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Quantifying molar tooth shape in primates using geometric morphometrics

使用几何形态计量学量化灵长类动物的臼齿形状

基本信息

批准号：
14540661
负责人：
KONDO Shintaro
金额：
$ 1.6万
依托单位：
Showa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

The occlusal shapes of molars in Macaca fuscata fuscata were analyzed by means of geometric morhpometrics. The central pit was selected as the origin, and the following points were selected as landmarks the cusp tips, the mesial and distal pits, and the intersection between central groove and buccal/lingual groove, and the most prominence points of occlusal outline. The two dimensional and three dimensional vectors for the landmarks were measured.Two dimensional measurements were made for the three permanent molars (M1, M2 and M3), and they were analysed by the Procrustes and thin-plate spline analyses. Sexual differences in molar shape were very small, but centroid size was significantly different between the two sexes. Sexual differences in size and shape of the molars were more conspicuous in the later-developed molar than in the early-developed molar. There were small differences between M1 and M2 in shape, but M2 had significantly larger centroid size than M1. The shape change from M1 to M3 is represented by mesiodistal elongation and buc colingual compression of the distal half of the crown.The occlusal shape differences between maxillary fourth deciduous premolar (dp4) and first permanent molar (M1) were analyzed by the thin-plate spline analyze. Three dimensional vectors of 8 landmarks were measured when the central pit was selected as the origin. The centroid size of the dp4 was significantly smaller than the M1 (P<0.01). The dp4 had shallower pits and well-developed metacone than M1, but the location of cusp tips on the occlusal plane did not different among the two molars.

用几何形态测量学方法对褐毛猕猴磨牙的咬合形态进行了分析。选取中心凹点作为原点，选取尖尖、中凹点和远凹点、中心沟与颊/舌沟的交点以及咬合轮廓最突出的点作为标志点。测量了地标的二维和三维矢量。对3颗恒磨牙（M1、M2、M3）进行二维测量，采用Procrustes和薄板样条分析。两性在磨牙形状上差异很小，但质心大小差异显著。磨牙大小和形状的性别差异在发育较晚的磨牙中比在发育较早的磨牙中更为明显。M1和M2在形状上差异不大，但M2的质心尺寸明显大于M1。从M1到M3的形状变化表现为中远端伸长和冠的远端一半的共舌压缩。采用薄板样条法分析上颌第四乳牙前磨牙（dp4）与第一恒磨牙（M1）的咬合形态差异。以中心坑为原点，测量8个地标的三维向量。dp4的质心大小显著小于M1 （P<0.01）。dp4的牙凹较M1浅，后凹发育较好，但两磨牙尖尖在咬合平面上的位置没有差异。