釉质矿化不足的矿物质密度。

Mineral density of hypomineralised enamel.

机构信息

Dept of Oral Sciences, Faculty of Dentistry, University of Otago, Dunedin, Otago, New Zealand.

出版信息

J Dent. 2010 Jan;38(1):50-8. doi: 10.1016/j.jdent.2009.09.002.

DOI:10.1016/j.jdent.2009.09.002

PMID:19737596

Abstract

OBJECTIVES

To characterize molar-incisor hypomineralisation (MIH) defects of different severities quantitatively and qualitatively using X-ray microtomography (XMT) and to measure the range of reduction in mineral density (MD) of MIH enamel compared with the normal range.

METHODS

Ten sound teeth and ten MIH teeth were scanned using a commercial XMT system. Four hydroxyapatite phantoms of different densities were used as calibration standards with each scan. A calibration equation derived from the phantoms with each tooth was used for MD calibration. MD was traced from the cementum-enamel junction (CEJ) to the cusp tip and from the dentine-enamel junction (DEJ) to the outer enamel surface.

RESULTS

In sound teeth, MD increased from CEJ to cusp/incisal tip, while in MIH teeth MD dropped from the CEJ to the occlusal region, then increased again at the cusp tip. MD was highest midway between DEJ and outer enamel in sound teeth. In MIH, enamel showed normal thickness and MD was highest near the DEJ and then decreased towards the outer enamel. MD of MIH enamel was on average about 19% lower than sound enamel. The MIH defects seemed to follow the incremental lines of enamel formation.

CONCLUSIONS

MIH defects are hypomineralised defects of different severities that follow the natural incremental lines of enamel formation. Cuspal areas are usually only mildly affected and cervical enamel always appears to be sound.

摘要

目的

使用 X 射线显微断层扫描（XMT）对不同严重程度的磨牙-切牙釉质发育不全（MIH）缺陷进行定量和定性描述，并测量与正常范围相比 MIH 釉质的矿物质密度（MD）降低范围。

方法

使用商业 XMT 系统对 10 颗健康牙齿和 10 颗 MIH 牙齿进行扫描。使用四个不同密度的羟基磷灰石幻像作为校准标准，每个扫描一个。用每个牙齿的幻像得出的校准方程用于 MD 校准。MD 从牙骨质-釉质交界处（CEJ）追踪到牙尖，从牙本质-釉质交界处（DEJ）追踪到外釉面。

结果

在健康牙齿中，MD 从 CEJ 到牙尖/切缘逐渐增加，而在 MIH 牙齿中，MD 从 CEJ 到咬合区下降，然后在牙尖再次增加。MD 在健康牙齿的 DEJ 和外釉面之间的中间处最高。在 MIH 中，釉质厚度正常，MD 在 DEJ 附近最高，然后向外釉质逐渐降低。MIH 釉质的 MD 平均比健康釉质低约 19%。MIH 缺陷似乎遵循釉质形成的增量线。