Lyngstadaas S P, Møinichen C B, Risnes S
Department of Oral Biology, Faculty of Dentistry, University of Oslo, Norway.
Anat Rec. 1998 Mar;250(3):268-80. doi: 10.1002/(SICI)1097-0185(199803)250:3<268::AID-AR2>3.0.CO;2-X.
Biomolecular research and genetic manipulations have stressed the importance of thorough knowledge of normal organ morphology. Mouse molar teeth are convenient models for studying basic interactions in organ development and morphogenesis. The aim of the present study was to provide basic information on their morphology.
Intact and sectioned/ground molars of mice of various ages were observed with SEM.
Enamel-free areas (EFA) were present on cusp tips at time of eruption. The dominating structural configuration in enamel was prism decussation in inner enamel and parallel prisms in outer enamel. Prism decussation tended to be absent at cusp ridges and in the bottom of grooves. In the former location, the distinction between prisms and interprism was often obscured in the middle enamel zone due to decreased difference in orientation of their crystals. A thin layer of enamel, often aprismatic, covered the distal aspect of cusps in maxillary molars and the mesial aspect of cusps in mandibular molars. The enamel abutting on EFA was often aprismatic. Aprismatic enamel exhibited incremental lines with a periodicity of about 1 microm and was often traversed by cracks. The enamel surface was porous in the bottom of grooves. Parts of mouse molar enamel were incompletely mineralized at the time of eruption.
SEM is a convenient method for combined studies of crown morphology and enamel structure. Based on morphological criteria, a modification of the cusp nomenclature is proposed. Enamel thickness and structure in mouse molars show regional variations. Fundamental similarities exist between mouse molar cusps and mouse incisors. Mouse molar enamel undergoes posteruptive maturation.
生物分子研究和基因操作强调了全面了解正常器官形态的重要性。小鼠磨牙是研究器官发育和形态发生中基本相互作用的便捷模型。本研究的目的是提供有关其形态的基础信息。
用扫描电子显微镜观察不同年龄小鼠完整的、切片的/磨制的磨牙。
萌出时牙尖处存在无釉质区（EFA）。釉质的主要结构构型是内釉质中的棱柱交叉和外釉质中的平行棱柱。棱柱交叉在牙尖嵴和沟底部往往不存在。在前一个位置，由于棱柱和柱间质晶体取向差异减小，在釉质中间区棱柱和柱间质之间的区别常常模糊不清。一层薄的、通常无棱柱的釉质覆盖上颌磨牙牙尖的远中面和下颌磨牙牙尖的近中面。邻接无釉质区的釉质通常无棱柱。无棱柱釉质呈现出周期性约为1微米的生长线，且常被裂纹穿过。沟底部的釉质表面多孔。小鼠磨牙釉质的部分区域在萌出时矿化不完全。
扫描电子显微镜是联合研究牙冠形态和釉质结构的便捷方法。基于形态学标准，提出了牙尖命名法的修改。小鼠磨牙的釉质厚度和结构存在区域差异。小鼠磨牙牙尖和小鼠切牙之间存在基本相似性。小鼠磨牙釉质在萌出后会成熟。
