ANATOMY

Detailed explanation-1: -Hertwig epithelial root sheath is derived from the inner and outer enamel epithelium of the enamel organ.

Detailed explanation-2: -The Hertwig’s epithelial root sheath (HERS) is a bilayer epithelial sheath originated from the apical region of the enamel organ [5]. As for the process of tooth root development, HERS plays an important role in guiding root formation and determining the size, shape, and number of tooth roots [6].

Detailed explanation-3: -Hertwig’s Epithelial Root Sheath (HERS) was first discovered as a bi-layered cell sheath surrounding the roots of amphibian teeth (e.g. in Triturus and Salamandra)(Hertwig, 1874). HERS descends from the oral epithelium and the enamel organ to form a collar around the cervical part of the amphibian tooth root (Fig.

Detailed explanation-4: -The reduced enamel epithelium, sometimes called reduced dental epithelium, overlies a developing tooth and is formed by two layers: a layer of ameloblast cells and the adjacent layer of cuboidal cells (outer enamel epithelium) from the dental lamina.

Detailed explanation-5: -Hertwig’s epithelial sheath is the origin of the epithelial rests of Malassez (ERMs) and contributes to the growth of roots. ERMs are considered to participate in the development of radicular cysts.