Etiology of dental caries

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  • 1. Etiology of Dental Caries 上海交通大学医学院 附属第九人民医院 黄正蔚 牙体牙髓病科
  • 2. Etiology is the study of causation. Derived from the Greek αἰτιολογία "giving a reason for" 九院牙体牙髓病科 黄正蔚
  • 3. 九院牙体牙髓病科 黄正蔚
  • 4. What is this disease? Color form Texture 九院牙体牙髓病科 黄正蔚
  • 5. To find the causes … 九院牙体牙髓病科 黄正蔚
  • 6. Cause of dental caries? 九院牙体牙髓病科 黄正蔚
  • 7. 虫 齿龋 = 齿 + 禹 (虫 ) 九院牙体牙髓病科 黄正蔚
  • 8. Where arethose worms ? 九院牙体牙髓病科 黄正蔚
  • 9. Other explanations ? Might erosion be one cause? 九院牙体牙髓病科 黄正蔚
  • 10. Where isthe acid ? 九院牙体牙髓病科 黄正蔚
  • 11. 17th Century Anton van Leeuwenhook 九院牙体牙髓病科 黄正蔚
  • 12. 九院牙体牙髓病科 黄正蔚
  • 13. Louis Pasteur九院牙体牙髓病科 黄正蔚
  • 14. chemico-parasitic hypothesis —— WD. Miller(1890) 化学细菌学 说 九院牙体牙髓病科 黄正蔚
  • 15. dietary carbohydrates oral bacteria acid production solubilizecalcium phosphate caries 九院牙体牙髓病科 黄正蔚
  • 16. Bacteriafrom plaque Sugar Acid Acid Healthy Decay Tooth 九院牙体牙髓病科 黄正蔚
  • 17. Miller’s experiments :teeth + bread/carbohydrates + saliva demineralizationteeth + meat/lipids + saliva non-demineralizationteeth + bread + boiled saliva non-demineralization 不脱矿 脱矿 九院牙体牙髓病科 黄正蔚
  • 18. Evidences for caries as an infectious disease 1. No bacteria no caries germfree rats Sound teethBacteria seperated from caries inoculated ? 九院牙体牙髓病科 黄正蔚
  • 19. Evidences for caries as an infectious disease 2. Caries developed with bacteria inoculated inoculatedStreptococci seperated from caries lesion caries 九院牙体牙髓病科 黄正蔚
  • 20. Evidences for caries as an infectious disease 3. Antibiotics inhibited caries Penicillin caries McClure & Hewitt 1946 九院牙体牙髓病科 黄正蔚
  • 21. Evidences for caries as an infectious disease 4. Bacteria found in all caries specimensCaries = lesion infected with bacteria microscopically 九院牙体牙髓病科 黄正蔚
  • 22. Dentinal Liquefactiontubules focus 九院牙体牙髓病科 黄正蔚
  • 23. Carious human molar infected affected 九院牙体牙髓病科 黄正蔚
  • 24. 九院牙体牙髓病科 黄正蔚
  • 25. 九院牙体牙髓病科 黄正蔚
  • 26. Conclusiondental caries may be caused bymembers of the commensal oralmicroflora 九院牙体牙髓病科 黄正蔚
  • 27. But …For any microbe to be consideredresponsible for a given condition Koch’s principles 郭霍原则 九院牙体牙髓病科 黄正蔚
  • 28. Koch’s postulates The microbe should be found in all cases 九院牙体牙髓病科 黄正蔚
  • 29. Koch’s postulates The microbe should be grown on artificial media 九院牙体牙髓病科 黄正蔚
  • 30. Koch’s postulates A pure subculture should produce the disease 九院牙体牙髓病科 黄正蔚
  • 31. And… A high antibody titre to the microbe should be detected 九院牙体牙髓病科 黄正蔚
  • 32. What’s then? No single microbe has beenfound which completely satisfies Koch’s postulates for caries 九院牙体牙髓病科 黄正蔚
  • 33. Hypothesis on caries ecological plaque hypothesis Caries is a result of a shift in the balance of the resident microflora 生态菌斑学说 九院牙体牙髓病科 黄正蔚
  • 34. Reevaluation of the microbial aetiology of dental caries S. oralis Re-Fermentable Neutral S. sanguis mineralization sugar pH Enviromental Ecological Change Change S. mutans De- Low Acid Lactobacilli mineralization pH 九院牙体牙髓病科 黄正蔚
  • 35. Stephan curve 九院牙体牙髓病科 黄正蔚
  • 36. multifactorialdental caries disease 九院牙体牙髓病科 黄正蔚
  • 37. Introduction Host“Plaque-Host-Substrate” theory 九院牙体牙髓病科 黄正蔚
  • 38.  Factor 1 Microbiota not only Bacteria 九院牙体牙髓病科 黄正蔚
  • 39. Definitions Dental plaque ( 菌斑 ) Materia alba ( 软垢 ) Pellicle ( 获得性膜 ) Calculus ( 牙结石 ) 九院牙体牙髓病科 黄正蔚
  • 40. Dental plaqueDental plaque is the soft, nonmineralizedbacterial deposit which forms on teeth anddental protheses that are not adequatelycleaned. ------ LÖe 1965 九院牙体牙髓病科 黄正蔚
  • 41. Dental plaqueMicroscopically, plaque is simply confluentcolonies of microorganisms connected by amatrix consisting predominantly ofbacterial and salivary polymers. 九院牙体牙髓病科 黄正蔚
  • 42. What is dental plaque…  Bacteria deposit  On hard surfaces  Bacteria + matrix 九院牙体牙髓病科 黄正蔚
  • 43. 九院牙体牙髓病科 黄正蔚
  • 44. erythrosin stained 九院牙体牙髓病科 黄正蔚
  • 45. Materia albabacterial aggregations, leucocytes anddesquamated oral epithelial cellsaccumulating at the surface of plaque andteeth, but lacking the regular internalstructure observed in dental plaque. 九院牙体牙髓病科 黄正蔚
  • 46. Differences betweenmateria alba and plaque  Bacteria composition  Internal structure  Adherence strength 九院牙体牙髓病科 黄正蔚
  • 47. Pelliclean organic film derived mainly from thesaliva and deposited on the tooth surface. 九院牙体牙髓病科 黄正蔚
  • 48. Calculuscalcified dental plaque, it is always covered with a superficial layer of noncalcified plaque. 九院牙体牙髓病科 黄正蔚
  • 49. Chemical composition of dental plaque (biofilm) 11 microorganisms > 2X10 per gram per wet weightDental plaque (biofilm) extracellular matrix 九院牙体牙髓病科 黄正蔚
  • 50. Function of extracellular matrix  carbohydrate reserve  framework of the biofilm  inflammation-inducing, toxic substances 九院牙体牙髓病科 黄正蔚
  • 51. Chemical composition of dental plaque (biofilm) microorganisms Protein 45%Dental plaque Organic Carbohydrate 15% (biofilm) content extracellular matrix Lipid 12% Inorganic content (Ca, P) 九院牙体牙髓病科 黄正蔚
  • 52. Formation of dental plaque 九院牙体牙髓病科 黄正蔚
  • 53. Formation of dental plaque1 hr 30 d 九院牙体牙髓病科 黄正蔚
  • 54. Influence factors  Diet  Age  Salivary factors  Oral hygiene  Tooth alignment  Systemic disease  Host factors 九院牙体牙髓病科 黄正蔚
  • 55. Acquired enamel pellicle Initial colonization九院牙体牙髓病科 黄正蔚
  • 56. Micro-colonies 九院牙体牙髓病科 黄正蔚
  • 57. Microcolonies coalescing 九院牙体牙髓病科 黄正蔚
  • 58. 九院牙体牙髓病科 黄正蔚
  • 59. Filamentous bacteria九院牙体牙髓病科 黄正蔚
  • 60. “corn-cob” associations九院牙体牙髓病科 黄正蔚
  • 61. Plaque formation Acquired enamel pellicle formation Initial adherence and subcequent proliferation Further aggregation 九院牙体牙髓病科 黄正蔚
  • 62. Formation Mechanisms Co-aggregationReversible adhesion Irreversible adhesion ENAMEL 九院牙体牙髓病科 黄正蔚
  • 63. Formation Mechanisms Plaque formation Detachment ENAMEL 九院牙体牙髓病科 黄正蔚
  • 64. 九院牙体牙髓病科 黄正蔚
  • 65. Remember… Attachment, growth, removal and reattachment of bacteria is a continuous and dynamic process Dental plaque will undergo continuous reorganization 九院牙体牙髓病科 黄正蔚
  • 66. Biofilm ( 生物膜 ) 九院牙体牙髓病科 黄正蔚
  • 67. Bacteria living in planktonic (free swimming) or in biofilm (dental plaque)? 九院牙体牙髓病科 黄正蔚
  • 68. Batch culture Biofilm 九院牙体牙髓病科 黄正蔚
  • 69. 九院牙体牙髓病科 黄正蔚
  • 70. 九院牙体牙髓病科 黄正蔚
  • 71. definition Surface-associated bacterial community-forming microcolonies surrounded by amatrix of exopolymers 九院牙体牙髓病科 黄正蔚
  • 72. Dental plaque ? Biofilm 九院牙体牙髓病科 黄正蔚
  • 73. Why study biofilm? Attached planktonicBiofilm cells (liquid phase) cells Biofilm Sum of constitutivecommunities populations 1 + 1 2 九院牙体牙髓病科 黄正蔚
  • 74. Researches revealed …cells growing as biofilm haveunique properties, some of whichhave great clinical significance 九院牙体牙髓病科 黄正蔚
  • 75. General propertiesProtection from host defense and predatorsProtection from desiccationProtection from antimicrobial agents Surface-associated phenotype Slow growth rate Poor penetration Inactivation/neutralizationNovel gene expression and phenotypePersistence in flowing systemsSpatial and environmental heterogeneitySpatial organization facilitating metabolic interactionsElevated concentration of nutrients
  • 76.  Factor 2 Host 九院牙体牙髓病科 黄正蔚
  • 77.  Tooth morphology 九院牙体牙髓病科 黄正蔚
  • 78. caries susceptibility66
  • 79. Tooth morphology  Pits & fissures  Irregularities in arch form  crowding  overlapping 九院牙体牙髓病科 黄正蔚
  • 80. Tooth composition  Mineralization  Trace elements  fluoride 九院牙体牙髓病科 黄正蔚
  • 81. Enamel surface is more caries-resistant than the subsurface 九院牙体牙髓病科 黄正蔚
  • 82.  Host factor : Saliva 九院牙体牙髓病科 黄正蔚
  • 83.  Effect of desalivation on incidence and extent of caries in animals caries 九院牙体牙髓病科 黄正蔚
  • 84. Decreased salivary flow and caries in humans Xerostomia 九院牙体牙髓病科 黄正蔚
  • 85.  Salivary flow rate Salivary composition and caries Salivary buffers Antibacterial factors of Glandular origin 九院牙体牙髓病科 黄正蔚
  • 86.  Factor 3 Substrate: diet and caries 九院牙体牙髓病科 黄正蔚
  • 87.  Epidemiological observations 九院牙体牙髓病科 黄正蔚
  • 88.  Experimental caries of animals Caries susceptibility 九院牙体牙髓病科 黄正蔚
  • 89.  Controlled human studies: VipeholmMental institution 九院牙体牙髓病科 黄正蔚
  • 90. Toffee Chocolate Caramel 九院牙体牙髓病科 黄正蔚
  • 91.  Factor 4 Time 九院牙体牙髓病科 黄正蔚
  • 92. Thanks! 九院牙体牙髓病科 黄正蔚