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Tooth and Its Supporting Tissues - Coggle Diagram
Tooth and Its Supporting Tissues
Microscopic structure of dental tissue
Enamel
Enamel Rod
Located in the cusps
Formed by the enamel crystals
Enter the tooth's surface from the dentinoenamel junction
Interrod Enamel
Located on the outside of the enamel rod
The interrod enamel crystals are oriented at an angle to those of the rod
The boundary between rod and interrod enamel is known as the rod sheath
Dentinoenamel Junction
Located between dentin and enamel
The convex side is on the dentin and the concave side is on the enamel
Enamel Lamellae
Lamellae extend from the surface of enamel toward the dentinoenamel junction
During enamel development, creating an organic pathway or tract.
Occur because of impact or temperature changes
Example: Spaces between groups of rods
Enamel Tufts
Shaped like a small, dark brush
Located at the dentinoenamel junction and appear at right angles
Form between groups of enamel rods
Dentin and enamel's contact is scalloped, and these scalloped peaks frequently generate tufts.
Enamel Spindles
Appear leaflike, extending around the crown
Occur at the dentinoenamel junction and extend into enamel.
Extensions of dentinal tubules that pass through the junction into enamel
Result of the odontoblast crossing the basement membrane.
Microscopic Structure - Dentin
Originates from ectomesenchyme → formed by odontoblasts derived from dental papilla
Formation of dentin is a lifelong process
Location : between pulp and external surface tissue
Color : yellowish, darkens as age advances
Elasticity : flexible. The peripheral layer makes it more resilient in depressing forces/stress → masticatory process
Permeability : highly permeable. Its permeability depends on patency of the tubules. When tubules are blocked, permeability decreases considerably.
Inorganic Components :
Calcium and phosphate (in the form of hydroxyapatite crystals
Primary Dentin : formed until the root formation is completed
Microscopic Structure - Pulp
The tooth's deepest layer, which houses the nerves and blood vessels
Dental pulp fills the core pulp cavity of each tooth and is an unmineralized oral tissue made up of soft connective tissue, vascular, lymphatic, and neurological components.
The texture of pulp is gelatinous and soft.
Histological Appearance
Odontoblastic Zone :
Made of odontoblasts
Cells that are in charge of dentinogenesis
Most peripheral zone of pulp
Cell Free zone of Weil : Rich in capillaries Located below the odontoblasts & Significant in the coronal pulp
Classification according its anatomy
Coronal Pulp
Radicular Pulp
Periodontal Ligament
Made up of bundles of collagenous fibers that each include hundreds/thousands of collagen fibril
Periodontal ligament fibroblasts synthesize and maintain the collagen fibrils and other extracellular matrix elements
Sharpey’s fibers are embedded in cementum on the root and in the alveolar bone confronting
Cementum – Histology
Cementum is a hard tissue part of periodontium that attaches the teeth to alveolar process by anchoring periodontal ligament
Usually not visible in healthy patient since it covers entire root, overlying tomes granular in dentin
Avascular (without blood vessels) and no nerve supply
Sharpey Fibers
Collagen fibers from the PDL that are partially inserted into the outer surface of cementum (90° or perpendicular angle); the other end is inserted to alveolar process.
Types
Acellular Extrinsic Fiber
Cellular Intrinsic Fiber
Cellular Mixed Stratified
Acellular Afibrillar
Alveolar Bone
Portion of maxilla and mandible that forms and supports the tooth sockets (alveoli) Forms when tooth erupts to provide osseous attachment to PDL
Tooth dependent bony structure
Morphology determined by size, shape, function and location of teeth
Formed during fetal growth by intramembranous ossification
Enamel
Function
Toughest biologic tissue within the body
Protective outer layer, coats tooth crown
Shapes & contours tooth crowns, coats part of the tooth exposed to oral environment
Composition
Interlocking rods, withstand masticatory forces.
Ameloblasts travel in different directions --> causes rods to bend.
In incidental light, enamel rod look like dark & light bands of rod groups = Hunter-Schreger bands.
All enamel rods are placed at a daily appositional rate of 4 mm increments.
Growth lines appear on the enamel surface as ridges = perikymata
Dentin
Composition: Dentin is approximately 55 vol% mineral, 30 vol% organic material (primarily type I collagen), and 15 vol% fluid, but dentin composition varies with the age and tooth type.
Properties: By volume, 45% of dentin consists of the mineral hydroxyapatite, 33% is organic material, and 22% is water.
Function: Its primary function is to support the structure of enamel. Due to its softer texture than enamel, it helps in absorbing the pressure from eating.
Tooth Supporting tissues
Consist of the :
cementum -> mineralized tissue that covers the root dentin
Periodontal ligament (PDL) -> structure that attaches to and holds the tooth in its socket (alveolus)
Alveolar bone -> forms the alveolus using the portion of the jaw
Gingivae -> portion of the oral mucosa adjacent to the teeth
Vascular
PULP VASCULARIZATION
The establishment of a network forming the rudiment of vessels occurs as the crown develops as a result vascular cells penetrating the tooth germ at the late bell stage.
Single CD34+ cells
generating vascular cords inside the growing connective tissue are the origin of pulp vascularization
A Capillary Network
fills the pulp's periphery during root formation, whereas arterioles and venules are found in the pulp's center.
Following post-capillary venules, pre-capillaries continue in continuity with capillaries.
Pericutes are embedded in here
Tissue engineering
A field which combines the engineering and life science concepts
Acid etching process → to remove plague, continued by the remineralization of enamel
Growth factors → critical factor for regeneration process
Clinical implications
Enamel regeneration
Dentin regeneration
Pulp regeneration