PULP

DEVELOPMENT, AGE CHANGES, BLOOD SUPPLY, PULP VITALITY TESTS

1. 1 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

2. PULP PRESENTED BY AKSHARA E S FIRST YEAR PG DEPARTMENT OF CONSERVATIVE DENTISTRY AND ENDODONTICS MDC,EDAPPAL 2

3. CONTENTS INTRODUCTION DEFINITION DEVELOPMENT ANATOMY HISTOLOGIC STRUCTURE STRUCTURAL FEATURES FUNCTIONS OF PULP PRIMARY AND PERMANANT PULP AGE CHANGES IN PULP PULP VITALITY TEST CLINICAL CONSIDERATION ANATOMIC CONSIDERATION OPERATIVE PROCEDURES PULP AND SYSTEMIC DISEASES CONCLUSION REFERENCES 3 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

4. 4 PREVIOUS YEAR QUESTIONS Internal anatomy of permanent tooth and its significance? June 2018 Describe the structure and early functions of pulp? April 2009 Describe structure and functions of pulp? August 2003 Describe regressive changes in pulp? June 2002 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

5. INTRODUCTION Pulp is the soft connective tissue component of tooth Housed in pulp chamber of crown and root canal of root Consist of nerves, blood vessels, ground substance, interstitial fluid, odontoblasts, fibroblasts and other cellular components Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 5

6. DEFINITION Dental pulp can be defined as a richly vascularized and innervated connective tissue of mesodermal origin enclosed by dentin with communications to the periodontal ligament( Orbans ) According to Cohen pulp is a soft tissue of mesenchymal origin residing within the pulp chamber and root canals of teeth Dental pulp is a connective tissue uniquely situated within the rigid encasement of mineralized dentin ( Seltzer and Bender ) Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 6

7. DEVELOPMENT FORMATION OF DENTAL LAMINA Oral ectoderm Ectomesenchyme Primary epithelial band Dental lamina (lingual extension) Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 7

8. 8 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

9. 9 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

10. 10 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

11. 11 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

12. ANATOMY General features of pulp 52 pulp organs in human dentition;- 32 in permanent teeth 20 in deciduous teeth Total volume of pulp organ -0.38cc mean Single volume of 0.02cc Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 12

13. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 13

14. The pulp cavity i s divided into Co r onal pulp R ad i cular pulp Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 14

15. CORONAL PULP It occupies the crown portion of the teeth Six surfaces in coronal pulp:- Roof, Mesial, Distal, Lingual, Buccal, Floor. Pulp horns are the projections into the cusps. It depends upon the cuspal number. It constricts at the cervical region where it continues as the radicular portion. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 15

16. RADICULAR PULP Pulp located in the root portion of the teeth. In the anterior teeth, it is single and the posterior tooth it is multiple. The radicular portion of the pulp is continuous with the periapical tissues. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 16

17. APICAL FORAMEN It is the terminal end of the pulp space by which it communicate with the periapical region Average size of the apical foramen Maxillary teeth in the adult is 0.4mm Mandibular teeth in the adult is 0.3mm The location and shape of the apical foramen may undergo changes as a result of functional influences on the teeth Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 17

18. 18 APICAL ROOT CANAL ANATOMY Apical part of root canal consists of: Apical foramen (major diameter) Apical constriction(minor diameter) Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

19. 19 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

20. ACCESSORY CANALS Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 20 Accessory canals leading from the radicular pulp laterally through the root dentin to the periodontal tissue. Clinically significant in spread of infection Occur in areas where there is premature loss of root sheath cells.

21. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 21 Accessory canal formation which are an inefficient source of collateral circulation for the pulp are formed during the development of the root Defect in the epithelial root sheath Failure in the induction of dentinogenesis The presence of small blood vessels Acessory canals are more prevalent in the apical third of the root produce a gap - accessory canal

22. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 22 SIGNIFICANCE OF APICAL THIRD The root canal treatment of apical part of root is difficult sometimes because of presence of accessory and lateral canals, pulp stones, varying amounts of irregular secondary dentin and area of resorption. Most of the curvature occur in the apical third. Obturation should end at apical constriction. Apical 3mm of root is generally resected during endodontic surgery in order to eliminate canal aberrations.

23. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 23 LATERAL CANALS Lateral canal is an accessory canal that branches to the lateral surfaces of the root.

24. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 24 APICAL DELTA It is the triangular area of root surrounded by main canal, accessory canal and periradicular tissue. ACCESSORY FORAMINA Opening of the accessory and lateral canals in the root surface.

25. Difference between lateral canal and an accessory canal is that Lateral canal extends from the main, central canal to the periodontal ligament. The accessory canal is found in the apical regions of the tooth and goes from apical secondary branching of the canal to the periodontal ligament. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 25

26. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 26 ISTHMUS Isthmus is a narrow, ribbon shaped communication between two root canals which can be complete or incomplete. it contains pulp or pulpally derived tissue and acts as store house of bacteria so the isthmus should be well prepared and filled if seen on resected surface

27. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 27 CLASSIFICATION

28. VARIATIONS IN INTERNAL ANATOMY OF PULP Gemination Fusion Concrescence Taurodontism Talon’s cusp Dilaceration Extra root canal Dens evaginatus Dens invaginatus Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 28

29. VOLUME OF PULP ORGANS Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 29

30. HISTOLOGIC STRUCTURE Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 30

31. Found at periphery of pulp Consist of cell bodies of odontoblasts and their cytoplasmic processes Cell bodies form odontoblastic zone Cytoplasmic process are located within predentin matrix and dentinal tubules Capillaries and unmyelinated sensory nerves are found ODONTOBLASTIC ZONE 31 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

32. Called as zone of Weil or sub odontoblastic layer Acellular zone, located centrally to odontoblast zone More prominent in coronal pulp Major component are ground substance with reticular fibres Consist of network of nerve fibres that have lost their myelin sheath – Plexus of Rashkow Ground substance is involved in metabolic exchange of cells CELL FREE ZONE 32 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

33. CELL RICH ZONE Located below cell-free zone More prominent in coronal pulp Main components – ground substance, fibroblasts, collagen fibres, mesenchymal cells and macrophages Act as reservoir for replacing destroyed odontoblasts Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 33

34. PULP PROPER Also known as pulp core Located in the centre of coronal and radicular pulp Contains blood vessels and nerves that are embedded in pulp matrix Abundant cellular elements In young pulp, more cells In older pulp, more fibrous components Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 34

35. STRUCTURAL COMPONENTS 35 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

36. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 36

37. CELLS 37 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

38. ODONTOBLASTS Second most prominent cell Reside adjacent to predentin 5 – 7um diameter and 25-40um length Cell bodies in pulp and cell processes in dentinal tubules Number of odontoblasts corresponds to the number of dentinal tubules Constant location adj to predentin called as odontogenic zone of the pulp. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 38

39. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 39 Numerous and larger in coronal pulp Form and arrangement of the bodies of the odontoblasts are not uniform throughout the pulp More cylindrical and longer (tall columnar)– crown Cuboid – middle of root Ovoid/spindle shaped – apex of root The odontoblast morphology and its organelles vary with the functional activity of the cell.

40. Synthetic/active odontoblasts : Appears elongated Basally placed nucleus Basophilic cytoplasm Abundant synthetic cellular organelles Vesicles are seen along periphery of process Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 40

41. Intermediate/transitional odontoblasts : Cells are narrower Fewer synthetic organelles Presence of autophagic vacuoles Nucleus shows condensation of chromatin Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 41

42. Resting/aged odontoblasts : Stubby cells Little cytoplasm More hematophilic nucleus Less cellular organelles Secretory granules are scarce or absent Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 42

43. FIBROBLASTS Most numerous cell type Function in collagen fiber production throughout the pulp during the life of the tooth Have stellate shape and extensive processes Abundant cell organelles In young pulp, cells divide and active in protein synthesis Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 43

44. In older pulp, cells appear rounded or spindle shaped with short processes and exhibit fewer intra cellular organelles. They are termed as fibrocytes. In young pulp, cells divide and are active in protein synthesis, cellular elements predominate In older pulp, fibrous components predominate Have dual function of both synthesis and degradation Role in inflammation and healing Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 44

45. UNDIFFERENTIATED MESENCHYMAL CELLS Primary cells in very young pulp Larger than fibroblast and polyhedral in shape Have large oval nuclei and peripheral processes Found in cell-rich zone It is totipotent cell in nature Decrease in number with age Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 45

46. IMMUNO-COMPETENT CELLS MACROPHAGES :- Irregular shaped nucleus with blunt, short processes Small, rounded and dark stained nucleus In pulpal inflammation, cells exhibit granules and vacuoles Phagosomes are present Function as scavenger cells Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 46

47. DENDRITIC CELLS :- Seen in contact with cell membrane of endothelial cells They present antigen to T cells In primary teeth, cells are seen associated with odontoblast with their processes extended into dentinal tubules Increase in areas affected by caries, attrition or restorative procedures Increase in number during shedding Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 47

48. LYMPHOCYTES AND ESINOPHILS :- Found extravascular Increase in number during inflammation Most commonly T lymphocytes are seen MAST CELLS :- Seen along vessels Round nucleus and granules in cytoplasm Increases during inflammation Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 48

49. PLASMA CELLS :- Seen during pulpal inflammation Nucleus appears small and concentric Cell have cartwheel appearance Basophilic cytoplasm Mature and immature cells are seen Help in production of antibodies Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 49

50. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 50

51. EXTRACELLULAR COMPONENTS 51 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

52. GROUND SUBSTANCE Dense and gel like in nature Finely granular to fibrillar in appearance Composed of mucopolysaccharide and protein polysaccharide Glycoproteins are also seen Lends support to the cells Means of transport for nutrients and metabolites Glycosaminoglycans – high tissue fluid pressure Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 52

53. FIBERS Exhibit typical cross striations at 64nm Length – 10 to 100nm Main type of fibers are Type I and III In young pulp, fine fibers of 10 to 12nm – fibrillin After root completion, increase in no of fibers Appear in bundles or scattered – diffuse/bundle collagen Prevalent in root canals Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 53

54. CONNECTIVE TISSUE STRUCTURE 54 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

55. BLOOD VESSELS Blood vessels of both the pulp and periodontium arise from Inferior or superior alveolar artery and also drain by the same vein Pulp vessels communicate to periodontium via apical foramen and accessory canal Periodontal vessel become thinner when they enter the pulp Small arteries and arterioles enter apical canal and pursue a direct route to the coronal pulp Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 55

56. 56 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

57. During the course they give off numerous branch in radicular pulp and which pass peripherally to form plexus in Odontogenic region Pulpal pressure highest among among body tissues The Flow of Blood Arterioles-0.3 to 1mm/sec Venules-0.15mm/sec Capillaries-0.08mm/sec Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 57

58. Arteries Largest one 50 to 100 micrometres 3 LAYERS Tunica Intima - squamous or cuboidal endothelial cells surrounded by a closely associated basal lamina. Tunica Media - approx 5 µm thick and consists of 1 to 3 layers of smooth muscle with basal lamina Tunica Adventiatia – Loose network of collagen fibers Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 58

59. 59 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

60. Arterioles Diameter 20-30micrometers 1 or 2 layers of smooth muscle cells are common throughout the coronal pulp. Tunica adventitia blends with fibres of intercellular tissues Terminal arterioles of 15µm appear peripherally in the pulp. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 60

61. Capillaries Function as exchange vessels regulating the transport and diffusion of substances between blood and local interstitial tissue elements They consists of single layer of endothelium surrounded by basement membrane Capillary wall acts as semi permeable membrane Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 61

62. CAPILLARY FEATURE LOCATION Fenestrated capillary Endothelium with openings Pulp, sulcular gingiva, renal glomerulus Continuous capillary Endothelium devoid of fenestrations Dental pulp, near odontoblasts during tooth development, heart, lungs Discontinuous capillary Discontinuous endothelium with wide intercellular space Spleen, liver, bone marrow Tight-junction capillary Central nervous system Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 62

63. Veins and venules Central region of pulp, and larger than arteries(100-150 micrometres) Thinner wall compared to arteries Flat endothelial cell without cytoplasmic projection to lumen Tunica Media-Single layer or two thin smooth muscle Tunica Adventitia-Absent or appears as fibroblast and fibers are continuous with surrounding pulp tissues. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 63

64. 64 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

65. Lymphatics Lymphatic vessels are formed from fine meshwork of small, thin walled lymph capillaries Lymph capillaries coalesce to form larger lymphatic vessels with valves They start as blind openings near Weil’s zone & odontoblastic layer The larger lymphatic vessels run along the blood vessels & nerves 65 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

66. 66 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

67. Nerve Innervation Follow distribution of blood vessels Majority are Nonmyelinated and gain myelin sheath in later stage. Very little Branching in Radicular Pulp Nerve fibers terminate adjacent to Odontoblast or in dentinal tubules Only Free Nerve Endings in pulp-ONLY PAIN SENSATION IS FELT Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 67

68. 68 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

69. C NERVE FIBRES A DELTA NERVE FIBRES Unmyelinated Myelinated Diameter 0.3 to 1.2micrometer Diameter 2 to 5 micrometer Conduction velocity 0.4 to 2 m/s Conduction of velocity to 6 to5 micrometer Conduction is slow than A delta fibres Conducts impulses at faster rate Dull, poorly localised and lingering pain Short well localised sharp and pricking pain 69 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

70. C FIBRES A DELTA FIBRES Mechanism of stimulation ; inflammation that accompanies tissue injury leads to increase in tissue pressure and release of chemical mediators. This in turn stimulates the c fibers that results in pain Mechanism of stimulation explained by three theories; Direct stimulation theory Odontoblastic theory- proposes that the odontoblast function as nerve endings Hydrodynamic theory- states that any fluid movement in the dentinal tubule and around the odontoblast are the result of stimulus excites o the nerve endings. This theory is most accepted 70 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

71. 71 To be continued…… Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

72. 72 SESSION 1 INTRODUCTION DEFINITION DEVELOPMENT ANATOMY HISTOLOGIC STRUCTURE STRUCTURAL FEATURES SESSION 2 FUNCTIONS OF PULP PRIMARY AND PERMANANT PULP AGE CHANGES IN PULP PULP VITALITY TEST CLINICAL CONSIDERATION ANATOMIC CONSIDERATION OPERATIVE PROCEDURES PULP AND SYSTEMIC DISEASES CONCLUSION REFERENCES CONTENTS Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

73. 73 DEVELOPMENT FORMATION OF DENTAL LAMINA Oral ectoderm Ectomesenchyme Primary epithelial band Dental lamina (lingual extension) Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

74. 74 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

75. 75 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

76. 76 HISTOLOGIC STRUCTURE Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

77. 77 STRUCTURAL COMPONENTS Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

78. FUNCTIONS OF PULP 78 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

79. INDUCTIVE It interacts with the oral epithelial cells, which leads to differentiation of dental lamina and enamel organ formation It also interacts with the developing enamel organ to differentiate into a particular type of tooth. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 79

80. FORMATIVE The pulp organ cells produce the dentin that surrounds and protects the pulp Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 80

81. FORMATIVE The pulp organ cells produce the dentin that surrounds and protects the pulp The pulpal odontoblast develop the organic matrix and function in its calcification Through the development of the odontoblast processes , dentin is formed along the tubule wall as well as the pulp- predentin front. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 81

82. FORMATIVE The pulp organ cells produce the dentin that surrounds and protects the pulp The pulpal odontoblast develop the organic matrix and function in its calcification Through the development of the odontoblast processes , dentin is formed along the tubule wall as well as the pulp- predentin front. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 82

83. NUTRITIVE The pulp nourishes the dentin through the odontoblasts and their processes and by means of the blood vascular system of the pulp. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 83

84. PROTECTIVE The sensory nerves in the tooth respond with pain to all stimuli such as heat, cold, pressure, chemical agents , operative cutting procedures The nerves also initiate reflexes that control circulation in the pulp. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 84

85. DEFENSIVE Pulp has remarkable reparative abilities and excellent regenerative properties. It responds to irritation by producing reparative dentin and mineralizing any affected dentinal tubules. Mild to moderate irritation results in continued peritubular dentin formation, sclerosis and intratubular calcification ( Tublar sclerosis) Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 85

86. PRIMARY and PERMANENT PULP PRIMARY PULP : Functions for shorter period of time – 8.3yrs Divided into three time periods:- Pulp organ growth – 1 year Pulp maturation – 3yrs 9 months Pulp regression – 3yrs 6 months Amount of time pulp undergoes changes – 4yrs 2 months Maximum life of primary pulp – 9.6yrs Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 86

87. PERMANENT TEETH : Crown completion – 5yrs 5 months Time of crown completion to eruption – 3yrs 6 months Time from eruption to root completion – 3yrs 11 months Pulp undergoes development for 12 yrs 4 months Aging requires much of adult life span Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 87

88. 88 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

89. AGE CHANGES IN PULP 1.CELL CHANGES :- Decrease in cell size Decrease in number of cytoplasmic organelles Fibroblast in aging pulp has less perinuclear Cytoplasm, long thin cytoplasmic processes 2. VASCULAR CHANGES :- Atherosclerotic plaques appears in pulpal vessels Calcifications in the walls of vessels Outer diameter becomes greater Endothelium shows numerous pinocytic vesicles. Blood flow decreases with age Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 89

90. 3. FIBROSIS :- Accumulation of collagen fibres Arranged longitudinally in bundles in radicular pulp and diffuse arrangement in coronal area External trauma causes localized fibrosis or scarring effect 4. DIFFUSE CALCIFICATIONS :- Appear as irregular calcific deposits in pulp tissue Usually found in root canal Denticles more frequently in coronal pulp Surrounds blood vessels – dystrophic calcification Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 90

91. 5. PULP STONES :- Nodular, calcified masses appearing in either or both coronal and root portion of the pulp organ Usually asymptomatic Histologically 2 types Laminated / unlaminated stones Etiology unknown Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 91

92. TRUE DENTICLE Have dental tubules and contain processes of odontoblasts Rare and located close to apical foramen Caused by inclusion of remnants of epithelial root sheath FALSE DENTICLE Don’t have dentinal tubules Appear as concentric layers of calcified tissue Appear within free of collagen fibres Centre of layers contain remnants of necrotic and calcified cells 92 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

93. Free denticles – surrounded by pulp tissue Attached denticles – Partly fused with dentin Embedded denticles – Entirely surrounded by dentin 93 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

94. 94 The presence of pulp stones is significant in that They reduce the overall number of cells within the pulp and Act as an impediment to debridement and enlargement of the root canal system during endodontic treatment. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

95. 95 Attrition of the pulp Normal appearance of the pulp cavity (P) at a young stage Schematic representation of aging of pulp Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

96. 96 Pulp cavity size by middle age Pulp cavity in old age Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

97. 97 In young persons pulp horns are long, pulp chambers are large, root canals are wide, apical foramens are broad With increasing age pulp horns recede, pulp chambers become smaller in height rather than in width Root canals also become narrower due to deposition of dentin Apical foramina also deviate from exact anatomic apex Their minor diameter becomes narrower and major diameter becomes wider from deposition of dentin and cementum Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

98. 98 With advancing age, there is a difficulty in the endodontic treatment due to: Excessive dentin formation at the roof and floor of the pulp chamber Presence of pulp stones at the opening of the root canal The apical foramen is narrowed by cementum Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

99. PULP VITALITY TEST 99 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

100. 100 The most accurate way of evaluating the pulp status is by examination of histological sections of the tissue specimen involved to assess the extend of inflammation or presence of necrosis as a mean of gauging pulp health. Unfortunately in the clinical scenario. These are both impractical and not feasible; hence clinicians must use investigations such as pulp tests to provide additional diagnostic information. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

101. 101 Pulp vitality testing- Assessment of pulp’s blood supply Pulp tissue may have an adequate vascular supply, but is not necessarily innervated. Hence, most of the current pulp testing modalities do not directly assess the pulp vascularity. Example is tooth with fresh trauma can have no response to cold for a period of time stimulus following injury, newly erupted tooth. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

102. 102 Pulp sensibility test- Assessment of the pulp sensory response Sensibility test is defined as a ability to respond to stimulus, and hence this is a accurate and appropriate term for typical and common clinical pulp tests such as thermal and electrical tests given that they do not detect or measure the blood supply of the dental pulp. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

103. 103 Pulp sensitivity: Condition of pulp being very responsive to a stimulus Thermal and electrical pulp tests are not sensitivity tests though they can be used as sensitivity tests when attempting diagnosis a tooth with pulpitis since such teeth are more responsive than others Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

104. 104 Gopikrishna V, Suresh Chandra B. Grossman’s endodontic practice. Methods of tooth vitality assessment Test cavity Neural sensibility tests Thermal tests Electric pulp tests Anaesthetic tests

105. 105 Pulp vascularity tests Pulp oximetry Laser doppler flowmetry others Dual wave length spectrometry Thermography Crown surface temperature Transmitted light photoplethysmography Gopikrishna V, Suresh Chandra B. Grossman’s endodontic practice.

106. HEAT TEST 106 Heat testing is most useful when a patients complaint is intense dental pain upon contact with any hot liquid or food , in instances where a patients is unable to identify which tooth is sensitive ,a heat test is appropriative. Starting with the most posterior tooth in that area of the mouth , each tooth is individually isolated with the rubber dam. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

107. 107 An irrigating syringe is filled with a liquid that has a temperature similar to that which would cause the painful sensation (42 C). The liquid is then express from the syringe onto the isolated tooth to determine whether the response is normal or abnormal Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

108. 108 Other used: Heated gutta percha/compound Heated ball ended metallic instruments Electrical heat carrier Hot water bath If this method is used, a light layer of lubricant should be placed onto the tooth surface prior to applying the heated material to prevent the hot gutta percha 78 c to 150 c or compound from adhering to the dry tooth surface. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

109. 109 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

110. 110 Cold is the primary pulp testing method for many practitioners today. Cold testing should be used in conjunction with the electric pulp tester so that results from one test will verify the findings of the other test. It can be accomplished similarly to heat testing by individually teeth with a rubber dam. Another benefit of this technique for cold testing is that it requires no armamentarium except for a rubber dam. COLD TESTS Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

111. Is believed that cold testing cause contraction of dentinal fluids, this results in outward flow of fluids with in patent tubules. This rapid flow results in hydrodynamic forces acting on A delta fibers in dentino-pulpal complex leading to sharp sensation for few seconds in sound tooth. Refrigerant Spray -dichloro-difluoromethane-DDM, Ethyl chloride- -41 C Carbon-dioxide snow (-56 c to -98 c) Recently ozone free non fluorocarbons sprays 1,1,1,2-tetrafluroethane - 26.2 c 111 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

112. 112 Frozen carbon dioxide (co 2 ) also known as dry ice or carbon dioxide snow, has been found to very reliable in eliciting a positive response if vital pulp tissue is present in the tooth. Carbon dioxide has also been found to be effective in evaluating the pulp response in teeth with full coverage crowns for which electric pulp testing is not possible. For testing purposes a solid stick of co2 gas into a specially design plastic cylinder. The resulting co2 is stick is applied to the facial surface of either natural tooth structure or crown. several tooth can be tested with single stick. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

113. 113 The most popular method of testing is with a refrigerant spray. It is readily available and easy to use, and provides test result that are reproducible, reliable and equivalent to that co 2 The current product contain 1,1,1,2-tetrafluroethane , which has zero ozone depletion potential and is environmentally safe. It has temperature -26.2 c The spray is most effective or testing purpose when it is applied to the tooth on large cotton pellete. The sprayed cotton pellete should be applied to the midfacial of the Crown. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

114. 114 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

115. ELECTRIC PULP TEST Assessment of the pulp vitality test is most frequently accomplished by electric pulp testing or cold testing. The vitality of the pulp is determined by the intactness and health of the vascular supply, not the status of the pulpal nerve fibers. Even though advances are being made with regard to determine the vitality of the pulp regard to the blood supply, this technology is not accurate enough to be used on a routine basis in clinical setting The electric pulp tester has limitations in providing information about the pulp. 115 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

116. 116 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

117. 117 The response of the pulp to electric testing is not reflecting the histologic health status of the pulp. A response by the pulp to the electric current only denotes that some viable nerve fibres are present in the pulp and are capable of responding. The lack of response has been found most frequently when an electric pulp is present. With the advent of universal precautions for infection control, the patient may be required to place a finger on the tester probe to complete the electric circuit for the models, however lip clips are an alternative to having patients hold the tester. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

118. 118 proper use of the electric pulp tester requires that the tooth to be evaluated be isolated and dried. A control tooth of similar tooth type and location in the arch should be tested first in order to establish a base line response and to inform the patients with a normal sensations. The suspected tooth should be tested at least twice to confirm the results. The tip of the testing probe that will be placed in contact with the tooth structure must be coated with the electric conducting based media. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

119. 119 The sensitivity which is the ability of a test to identify teeth that are diseased , was 0.83 for cold and 0.86 for heat and 0.72 for the electric test. This means the cold test correctly identified 83% of the teeth that had A necrotic pulp while heat test where correct 86% of the time and electric pulp test were correct only 72% of the time. However, unlike electric pulp testing, cold testing can reveal the health and integrity of pulp tissue response. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

120. LASER DOPPLER FLOWMETRY 120 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. Laser Doppler flowmetry is a method used to assess blood flow in micro vascular system Attempts are being made to adapt this technology to assess pulpal blood flow A diode is used to project a infrared light beam through the crown and pulp chamber of a tooth The Doppler principle states that the light beam will be frequency shifted by moving red blood cells but will remain un-shifted as it passes through static tissue This technique is accurate ,reliable and reproducible method of assessing pulpal blood flow

121. signal is commonly recorded as the concentration and velocity (flux) of cells using an arbitrary term “perfusion units” 121 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

122. PULSE OXIMETRY oximetry is defined as the determination of the percentage of oxygen saturation of the circulating arterial blood It works on the principle that two wavelengths 660 nm and 940 nm of light transmitted by a he, ne source and photoelectric diode detect oxygenated and deoxygenated haemoglobin as they pass through a body part to a receptor. The differences between the light emitted and the light received is calculated by a microprocessor to provide the pulse rate and oxygen concentrations in the blood. 122 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

123. 123 It also depends on the absorbance characteristics of haemoglobin in the red and infra-red range. In the red region, oxyhemoglobin absorbs less light than deoxyhaemoglobin and vice versa in the infrared region . Even with this positive findings ,the technology is not advanced enough for this method to be used on a routine basis in a dental practice. If technology can be developed whereby the testing with the LDF can be accomplished in minutes ,it will likely replace the thermal and electric pulp testing methods Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

124. 124 The system consists of a probe containing a diode that emits light in two wavelengths: Red light of approximately 660 nm Infra-red light of approximately 850 nm It is also useful in cases of impact injury where the blood supply remains intact but the nerve supply is damaged Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

125. Photoplethysmography :- analysis of the optical property of a selected tissue light with a shorter wavelength The detection of blood flow within the pulp by passing light through the tooth has been reported . Hemoglobin absorbs certain wavelengths of light, while the remaining light passes through the tooth and is detected by a receptor. Photoplethysmography has been compared with LDF in experiments on skin, and found to be of similar value . The technique has not been successfully developed further for dental application apart from one recent investigation 125 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

126. 126 Spectrophotometry :- uses dual wavelength lights in an effort to ascertain the contents of enclosed spaces. is a method independent of a pulsatile circulation Transillumination :- utilises a strong light source which identifies colour changes help to identify cracks in teeth Not useful in posterior teeth n teeth with restorations. Use as an adjunct to conventional technique. Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

127. Transmitted Laser Light :- aimed at eliminating the non-pulp signals the laser beam is passed through from the labial or buccal side of the tooth to the receiver probe which is situated on the palatal or lingual side of the tooth Ultraviolet light photography :- examines different fluorescence patterns that may allow additional contrast only an adjunct to conventional pulp tests 127 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

128. 128 False responses from pulp testing False positives Anxious patients Liquefaction necrosis Contact with metal restorations Vital tissue still present in partially necrotic root canal system False negatives Incomplete root development Recently traumatized teeth Sclerosed canals Recent orthodontic activation Patients with psychotic disorders Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

129. 129 Ideal features of a pulp vitality tester: Assesses pulp blood flow Objective measurements Free from error Effective for heavily restored teeth Effective when the pulp size is reduced Quick and easy to use Inexpensive Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

130. 130 Normal Patient reports a thermal sensation and stops feeling it when the stimulus is removed Reversible pulpitis Thermal sensation causes discomfort/pain and the magnitude of response is different from adjacent and/or contralateral teeth;sensation may linger briefly Symptomatic irreversible pulpitis After thermal stimulus is applied, patient reports pain/discomfort is more pronounced than on adjacent teeth and/or contralateral tooth;sensation lingers Asymptomatic irreversible pulpitis Same response as normal or reversible pulpitis, except the patient has a history of pulpal inflammation such as caries, carious exposure, or trauma Necrosis Necrosis Patient reports feeling no sensation when thermal stimulus is applied for more than 15 seconds in case of cold test n more than 5 sec in case of hot test. Possible diagnoses, based on patient responses to thermal stimuli Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

131. CLINICAL CONSIDERATION 131 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

132. ANATOMIC CONSIDERATIONS Shape of the pulp chamber and its extensions into the cusps, the pulpal horns is important. Wide pulp chamber in the tooth of a young person will make a deep cavity preparation hazardous Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 132

133. In some instances, the pulpal horns project high into the cusps exposure of pulp can occur When opening a pulp chamber for treatment, its size and variation in shape must be taken into consideration Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10. 133

134. FACTORS TO BE CONSIDERED DURING ENDODONTIC PROCEDURES Age advance , the pulp chamber becomes smaller difficult to locate the root canals. Shape of the apical foramen and its location may play an important part in treatment of root canals. Accessory canals, and multiple canals are rarely seen in roentgenograms Prominent cingulum of mandibular incisor – an extra canal may be present lingually 134 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

135. 135 Prominent buccal cusp and wide crown mesio - distally, a mesial buccal canal or root may be found in maxillary 1st premolar Prominent buccal cusp, wide crown buccolingually on mesial half in maxillary molar, second mesial buccal canal be found roof is wider buccolingually An extra canal be found in mandibular molar distal root if distal cusps are prominent Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

136. 136 A young permanent usually takes 2-3 years for completion of root formation after eruption. So an young permanent tooth posses an immature apex initially and then matures due to deposition of dentin and cementum. If endodontic intervention is done in these kind of teeth then treatment varies according to the condition of pulp. If radicular pulp is vital then, only coronal pulp is treated so as to form a physiological and anatomical mature apex. TREATMENT CONSIDERATIONS IN YOUNG PERMANENT TEETH Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

137. FACTORS TO BE CONSIDERED DURING OPERATIVE PROCEDURES The pulp is highly responsive to stimuli, even slight stimulus cause inflammatory cell infiltration. Dehydration causes pulpal damage, operative procedures producing this condition should be avoided. In cavity preparation: speed, heat, pressure & coolant may all cause pulp irritation. 137 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

138. 138 Effects of cavity Preparation: Frictional heat Desiccation Exposure of dentinal tubules Direct damage to odontoblast processes Chemical treatment to exposed dentinal surface Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

139. 139 Factors associated with the restorative material & its placement Material toxicity Insertion pressure Thermal effects Induced stresses Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

140. Various dental procedures can cause temperature increases on the teeth surfaces 140 PROCEDURE INTRAPULPAL TEMPERATURE CAVITY PREPARATION 0.8 - 3.0℃ COMPOSITE RESIN POLYMERIZATION 7.8℃ PROVISIONAL CROWN FABRICATION 3.4 - 12.3℃ Thermal irritation of pulp Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

141. Factors influencing temperature rise :- Remaining dentin thickness Type of handpieces used Light curing unit Type of ultrasonic device Water spray 141 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

142. LIGHT CURING OF COMPOSITE RESIN Light-cured composite resin is a commonly used restorative material Disadvantage - shrinkage and heat production during polymerization Temperature rise is caused by exothermic reaction process and the radiant heat from the light curing unit 142 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

143. Factors that affect the temperature rise during light curing :- Type of LCU Curing light intensity Curing time Curing technique Type of composite resin Amount of composite resin Remaining dentin thickness Presence of thermal barrier layers 143 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

144. TYPE OF CURING LAMP INTRAPULPAL TEMPERATURE Plasma arc curing 7.8℃ Halogen 7.3℃ light-emitting diode 6.9℃ conventional curing unit 2.9℃. 144 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

145. PULP AND SYSTEMIC DISEASES 145

146. INFECTIOUS DISEASES HUMAN IMMUNODEFICIENCY VIRUS :- Oral lesions include candidiasis, hairy leukoplakia, Kaposi sarcoma, non-Hodgkin lymphoma, periodontal disease Identified in dental pulp and in periradicular lesions of pulpal origin 146 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

147. HERPESVIRUS INFECTION :- HSV-1 is a potential etiologic factor for pulpal necrosis Zoster of maxillary or mandibular branch affect dentoalveolar structures Leads to pulpal death, tooth exfoliation, internal root resorption, tooth neuralgia CMN and EBV play role in the etiopathogenesis of periapical pathoses 147 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

148. GENETIC AND DEVELOPMENTAL DISORDERS TAURODONTISM :- Developmental disturbance of teeth that results in abnormal large pulp chambers at the expense of root length Radiographically – elongated pulp chamber and shortened roots Complicate the provision of endodontic therapy 148 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

149. DENS IN DENTE :- Portion of crown undergo invagination prior to calcification Divided into three types; Type 1 – enamel lined Type 2 – enamel lined blind sac that invades the root Type 3 – invades root and have secondary foramen Clinical significance :- Increased risk of bacteria induced pulpal necrosis Anatomical complexity makes tissue debridement and obturation challenging 149 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

150. DENS EVAGINATUS :- Outgrowth of ameloblasts that appear clinically as globule Narrow shelf of enamel, once penetrated results in pulpal exposure 150 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

151. DENTINOGENESIS IMPERFECTA :- Type I – associated with osteogenesis imperfecta Type II & III – mutation of DSPP gene Radiographically, Type I & II shows bulbous crown structure, cervical constriction, short roots, obliteration of pulp chamber Type III – pulp chamber appears normal or elongated and periradicular radiolucencies are present Compromise access, canal identification and debridement 151 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

152. AMELOGENESIS IMPERFECTA :- Developmental disorder that affects both primary and permanent dentition Pulp calcifications are seen Seen associated with autosomal recessive hypoplastic form 152 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

153. PAGET DISEASE:- Heterogenous, focal, progressive bone disorder characterized by active bone turnover Hypercementosis, tooth mobility, root resorption, pulp calcification Radiographic findings – thickening of PDL space, root resorption, pulpal obliteration Mosaic pattern interfere with ability to establish proper working length 153 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

154. SICKLE CELL ANEMIA :- Asymptomatic pulpal necrosis, symptomatic pulpitis, paraesthesia, referred odontalgia Endodontic treatment is preferred to reduce risk of osteomyelitis 154 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

155. ENDOCRINE DISORDERS DIABETES MELLITUS :- Characterized by an absolute or relative insulin insufficiency or target resistance to insulin activity Patients in need of endodontic treatment shows larger periradicular lesions, more virulent pathogens, experience perioperative symptoms, higher incidence of failure ADRENAL DYSFUNCTION :- Insufficient cortisol production – Addison’s disease Chronic exposure to excess glucocorticoid – stimulate odontoblast like cells – pulpal obliteration 155 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

156. CANCER Therapeutic interventions affect dental pulp Radiation induced collagen damage , results in impaired odontoblastic metabolism Endodontic treatment is preferred in managing problematic teeth Interventional chemotherapy and radiotherapy affect development in growing child Hypodontia, root stunting, microdontia, enlarged pulp chambers are seen 156 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

157. BARODONTALGIA Also know as Aerodontalgia Pain experienced in a recently restored tooth during low atmospheric pressure. Pain experienced either during ascent or descent 157 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

158. STRESSED PULP Preventive Concept to describe pulp that are neither healthy nor obviously diseased Clinical concept that describe pulp that received repeated previous injury and survived with diminished response and lessened repair potential. Usually do not require treatment, however patient should be advised that the tooth become asymptomatic in future Treatment option is RCT 158 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

159. HOT TOOTH Teeth that is difficult to anesthetize Special class of sodium channels on C fibres tetrodotoxin resistant( TTXr ) Relatively resistant to lignocaine 159 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

160. TECHNOLOGIES FOR REGENERATIVE ENDODONTICS 160 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

161. PULP STEM CELLS Dental pulp contain stem cells called pulp stem cells In immature teeth, stem cells from human exfoliated deciduous teeth are seen Pulp stem cells are also called odontoblastoid cells – synthesize dentin matrix 161 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

162. Similar types of cells include – Dental pulp stem cells from the apical papilla (SCAP) Dental follicle progenitor cells (DFPCs) These cells have potent capacity to differentiate into odontogenic cells Ability to give rise to osteogenic, chondrogenic, adipogenic , myogenic, neurogenic cells 162 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

163. POSTNATAL STEM CELL THERAPY To inject postnatal stem cells into disinfected root canal systems to permit revascularization Postnatal stem cells can be derived from skin, buccal mucosa, fat and bone Dental stem cells can be derived from:- Patients cells retrieved from umbilical cord stem cells that are cryogenically stored Allogenic purified stem cell line Xenogenic pulp stem cells grown in laboratory 163 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

164. ADVANTAGES :- Easy to harvest and deliver Potential to induce new pulpal regeneration Approach is already in use in medical applications DISADVANTAGES :- Low cell survival Cells migrate to different locations 164 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

165. CONCLUSION Pulp is an integral part of the tooth both structurally and functionally. Thus the preservation of a healthy pulp during operative procedures and successful management in case of diseases are the two most important challenges 165 Cohen, Stephen, et al. "Pathways of the Pulp (1)." Learning 30 (1998): 10.

166. REFERENCES Cohen’s Pathway of the Pulp – Tenth Edition Endodontic Practice ( 11 th edition ) – Louis I Grossman Seymour Oliet Carlos E Del Rio Grossman’s Endodontic Practice – 13 th edition Orban’s Oral Histology and Embryology – 12 th edition 166

167. Shafer’s Text Book of Oral Pathology ,6 th Edition Ten Cate’s Oral histology; Development, Structure and Function, 7th Edition 167

168. THANK YOU 168