Dental caries is a progressive bacterial infection that causes demineralization and destruction of tooth structure. It develops due to an imbalance between demineralization and remineralization when acid is produced by bacteria in dental plaque from sugars. Key factors in development include acidogenic bacteria, fermentable carbohydrates, and the presence of dental plaque. Prevention strategies aim to reduce bacterial acid production, remineralize enamel, and remove plaque through chemical, nutritional, and mechanical methods like fluorides, restricted sugars, toothbrushing, and dental sealants.

2. Prof .Dr.Amal M. El Deeb
PROF.OF ORAL PATHOLOGY
FACULTY OF DENTISTRY,UMM AL
QURRA UNIVERSITY,MAKKA,SA

4. Dental caries
Is a progressive irreversible bacterial damage of the tooth
structure exposed to the oral environment characterized by
demineralization of the inorganic portion and destruction of
the organic substances of the tooth.
Etiology of d. Caries
(Multi factorial process)
3 theories have been proposed:
Acidogenic theory
Proteolytic theory
Proteolysis chelation theory

5. Acidogenic
theory
Carbohydrates Micro-organisms
Susceptible
Acid &
tooth surface &
time
dental plaque

6. Contributing factors for development of
dental caries
1- Saliva 2- diet
3- Systemic condition 4- Immunity
Susceptible tooth surface
1- Composition 2- Position
3- Morphological characteristics

7. Acidogenic theory
1- Acidogenic + Carbohydrates
Bacteria
(Enzymes)
Acid
2- Acid + Enamel mineral  demineralization
3- Acid + Dentine mineral  demineralization
4- Proteolytic bacteria + organic M.  digestion

8. Role of carbohydrates
Factors affecting cariogenicity of CHO:
1- Type of CHO.
2- Total amount.
3- Frequency of intake.
4- Route of administration.
5- Consistency & texture of CHO.
6- Refinement of CHO.

9. Types of CHO
Monosaccharides Disaccharides Polysaccharides
Glucose Sucrose starch
Fructose Lactose glycogen
Glactose Maltose
Polysaccharides salivary amylaze enzyme Disaccarides
Disacc Maltaze enzyme st. mutans Monosaccharides
Monosacc Lactase enz. Lactic acid  decalcification
Lactobacilli

10. Sucrose ( gluo + fru )
Extrcellular polysacc.
Dextran Levan
- Polymer of glucose - Polymer of fructose
- H2O insoluble - H2O soluble
- Highly adhesive - less adhesive
- Resist degradation - Rapidly broken & lost
within few hours

11. Stephan curve

12. The demineralization – remineralization
balance
Factors involved
 PH conc. Or acid levels
 Mineral ions conc.
 Carbohydrates
 Complexing agents
 Fluoride
 Frequency & severity of
cariogenic challenge
 Brushing

13. Role of MOS.
The essential features of cariogenic
bacteria
1- Acidogenic.
2- Aciduric.
3- Adhere to the tooth surface.
4- Producing extracellular polysaccharides
for dental plaque formation.
5- Able to produce intracellular polysacc.
6- Have a proteolytic property.

14. Role of dental Plaque
Composition of D.P.
- 50-60% microorganisms - 30 % Mucin
- 10% Glucan - Inorganic salts ca, Ph, cl, K
- Mineral ions Zn, Cu, Fe, FL - Desquamated epithelial cells
- Food debris
Function of D.P.
- Provide nutrition for bacterial metabolism to produce acid.
- Helps to retain acid-in contact with the tooth surface for long
time.
- Protects the acid from the diluting effect of saliva.

15. Mechanism of D.P. formation
1- Deposition of the acquired pellicle.
2- colonization of the acquired pellicle by bacteria.
3- Maturation & proliferation of Mo.s  in the thickness of
D.P.
Formation of the matrix of dental plaque
1- protein
Glycosidaze enzym
Salivary mucin (glycoprotein) Loss of CHOs long hilical
protein core  less soluble protein deposits around
mos  increase bulk of d.p
2- Carbohydrate (CHOs)

16. Arrow : Enamel pellicle Colonization of the pellicle with
MOs
De-mineralized
enamel surface

17. Proteolysis chelation theory
Keratinolytic Mos organic sub. Chelating agent +
mineral ions  Decalcification

18. Contributing of factors of D.C
Saliva
1- Composition 2- PH 3- quantity
4- Viscosity 5- Buffer action
6- Antibacterial effects
Diet
1- Physical factors 2- Local factors
Carbohydrate content Vitamin content
Ca, ph. content Fluoride content

19. Clinical aspects of dental caries
Pit & fissure C.

20. Pit & fissure
caries….. continued

21. Smooth surface c.

22. Root caries
Radiation caries

23. Acute forms of D.C.
Rampant caries

24. Acute forms of D.C.
Nursing caries
(Baby bottle
syndrome, bottle
mouth syndrome)

25. Radiographic
diagnosis of
D.C. Occlusal
caries
Recurrent Interproximal
caries caries

26. Histopathology
of D.C.
Enamel Caries

27. Enamel Caries …continued

28. Dentin
caries

29. Dentin caries
Early changes

30. Dentin caries
Advanced
changes

31. Pulp abscess 2ry to
advanced D.C.

32. Methods of caries control
Control of dental caries presents one of the greatest
challenges that must be met today by the dentist
1- Chemical measures
 Substances alter the tooth surface or structure.
 Substances interfere with CHO degradation via
enzymatic alterations.
 Substances interfere with bacterial growth &
metabolism.
2- Nutritional measures
3- Mechanical measures

33. 1- Chemical measures
* Fluorine
1) Systemically applied  water fluoridation [1 ppm ]
2) Topically applied  lozenges, gels, mouth-rinses,
chewing gums , prophylactic pastes .. etc
( Sodium fluoride, potassiun fluoride, ammonium
fluoride, stannous fluoride & acidulated fluoride-
phosphate [ AFP ]. )
* Bis-biguanides
Chlorhexidine & alexidine  anti-plaque agents
* Zinc chloride & Potassium ferrocyanide  impregnated
on the tooth surface thus blocking the caries
pathways (little clinical value)

34. Substances interfering with carbohydrate
degradation via enzymatic alterations:
To be effective
 it must reach the susceptible areas of the mouth
 in sufficient concentration
 & at the time of sugar breakdown.
Vitamin K ( prevents acid formation in incubated
mixtures of glucose & saliva )
Sarcoside ( able to penetrate the D.P. & may prevent
the PH fall below 5.5 after carbohydrate ingestion )

35. Substances interfere with bacterial growth &
metabolism
Urea & ammonium compounds
Urea urease enz. Ammonia
Ammonia
 neutralizes acids formed through CHO digestion.
 interferes with bacterial growth.
Chlorophyll
 Reduce PH fall in CHO-saliva mixtures in vitro.
 Bacteriostatic effect on many oral M.O.
Antibiotics (Erythromycin, Kanamycin, Spiramycin,
Tetracycline, Tyrothricin, Vancomycin )

36. 2- Nutritional measures
1- Restriction of refined CHO & sugar intake.
2- Moving to certain food stuffs such as Cheddar cheese which
can reverse the rise in acidity .
3- Phosphated diets ( dibasic calcium phosphate or sodium
dihydrogen phosphate )  cariostatic properties.
1- Dental prophylaxis
3- Mechanical 2- Tooth brushing
measures 3- Mouth rinses
4- Dental floss
5- Chewing gum ( sugar-free )
6- Detergent food
7- Pit & fissure sealant application