Dental Caries Overview and Treatment

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which type of bacteria is primarily responsible for acid production in dental caries?

Streptococcus mutans (correct)

Actinomyces

Clostridia

Aspergillus

What is the role of fluoride in the prevention of dental caries?

Increases the acidity of plaque

Increases bacterial adhesion

Enhances glucose uptake by bacteria

Decreases the solubility of hydroxyapatite (correct)

Which classification of dental caries refers to decay occurring on smooth surfaces of teeth?

Smooth surface caries (correct)

Cemental caries

Pits & fissures caries

Recurrent caries

What characteristic defines aciduric bacteria in dental plaque?

They can survive in low pH environments. Signup and view all the answers

Which factor regarding carbohydrates contributes to the risk of dental caries?

Type of carbohydrates consumed Signup and view all the answers

Which component of dental plaque is predominantly responsible for its protective function?

Extracellular polysaccharides Signup and view all the answers

What is the main characteristic of recurrent caries?

It occurs on previously treated areas. Signup and view all the answers

What effect does the presence of dental plaque have on the teeth?

It creates an environment conducive to caries. Signup and view all the answers

What characterizes the phase of bacterial invasion in enamel?

Sufficient spaces are created by acid action before bacterial invasion begins. Signup and view all the answers

Which phase describes the complete destruction of enamel due to proteolytic bacteria?

Phase of destruction Signup and view all the answers

What is NOT true about the infected lesion that occurs after enamel cavitations?

It only features acidogenic bacteria. Signup and view all the answers

Which zone is characterized by the presence of decalcified infected material?

Body of the lesion Signup and view all the answers

In the clinical picture of dentine caries, what shape is the lesion described as?

Cone shaped with the base toward the DEJ Signup and view all the answers

What does the term 'liquefaction foci' refer to in infected lesions?

The coalescence of neighboring beads along tubules Signup and view all the answers

What is the primary action of acidogenic bacteria during the first wave of infection in dentine?

They decalcify dentine while preserving the organic matrix. Signup and view all the answers

Which zone is responsible for the formation of secondary or reactionary dentine?

Zone of reactionary dentine formation Signup and view all the answers

What is one of the primary roles of the plaque matrix in dental health?

Acting as a diffusion limiting membrane Signup and view all the answers

Which factor does NOT directly influence plaque formation?

Type of dental floss used Signup and view all the answers

In the pathology of enamel caries, which phase truly signifies the destruction of dental tissue?

Destruction phase Signup and view all the answers

Which zone of the carious lesion lies at the advancing front and is due to initial demineralization?

Translucent zone Signup and view all the answers

Which of the following theories best explains the process of caries developing under restorations?

Proteolytic theory Signup and view all the answers

Which of the following elements in saliva contributes to its buffering effect?

Bicarbonate Signup and view all the answers

What is the composition of the 'dark zone' in the carious lesion?

Contains micro-pores accounting for 2-4% of enamel volume Signup and view all the answers

What is a characteristic of the surface zone in enamel caries?

It may be more radio-opaque and harder than deeper zones Signup and view all the answers

Study Notes

Dental Caries

A disease characterized by demineralization of tooth's inorganic part followed by the dissolution of its organic part due to bacteria.
The most common dental disease worldwide.

Classification

Pit & fissure caries
Smooth surface caries
Cemental (root) caries
Recurrent caries
Acute (rampant) caries
Arrested caries

Contributing Factors

Susceptible tooth surface
- Tooth position
- Tooth morphology
- Tooth structure
- Genetic factors
- Fluorides

Mechanisms of cariostatic effect of fluoride

Reduction of apatite solubility by converting hydroxy-apatite to fluoro-apatite crystals.
Enhancement of re-mineralization of the carious lesion.
Anti-bacterial activity

Anti-bacterial activity of fluoride

Decreased lactic acid production, making organisms less cariogenic.
Decreased glucose uptake by organisms, leading to a decrease in energy reserve and metabolic activity.
Decreased bacterial adhesion.

Carbohydrates

Type: mono, di & polysaccharides
Total amount of carbohydrate intake
Frequency of carbohydrate intake
Consistency of carbohydrates

Micro-organisms

Acidogenic bacteria: Lactobacilli & Streptococci (Strept.Mutans)
Proteolytic bacteria: Actinomyces, Clostridia & Pseudomonas
Chromogenic bacteria: Asprigillus

Essential features of cariogenic bacteria

Acidogenic
Production of low pH (lower than 5.5)
Aciduric
Attachment mechanisms for firm adhesion to the tooth surface
Production of abundant polysaccharides for plaque matrix formation

Dental Plaque

An adherent bacterial structure on tooth surfaces.
Contains a large number of closely packed micro-organisms surrounded by an extracellular material of bacterial and salivary origin.
Two major interfaces:
- Internal one (pellicle)
- External one (plaque saliva interface)

Types of Dental Plaque

Sub-gingival
Supra-gingival

Composition of Dental Plaque

Micro-organisms
Matrix: protein, lipids, carbohydrates, inorganic component, and water

Role of plaque matrix

Acts as a diffusion limiting membrane retaining acid in high concentration to initiate caries.
Slows down the entry of buffers from saliva, delaying their neutralizing action.

Factors affecting plaque formation

Anatomy & position of tooth
Presence of appliance
Structure of tooth surface
Friction from diet
Oral hygiene procedures
Composition of the diet

Mechanism of action of dental plaque

Allows adhesion of bacteria & acids on the surfaces of teeth
Prevents escape of acids and entry of salivary buffers

Saliva & Caries

Washing effect of saliva
Buffering effect of saliva by phosphate and bicarbonate content
Salivary antibodies (IgA)
Antibacterial substances: lysozymes, Peroxidases & lactoferrin

Theories of dental caries

Acidogenic theory (Miller's chemico-parasitic theory): most accepted.
Proteolytic theory: Explains penetrating caries under restorations & caries of impacted teeth.
Proteolosis- chelation theory

Pathology of Enamel Caries

Clinical picture
- White chalky area
- Rough to the probe with staining
- Cavitations
- Cone-shaped carious lesion
  - Pits & fissure caries: Base toward DEJ, apex toward surface
  - Smooth surface caries: Base toward surface, apex towards DEJ
Microscopic picture (With polarized light microscope):
- 4 phases:
  - Initiation phase
  - Bacterial invasion phase
  - Destruction phase
  - Phase of secondary enamel caries

Initiation phase (4 zones)

Translucent zone
- Lies at the advancing front of the carious lesion
- Due to initial demineralization
- Contains pores accounting for 1-2% of enamel volume
Dark zone
- Lies superficial to the translucent zone
- Due to further enamel demineralization
- Contains micro-pores accounting for 2-4% of enamel volume
Body of the lesions
- Lies under the surface zone and constitutes the largest area of the carious lesion.
- Due to advanced demineralization
- Contains pores accounting for 5% at the periphery and 25% at the center of the zone
- Appears translucent
Surface zone
- Although not intact, it appears more radio-opaque and harder than deeper zones.
- Continuous re-mineralization from saliva
- Contains much fluoride
- Contains much insoluble proteins
- Prism-less enamel may delay diffusion of acids.

Phase of bacterial invasion

Bacteria begin to invade enamel when sufficient spaces are created by the action of acids.

Phase of destruction

Proteolytic bacteria begin to act on the organic matrix of the enamel leading to complete destruction of enamel.

Phase of secondary enamel caries

Acid and bacteria reach DEJ, spread laterally along it and begin to invade enamel from beneath leading to its undermining.

Pathology of Dentin caries

Clinical picture
- Appears brownish & soft to the probe
- Cone-shaped with the base toward DEJ & the apex toward the pulp
Microscopic picture
- Initial uninfected lesions (occur before enamel cavitations)
  - Zone 1: Zone of reactionary or reparative dentine formation (secondary dentine)
  - Zone 2: Zone of sclerotic or translucent dentine formation (Ca.ion deposition)
  - Zone 3: Zone of the body of the lesion (dead tract)

Infected lesion (occurs after enamel cavitations)

Dentinal tubules provide a pathway of bacterial invasion in 2 waves:
- 1st wave: Pioneer bacteria consists of acidogenic bacteria that decalcify dentine leaving organic matrix intact.
- 2nd wave: Consists of mixed infection containing proteolytic bacteria that distort the organic matrix.
Consists of 4 zones :
- Zone 1: Mild pulp inflammation
- Zone 2: Reparative or reactionary dentine
- Zone 3: Sclerotic dentine
- Zone 4: Body of the lesion
  - Decalcified uninfected zone
  - Decalcified infected zone
  - Destruction zone

Decalcified infected zone

Beading: lateral distension of dentinal tubules by the action of bacteria.
Liquefaction foci: Coalescence of neighboring beads and lie at the long axis of dentinal tubules.
Transverse clefts: Liquefaction foci lie at right angles to dentinal tubules due to their existence on a lateral branch of dentinal tubules.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores the intricacies of dental caries, including its classification, contributing factors, and the mechanisms by which fluoride combats this common disease. Test your knowledge on how dental health professionals address and prevent the progression of carious lesions.