file (6).pdf pulp soft tissue bds first year
- 1. PULP
- 2. Introduction: It is a specialized loose non- mineralised vascularised connective tissue Responsible for the formation of dentine. Contained within pulp chamber and root canal of the tooth. Remains active through out life.
- 3. Every person normally has a total of 52 pulp organs, 32 in the permanent 20 in the primary dentition . The total volumes of all the permanent teeth pulp organs is 0.38 cc. The apical foramen is the opening from the pulp at the apex of the tooth which is to be continuous with the periapical tissue
- 4. The average size of apical foramen of the maxillary teeth in the adult is 0.4 mm. In the mandibular teeth it is slightly smaller with 0.3 mm in diameter. ACCESSORY CANALS Found in apical third region furcation region.
- 5. Anatomy of Pulp -: Pulp horns or Cornua Pulp Chamber Coronal Pulp Accessory Canal or Lateral Canals Apical Foramen Root Canals Radicular Pulp
- 6. PRIMARY PULP ORGANS Primary pulp undergoes development in the oral cavity for about 8.3 years which can be divided into three periods :- Pulp organ growth time during crown root are developing Pulp maturation from root formation till start of root resorption Pulp regression from root resorption to tooth exfoliation
- 7. Pulp of the permanent teeth undergoes development for about 1 2 years and 4 months. The maxillary arch pulp organs require slightly more time to complete each process of development than do the mandibular arches. PERMANENT PULP ORGANS
- 8. Pulpogenesis-: The development of pulp is similar to dentin as both are derived from the dental papilla. Proliferating Dental papilla invaginates and encloses the Enamel organ. Cells of dental papillae appear as undifferentiated mesenchymal cells differentiate into stellate shaped ļ¬broblasts. Odontoblasts differentiation starts from the peripheral cells of dental papillae dentine formation starts Inner enamel epithelium is stimulated IEE cells differentiates into Ameloblasts Enamel is laid down.
- 9. Dental papilla Pulp Organ Nerve terminals appear in the dental follicle in 1 1 th week of intrauterine life 1 8 th week in dental papilla 24 th week in subodontoblastic region after formation of 1 st layer of enamel dentin
- 10. Increase in the nerve ļ¬bres neurovascular bundles in central portion of the pulp Nerve myelination starts in few large nerves of pulp when dentin formation is in progress about to ļ¬nish Finally, nerves reach odontogenic zone of pulp
- 11. The dental pulp occupies center of each tooth and consists of soft connective tissue. Pulp is divided into :- Coronal Pulp - located centrally in the crowns of teeth Radicular Pulp - located in the root portion
- 12. CORONAL PULP It has pulp horns, which are protrusions that extend into the cusps of each tooth. The number of these horns thus depends on the number of cusps.
- 13. The cervical region of the pulp organs constricts follows the contour of the crown and at this zone the coronal pulp joins the radicular pulp.
- 14. RADICULAR PULP The radicular pulp is that pulp extending from the cervical region of the crown to the root apex. In the anterior teeth the radicular pulp are single and in posterior teeth are multiple.
- 15. They are not always straight and vary in size, shape and number. The radicular portion of the pulp organ is continuous with the periapical connective tissue through apical foramen.
- 16. APICAL FORAMEN Average size of apical foramen of the maxillary teeth in the adult is 0.4mm in diameter. In the mandibular teeth it is slightly smaller being 0.3mm in diameter. The location and shape of the apical foramen may undergo change as a result of functional inļ¬uence on the teeth.
- 17. Histological structure of the pulp Cells Intercellular substance Blood vessels, Lymph vessels, Nerves FIBRES Collagen I III Elastic ļ¬bres (B.V walls) GROUND SUSBSTANCE Glycosaminoglycans Glycoproteins
- 18. STRUCTURAL FEATURES The central region of both coronal and radicular pulp contains large nerve trunks and blood vessels and is termed as Pulp Core.
- 19. Peripherally , pulp is circumscribed by the specialized odontogenic region composed of-: 1 ) The Odontoblast 2) Cell free zone (Zone of Weil) 3) Cell rich zone 4) Pulpal Core
- 20. Zones of Pulp -:
- 22. INTERCELLULAR SUBSTANCES The intercellular substance is dense, and gel like in nature, varies in appearance from ļ¬nely granular to ļ¬brillar and appears denser in some areas.
- 23. Composed of glycosaminoglycans and proteoglycans. The ground substance lends support to the cells of the pulp while it also serves as a means for transport of nutrients from the blood vessels to the cells, as well as for transport of metabolites from cells to blood vessels.
- 24. FIBROBLAST The pulp organ consist of specialized connective tissue and lacks elastic ļ¬bers . Fibroblasts are the most numerous cell type in the pulp.
- 25. Help in collagen ļ¬ber formation through the entire pulp during the life of the tooth. They have typical stellate shape and extensive processes that contact and are joined by intercellular junctions to the processes of another ļ¬broblast.
- 26. Microscopically the ļ¬broblast nuclei stain deeply with basic dyes and their cytoplasm is lighter stained and appears homogenous. Electron microscope reveal abundant rough surfaced endoplasmic reticulum, mitochondria, and other organelles in the cytoplasm.
- 27. This indicates these cells are active in pulpal collagen production. In older pulp these ļ¬broblast appear rounded, or spindle shaped with short processes and exhibit fewer intracellular organelles, they are then termed as FIBROCYTES.
- 28. In addition to forming the pulp matrix, they also have capability of ingesting and degrading this same matrix. These cells thus have a dual function with pathways for both synthesis and degradation in the same cell.
- 29. FIBRES The collagen ļ¬bers in the pulp exhibit typical cross striations at 64nm and range in length from 1 0 to 1 00 nm or more. Bundles of these ļ¬bers appears throughout the pulp.
- 30. After root completion the pulp matures and bundles of collagen ļ¬bers increase in number. They may appear scattered throughout the coronal or radicular pulp, or they may appear in bundles and are termed as DIFFUSE or BUNDLE COLLAGEN.
- 31. UNDIFFERENTIATED MESENCHYMAL CELLS These cells are the primary cells in very young pulp, but a few are seen in the pulp after root completion. They appear larger then ļ¬broblast and are polyhedral in shape with peripheral processes and large oval staining nuclei.
- 32. They are found along pulp vessels, in the cell rich zone and scattered throughout the central pulp. They are believed to be totipotent cells and when need arises they can become Odontoblast ,ļ¬broblasts or macrophages.
- 33. ODONTOBLAST They are the second most prominent cell in the pulp, reside adjacent to the predentine with cell bodies in the pulp and cell processes in the dentinal tubules. They are approximately 5 to7Āµm in diameter and 25 to 40mu m in length.
- 34. They have a constant location, that is in the āOdontogenic zone of the pulpā. The cell bodies of the odontoblasts are columnar in appearance with large oval nuclei, which ļ¬ll the basal part of the cell.
- 35. Immediately adjacent to the nucleus basally is rough endoplasmic reticulum and golgi apparatus. The cells in the odontoblastic row lie very close to each other, and the plasma membranes of adjacent cells exhibit junctional complexes. Towards the apex of the cell appears an abundance of rough endoplasmic reticulum.
- 36. DEFENSE CELLS In addition to ļ¬broblasts, odontoblasts, and the cells that are a part of the neural and vascular systems of the pulp, there are cells important to the defense of the pulp.
- 37. These are -: 1 ) Histiocytes or Macrophages 2) Mast cells 3) Plasma cells In addition there are blood vascular elements such as neutrophils (PMN), eosinophil, basophils, lymphocytes monocytes. These latter cells migrate from the pulpal blood vessels and develop in response to inļ¬ammation.
- 38. BLOOD VESSELS The pulp organ is extensively vascularized. The blood vessels of both the pulp periodontium arise from the inferior or superior alveolar artery also drain by the same veins in both the mandibular maxillary regions.
- 39. Although branches of the alveolar arteries supply both the tooth and its supporting tissues, those entering the pulp are different in structure from the branches to the periodontium.
- 40. As vessels enter the tooth their walls become considerably thinner than those surrounding the tooth. Small arteries and arterioles enter the apical canal and pursue a direct route to the coronal pulp.
- 41. Along their course they give off numerous branches in the radicular pulp that pass peripherally to form a plexus in the odontogenic region.
- 42. Pulpal blood ļ¬ow is more rapid than in most areas of the body. Veins and venules that are larger than the arteries also appear in the central region of the root pulp.
- 43. LYMPH VESSELS Lymph capillaries are endothelium- lined tubes that join thin-walled lymph venules or veins in the central pulp. Lymph vessels draining the pulp and periodontal ligament have a common outlet.
- 44. Those draining the anterior teeth pass to the submental lymph nodes; those of the posterior teeth pass to the submandibular and deep cervical lymph nodes.
- 45. NERVES The abundant nerve supply in the pulp follows the distribution of the blood vessels. The majority of the nerves that enter the pulp are nonmyelinated.
- 46. The nonmyelinated nerves are found in close association with the blood vessels of the pulp and many are sympathetic in nature. Thick nerve bundles enter the apical foramen and proceed to the coronal area where their ļ¬bers separate and radiate peripherally to the odontogenic zone.
- 47. The peripheral axons form a network of nerves located adjacent to the cell- rich zone. This is termed as the Parietal layer of nerves, also known as Plexus of Rashkow.
- 48. Most of the nerve endings located among the odontoblasts are sensory receptors.
- 49. Sensory response in the pulp cannot differentiate between heat, touch, pressure, or chemicals . This is because the pulp organs lack those types of receptors that speciļ¬cally distinguish these other stimuli.
- 51. INDUCTIVE :- The ļ¬rst role of the pulp is to induce oral epithelial differentiation into dental lamina and enamel organ formation. The pulp anlage also induces the developing enamel organ to become a particular type of tooth.
- 52. FORMATIVE :- The pulp organ cells produce the dentin that surrounds and protects the pulp. The pulpal odontoblasts develop the organic matrix and function in its calciļ¬cation.
- 53. NUTRITIVE :- The pulp nourishes the dentin through the odontoblasts and their processes and by means of the blood vascular system of the pulp. PROTECTIVE :- The sensory nerves in the tooth respond with pain to all stimuli such as heat, cold, pressure, operative cutting procedures, and chemical agents.
- 54. DEFENSIVE OR REPARATIVE:- The pulp is an organ with remarkable reparative abilities. It responds to irritation, whether mechanical, thermal, chemical, or bacterial, by producing reparative dentin and mineralizing any affected dentinal tubules.
- 55. DEVELPOMENT The tooth pulp is initially called the dental papilla. This tissue is designated as āpulpā only after dentin forms around it. The development of the dental pulp begins at about the eighth week of embryonic life in the human.
- 56. As this occurs, the tissue is no longer called dental papilla but is now designated the pulp organ.
- 57. REGRESSIVE CHANGES 1 ) CELL CHANGES 2) FIBROSIS 3) PULP STONES OR DENTICLES 4) DIFFUSE CALCIFICATIONS
- 58. CELL CHANGES In addition to the appearance of fewer cells in the aging pulp, the cells are characterized by a decrease in size and number of cytoplasmic organelles. The ļ¬broblasts in the aging pulp exhibit less perinuclear cytoplasm and possess long, thin cytoplasmic
- 59. PULP STONES OR DENTICLES Pulp stones, or denticles , are nodular, calciļ¬ed masses appearing in either or both the coronal or root portions of the pulp organ. They develop in teeth that appear normal in other aspects.
- 61. Pulp stone are classiļ¬ed as :- I.According to their structure a) True denticles b) False denticles c) Diffuse calciļ¬cations II. According to their location :- a) Free b) Attached c) Embedded
- 62. TRUE DENTICLES The structure is similar to dentin in that they exhibit dentinal tubuli containing the processes of the odontoblast that formed them. True denticles are rare and are usually located close to the apical foramen.
- 63. FALSE DENTICLES They do not exhibit dentinal tubules but appear instead as concentric layers of calciļ¬ed tissue. All denticles begins as small nodules but increase in size by incremental growth on their surface.
- 65. DIFFUSE CALCIFICATIONS It appear as irregular calciļ¬c deposits in the pulp tissue, usually following collagenous ļ¬bers bundles or blood vessels. Sometime they develop into larger masses but usually persist as ļ¬ne calciļ¬ed spicules.
- 66. Diffuse calciļ¬cation are usually found in the root canal and less often in the coronal area, whereas denticles are seen more frequently in the coronal pulp.
- 67. II. According to the location: Free denticles are entirely surrounded by pulp tissue. Attached denticles are partly fused with the dentin.
- 68. Embedded denticles are entirely surrounded by dentin. All are formed free in the pulp and later become attached or embedded as dentin formation progresses.
- 69. The incidence as well as size of pulp stones increases with age. 66% 1 0 to 30 years of age 80% 30 to 50 years of age 90% over 50 years of age
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