Menegaz Rachel A, Sublett Samantha V, Figueroa Said D, Hoffman Timothy J, Ravosa Matthew J
Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, One Hospital Drive, Columbia, MO 65212, USA.
Anat Rec (Hoboken). 2009 Feb;292(2):277-84. doi: 10.1002/ar.20840.
Morphological variation related to differential loading is well known for many craniomandibular elements. Yet, the function of the hard palate, and in particular the manner in which cortical and trabecular bone of the palate respond to masticatory loads, remains more ambiguous. Here, experimental data are presented that address the naturalistic influence of biomechanical loading on the postweaning development and structure of the hard palate. A rabbit model was used to test the hypothesis that variation in the morphology of the hard palate is linked to variation in masticatory stresses. Rabbit siblings were divided as weanlings into soft and hard/tough dietary treatment groups of 10 subjects each and were raised for 15 weeks until subadulthood. MicroCT analyses indicate that rabbits subjected to elevated masticatory loading developed hard palates with significantly greater bone area, greater cortical bone thickness along the oral lamina, and thicker anterior palates. Such diet-induced levels of palatal plasticity are comparable to those for other masticatory elements, which likely reflect osteogenic responses for maintaining the functional integrity of the palate vis-à-vis elevated stresses during unilateral mastication. These data support a role for mechanical loading in the determination of palatal morphology, especially its internal structure, in living and fossil mammals such as the hominin Paranthropus. Furthermore, these findings have potential implications for the evolution of the mammalian secondary hard palate as well as for clinical considerations of human oral pathologies.
许多颅下颌骨元件因不同负荷而产生的形态变化已为人熟知。然而，硬腭的功能，尤其是硬腭的皮质骨和小梁骨对咀嚼负荷的反应方式，仍较为模糊。在此，我们展示了实验数据，这些数据探讨了生物力学负荷对断奶后硬腭发育和结构的自然影响。我们使用兔模型来检验硬腭形态变化与咀嚼应力变化相关的假设。兔幼崽在断奶时被分为软食和硬/韧性食物处理组，每组10只，饲养15周直至接近成年。显微CT分析表明，承受较高咀嚼负荷的兔子发育出的硬腭具有显著更大的骨面积、沿口腔板的皮质骨更厚以及前硬腭更厚。这种由饮食诱导的腭部可塑性水平与其他咀嚼元件相当，这可能反映了在单侧咀嚼过程中，为应对增加的应力而维持腭部功能完整性的成骨反应。这些数据支持了机械负荷在决定现存和化石哺乳动物（如人科傍人）腭部形态，尤其是其内部结构方面的作用。此外，这些发现对哺乳动物次生硬腭的进化以及人类口腔病理学的临床考量具有潜在意义。
