The growth of plants, animals, and humans can give rise to layered structures associated with annual periodicity. Thickness variations are often correlated to nutrition supply and stress factors. The annual layers in a tree trunk with millimeter thickness can be directly counted, whereas the layers in tooth cementum with micrometer thickness are made visible using optical microscopy. These optical techniques rely on the surface evaluation or thin, optically transparent slices. Hard Xray tomography with micrometer resolution, however, provides a three-dimensional view without physical slicing. We have developed a procedure to enhance the tomography data of annual layers in human and bovid tooth cementum. The analysis of a substantial part of an archeological human tooth demonstrated that the detected number of layers depended on the selected region and could vary between 13 and 27. The related average thickness of the annual layers was found to be (5.4 ± 1.9) µm for the human tooth, whereas the buffalo tooth exhibited a layer periodicity of 46 µm. The present study elucidates the potential of combining computational tools with high-quality micro computed tomography data to quantify the annual layers in tooth cementum for a variety of purposes including age-at-death determination.
Background: Common surgical techniques aim to turn the entire vomerine mucosa with vomer flaps either to the oral side or to the nasal side. The latter approach is widely performed due to the similarity in color to the nasal mucosa. However, we lack a histologic description of the curved vomerine mucosa in cleft lip and palate malformations. Methods: We histologically examined an excess of curved vomerine mucosa in 8 patients using hematoxylin–eosin, periodic acid–Schiff, Elastin van Gieson, and Alcian blue stains. Tissue samples were obtained during surgery at 8 months of age. Results: Our histological analysis of the mucoperiosteum overlying the curved vomer revealed characteristics consistent with those of an oral mucosa or a squamous metaplasia of the nasal mucosa, as exhibited by a stratified squamous epithelium containing numerous seromucous glands. Some areas showed a palisaded arrangement of the basal cells compatible with metaplasia of respiratory epithelium, but no goblet cells or respiratory cilia were identified. Abundant fibrosis and rich vascularity were present. Conclusion: The vomer mucosa showed no specific signs of nasal mucosa. These findings should be considered in presurgical cleft orthopedics and palatal surgery for further refinement. Shifting the vomer mucosa according to a fixed physiologic belief should not overrule other important aspects of cleft repair such as primary healing and establishing optimal form and function of palatal roof and nasal floor.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.