Chemical, mechanical and morphological properties of hypomineralized enamel of permanent first molars
Chemical, mechanical and morphological properties of hypomineralized enamel of permanent first molars
复制标题
DOI：
10.3109/00016351003752395
复制
发表时间：
2010-07-01
影响因子：
2
通讯作者：
Noren, Jorgen G.
中科院分区：
文献类型：
--
作者：
Fagrell, Tobias G.;Dietz, Wolfram;Noren, Jorgen G.
Objective.在一些研究中，恒牙中矿化不足的釉质的微观结构被描述为不太明显的棱柱鞘和釉质晶体缺乏组织的紊乱的釉质。低矿化牙釉质的力学性能、硬度和弹性模量均低于正常牙釉质。本研究的目的是检查正常和低矿化牙釉质扫描电子显微镜（SEM），硬度测量和X射线显微分析（XRMA）。材料和方法。对4颗离体低矿化恒磨牙进行了扫描电镜、X射线微区分析和硬度测定。结果结果表明，正常牙釉质和低矿化牙釉质的显微硬度与Ca：C比值呈负相关。酸蚀低矿化釉质在SEM上显示为覆盖有无结构层，棱柱显示为无组织，具有厚的棱柱鞘和松散堆积的微晶。此外，在接近釉质-牙本质交界处的多孔性低矿化釉质深处发现了细菌。结论.与正常牙釉质相比，诊断为臼齿切牙矿化不足的牙齿在矿化不足的牙釉质中具有显著较低的硬度值。硬度值根据形态和化学性质而变化。
Objective. The microstructure of hypomineralized enamel in permanent teeth has been described in several studies as less distinct prism sheaths and disorganized enamel with lack of organization of the enamel crystals. The mechanical properties, hardness and modulus of elasticity of the hypomineralized enamel have lower values compared with normal. The aim of this study was to examine normal and hypomineralized enamel using scanning electron microscopy (SEM), hardness measurements and X-ray microanalysis (XRMA). Material and methods. Four extracted hypomineralized permanent first molars, sectioned and cut in half, were analyzed with SEM, XRMA and hardness measurements. Results. An inverse relation was found between the micro hardness and the Ca:C ratio in hypomineralized and normal enamel. The acid-etched hypomineralized enamel appeared on SEM to be covered with a structureless layer and the prisms appeared disorganized, with thick prism sheaths and loosely packed crystallites. Furthermore, bacteria were found deep in porous hypomineralized enamel close to the enamel-dentin junction. Conclusions. Teeth diagnosed with molar incisor hypomineralization have significantly lower hardness values in the hypomineralized enamel compared with normal enamel. The hardness values vary according to the morphological and chemical properties.