ROOT FORMATION 2023-2024 PDF

Morphological stages of tooth development 1- Dental lamina. 2- Bud stage. 3- Cap stage. 4- Bell stage A- Early bell stage. B- Late bell stage.  Late bell stage Dental Dental...

Morphological stages of tooth development 1- Dental lamina. 2- Bud stage. 3- Cap stage. 4- Bell stage A- Early bell stage. B- Late bell stage.  Late bell stage Dental Dental Enamel organ lamina Outer enamel epithelium papilla Inner enamel epithelium & Stellate reticulum Dental sac Stratum intermedium Cervical loop  Reduced enamel epithelium After the crown thickness is fully formed the layers of the enamel organ get compressed in few layers where its hard to identify IEE from OEE from stratum or stellate. The whole thickness of the cells collapses or get reduced and turn into what is known as reduced enamel epithelium that protects the crown till eruption. Reduced enamel epithelium  Root Formation Two types of roots are formed: 1-Single root formation 2-Multiple root formation  Single Root Formation The start point for root formation is that enamel and dentin reach the future level of cemento-enamel junction or simply the cervical line or crown neck  1- Epithelial diaphragm. The part of the crown that starts the process for root formation is the cervical loop at the cervical line or crown neck level begins to proliferate to form Epithelial diaphragm. Cervical loop The elongated cervical loop is now called the epithelial diaphragm Cervical loop Epithelial diaphragm Primary closure The cells cervical loop ( IEE & OEE) proliferate obliquely together in a central direction aiming to reduce the cervical opening of the crown. This will prepare the tooth to form a future apical foramen called primary closure. Epithelial diaphragm Reduction of the wide cervix to give apical foramen primary closure  2- Epithelial Root sheath of Hertwig (ERSH) It is a bilayered enamel epithelial structure following crown formation. Proliferates in coronal direction Epithelial root sheath of Hertwig 3- Differentiation Of Odontoblasts 4- Dentin Formation TF DP TF DP 5-Degeneration of Hertwig Fate of ERM??????? TF DP Epithelial rests of Malassez (ERM) 6– Cementoblast differentiation 7-Cementum Deposition 8- Fibroblast differentiation 9- Periodontal fibers assembly Cementoblast Cementum TF DP Lateral periodontal Cyst Single root formation MULTI-ROOT FORMATION Tongue Like Extensions Epithelial diaphragm Epithelial diaphragm Cervical loop Root Epith. Diaphragm& 1ry closure Formation Epith. root sheath of Hertwig sequence of coronal growth events Odontoblast differentiation Dentin formation Disintegration of root sheath Cementoblast & fibroblast differentiation CLINICAL CONSIDERATIONS ACCESSORY ROOT CANAL  ACCESSORY ROOT CANAL *Root sheath degenerates before odontoblast differentiation * Failiure of fusion of tongue like extension * Blood vessels in place Abscess may be related to the accessory root canal due to failure of its cleaning in root canal treatment  INTERMEDIATE CEMENTUM *Root sheath degenerates CEMENTUM after odontoblast differentiation And before dentin formation And creates a layer in between not DENTIN related to dentin nor cementum * If root sheath remain adherent to dentin surface for longer than it should be Bare Enamel dentin Pearl ENAMEL PEARL Enamel pearl cause Remember Fate of dental lamina Fate of ERM Fate of reduced (collapsed) enamel organ cells Thank you