tooth development, formation of enamel root formation, hertwing epithelial root sheath development of the enamel ,dentin, pulp ,root . preparation of NEET MDS • AMELOGENESIS • The preameloblasts differentiate into tall columnar epithelial cells with their nuclei polarized toward the stratum intermedium –Ameloblast • The inner enamelepithelium is being resorbed and dentin is being deposited to follow the contour established by the basement membrane. This process forms the future dentinoenamel junction • The deposition of enamel matrix causes the ameloblasts to migrate peripherally and form conic projections – Tomes process • This maturation process begins in the dentinoenamel junction and progresses peripherally to the enamel surface. • During the final phase of the maturation process, the ameloblasts join the stratified epithelium to form the reduced enamel epithelium and to cover and protect the enamel until eruption of the tooth. • DEVELOPMENT OF THE ROOT • Outer and inner enamel epithelia proliferate to form the HERS(Hertwig’s Epithelial Root Sheath) • Hertwig’s epithelial root sheath- which determines the size and shape of the root of the tooth. • the Hertwig’s epithelial root sheath proliferateshorizontally between the dentinal papilla and the dentalfollicle; this process partially encloses the dental papilla anddelineates the apical foramen or foramina. This proliferationis called the epithelial diaphragm. • In multirooted teeth, the epithelial diaphragm guides the formation of the furca, roots, root canals, and apical foramina. • CEMENTOBLAST • These mesenchymal cells differentiate into cementoblasts, which are round, plump cells that have basophilic cytoplasm. • The cell rests of Malassez remain dormant in the mature PDL and have the potential of proliferating into periradicular cysts if stimulated by chronic inflammation. • Accessory canals are more prevalent in the apical third of the root.

1.  AMELOGENESIS
 The preameloblasts differentiate into tall columnar epithelial cells with their nuclei polarized toward the
stratum intermedium –Ameloblast
 The inner enamelepithelium is being resorbed and dentin is being deposited to follow the contour
established by the basement membrane. This process forms the future dentinoenamel junction
 The deposition of enamel matrix causes the ameloblasts to migrate peripherally and form conic projections
– Tomes process
 This maturation process begins in the dentinoenamel junction and progresses peripherally to the enamel
surface.
 During the final phase of the maturation process, the ameloblasts join the stratified epithelium to form the
reduced enamel epithelium and to cover and protect the enamel until eruption of the tooth.
 DEVELOPMENT OF THE ROOT
 Outer and inner enamel epithelia proliferate to form the HERS(Hertwig’s Epithelial Root Sheath)
 Hertwig’s epithelial root sheath- which determines the size and shape of the root of the tooth.
 the Hertwig’s epithelial root sheath proliferateshorizontally between the dentinal papilla and the
dentalfollicle; this process partially encloses the dental papilla anddelineates the apical foramen or
foramina. This proliferationis called the epithelial diaphragm.
 In multirooted teeth, the epithelial diaphragm guides the formation of the furca, roots, root canals, and
apical foramina.
 CEMENTOBLAST
 These mesenchymal cells differentiate into cementoblasts, which are round, plump cells that have
basophilic cytoplasm.
 The cell rests of Malassez remain dormant in the mature PDL and have the potential of proliferating into
periradicular cysts if stimulated by chronic inflammation.
 Accessory canals are more prevalent in the apical third of the root.