乳牙釉、牙本质钙含量之分析研究

Study on the Calcium Content of Enamel and Dentin in Deciduous Teeth.

目的:分析探讨乳牙釉质、牙本质钙含量状况与龋病关系.方法:对37例5～7岁幼儿园乳恒牙替换所拔除的下颌乳中切牙,用电子探针X线显微分析仪检测各牙之近中侧、远中侧、唇侧和舌侧之釉质和牙本质不同深度之钙含量.受检测牙37颗(1|18颗,|1 19颗).37例中dft=0者14名,为无龋组;dft＞0者23名,为有龋组.有龋组中0＜dft＜5者9名,为低危组;dft≥5者14名,为高危组.结果:1)釉质Ca含量在各侧间以舌侧之含量最少(P=0.0001),且舌侧釉质各深度间之Ca含量有明显差异,浅层最多、中层次之,深层最少(P=0.037).其余各侧间及各侧之各不同深度间均无明显差异.2)牙本质Ca含量在各侧间均无明显差异.各侧之各深度间Ca含量除远中侧无明显差异,近中侧(P=0.0152)、舌侧(P=0.0152)、唇侧(P=0.0167)的各深度间均呈非常明显之差异.总体牙本质之钙含量呈深层最高、中层为次、浅层最低(P=0.0001).3)牙釉质和牙本质之钙含量在无龋组和有龋组间无明显差异(P=0.9692,P=0.2705).有龋组之钙含量与dft仅在近中侧和唇侧釉质中呈低度负相关关系(r=-0.46052和-0.40139,P=0.0310和0.0576),除此在釉质和牙本质中均未呈相关关系.结论:釉质和牙本质中钙含量与龋病无非常明显的相关关系.

Objective: To analyze the content of calcium in enamel and dentin of deciduous teeth and study their relationships with caries status. Methods: 37 children aged 5~7 years were enrolled in this study. 37 lower primary incisors were collected. They were divided into caries-free group (dft = 0, n =14) and caries group (dft>0, n =23). Caries group were further divided into low-caries-risk group (0<dft<5, n =9) and high-caries-group (dft≥5, n =14). EPMA was used to analyze the Ca content in deciduous teeth. Ca content in enamel and dentin with different sides (mesial, distal, labial, lingual) and depths (outer layer, medium layer, inner layer) were investigated and compared. The relationship between Ca content and dft was also discussed. Results: 1) In enamel, Ca content is the lowest in lingual side ( P = 0.0001 ). Difference of Ca content in depths was only found in lingual side ( P =0.037), while the highest in outer layer and lowest in inner layer. 2) In dentin, there is no difference of Ca content among different positions ( P >0.05). Difference of Ca content in depths is found in labial, lingual and mesial sides except distal side. Totally in dentin, the Ca content is the highest in inner layer, then medium layer, and lowest in outer layer. 3) There is no difference of Ca content in enamel or dentin between caries-free group and caries-group. A relatively lower negative correlation is found between contents in Ca of mesial and labial enamel with dft ( r =-0.46, r =-0.40) and not in any other parts. Conclusions: Distribution of Ca content in enamel and dentin in deciduous teeth was investigated. There was no obvious relationship between Ca contents in enamel, dentin in deciduous teeth and caries status.