Histological structure of the human and rodent periodontium

摘要

Adult human dental tissue and young rat jaws with developing teeth were in TRACT -vestigated. The tissues were fixed by immersion in 4% buffered paraformaldehyde. Decalcifiedtissues were embedded into paraffin or sectioned on a freezing microtome. Paraffin sectionswere stained with hematoxylin and eosin. Frozen sections were stained with calcitonin generelatedpeptide (CGRP) antibodies using avidin-biotin systems and peroxidase labelling. Thehistology of the acellular cement and the histology of the periodontal ligament were analyzedand the course of the Sharpey-fibers and the epithelial rests of Malassez were described in humansamples. The epithelial sheath of Hertwig in developing rat maxillae and mandibles (postnataldays 1-11) were depicted. The layers of the Hertwig-sheath were described. We observed thenumerical increase of CGRP-stained nerve fibers during these postnatal days. The CGRP-stainednerve fibers appeared before the development of the dental root indicating the presence ofgrowth factors which guide the sensory axons. We hypothesize that the epithelial sheath ofHertwig plays essential role in the development of cementoblasts, periodontal fibroblasts andalveolar osteoblasts. Furthermore, the growth factors secreted by the Hertwig-sheath maystimulate the axonal growth, too.