Lukacs John R
Department of Anthropology, 1218 University of Oregon, Eugene, OR 97403-1218, USA.
Am J Phys Anthropol. 2009 Jul;139(3):339-52. doi: 10.1002/ajpa.20990.
A reduction in enamel thickness due to disrupted amelogenesis is referred to as enamel hypoplasia (EH). Linear EH in permanent teeth is a widely accepted marker of systemic physiological stress. An enigmatic, nonlinear form of EH commonly manifest in great ape and human deciduous canines (dc) is known as localized hypoplasia of primary canines (LHPC). The etiology of LHPC and what it signifies-localized traumatic or systemic physiological stress-remains unclear. This report presents frequency data on LHPC, hypostotic cranial traits, and tooth size in a sample of juvenile bonobos, then tests hypotheses of intertrait association that improve knowledge of the etiology and meaning of LHPC. The fenestration hypothesis is tested using hypostotic cranial traits as a proxy for membrane bone ossification, and the relationship between tooth size, LHPC, and hypostosis is investigated. Macroscopic observations of EH, hypostotic traits, and measurements of buccolingual tooth size were conducted according to established standards. LHPC was found in 51.2% of bonobos (n = 86) and in 26% of dc teeth (n = 269). Hypostotic traits were observed in 55.2% of bonobos (n = 96). A test of the association between LHPC and hypostosis yielded nonsignificant results (chi(2) = 2.935; P = 0.0867). Primary canines were larger in specimens with LHPC than in unaffected specimens (paired samples t test; udc, P = 0.011; ldc, P = 0.018), a result consistent with the fenestration hypothesis of LHPC pathogenesis. Hypostosis was not associated with differences in tooth size (P > 0.05). LHPC may be an indirect indicator of physiological stress, resulting from large, buccally displaced primary canines.
由于釉质形成受到干扰导致的牙釉质厚度减少被称为釉质发育不全（EH）。恒牙中的线性EH是系统性生理应激的一个广泛认可的标志。一种神秘的、非线性形式的EH通常出现在大猩猩和人类的乳犬齿（dc）中，被称为原发性犬齿局部发育不全（LHPC）。LHPC的病因及其所代表的意义——局部创伤或系统性生理应激——仍不清楚。本报告呈现了幼年倭黑猩猩样本中LHPC、颅骨发育不全特征和牙齿大小的频率数据，然后检验性状间关联的假设，以增进对LHPC病因和意义的了解。使用颅骨发育不全特征作为膜性骨骨化的替代指标来检验开窗假说，并研究牙齿大小、LHPC和发育不全之间的关系。根据既定标准对EH、发育不全特征进行宏观观察，并测量颊舌向牙齿大小。在51.2%的倭黑猩猩（n = 86）和26%的乳犬齿（n = 269）中发现了LHPC。在55.2%的倭黑猩猩（n = 96）中观察到发育不全特征。对LHPC和发育不全之间关联的检验结果不显著（卡方 = 2.935；P = 0.0867）。有LHPC的标本中，原发性犬齿比未受影响的标本更大（配对样本t检验；上犬齿，P = 0.011；下犬齿，P = 0.018），这一结果与LHPC发病机制的开窗假说一致。发育不全与牙齿大小的差异无关（P > 0.05）。LHPC可能是生理应激的间接指标，由颊侧移位较大的原发性犬齿导致。
