华中地区近代人群上、下颌第一臼齿齿冠及齿尖面积

目的 通过对282枚华中地区新石器时代到明清时期(距今5 000～200年)人类上、下颌骨第一臼齿(M1和M1)齿冠和齿尖面积的测量和分析,取得华中地区近代人群牙齿尺寸的准确数据和变异情况. 方法 采用统一标准对每颗牙齿咬合面行高分辨率摄片.运用数字图像技术与形态测量方法获取每颗牙齿的齿冠绝对面积和单个齿尖相对面积. 结果 齿尖相对面积大小顺序为:M1:原尖>前尖>后尖>次尖;M1:原尖>后尖>下次尖>内尖>下次小尖;M1齿尖相对面积的变异总体上大于M1;从大约5 000年前的新石器时代到明清时期,华中地区人类M1和M1齿冠绝对面积分别缩小了6.57%和6.15%. 结论 食物结构的变化可能是造成臼齿结构变化的主要原因,在此期间M1和M1相对齿尖面积一直保持稳定,提示现代人类相对齿尖大小比例至少在距今5 000年前的新石器时代就已经形成.

Crown and cusp areas of upper and lower first molars of recent central Chinese population

Objective Total crown basal area (TCBA) and relative basal cusp area (RBCA) of 282 MSUP>1/SUP> and MSUB>1/SUB> from archeological sites spanning from Neolithic time to Qing dynasty (5 000|200 years BP) were measured and analyzed to obtain tooth size and variations of recent Chinese populations in central China. Methods With the same standard, the high resolution pictures of occlusal surface were taken for each tooth. Digital image technique and morphometric analysis were used to obtain the TCBA and RBCA for each tooth. Results The RBCAs exhibits a sequence of protocone >paracone> metacone > hypocone in MSUP>1 /SUP>and protoconid > metaconid > hypoconid> entaconid >hypoconulid in MSUB>1/SUB>; the RBCA variations of MSUB>1/SUB> are collectively larger than those of MSUP>1/SUP>. From Neolithic time to Qing Dynasty, the MSUP>1/SUP> and MSUB>1/SUB> TCBA reduced about 6.57% and 6.15% respectively. In contrast, the RBCAs of either MSUP>1/SUP> or MSUB>1/SUB> stay relatively stable in the same period of time. Conclusion Change of food structure is thought to be the most probable reason accounting for this change in consideration of the archeological sites background. The RBCA now presented by MSUP>1/SUP> and MSUB>1 /SUB>of modern humans formed at least 5 000 years ago.