Search results
Results from the WOW.Com Content Network
The sheath is also responsible for multiple or accessory roots (medial growth) and lateral or accessory canals in the root (break in epithelium). [3] It is controversial, but HERS may be involved in cementogenesis and the secreting of cementum, or that HERS-derived products might be related to enamel-related molecules, and that these proteins might initiate acellular cementum formation.
For cementogenesis to begin, Hertwig epithelial root sheath (HERS) must fragment. HERS is a collar of epithelial cells derived from the apical prolongation of the enamel organ. Once the root sheath disintegrates, the newly formed surface of root dentin comes into contact with the undifferentiated cells of the dental sac (dental follicle).
Root sheath may refer to any of these biological structures: Epithelial root sheath, a proliferation of epithelial cells located at the cervical loop of the enamel organ in a developing tooth; Root sheath (hair), at the base of a hair follicle Inner root sheath; Outer root sheath; Seed root sheath, root sheaths in the seeds of plants
The inner root sheath (IRS) consists of: a delicate cuticle next the hair, composed of a single layer of imbricated scales with atrophied nuclei; Huxley's layer; Henle's layer; The term "trichilemmal" refers to the outer root sheath. [2] The IRS functions to mould, adhere, as well as participate in the keratinization of growing hair. [3]
The sheath is irregularly fragmented in time and space as it promotes cementum deposition on the newly formed dentin. After this fragmentation, Hertwig's epithelial root sheath also participates in cementogenesis and formation of the periodontal ligament, giving rise to the epithelial rests of Malassez
The mechanism of differentiation of the cementoblasts is controversial but circumstantial evidence suggests that an epithelium or epithelial component may cause dental sac cells to differentiate into cementoblasts, characterised by an increase in length. [1] Other theories involve Hertwig epithelial root sheath (HERS) being involved. [2]
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.
The outer root sheath or external root sheath of the hair follicle encloses the inner root sheath and hair shaft. [1] It is continuous with the basal layer of the interfollicular epidermis (skin) . See also