PULP-Theory class.ppt
- 2. Pulp Mesenchyme connective tissue that occupies pulp cavity in the central part of the teeth Surrounded by dentin on all sides except at the apical foramen & accessory canal openings
- 3. There are a total of 32 pulp cavities in the adult dentition. The pulp cavities of molar teeth are approximately four times larger than those of incisors. The pulp cavity extends down through the root of the tooth as the root canal which opens into the periodontium via the apical foramen. The blood vessels, nerves etc. of dental pulp enter and leave the tooth through this foramen. Pulp Cavity
- 5. Pulp tissue removed during endodontic therapy by a size 20 broach file
- 6. Pulp 32 (permanent) + 20 (primary) = 52 Pulp organs Total volumes of perm. teeth pulp organs = 0.38 cc Mean volume of a single adult human pulp = 0.02 cc Molar pulps are 3-4 times larger than incisor pulps
- 7. DEVELOPMENT Formed by dental papilla. Odontoblasts – neural crest origin (ectodermal). Other pulpal cells - mesenchymal origin. Immature dendritic cells appear in and around the odontoblastic layer at early stage. First layer of dentin deposited- dental papilla becomes dental pulp. Numerous fibroblasts-remain closely packed, are stellate shaped with large nucleus and little cytoplasm and lay down fine collagen fibres.
- 8. DEVELOPMENT Developing pulp has high GAG content. Chondroitin sulphate is higher with little hyaluronan, while opposite is true for mature pulp. Enamel organ extends as HERS and determines final morphology of the space (pulp chamber and root canals). Once full length of roots is established, the developmental stage of dental pulp can be considered complete.
- 10. Coronal pulp Has pulp horns which are protrusions that extend into the cusps of each crown Number depends on the cuspal number Pulp becomes smaller with age
- 12. Radicular pulp Extends from the cervical region of the crown to the root apex Anterior teeth-single Posterior teeth-multiple Continuous with the periapical connective tissues through the apical foramen
- 13. Histology 4 zones: Odontoblastic zone Cell free zone of weil Cell-rich zone Pulp Core
- 15. • The peripheral aspect of dental pulp, referred to as the odontogenic zone , differentiates into a layer of dentin- forming odontoblasts . •Immediately subjacent to the odontoblast layer is the cell-free zone (of Weil). The cell-free zone of Weil is also called “sub-odontoblastic layer” or “Hoehl's layer.” •This region contains numerous bundles of reticular (Korff's) fibers . These fibers pass from the central pulp region, across the cell-free zone and between the odontoblasts, their distal ends incorporated into the matrix of the dentin layer. Numerous capillaries and nerves are also found in this zone. •
- 16. Just under the cell-free zone is the cell-rich zone containing numerous fibroblasts the predominant cell type of pulp. Fibroblasts of the pulp have demonstrated the ability to degrade collagen as well as form it. The pulp core zone comprises prominent blood vessels and nerves and is present below the cell rich zone.
- 19. Odontoblasts: Second most prominent cells of pulp palisade pattern of arrangement in the crown of the mature tooth Constant location adjacent to the predentin-odontogenic zone of the pulp Cell body in pulp & cell processes in the dentinal tubules Tall columnar in crown, cuboidal in middle of root & flat spindle shaped near the apex of tooth
- 21. Microvasculature of dental pulp:
- 23. Odontoblasts: Diameter -5-7micronm Length-25-40micronm Pulp-dentine interface-59,000-76,000 per square millimeter in coronaldentin with less in root Active cell-elongated ,basally placed nucleus & a basophilic cytoplasm Resting cell-stubby,little cytoplasm & haematoxyphilic nucleus Transitional stage-intermediate beteen active & resting stage
- 24. Odontoblasts: Undergo apoptotic cell death –shown by marker bcl-2 Release interleukin -8 Nitric oxide synthetase have been identified in odontoblasts
- 25. Fibroblasts: Cells occurring in greatest numbers in the pulp More in number in the coronal portion of pulp where they form the cell-rich zone Form &maintain the pulp matrix, which consists of collagen & ground substance
- 26. Fibroblasts: They function in collagen fiber formation In young pulp the cells divide & are active in protein synthesis In older pulp they appear rounded or spindle shaped with short processes & exhibit fewer intracellular organelles –fibrocytes
- 27. Fibroblasts: Immature pulp - cellular elements predominate Mature pulp - fibrous components predominate Dual function; In addition to forming the pulp matrix, capable of ingesting °rading the same matrix
- 28. Fibroblasts…. Secrete angiogenic factors like FGF-2 & VEGF Secrete colony stimulating factor In cell culture on stimulation form mineralized tissue
- 30. Macrophages Oval or spindle shaped Macrophages are present in the normal dental pulp & are more dense around the blood vessels of the inner pulp & around the odontoblast layer
- 31. Dendritic cells: Bone marrow- derived, antigen presenting dendrite cells are found in & around the odontoblast layer in nonerupted teeth & in erupted teeth beneath the odontoblast layer Function is similar to Langerhans cells in that they capture & present foreign antigen to the T cells
- 32. Dendritic cells: Participate in immunosurveillance & increase in number in carious teeth Dendritic cells & macrophages constitute some 8% of the total cell population, with dendritic cells exceeding macrophages
- 33. Undifferentiated ectomesenchymal cells Totipotent cell Depending upon the stimulus these cells may give rise to odontoblasts , fibroblasts or macrophages. Represent the pool from which connective tissue cells of the pulp are derived
- 34. Matrix & ground substance Collagen-typeI & typeIII Ground substance composed of glycosaminoglycans, glycoproteins & water Ground substance lend support to the cells of the pulp& also serve as transport medium of nutrients from the blood vessels to the cells & transport of metabolites from cells to blood vessels
- 35. Pulpal stem cells Migrate to the site of injured odontoblasts & produce dentin TGF beta 1 & BMP-2 involved in the migration of stem cells Pluripotent-adipocytes & neural cells
- 36. Pulpal stem cells Produce dentinogenesis & osteogenesis Dentin sialoprotein present Dentonin stimulate dental pulp stem cell Pulp tisue of 3rd molars - viable after cryopreservation
- 37. Functions of pulp 1. Inductive: interact with oral epithelial cells leading to differentiation of dental lamina & enamel organ formation 2. Formative: formation of dentin 3. Sensory: sensation of tooth is felt through the nerves of the pulp
- 38. Functions of pulp 4. Nutritive: supplies nutrition to the dentin through blood vessels & odontoblastic processes & maintain the vitality of tooth 5. Defensive or reparative: protects it self & vitality of the tooth by producing reparative dentin
- 39. Blood vessels of the dental pulp: Supply oxygen & nutrients where they are most needed during dentinogenesis Pulpal blood flow- 1.in arterioles-0.3to1mm/sec 2.In venules-approx.0.15mm/sec 3.In capillaries-approx.0.08mm/sec Arise from inferior or superior alveolar artery
- 40. Blood vessels of the dental pulp: Pericyte lies on the surface of vessels Arterio-venous shunts regulate blood flow Blood capillaries – 8-10microm in diameter Fenestrated capillaries-rapid transport of metabolites during dentinogenesis
- 43. Nerves of the dental pulp Nerves enter pulp through apical foramen, along with afferent blood vessels & together form the “neuro- vascular bundle” Nerve bundles that enter the pulp consists principally of sensory afferents of the trigeminal nerve & sympathetic branches from the superior cervical ganglion
- 44. Nerves of the dental pulp In the crown there is a pronounced plexus of nerves beneath the odontoblasts, known as the plexus of Raschkow – occupy the cell- free zone of weil & can be demonstrated in silver stained sections under light microscope or by immunocytochemical techniques In the root-no corresponding plexus
- 47. AGE CHANGES OF PULP
- 48. Regressive changes (aging) Fibrosis • Accumulation of both diffuse fibrillar components & bundles of collagen fibers • External trauma such as dental caries or deep restorations causes localized fibrosis or scarring effect • Atherosclerotic plaques may appear in pulpal vessels • Calcifications are found that surround vessels
- 49. Regressive changes (aging) Pulp stones (denticles): • Nodular, calcified masses appearing in either or both the coronal & root portions of the pulp organ • Asymptomatic, unless they impinge on nerves or blood vessels • Seen in functional as well as embedded unerupted teeth
- 51. Regressive changes (aging) Pulp stones (denticles): True denticles False denticles
- 52. Pulp stones: True denticles: • Similar in structure to dentin • Are rare, located close to the apical foramen • Development is caused by the inclusion of remnants of the epithelial root sheath within the pulp • These epithelial remnants induce the cells of the pulp to differentiate into odontoblasts, which then form the dentin masses called true pulp stones
- 53. Pulp stones: False denticles: • Do not exhibit dentinal tubules • Concentric layers of calcified tissue • Some cases calcification sites appear within a bundle of collagen fibers • Phleboliths-serve as nidi for false denticles • All denticles begin as small nodules but increase in size by incremental growth on their surface
- 54. Pulp stones:
- 55. Pulp stones (depending on their relation to the dentin of tooth) Free Attached Embedded
- 57. Pulp stones: Free denticles: entirely surrounded by pulp tissue Attached denticles: partly fused with the dentin Embedded denticles: entirely surrounded by dentin
- 58. Pulp stones: Incidence – 66%of teeth-10-3oyears 80% of teeth-30 & 50 years 90%-over 50 years of ageFree denticles:
- 59. Diffuse calcifications Irregular calcified deposits following collagen fibre bundles or blood vessels Found more in the root canal & less in coronal area Surround blood vessels-dystrophic calcification
- 61. Clinical considerations: Wide pulp chamber in the tooth of a young person will make a deep cavity preparation hazardous Dehydration cause pulpal damage Associated with trauma, the pulp becomes transformed into granulation tissue and the dentine commences to be resorbed internally at the pulp-dentine surface
- 62. Diseases of dental pulp Etiology – 1. Dental caries 2. Tooth fracture – trauma cracked tooth syndrome 3. Anachorectic pulpitis - anachoresis – phenomenon by which blood borne bacteria, dyes, pigments, metallic substances, foreign products & other materials are attracted towards the site of inflammation - probable cause – increased capillary permeability in particular area
- 63. 4. Chemical irritation – erosion acidic restorative material 5. Thermal changes – polishing procedures cavity preparation tooth restored with exothermic restorative material. 6. Galvanic currents 7. Periapical tissue – accessory canals 8. Aerodontalgia
- 64. Classification of pulpitis •Acute •Chronic •Both acute and chronic – Partial or focal pulpitis Total or generalised •Closed pulpitis •Open pulpitis
- 65. References Orban’s oral histology &embryology-12th edition Ten Cate’s oral histology-7th edition Oral anatomy, histology and embryology; Berkovitz, 3rd edition Essentials of oral histology & embryology, 2rd edition, James k . avery