Collaborative Research: Normal and pathological covariation in the masticatory apparatus of anthropoid primates

研究人员将研究灵长类动物的头骨和颌骨解剖学，以更好地了解咀嚼系统的解剖学组成部分（牙齿、颌骨和相关关节）如何协同工作，以及这些组成部分如何受到衰老和病理变化的影响。虽然咀嚼系统的组成部分被认为是作为一个整体一起工作的，但之前对该系统的分析通常是将特定的组成部分与解剖学的其余部分隔离开来，从而提供了解剖学相互关系的不完整图景。该项目将探讨在个体一生中可能发生的变化（如正常和病理性牙齿磨损、正常和异常（如关节炎）的颞下颌关节（TMJ）形状变化）的背景下，不同的解剖成分如何在整个咀嚼系统中相互关联。在齿列和颞下颌关节中使用三维建模来量化解剖相关性，将允许对骨骼咀嚼系统进行新的解释，并提高对灵长类动物不同摄食行为和饮食相关的进化压力的理解。确定多种非人类物种的TMJ病理是否与牙齿磨损和病理共同变化，将为人类中非常常见的牙齿和TMJ疾病提供进化背景。本研究的更广泛影响包括，通过为主要教育第一代大学生和少数民族学生的大学的本科生提供研究机会，鼓励科学领域的性别和种族多样性；支持3名早期职业女性科学家的研究；培养一名研究形状变化捕获和分析先进技术的博士后；建立一个大型3D数据数据库，供人类学和生物医学研究人员使用，并可为人类牙齿问题的临床研究提供信息；并开展社区外展活动，进一步传播调查结果，帮助公众对STEM研究产生兴趣。由于饮食和生存模式的变化往往是主要进化转变的根源，记录和理解咀嚼系统在人类进化过程中的适应意义，以及在现存灵长类动物中，一直是生物人类学功能形态学研究的主要目标。咀嚼系统作为一个单一的功能单元，因此，该系统的一个部分的扰动可能会影响解剖学的其他区域；因此，与年龄相关的咀嚼器官的变化和病理状况可能是多因素的，并影响整个系统。通过详细评估牙齿和TMJ的形态以及牙列和TMJ之间的协方差，本研究研究了包括人类在内的16个类人猿灵长类类群的正常和病理牙齿磨损和TMJ重塑。具体目的包括检测上颌牙和下颌牙、颞下颌关节的颅部和下颌部成分、牙齿和颞下颌关节以及牙齿和颞下颌关节病理之间的共变。牙列和颞下颌关节的形状变化将使用先进的形态测量技术进行量化，包括3D地标和表面数据。标本将根据已公布的死前牙齿脱落、牙齿磨损、牙髓腔暴露和TMJ骨关节炎的病理标准进行评估。通过确定人类和非人类灵长类动物的TMJ病理是否与牙齿磨损和病理相关，本研究将为灵长类动物摄食行为和人类TMJ疾病的进化提供一个进化背景。鉴于现代人生前牙齿脱落和颞下颌关节疾病的高患病率，该研究具有公共卫生相关性。由此产生的数据和分析将与各种领域相关，包括公共卫生、牙科、生物力学/运动学、喂养生态学、功能形态学和哺乳动物进化。

The investigators will study skull and jaw anatomy in primates, to better understand how the anatomical components of the chewing system (teeth, jaws, and related joints) work together and how these components are affected by aging and pathological changes. Although the components of the masticatory (chewing) system are known to work together as a unit, previous analyses of this system have typically examined specific components in isolation from the rest of the anatomy, providing an incomplete picture of anatomical interrelationships. This project will address how the different anatomical components are correlated with each other across the entire masticatory system, in the context of changes that may occur during the lifetime of an individual, such as normal and pathological dental wear, and normal and abnormal (e.g. arthritis) changes in temporomandibular joint (TMJ) shape. Quantifying anatomical correlations using three-dimensional modeling in the dentition and TMJ will allow for new interpretations of the skeletal masticatory system and an improved understanding of the evolutionary pressures associated with different feeding behaviors and diets across primates. Determining whether TMJ pathology covaries with dental wear and pathology in multiple non-human species will provide an evolutionary context for dental and TMJ disorders that are very common in humans. The broader impacts of this research include encouraging gender and ethnic diversity in science by providing research opportunities for undergraduate students at universities that primarily educate first generation college and minority students; supporting the research of three early career female scientists; training a postdoctoral researcher in advanced techniques for capturing and analyzing shape variation; building a large database of 3D data that will be available to both anthropological and biomedical researchers and that may inform clinical studies of dental problems in humans; and conducting community outreach that will further disseminate the results of this investigation and help generate public interest in STEM research. Because changes in diet and subsistence patterns often lie at the root of major evolutionary shifts, documenting and understanding the adaptive significance of the masticatory system during human evolution, as well as across living primates, has been a major goal of functional morphological studies in biological anthropology. The masticatory system acts as a single functional unit, such that perturbations in one portion of this system may affect other regions of anatomy; thus, age-related changes and pathological conditions of the masticatory apparatus are likely to be multifactorial and affect the entire system. Through a detailed assessment of dental and TMJ morphology and covariance between the dentition and the TMJ, this study examines both normal and pathological dental wear and TMJ remodeling in 16 anthropoid primate taxa, including humans. The specific aims include testing for covariation between the maxillary and mandibular teeth, the cranial and mandibular components of the TMJ, the teeth and TMJ, and dental and TMJ pathologies. Shape variation in the dentition and TMJ will be quantified using advanced morphometric techniques, including 3D landmark and surface data. Specimens will be assessed for pathology using published criteria for antemortem tooth loss, tooth wear, pulp cavity exposure, and TMJ osteoarthritis. By determining whether TMJ pathology covaries with dental wear and pathology in humans and non-human primates, this research will provide an evolutionary context for the evolution of primate feeding behaviors and of TMJ disorders in humans. The research has public health relevance, given the high prevalence of antemortem tooth loss and TMJ disorders in modern human populations. The resulting data and analyses will be relevant to a variety of fields including public health, dentistry, biomechanics/kinematics, feeding ecology, functional morphology, and mammalian evolution.