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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Area of Rests of Malassez in Young and Adult Rat Molars: Evidences in the Formation of Large Rests

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Author(s):
Cerri, Paulo Sergio [1] ; Goncalves, Jakobe De Souza [1] ; Sasso-Cerri, Estela [1]
Total Authors: 3
Affiliation:
[1] Sao Paulo State Univ, UNESP, Sch Dent, Dept Morphol, Lab Histol & Embryol, BR-14801903 Araraquara, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology; v. 292, n. 2, p. 285-291, FEB 2009.
Web of Science Citations: 7
Abstract

Recently, we have demonstrated that the reduction in the number of rests of Malassez (RM) according to age may be due to epithelial cell death by apoptosis. It is known that, under experimental or pathological conditions, the epithelial cells of RM can proliferate, resulting in the formation of odontogenic cysts and tumors. In this study, the area of RM profiles and the number of profiles of epithelial cell nuclei/RM were investigated in young and adult rats. Fragments containing upper molars of rats aged 29, 45, and 120 days were fixed, decalcified, and embedded for light microscopy. In the sections stained by hematoxylin and eosin, the numerical density of RM profiles/mm(2) of periodontal ligament, the area of each RM profile and the number of epithelial cell nuclei profile/RM were obtained. Moreover, detection of cytokeratin by immunohistochemistry and ultrastructural analysis of RM were carried out. Smaller RM were found in all groups, but the very large RM were only observed in the 120-day-old rats. The presence of cells in close juxtaposition exhibiting cytokeratin filaments in their cytoplasm, including in the large RM, characterized their epithelial nature. The number of epithelial cells/RM varied proportionally to the area. Moreover, epithelial cells in mitosis were found in small and large RM, indicating that cellular proliferation can be responsible for the enlargement of RM, under physiological conditions. The results suggest that a possible disequilibrium between the proliferative and apoptotic processes can be related to the enlargement of some RM in the 120-day-old rats. Anat Rec, 292:285291, 2009. (C) 2008 Wiley-Liss, Inc. (AU)