人下颌第一磨牙釉质帽与牙本质核三维形态的初步研究

A preliminary 3-dimensional study of the enamel cap and dentin core of human mandibular first molar

目的:通过人下颌第一磨牙釉质帽和牙本质核的三维重建模型,探讨其内在三维形态规律。方法:选取人下颌第一磨牙20个,采用显微CT对其进行三维扫描及重建后,在逆向工程软件中精确测量髓室各髓角至其各自相应牙本质尖、牙尖表面的距离,并同时测量其牙釉质帽、牙本质核、牙髓的体积和面积。结果:成功获得人下颌第一磨牙釉质帽与牙本质核的三维模型,测量和统计结果显示:牙本质核、牙髓组织体积和面积之间存在统计学相关(P﹤0.05),各髓角至各自相应牙本质尖的距离以远舌牙本质尖最大,依次为:远舌牙本质尖>远颊牙本质尖>远中牙本质尖>近舌牙本质尖>近颊牙本质尖,其中远舌尖、远颊尖、远中尖分别与近舌尖、近颊尖相比,差异均有统计学意义(P﹤0.05);各髓角至各自相应牙尖的距离以远舌尖最大,依次为远舌尖>近舌尖>远中尖>远颊尖>近颊尖,各组间两两相比差异均有统计学意义(P﹤0.05)。结论:成功获得了精确的下颌第一磨牙三维模型,并初步归纳出其牙釉质帽和牙本质核的内在三维形态规律。

AIM：To build up a 3-D model of human mandibular first molar by Micro CT and to reveal its morphological rule for the enamel cap and dentin core.METHODS：20 human mandibular first molars were selected and scanned by Micro CT.The morphological characteristics of enamel cap, dentin core and pulp chamber were meas-ured by the reversed engineering software individually.Both the distance of pulp horn-dentin cusp, the volume and area of each part of tooth were calculated.Statistical tool was applied for the analysis of all data.RESULTS：The vivid 3-dimensional model of enamel cap, dentin core and pulp chamber was successfully reconstructed.There was signifi-cant correlation between the dentin core and pulp chamber for either volume or area （P﹤0.05）.The result of two-factor analysis of variance of the distance of pulp horn-dentin cusp showed that the distal lingual dentin cusp〉distal buccal dentin cusp〉distal dentin cusp〉mesial lingual dentin cusp〉mesial buccal dentin cusp （ P﹤0.05） .The re-sult of two-factor analysis of variance of the distance of pulp horn-dental cusp showed：distal lingual dental cusp〉me-sial lingual distal dental cusp〉distal dental cusp〉distal buccal dental cusp〉mesial buccal dental cusp （P﹤0.05）. CONCLUSION：This study obtained the accurate 3-dimensional models of the mandibular first molars, and prelimi-narily summarized the enamel cap and dentin core morphological characteristics.