Objective To observe the morphology and proliferation of epithelial cell rests of Malasse（z ECRM） during tooth emergence and occlusal function, and to evaluate its roles. Methods Cytokeratin 14 （ CK14） was applied as special marker of ECRM cells. The morphology and distribution of ECRM were examined by light and transmission electron microscopy. PV two- step immunohistochemical method was used to detect the expression of CK14 and proliferating cell nuclear antige（n PCNA）in ECRM. Results ECRM experienced instinct morphological changes during tooth emergence and occlusal function. They were observed as network of epithelial cells labeled by CK14, especially in furcation level regions of mouse molars and active cell proliferation during occlusion found period. Cell apoptosis was observed in many ECRM by transmission electron microscopy during late stage of the progess. Conclusion ECRM may not only an accidental left- over of early embryonic development but rather play significant roles in occlusion found period.
