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Daranee Versluis-Tantbirojn DENT 5302 TOPICS IN DENTAL BIOCHEMISTRY The caries process Dietary factor and cariogenic aspects of dental plaque Plaque fluid.

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Presentation on theme: "Daranee Versluis-Tantbirojn DENT 5302 TOPICS IN DENTAL BIOCHEMISTRY The caries process Dietary factor and cariogenic aspects of dental plaque Plaque fluid."— Presentation transcript:

1 Daranee Versluis-Tantbirojn DENT 5302 TOPICS IN DENTAL BIOCHEMISTRY The caries process Dietary factor and cariogenic aspects of dental plaque Plaque fluid and the caries process Fluoride and dental caries Anticario mechanisms of fluoride Fluoride metabolism Fluoride toxicity Application of fluoride (& Ca P) in caries control measures

2 DENT 5302 TOPICS IN DENTAL BIOCHEMISTRY 28 March 2007 Nature and character of dental caries Factors influencing the caries process Development of early caries lesion in enamel Dentin caries Objectives:

3 Outline Nature of dental caries Key features of dental caries Multi-factorial Site specific Dynamic Formation of early enamel lesion Microscopic features of early enamel lesion Demineralization-Remineralization History & Epidemiology Dentin caries Caries free vs Caries controlled

4 Roman Industrialize Carious Teeth (%) 1950 Epidemic Percentage of carious teeth in English population 020001000 2000 20 15 10 5 0

5 Evans CA, Kleinman DV (2000). The Surgeon General's report on America's oral health: opportunities for the dental profession. J Am Dent Assoc. 131: 1721-8. Dental caries: the most prevalent infectious disease 5x > childhood asthma ; 7x > hay fever Affects 85% of adults (>18 years old) in the US 80% of caries occurs in 20% of the population Less than high schoolHigh school At least some collegeTotal children www.surgeongeneral.gov/library/oralhealth/ Underprivileged population?

6 70% of 12-17 years old had caries 94% of dentate adults (18 years or older) had caries The nature of caries has changed: Rapidly progressing childhood disease Slow but steadily progressing disease in adulthood 75% of children aged 5-11 years old were caries-free

7 Discussion: Give some examples of using knowledge and understanding of dental caries in your future dental practice.

8 Cariogenic bacteria (dental plaque) Host factors: Tooth Saliva Diet: Fermentable carbohydrate Dental caries is multifactorial Characters of caries Characters of caries Traditional concept

9 Social class Education Behavior Attitude Knowledge Income BiofilmTooth Saliva Fluoride Microbial species Diet Flow rate Composition Buffer Composition Sugar Frequency Time Genetic Dental caries is multifactorial Characters of caries Characters of caries Modern concept Biological determinants Socio- economical factors

10 Erosion Tooth morphology affects plaque accumulation Metabolism of microorganisms in dental plaque (biofilm) Microenvironment (plaque composition, thickness, diffusion properties) Access to dietary substrates, saliva, anticaries agents Dental caries: Localized destruction of tooth tissues Why localized? Characters of caries Characters of caries Dental caries is site specific

11 Demineralization vs Remineralization breakfast lunch coffee break snack dinner snack midnight 6 am brushing noon 6 pm Mineral content Net loss Characters of caries Characters of caries Dental caries is dynamic

12 Brown spot (Arrested lesion) Change in microenvironment Reduced plaque accumulation Access to saliva www.recaldent.com

13 acid H + + apatite Ca 2+ + PO 4 3- + OH - saliva plaque sound enamel subsurface lesion OH - Ca 2+ PO 4 3- F-F- surface zone (repair) H2OH2O HPO 4 2- diffuse & dissociate Formation of early enamel lesion

14 1 1 1 2 2 2 3 3 3 4 4 4 1. Surface Zone Intact surface 20-100  m thick, <10% mineral loss 2. Body of the LesionLargest zone, highest mineral loss (24%) 3. Dark zoneVery small pores, <10% mineral loss 4. Translucent zoneAdvancing front, 1% mineral loss Microscopic features of early enamel lesion

15 At this stage the lesion is reversible Fluoride and preventive treatment are most effective at this stage Clinical appearance: White spot lesion First clinical sign of enamel caries lesion Not that early! 300 – 500  m depth to be visible Why are we interested in early caries lesion?

16 Study done in community with water fluoridation Only 9 of 72 white spot lesions became cavitated after 7 years More than half of early lesions regressed to ‘normal’ enamel (Baker-Dirks, 1966) Age 8Age 15 Sound enamel 93 74 37 15 White spot 72 26 4 9 Cavitated lesion 19 19 111 sound enamel 41 white spots 32 cavitated lesions Early carious lesions are reversible

17 White spot lesions around orthodontic bracketts Dr. J.P. Byers

18 Is there a ‘caries-free’ individual? Discussion: ‘caries-free’ vs ‘caries-controlled’ Q1 Do you have any cavities or fillings Q2 Do you think you have demin-remin periods?

19 Progression of Carious Lesion 012 34 Proximal lesions in permanent teeth can take 3-4 years through enamel, unless in caries active individuals. (Pitts, 1983) How long? Late teen Danish population From 2 – 3: 9.2 surface % per year From 3 – 4: 2.3 surface % per year Median survival time from stage 2 to 3 was ~ 3 years

20 Rampant caries in Mountain Dew drinker

21 A = zone of decomposed dentin B = zone of bacterial invasion C = zone of demineralization D = sclerotic dentin E = reparative dentin Microscopic features carious dentin Outer carious dentin Inner carious dentin Dentin caries Progression of dentin caries Demineralization of inorganic substance Breakdown of organic matrix by proteolytic enzymes Bacterial invasion

22 Inner carious dentin uninfected remineralizable vital sensitive Fusayama T, Okuse K, Hosoda H. J Dent Res. 1966;45:1033-46. Relationship between hardness, discoloration, and microbial invasion in carious dentin. Turbid layer Transparent layer Sub- trans parent layer Crystals in tubule lumen Pulp wall Pulp wall Sound dentin DEJ10002000 3000  m Knoop Hardness Number 70 - 60 - 50 - 40 - 30 - 20 - 10 - Odontoblast Outer carious dentin infected nonremineralizable nonvital insensitive Bacteria Two layers of carious dentin Dentin caries

23 Discussion: What do you learn today that can be used in future practice? 2. What should we do with white spot lesion? 1. Why underprivileged population have more caries? 3. How much carious dentin should be removed?

24 Recommended references 1. Clarkson BH. Introduction to Cariology. Dent Clin North Am 1999;43(4):569-578. 2. Zero DT. Dental Caries Process. Dent Clin North Am 1999;43(4):635-664. 3. Featherstone JD. The science and practice of caries prevention. J Am Dent Assoc 2000;131:887-899. 4. Gordon Nikiforuk. Understanding Dental Caries 1. Etiology and Mechanisms, Basic and Clinical Aspects. Basel; New York: Karger 1985. Chapter 10. 5.Gao W, Smales RJ, Yop HK. Demineralisation and remineralisation of dentine caries, and the role of glass-ionomer cements. Int Dent J 2000;50:51-56. 6. Fejerskov O. Changing paradigms in concepts of dental caries: Consequences for oral health care. Caries Res 2004;38:182-191.


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