CARIOLOGY

Dr. Shahzadi Tayyaba Hashmi Shahzadi@inaya.edu.sa

• 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

LEARNING OBJECTIVES

• 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

INTRODUCTION

• Dental caries is a multifactorial disease of teeth.• The major factors in the etiology of dental caries

are as follows:DietBacteriaSusceptible tooth surfaceTime

ETIOLOGY OF DENTAL CARIES

• Cariogenic (acidogenic) bacteria• Bacterial plaque• Stagnation areas• Fermentable bacterial substrate(sugar)• Susceptible tooth surfaces• time

Essential requirements for development of dental caries

• 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

1) Essential properties of cariogenic bacteria

• 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

Microbiological aspects of dental caries

• 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• Biofilm consist of hydrated viscous phase

formed from bacteria and their extracellular polysaccharide matrices

• Biofilm may be resistant to antimicrobials

2) 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

Clinical appearance of bacterial plaque

DENTAL PLAQUE

Appears as translucent film

• 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

Stages of plaque formation

• 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

3)Factors determining the cariogenecity of sucrose