层向釉牙本质界方向呈逐渐下降趋势;牙本质钙含量从釉牙本质界向髓腔侧呈逐渐上升趋势。发育正常的乳牙钙含量不能作为反映个体龋患状况的单一指标。

Objective To study the calcium content and distribution of deciduous teeth enamel and dentine and to discuss its relationship with caries.Methods Using Electron Probe X-ray Microanalysis（EPMA） microanalyzer to measure the calcium content at different depths on the vertical section of 40 mandibular deciduous central incisors and then grouping according to caries status of individual sample,each group is analyzed statistically respectively.Results The average value of total calcium content for the 40 mandibular deciduous central incisors is 37.13 ± 1.10（wt%）,the calcium content of enamel is 38.31 ± 0.94（wt%）,the calcium content of dentine is 36.66 ± 1.38（wt%）;the calcium content of enamel subsurface 50μm and 100μm is higher than enamel subsurface 250μm;the calcium content of dentine under-enamelo-dentinal junction 50μm and 100μm is lower than respectively dentine under-enamelo-dentinal junction 450μm,500μm,550μm and 600μm.A statistics difference is not seen for the normal deciduous teeth＇s calcium content between caries-free group,low caries risk group and high caries risk group,and the normal deciduous teeth＇s calcium content has no correlation with decayed-filled tooth,decayed-filled surface and caries severity index.Conclusion The calcium distribution of normal deciduous teeth is non-homogeneous state.The calcium content of enamel showed a gradual decreasing trend from surface towards enamelo-dentinal junction;the calcium content of dentine showed a gradual increasing trend from enamelo-dentinal junction towards pulp cavity side.The calcium content of normal development deciduous teeth does not reflect the situation of individual caries as a single indicator.