Cariology

Define dental caries.

-biofilm (plaque) mediated

-sugar-driven, multi factorial

Results from an imbalance between demineralization and remineralization of the teeth.

How many Americans have some sort of dental disease?

98%

• more individuals suffer from dental disease than from any other form of illness known

Explain dental caries.

dental caries develops because certain bacteria in the oral cavity ferment carbohydrates (sugars) into organic acids, which in the case of lactic acid may result in dissolution of dental hard tissue.

Which 3 things interact in the caries process?

• Teeth

• Microorganisms

• Saliva

What is demineralization? What causes it ? Name 3.

• The dissolution of tooth matter/minerals.

• It is caused by acids that form during fermentation of sugars by oral bacteria.

  • Acidic drinks and foods

  • Lack of protective saliva

  • Tooth morphology/composition (crooked teeth)

Define Remineralization and name 6 things that cause it.

• the removal cariogenic bacteria by maintaining healthy teeth.

  • Effective oral hygiene

  • Good salivary flow

  • Topical fluoride applications

  • Sealants

  • Use of remineralizing agents or anti caries

  • Modifying diet

What are the usual causes of caries? Name the major 4.

1. Genetics

2. Bacteria

3. Diet

4. Saliva

What is enamel? Name its characteristics.

The outermost layer of the tooth composed of calcium hydroxyapatite.

• hardest substance in the human body.

• 96-99% inorganic content (the rest is inorganic and water)

What is Dentin? Name its characteristics.

• a yellowish vital tissue underneath the enamel.

• Softer than enamel

• 70% inorganic content; 18% organic and 12% water

What is the pulp? Name its characteristics.

A highly vascular component of the tooth and is composed of connective tissue

• arterioles and venules enter and exit through the apical forsaken

• 25% organic material and 75% water

Which 3 glands is saliva produced by?

1. Parotid

2. Submandibular

3. Sublingual

What does saliva consist of?

• 99% water

• Electrolytes

• Organic components (proteins, glycoproteins, enzymes)

What is the pellicle?

A thin, bacteria-free layer covering the teeth formed by the absorption of salivary proteins which have a HIGH affinity of mineral on the surface of the tooth.

-plays important role in protecting dental hard tissue against mechanical and chemical damage.

What does the water in saliva contribute to? (5 roles)

-rinsing effect of the mouth

-solubilization of food

-facilitates food clearance

-lubricates oral soft tissues

-facilitates mastication, swallowing, and speech

What do the electrolytes in saliva contribute to? (2 roles)

-maintains supersaturated calcium and phosphate concentrations

-neutralizes acid by buffering actions

What do the organic matter in saliva contribute to?

-enamel pellicle formation

-mucosal coating

-antimicrobial defense

-digestive actions

How does saliva protect against dental caries?

-counteracts demineralization by acting as a natural buffer neutralizing acids and helping RAISE the pH.

-is supersaturated with calcium and phosphate ions which can be REdeposited onto the tooth surface.

How does plaque (biofilm) form on the tooth?

Sticky glycoproteins in saliva from foods high in fermentable carbohydrates ADHERE to the tooth surface, forming a base for bacteria to attach/multiply.

What does the bacteria S.Mutans do on teeth?

Has an enzyme called glucosyltransferase which forms dextran, which is HIGHLY sticky and contributes to the adherence of plaque, further trapping bacteria/acids.

At what pH does enamel demineralization occur?

5.5

Where do caries typically form on younger people?

Pits and fissures (chewing surfaces)

Where do caries typically form on older patients?

Interproximal surfaces and gingival margin

What is the first visible sign of a caries-affected enamel?

The white spot lesion

• Super white porous body that follows the direction of enamel prisms.

Name the zones of enamel caries.

1. Surface zone (changes color)

2. Body of lesion (area of caries)

3. Dark zone (darker)

4. Translucent zone (becomes clear due to lack of minerals)

T or F? Dentin reacts to caries before the demineralization process reaches the DEJ.

True

What is the first sign of dentin-affected caries?

Tubular sclerosis

• defense mechanism where odontoblasts build a layer of reactive dentin.

What is the DEJ?

Dentin-Enamel Junction

When caries reaches the DEJ, which zones can be seen?

1. Zone of demineralization (ZD)

2. Dead tracts (DT)

3. Sclerotic zone (SZ)

4. Normal, but affected dentin (AD)

5. Tertiary dentin (TD)

What happens when the enamel surface has been broken down?

Hydrologic and proteolytic enzymes continue to destroy dentin.

What happens when the zone of penetration reaches the pulp?

Irreversible pulpal inflammation.

What happens as patients age?

Gingival recession»exposes more root surface

Lower salivary flow

Reduced oral capabilities

Describe Erosion

Caused by the direct dissolution of enamel and dentin due to acids, not by bacteria.

What causes erosion? (6 causes)

1. Diet (acidic food and drinks)

2. Stomach acids (acid reflux/vomiting)

3. Environmental (frequent exposure to acid vapors in industry)

4. Medications (chewable vitamin C tablets)

5. Grinding teeth while asleep (Bruxism)

6. Chewing on hard foods

What are the indirect causes of caries?

• education (lack of it)

• Socioeconomic status (lack of access to healthy food)

• Income (can’t afford dental care)

• Genetics

• Age (older»more prone to diseases)

• Dentist

What are direct factors of caries?

Fermentable carbohydrates

ACIDS

Biofilm with pathogenic flora ( lack of oral hygiene)

Where does lactic acid come from?

S. Mutans

• this bacteria ferments dietary sugar into lactic acid which lowers the pH

How many tsp of sugar do American eat per day?

22.7 tsp

Which sugars are the most cariogenic? (2)

Sucrose and glucose

What are the least cariogenic sugars? (2)

Sorbital and Mannitol

Which sugar is shown to be protective against tooth decay?

Xylitol

• cannot be metabolized by bacteria and humans

How many grams of sugar are in 1 teaspoon?

4g

What do “acidic” waters contain?

Phosphorous acid

Citric acid

What do “basic” waters contain?

Sodium bicarbonate