Dental caries

DENTAL CARIES

DR SUNNY PUROHITDept. of Preventive & Pediatric Dentistry

SDCH

DEFINITION Is an Irreversible microbial disease of

the calcified tissues of the teeth ,characterized by demineralization of the inorganic portion and destruction of the organic substance of the tooth, which often lead to cavitation.

HISTORY Dental Caries –Disease of modern Civilization

Studies revealed that Doliocephalic Skulls(Long Skull) from Preneolithic Periods did not exhibit Caries Neolithic period – Initiation of Farming

Brachycephalic skulls of Neolithic-Caries Present-Just below Contact area

DENTAL CARIES

Copyright © 2005 by Elsevier Inc. All rights reserved.

THE CARIES PROCESS

For caries to develop, three factors must occur at the same time:A susceptible tooth Diet rich in fermentable carbohydratesSpecific bacteria (regardless of other factors,

caries cannot occur without bacteria)


AREAS FOR DEVELOPMENT OF CARIES Pit and fissure caries occurs primarily on the

occlusal surfaces and buccal and lingual grooves of posterior teeth, as well as in lingual pits of the maxillary incisors.

Smooth surface caries occurs on intact enamel other than pits and fissures.

Root surface caries occurs on any surface of the root.

Secondary, or recurrent, caries occurs on the tooth surrounding a restoration.


STAGES OF CARIES DEVELOPMENT

It usually takes a period of time, from months to years, for a carious lesion to develop.

It is an ongoing process, characterized by alternating periods of demineralization and remineralization. Demineralization is the dissolving of the calcium and

phosphate from the hydroxyapatite crystals. Remineralization is the calcium and phosphate being

redeposited in previously demineralized areas. It is possible to have the processes of demineralization

and remineralization occur without any loss of tooth structure.


FIG. 13-4 A, THE EARLIEST SIGN OF DECAY IS DECALCIFICATION (COURTESY DR. JOHN FEATHERSTONE, UNIVERSITY OF CALIFORNIA, SAN FRANCISCO, SCHOOL OF DENTISTRY.)


FIG. 13-4 B, DENTAL CARIES (COURTESY DR. FRANK HODGES, SANTA ROSA, CA.)


FIG. 13-4 C, DENTAL CARIES (COURTESY DR. FRANK HODGES, SANTA ROSA, CA.)


FIG. 13-5 SEVERELY DECAYED MOLAR ON A CHILD


FIG. 13-6 DECAY ON THE LINGUAL OF A MAXILLARY LATERAL INCISOR


ETIOLOGY Many Theories 3 theories which have stood the test of

time 1.Acidogenic theory of Miller (Miller’s

Chemico-Parasitic Theory),2.The Proteolytic theory and 3. The Proteolysis Chelation Theory

EARLY THEORIES1.The Legend Of Worms- earliest reference to tooth Decay Ancient Sumerian Text Known as

“Legend of Worms”

Homer-Pain in tooth due to worm

2.ENDOGENEOUS THEORIES The ancient Greek theory of the four bo

dy humors (blood, yellow bile, black bile, and phlegm) that determined health and disease.

Caries is due to acid production and disturbance in body humors.

Also caries is similar to bone gangrene which initiates within itself.

CHEMICAL THEORY Parmly in 1920

Unidentified ‘Chymal Agent’ causes caries.

PARASITIC THEORY Erdl -1843

Filamentous organisms present in surface membrane of tooth

Dresden-German Physician-Dental Caries-”Denticolae”- Generic term for decay related microorganism.

MILLER’S CHEMICO-PARASITIC THEORY ‘ACIDOGENIC THEORY’

Blend of above theories

Willoughby D Miller (1882)Theory: Caries caused by acids produced by microorganisms of the mouthDental decay is a chemico-parasitic process consisting of 2 stages:1.Decalcification (preliminary step)2.Dissolution (subsequent step)Acids are produced by bacteria’s fermentation of sugar and starch

ACIDOGENIC THEORY Backbone of current knowledge and

understanding for etiology of dental caries

3 factors essential for caries production:Oral microorganism Carbohydrate substrateAcid

Acidogenic

theory

Unable to explain:Site predilectionDental plaqueCaries-free population

Role of plaque:1897 by Mr Williams localizes acid produced by bacteria prevents anti- caries effect of saliva

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THE PROTEOLYTIC THEORY

Gottlieb,1947 Enamel lamellae Organic matrix would be attacked

before mineral phase of enamel The proteolytic enzymes liberated by

oral bacteria destroy the organic matrix of enamel, loosening apatite crystals, so that they are eventually lost and the tissue collapses.

2 types of carious lesions:1. Microorganism enamel lamellae attack

enamel and dentin (before clinical evidence of caries)

2. No lamellae, bacteria in dental plaque acids enamel decalcification.

The early lesion chalky white

THE PROTEOLYSIS- CHELATION THEORY

Schatz and Martin (1955)

Initial attack breakdown of organic matter

Breakdown products chelate with minerals of enamel dissolves it

Chelates (Metal-substance Complex with Covalent bonds)can be formed at neutral or

alkaline pH, the theory suggests that demineralization of enamel could arise

without acid formation.

KEYES TRIAD

ETIOPATHOGENESIS OF CARIESNEWBRUN IN 1978 PROPOSED THAT DENTAL CARIES TO BE MULTIFACTORIAL DISEASE

Microorganisms

Host (saliva and teeth

)

Substrate

Time

CARIES

No caries

No caries

No caries

No caries

MODIFIED KEYES JORDAN

Micro flora: Acidogenic bacteria that colonize the tooth surface. Host: Quantity and quality of saliva, the

quality of the tooth, etc. Diet: Intake of fermentable carbohydrates,

especially sucrose, but also starch. Time: Total exposure time to inorganic acids

produced by the bacteria of the dental plaque

HOST FACTORS 1. TOOTHCOMPOSITION OF THE TOOTH Position Of teeth Surface enamel more resistant than subsurface

enamel Surface – More fluoride, zinc, iron and lead, Less dissolution to acids

More inorganic material and less water Subsurface – More carbonate, magnesium, sodium Decreased enamel density and increase permeability

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MORPHOLOGIC CHARACTERISTICS OF TEETH Deep occlusal fissures Buccal or lingual pits

Mand 1 molar > max 1st molar> max & mand 2nd molars

Mand incisors & canines - least

Surface susceptibilty molars → Occlusal lateral incisor → Lingual

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THE ROLE OF SALIVA Physical protection provides a cleansing effect.

Thick, or viscous, saliva is less effective than a more watery saliva in clearing carbohydrates.

Chemical protection contains calcium, phosphate, and fluoride. It keeps calcium there ready to be used during remineralization. It includes buffers, bicarbonate, phosphate, and small proteins that neutralize the acids after we ingest fermentable carbohydrates.

Antibacterial substances in saliva work against the bacteria.

If salivary function is reduced for any reason, such as from illness or medications or due to radiation therapy, the teeth are at increased risk for decay.


1. Fluoride in saliva Formation of fluoroapatite in surface enamel protection against caries.

Inhibits Enolase Enzyme –Inhibiting Glucose transfers in Micro organisams

predetermined by the amount ingested.

Composition of saliva

2.Organic componentsa)Ammonia High ammonia concentration retards plaque

formation, neutralizes acid reduction of caries

Urea converted to Ammonium carbonate which increases the neutralizing power of saliva


b)Histatins (Histidine rich proteins) Antibacterial action Released from Salivary glands present at the back of tongue(Ebner’s Gland)


ANTIBACTERIAL PROPERTIES OF SALIVA

1. LACTOFERRIN• Iron binding protein• Prevents iron utilization by aerobic and facultative anaerobic

bacteria prevents metabolism

2. Lysozyme

Hydrolytic enzyme with direct antimicrobial effect

Salivary gland fluid and crevicular fluid

Acts in many ways

1. Lysozyme - Positively charged enzyme

Binds to salivary ions like HCO3-, F-, I-, NO3

-

Complex binds to the cell wall of bacteria

Hydrolysis of glycosidic bonds between polysaccharides in the cell wall

Destabilization of cell wall

Autolysis

Antibacterial properties of salivaLysozyme

3. Salivary peroxidase system

Salivary Glands secrete salivary Periodase & Thiocyanate(SCN-)

Reacts With H2O2 produced by certain Bacterias

Oxidation of Thiocynate(OSCN-)

Inhibits Metabolisam of Bacteria

IMMUNOGLOBULINS IN SALIVA

IgA is predominant immunoglobin in saliva.• Inhibits adherence and prevents colonization on mucosal surfaces and teeth.

DIET Primitive Man-Roughage/Raw Food Soil along with food

Flattened Occlusal and Proximal Surface –Less caries

Modern DietSoft Sticky Carbohydrate-More cariousLess Roughage

TIME Total exposure time to inorganic acids

produced by the bacteria of the dental plaque

THANK YOU

Healthcare

Dental caries