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.

采用几何形态计量学方法对猕猴磨牙的咬合形态进行了分析。选择中央凹坑作为原点，选择牙尖尖、近中、远中凹坑、中央沟与颊舌沟交点、咬合轮廓最突出点等点作为标志。测量了界标的二维和三维矢量。对三个恒磨牙（M1、M2 和 M3）进行了二维测量，并通过 Procrustes 和薄板样条分析对其进行了分析。臼齿形状的性别差异非常小，但质心大小在两性之间存在显着差异。较晚发育的磨牙中，磨牙大小和形状的性别差异比早期发育的磨牙更为明显。 M1 和 M2 的形状差异较小，但 M2 的质心尺寸明显大于 M1。从M1到M3的形状变化表现为牙冠远中半部的近远中伸长和颊侧共舌压缩。通过薄板分析上颌第四乳牙前磨牙（dp4）和第一恒磨牙（M1）的咬合形状差异样条分析。当选择中心凹坑作为原点时，测量了8个标志的三维矢量。 dp4的质心尺寸显着小于M1（P<0.01）。 dp4 比 M1 具有更浅的凹坑和发达的后锥体，但两颗磨牙牙尖在咬合面上的位置没有差异。