Histology Of The Pulp Revision PDF

Histology of the pulp Neural crest cells Ectomesenchyme cells Lamina propria Pulp Cementum Periodontal Alveolar bone Odontoblasts ligament...

Histology of the pulp Neural crest cells Ectomesenchyme cells Lamina propria Pulp Cementum Periodontal Alveolar bone Odontoblasts ligament Dentine  Roof of pulp Pulp horn Coronal pulp Floor of pulp Pulp cavity Root pulp Apical foramen Cells: Composition Odontoblasts, fibroblasts, Highly vascular, soft connective tissue. undifferentiated cells & defence 75-80% water cells. 20-25% organic material; cells and Extracellular matrix: extracellular matrix. Fibres, ground substance, nerves, blood & lymph vessels. Structural composition - 4 different zones 1. Odontoblast zone - periphery of the pulp. 2. Cell free zone - space between zones, only a few fibres. 3. Cell rich zone - contains all cells, except odontoblasts. 4. Pulp core - contains blood vessels, nerves and some cells. Pulp - Cells Odontoblasts - Line periphery in odontogenic zone of pulp. Process extends into dentine. Perform dentinogenesis. Communicate senses. Fibroblasts - Most prevalent in cell rich zone. Supporting structure of pulp. Form and maintain extracellular matrix of collagen and ground substance. Very active in young pulps and reduces as pulp shrinks. Undifferentiated cells - Found in cell rich zone and pulp core. Don’t have final purpose yet. Ectomesenchymal cells - differentiate into odontoblasts and fibroblasts. Mesenchymal stem cells (MSC) - differentiate into various cells. Defence cells - Numerous located in pulp core. Macrophages, T-lymphocytes, B- lymphocytes , Dendritic cells. Some leukocytes increase during infection. Pulp - Extracellular matrix Fibres of collagen - Greatest concentration at apical pulp. Principally type I and III - increase with age. Ground substance - Loose connective tissue. Supports cells. Consists of glycosaminoglycogens, glycoproteins & water. Blood & lymph supply - Nerves Lymph Blood Supply circulation and found in pulp core. Enter and exit through apical foramen along with nerve supply. Some may access though accessory foramina. Largest vessels, arterioles and venules, branch into extensive capillary network in coronal pulp. Nerves - Richly supplied. Enter through apical foramen, follow same course as blood and lymph to pulp core. Enables pulp to recognise stimuli and trigger defence response. Nerve Plexus of Raschkow found just beneath cell free zone. Most end as free nerve endings, some continue to end between odontoblasts into dentinal tubules. Myelinated and unmyleinated. Sensory afferent nerves - trigeminal nerve, enable pain perception. Sympathetic nerve - branches from superior cervical ganglion, regulate blood flow.  Anomalies Clinical significance Formative Circulation -Developmental disruptions can lead to -Ingress of bacteria to pulp -Ability to continue -Able to receive required nutrients and break in Hertwig’s epithelial root sheath. if exposed. forming dentinogenesis. removed waste products. -Distruption in odontogenesis leads to -Periodontal and -Provides vitality to tooth. formation of accessory root canals. endodontic issues. Functions Clinical significance -Reduced cell content. Accessory canals Protective -Less space due to mineralised stones. -Respond to stimuli -Challenge for RCT. received; perceived as pain. -Triggers defence cells and Pulp stones Functions & clinical relevance inflammatory response. Anomalies -Small calcified areas of tissue found in pulp. Ectomesenchymal -Free or attached to dentine. cells in central ALL reduce pulp Deposition of Inflammation dental papilla form ability to respond & secondary repair. Irreversible pulpitis -In response to stimuli coronal pulp tissue. or injury. dentine -Limited room for swelling/inflammation. Impacts -Can lead to necrosis of Size reduction -Reduction circulation Reversible pulpitis pulp. -Reduced innervation -Reduces size of -Early stage of -VERY painful. -Fewer odontoblasts pulp tissue and apical inflammation; can be foramen. -Increased fibres and collagen repaired and reversed.