About the protein and carbohydrates, Quizzes of Biochemistry

Download About the protein and carbohydrates and more Quizzes Biochemistry in PDF only on Docsity! CEMENT UM Dr. Hisham I. Wali M.Sc. Conservative Tooth Structure: Cementum - Enamel - Dentin + Dental Pulp What is Cementum? It is a specialized calcified avascular ectomesenchymal tissue that covers the anatomic tooth’s root 2 The physical, chemical, and structural characteristics of cementum are similar to those of compact bone. Unlike bone, cementum is avascular and non-innervated. Composition of cementum Inorganic 45- 50% by volume Calcium & phosphorus as hydroxyapatite crystals Organic 50- 55% by volume 95% Type Ι collagen 5% Type ΙΙ collagen 5 Physical propertiesPermeability Color Hardness Light Yellow Slightly lighter than dentin Slightly more permeable than dentin & bone 6 Formation of Cementum 7 Enamel pearls (Enameloma): a developmental anomaly in which a small nodule of enamel is formed near the cementoenamel junction, usually at the bifurcation zone of molar teeth. Formation of Cementum 10 Classification of cementum Acellular (Primary) Cementum Cellular (Secondary) Cementum Classification of cementum 11 Classification of cementum Acellular (primary) cementum 12 Cells of Cementum 15 Cells of Cementum Cementoblast Cementoblasts lay down cementum on the surface of root dentin 16 Cells of Cementum Cementocytes Some cementoblasts become embedded in the cellular cementum. These cells become cementocytes 17 20 Cemento-enamel junction (CEJ) Overlapping 60% Butt joint 30% Gapping 10% 21 Cemento-enamel junction (CEJ) About the classification of CEJ, does it have any clinical significance? Gapping 10% The exposure of root dentin at the cervical margin can lead to sensitivity at this site. It has also been alluded to that such morphology may result in increased risk for idiopathic root resorption and root surface caries. 22 Dentin Sharpeys Fibers Cementicles TUSTIN Pen Oe SMUT LCN AMOUR EAT PCO NC MUL RUE CROC MU rm em eal mC in the periodontal ligament. IN cee eC Seen le NM CULT HOO el OOS OT ip 28 Periodontal ligament (PDL) fibers perforate cementum & attach it to alveolar bone thus they keep the tooth in its socket Attachment Functions of Cementum 31 Reparative Cementum has the ability to reverse root resorption by the deposition of additional layers of cementum Functions of Cementum 32 Aging of Cementum Increased Roughness Increased Thickness Resorption 33 Increased Thickness Aging of Cementum The thickness of cementum increases with age due to the continuous deposition of cementum especially in the apical zone of the root Figure: Thick cementum on root apices of an older tooth. Cementum is deposited around apical foramen and is lining the pulpal wall near the apex, constricting the foramen 36 Aging of Cementum Resorption Cementum resorption is one characteristic of aging cementum. Resorption becomes active for a period and then may stop. Deposition of cementum occurs in that period, creating reversal lines. Resorption can also occur in root dentin, and cemental repair can cover this defect 37 THANK YOU 38