Epithelial cell rests of Malassez explained

In dentistry, the epithelial cell rests of Malassez (ERM) or epithelial rests of Malassez (pax epithelialis pediodontii) are part of the periodontal ligament cells around a tooth. They are discrete clusters of residual cells from Hertwig's epithelial root sheath (HERS) that didn't completely disappear. It is considered that these cell rests proliferate to form epithelial lining of various odontogenic cysts such as radicular cyst under the influence of various stimuli. They are named after Louis-Charles Malassez (1842–1909) who described them. Some rests become calcified in the periodontal ligament (cementicles).

ERM plays a role in cementum repair and regeneration.^[1] The stem cells in ERM can undergo an epithelial–mesenchymal transition and differentiate into diverse types of cells of mesodermal and ectodermal origin like bone, fat, cartilage and neuron-like cells.^[2]

Further reading

• Ten Cate . A.R. . The epithelial cell rests of Malassez and the genesis of the dental cyst . Oral Surgery, Oral Medicine, Oral Pathology . December 1972 . 34 . 6 . 956–964 . 10.1016/0030-4220(72)90233-2 . 4509005 .
• Xiong . Jimin . Mrozik . Krzysztof . Gronthos . Stan . Bartold . P. Mark . Epithelial Cell Rests of Malassez Contain Unique Stem Cell Populations Capable of Undergoing Epithelial–Mesenchymal Transition . Stem Cells and Development . 20 July 2012 . 21 . 11 . 2012–2025 . 10.1089/scd.2011.0471 . 22122577 . 3396154 .
• Ohshima . Mitsuhiro . Yamaguchi . Yoko . Micke . Patrick . Abiko . Yoshimitsu . Otsuka . Kichibee . In Vitro Characterization of the Cytokine Profile of the Epithelial Cell Rests of Malassez . Journal of Periodontology . May 2008 . 79 . 5 . 912–919 . 10.1902/jop.2008.070553 . 18454671 .
• Shinmura . Yuka . Tsuchiya . Shuhei . Hata . Ken-ichiro . Honda . Masaki J. . Quiescent epithelial cell rests of Malassez can differentiate into ameloblast-like cells . Journal of Cellular Physiology . December 2008 . 217 . 3 . 728–738 . 10.1002/jcp.21546 . 18663726 .
• Li . S. . Ge . S. . Yang . P. . Expression of cytokeratins in enamel organ, junctional epithelium and epithelial cell rests of Malassez . Journal of Periodontal Research . December 2015 . 50 . 6 . 846–854 . 10.1111/jre.12272 .
• Yamanaka . Takenori . Sakamoto . Akihiko . Tanaka . Yoshiharu . Zhang . Yan . Hayashido . Yasutaka . Toratani . Shigeaki . Akagawa . Yasumasa . Okamoto . Tetsuji . Isolation and serum-free culture of epithelial cells derived from epithelial rests of Malassez in human periodontal ligament . In Vitro Cellular & Developmental Biology - Animal . 2000 . 36 . 8 . 548 . 10.1290/1071-2690(2000)036<0548:IASFCO>2.0.CO;2 .
• Davis . Eric M. . A Review of the Epithelial Cell Rests of Malassez on the Bicentennial of Their Description . Journal of Veterinary Dentistry . December 2018 . 35 . 4 . 290–298 . 10.1177/0898756418811957 .
• Hasegawa . Naohiko . Kawaguchi . Hiroyuki . Ogawa . Tetsuji . Uchida . Takashi . Kurihara . Hidemi . Immunohistochemical characteristics of epithelial cell rests of Malassez during cementum repair . Journal of Periodontal Research . February 2003 . 38 . 1 . 51–56 . 10.1034/j.1600-0765.2003.01636.x . 12558937 .

Notes and References

1. Rincon . J. C. . Young . W. G. . Bartold . P. M. . The epithelial cell rests of Malassez – a role in periodontal regeneration? . Journal of Periodontal Research . August 2006 . 41 . 4 . 245–252 . 10.1111/j.1600-0765.2006.00880.x . 16827716 .
2. Xiong . Jimin . Gronthos . Stan . Bartold . P. Mark . Role of the epithelial cell rests of M alassez in the development, maintenance and regeneration of periodontal ligament tissues . Periodontology 2000 . October 2013 . 63 . 1 . 217–233 . 10.1111/prd.12023 . 23931062 .