Khraisat Ameen, Alsoleihat Firas, Subramani Karthikeyan, Al-Rabab'ah Mohammad A, Al-Omiri Mahmoud K, Abu-Tahun Ibrahim
University of Jordan, Faculty of Dentistry, Department of Conservative Dentistry and Fixed Prosthodontics, Amman, Jordan.
Coll Antropol. 2013 Sep;37(3):885-94.
The objective was to determine the expression and fluctuating asymmetry of two dental morphological traits in the living Jordanians: The lingual cusp number on the lower premolars (LP1 and LP2) and the hypoconulid (distal cusp) reduction on the lower first molar (LM1). In addition, both intra- trait and inter- trait interactions were analyzed. Three hundred school children (15.5 +/- 0.4 years) were involved. Impressions for the mandibular dental arches were taken, and dental casts were reproduced. The above-mentioned traits were observed. Paired sample t test and nonparametric correlation analysis were used for data analysis. Three-cusped LP1 was found in 11.40 % of the examined students, while the two-cusped LP1 was found in 88.60%. In comparison, the Three-cusped LP2 was found in 61.40% while the two-cusped LP2 was found in 38.60% of the observed subjects. The frequencies of the 4-cusped and 5-cusped LM1 were found to be 8.65% and 91.35%, respectively. Nonparametric correlation analysis revealed positive and statistically significant association between the expression of two lingual cusps on LP1 and on LP2 in both genders (p < 0.01), while there was no significant correlation between expression of two lingual cusps on either LP1 or LP2 and the hypoconulid loss on LM1 in both genders (p > 0.05). Bilateralism was highly significant in the tested traits in both genders (p < 0.001). This finding might be a sign of relatively low environmental stresses experienced by the living Jordanians and/or great ability of its individuals to buffer the adverse effects of such stresses on dental development. This study is a useful addition to the existing literature in that it examines a previously poorly characterized population and assists in placing the contemporary Jordanian population within the current framework of human population groups globally.
下颌前磨牙（LP1和LP2）的舌侧尖数量，以及下颌第一磨牙（LM1）的下后尖（远中尖）退化情况。此外，还分析了性状内和性状间的相互作用。共有300名学童（15.5±0.4岁）参与研究。采集下颌牙弓印模并复制牙模，观察上述性状。采用配对样本t检验和非参数相关分析进行数据分析。在接受检查的学生中，发现11.40%的LP1有三个牙尖，而88.60%的LP1有两个牙尖。相比之下，在观察对象中，61.40%的LP2有三个牙尖，38.60%的LP2有两个牙尖。发现四尖和五尖LM1的频率分别为8.65%和91.35%。非参数相关分析显示，男女LP1和LP2上两个舌侧尖的表达之间存在正相关且具有统计学意义（p<0.01），而男女LP1或LP2上两个舌侧尖的表达与LM1上的下后尖缺失之间均无显著相关性（p>0.05）。双侧性在男女受试性状中均非常显著（p<0.001）。这一发现可能表明约旦在世人群所经历的环境压力相对较低，和/或其个体有很强的能力缓冲此类压力对牙齿发育的不利影响。本研究对现有文献是一个有益补充，因为它研究了一个此前特征描述较少的人群，并有助于将当代约旦人群置于全球人类群体的当前框架内。
