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cariology

DNT 353. cariology. Dr. Shahzadi Tayyaba Hashmi. LEARNING OBJECTIVES. To describe caries process To describe sites that are vulnerable to caries List bacterial strains most responsible for caries Explain importance of carbohydrates exposure to caries. INTRODUCTION.

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cariology

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  1. DNT 353 cariology Dr. Shahzadi Tayyaba Hashmi

  2. LEARNING OBJECTIVES • To describe caries process • To describe sites that are vulnerable to caries • List bacterial strains most responsible for caries • Explain importance of carbohydrates exposure to caries

  3. INTRODUCTION • The study of dental caries and cariogenesis is known as cariology DENTAL CARIES • also known as tooth decay or a cavity • It is defined as an infection which is bacterial in origin and causes demineralization and destruction of hard tissues of teeth (enamel, dentine and cementum) CARIOGENESIS • The Production of dental caries is termed as cariogenesis

  4. ETIOLOGY OF DENTAL CARIES • Dental caries is a multifactorial disease of teeth. • The major factors in the etiology of dental caries are as follows: • Diet • Bacteria • Susceptible tooth surface • Time

  5. Essential requirements for development of dental caries • Cariogenic (acidogenic) bacteria • Bacterial plaque • Stagnation areas • Fermentable bacterial substrate(sugar) • Susceptible tooth surfaces • time

  6. 1) Essential properties of cariogenic bacteria • Streptococci are essential for development of dental caries • Acidogenic • Able to produce a pH low enough (<5) to decalcify tooth substance • Able to survive and produce acid at low levels of pH • Able to produce polysaccharides (glucans) • It adheres to pellicle and contributes to plaque formation

  7. Microbiological aspects of dental caries • Dental caries is a bacterial disease • The organisms mainly responsible are specific strains of Streptococcus mutans • The presence of S.mutans in the human mouth is associated with caries activity • Other bacteria including lactobacilli and other strains of streptococci are weakly cariogenic

  8. 2) Bacterial plaque • Plaque is a tenaciously adherent deposit that forms on tooth surfaces • Consist of an organic matrix containing a dense concentration of bacteria • In microbiological terms, plaque is a biofilm • Biofilmconsist of hydrated viscous phase formed from bacteria and their extracellular polysaccharide matrices • Biofilm may be resistant to antimicrobials

  9. Clinical appearance of bacterial plaque • Clinically, bacterial plaque is a tenaciously adherent deposit on the teeth • It can only be readily removed by tooth brushing • However no tooth brushing removes plaque from inaccessible areas or pits (stagnation areas) • Plaque becomes visible, particularly on the labial surfaces of incisors, when tooth brushing is stopped for 12-24 hours • Appears as a translucent film

  10. DENTAL PLAQUE Appears as translucent film

  11. Stages of plaque formation • Deposition of cell-free pellicle of salivary glycoprotein • Further deposition of pellicle enhanced by bacterial action • Colonisation of cell free layer by bacteria, particularly by S.sanguis and S.mutans within 24 hours • Progressive build-up of plaque substance by bacterial polysaccharides

  12. 3)Factors determining the cariogenecity of sucrose • Sucrose forms up to a third of the carbohydrate content of many person’s diet • It promotes colonisation of teeth by streptococcus mutans • Its small molecular size allows it to diffuse rapidly into plaque • Its dissacharide bond contains enough energy to react with bacterial enzymes to form extracellular dextran matrix

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