* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Caries Intro - student.ahc.umn.edu
Fluoridation by country wikipedia , lookup
Water fluoridation controversy wikipedia , lookup
Forensic dentistry wikipedia , lookup
Crown (dentistry) wikipedia , lookup
Water fluoridation wikipedia , lookup
Focal infection theory wikipedia , lookup
Scaling and root planing wikipedia , lookup
Periodontal disease wikipedia , lookup
Tooth whitening wikipedia , lookup
Fluoride therapy wikipedia , lookup
Water fluoridation in the United States wikipedia , lookup
Calculus (dental) wikipedia , lookup
Dentistry throughout the world wikipedia , lookup
Dental hygienist wikipedia , lookup
Special needs dentistry wikipedia , lookup
Dental degree wikipedia , lookup
Dental emergency wikipedia , lookup
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 DENT 5302 TOPICS IN DENTAL BIOCHEMISTRY 28 March 2007 Objectives: • Nature and character of dental caries • Factors influencing the caries process • Development of early caries lesion in enamel • Dentin caries Outline Nature of dental caries History & Epidemiology Key features of dental caries Multi-factorial Site specific Dynamic Demineralization-Remineralization Formation of early enamel lesion Microscopic features of early enamel lesion Caries free vs Caries controlled Dentin caries Carious Teeth (%) Epidemic 1950 Industrialize 20 15 Roman 10 5 0 2000 1000 0 1000 2000 Percentage of carious teeth in English population 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 www.surgeongeneral.gov/library/oralhealth/ Underprivileged population? Less than high school High school At least some college Total children 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. 75% of children aged 5-11 years old were caries-free 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 Discussion: Give some examples of using knowledge and understanding of dental caries in your future dental practice. Characters of caries Traditional concept Dental caries is multifactorial Cariogenic bacteria (dental plaque) Host factors: Tooth Saliva Diet: Fermentable carbohydrate Characters of caries Dental caries is multifactorial Social class Modern concept Education Saliva Microbial species Biofilm Biological determinants Flow rate Composition Buffer Income Fluoride Tooth Genetic Time Behavior Socioeconomical factors Diet Composition Sugar Frequency Knowledge Attitude Characters of caries Dental caries is site specific Dental caries: Localized destruction of tooth tissues Erosion Why localized? 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 Characters of caries Dental caries is dynamic Mineral content Demineralization vs Remineralization breakfast coffee break Net loss lunch snack brushing dinner snack brushing Brown spot (Arrested lesion) • Change in microenvironment • Reduced plaque accumulation • Access to saliva www.recaldent.com Formation of early enamel lesion saliva plaque sound enamel subsurface lesion acid H2O H+ + apatite OHCa2+ HPO42- diffuse & dissociate Ca2+ + PO43- + OH- PO43Fsurface zone (repair) Microscopic features of early enamel lesion 1 2 3 1 2 3 4 2 4 34 1 1. Surface Zone Intact surface 20-100 mm thick, <10% mineral loss 2. Body of the Lesion Largest zone, highest mineral loss (24%) 3. Dark zone Very small pores, <10% mineral loss 4. Translucent zone Advancing front, 1% mineral loss Clinical appearance: White spot lesion First clinical sign of enamel caries lesion Not that early! 300 – 500 mm depth to be visible Why are we interested in early caries lesion? At this stage the lesion is reversible Fluoride and preventive treatment are most effective at this stage Early carious lesions are reversible Sound enamel White spot Cavitated lesion Age 8 Age 15 93 74 37 15 26 4 9 19 72 19 111 sound enamel 41 white spots 32 cavitated lesions (Baker-Dirks, 1966) 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 Dr. J.P. Byers White spot lesions around orthodontic bracketts Dr. J.P. Byers Discussion: ‘caries-free’ vs ‘caries-controlled’ Is there a ‘caries-free’ individual? Q1 Do you have any cavities or fillings Q2 Do you think you have demin-remin periods? Progression of Carious Lesion How long? Proximal lesions in permanent teeth can take 3-4 years through enamel, unless in caries active 0 1 2 individuals. (Pitts, 1983) Median survival time from stage 2 to 3 was ~ 3 years Late teen Danish population From 2 – 3: 9.2 surface % per year 3 4 From 3 – 4: 2.3 surface % per year Rampant caries in Mountain Dew drinker Dentin caries Microscopic features carious dentin A = zone of decomposed dentin B = zone of bacterial invasion C = zone of demineralization D = sclerotic dentin E = reparative dentin Progression of dentin caries Demineralization of inorganic substance Breakdown of organic matrix by proteolytic enzymes Bacterial invasion Outer carious dentin Inner carious dentin Dentin caries Knoop Hardness Number Two layers of carious dentin 70 -Outer carious dentin Inner carious dentin infected 60 nonremineralizable uninfected remineralizable 50 - nonvital insensitive 40 - vital sensitive Sound dentin 30 20 Turbid layer 10 - DEJ 1000 Transparent layer Subtrans parent layer 2000 Pulp wall 3000 mm Crystals in tubule lumen Bacteria Odontoblast Fusayama T, Okuse K, Hosoda H. J Dent Res. 1966;45:1033-46. Relationship between hardness, discoloration, and microbial invasion in carious dentin. Discussion: What do you learn today that can be used in future practice? 1. Why underprivileged population have more caries? 2. What should we do with white spot lesion? 3. How much carious dentin should be removed? 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.