Dental Caries Overview

Introduction

• Dental caries is a common disease known as tooth decay.
• It consists of a disease process and not simply holes in teeth.
• Dental caries is one of the most prevalent chronic diseases globally.
• It's a major cause of tooth loss and oral pain.

### Definition

• Also known as tooth decay or a cavity.
• A complex, multifactorial, biofilm-dependent disease of bacterial origin.
• It causes demineralization and destruction of hard tooth tissues (enamel, dentin, and cementum).
• It's a dynamic disease where demineralization by organic acids of microbial origin is followed by remineralization by salivary components. 
• Non-cavitated carious lesions are characterized by mineral loss beneath an intact enamel surface, creating porosities that change the refractive index.
• White or opaque areas on enamel surfaces are called “white spot lesions”.

### Etiology

• No single theory can adequately explain all aspects of caries. 
• The etiology of dental caries is a complex problem with many indirect factors that obscure the direct cause. 
• There are several theories: acidogenic, proteolytic, and proteolytic-chelation. 

Acidogenic Theory

• Proposed by Miller in 1884. 
• Explains that dental decay is a chemo-parasitic process caused by acids produced by microorganisms in the mouth.
• The acid is derived from carbohydrate fermentation lodged in the teeth's retentive centers.
• The theory emphasizes three factors:
  • Oral microorganisms.
  • Carbohydrate substrate.
  • Acids.
• Two stages occur:
  • Decalcification of enamel, leading to enamel destruction and dentin demineralization.
  • Dissolution of softened residue.

Proteolytic Theory

• Proposed by Gottlieve in 1944.
• It considers caries as a proteolytic process where organic and protein components are the initial pathway for microbial invasion.
• It proposes that proteolytic microorganisms invade the tooth's organic component.
• Proteolytic enzymes are released and destroy and dissolve the tooth's organic matrix.
• Amino acids are formed as acids, leading to the demineralization of the inorganic tooth.

Proteolytic-Chelation Theory

• Proposed by Schatz in 1955.
• It involves the simultaneous microbial degradation of organic components (proteolysis) and the dissolution of inorganic components through chelation.
• This process refers to compounds that can bind metallic ions like calcium, iron, copper, and zinc by valence bonds.
• The theory states that dental caries involves bacterial destruction of teeth, with the primary attack on the enamel's organic components. 
• Breakdown products of the organic matter have chelating properties and dissolve the minerals in the enamel.

### The Three Main Factors Involved in Caries

• Caries occur when there's an interaction between three principal factors:
  • The host. 
  • The microflora. 
  • The substrate (diet). 

Host Factors

• Tooth:
  • Physical factors: quality of diet, composition, morphologic characteristics, and position. 
  • Tooth Morphology and Position:
    • Deep pits and fissures make teeth more susceptible to caries due to food impaction and bacterial stagnation. 
    • Irregular arch forms, crowding, and overlapping also contribute to caries development.  
  • Tooth composition:
    • Partially impacted third molars have a higher risk of caries.
    • They form large amounts of extracellular sticky, insoluble glucan plaque matrices.
• Saliva:
  • Composition. 
  • pH. 
  • Quantity. 
  • Viscosity.   
  • Antibacterial factors.

Microflora

• The presence of acidogenic and aciduric bacteria is essential for caries progression. 
• Deep dentinal caries predominantly consist of lactobacilli, comprising about one-third of the oral flora. 
• Lactobacilli need retentive areas to proliferate, and a high count is often associated with frank cavitation.
• Actinomyces Viscosus is predominant in root caries (cemental caries). 

Substrate (Diet)

• Physical Nature of the Diet:
  • Refining carbohydrates is linked to an increased concentration of acid-producing bacteria and dental caries. 
  • Eating fibrous and tough foods at the end of a meal naturally scrubs teeth and gingival tissues during mastication.
• Chemical Nature of the Diet:
  • The carbohydrate content of the diet is critical to caries development. 
  • Refined carbohydrates are particularly effective in caries. 
  • Factors include:
    • Type of carbohydrates (monosaccharides, disaccharides, or polysaccharides). 
    • Frequency of intake. 
    • Time of stagnation.
• Sucrose is exceptional because it promotes the formation of insoluble extracellular polysaccharides, enhancing plaque formation.
• Snacking between meals contributes to caries.
• Vitamin Content:
  • Vitamin D and K might have a role in caries.
  • Vitamin D deficiency can cause enamel hypoplasia, making teeth more susceptible to caries. 
  • Vitamin K has enzyme-inhibiting action in carbohydrate degradation, potentially working as an anticariogenic agent. 
• Calcium and Phosphorus content
• Fluorine content
  • Topical and water fluoridation have been shown to be effective in caries control, but dietary fluorine may not have a significant role. 

### Time Factor

• Time plays a crucial role in caries development. 
• Prolonged, undisturbed plaque stagnation lowers the plaque pH, favoring organic acid production and tooth demineralization.

### Determinants and Confounders in Caries

• Determinants:
• Any factor that influences the outcome of caries.
• Major and minor components act as determinants due to their interactions that determine enamel dissolution.  
• Confounders:
• Factors that are not the direct cause of the disease but may influence its severity.

### Pathogenesis of Dental Caries

• These are the steps of caries development:

1. Pellicle formation:

• A thin, acellular proteinaceous film forms on the tooth surface.
• Microbial colonization:
  • Microorganisms adhere to the pellicle-coated surface within 4-24 hours.
• Microbial succession:
  • The initial streptococcal flora makes way for the proliferation of other organisms.  
• Mature biofilm:
  • After a week of undisturbed growth, a diverse bacterial community develops. 

### Role of Dental Biofilm in Caries

• Dental biofilm or plaque refers to a sticky, bacterial mass that grows on tooth surfaces.  
• Non-specific Plaque Hypothesis:
  • The overall total plaque microflora's activity determines the outcome.
• Specific Plaque Hypothesis:
  • Specific species like Streptococcus mutans are actively involved in caries disease.
• Ecological Plaque Hypothesis:
  • This theory combines both previous hypotheses.
  • It argues that disease-associated organisms might be present at healthy tooth sites but at lower levels.
  • Changes in local environmental conditions disrupt the balance of resident microflora, leading to caries.

### Histopathologic Features

• Caries lesions are recognized based on their morphology and location.
• Primary caries occurs when there is no previous damage or restoration on the tooth surface.
• Secondary caries develops around existing restorations.

### Classification

• Many systems classify dental caries lesions based on their clinical presentation, lesion depth, and location.
• The Black Classification system is a method used by dentists to classify cavities:
  • Class I Cavities - Found in pits and fissures of the occlusal surfaces of molars and premolars.  
  • Class II Cavities - Found on the proximal surfaces of premolars and molars (between the teeth). 
  • Class III Cavities - Located on the proximal surfaces of incisors and canines.
  • Class IV Cavities - Found on the proximal surfaces of incisors and canines and involve the incisal edge or the cusp tip.
  • Class V Cavities - Located on the gingival third of the facial or lingual surfaces of any tooth.
  • Class VI Cavities - Found on the incisal edges of anterior teeth or the cusp tips of posterior teeth caused by wear or erosion.
• The ICDAS System (International Caries Detection and Assessment System) is used to assess and monitor the progression of caries.

### Clinical Signs and Symptoms of Dental Caries

• The symptoms of dental caries depend on the stage of the lesion, the location, and the individual's sensitivity.

### Diagnosis

• A dental exam, including visual inspection, use of a dental explorer tool, and radiographic examination, can be used to diagnose dental caries. 

### Prevention of Dental Caries

• Practice good oral hygiene: Brushing twice daily with fluoride toothpaste and flossing at least once a day.
• Consume a healthy diet: Limit sugary foods and drinks, and eat a well-balanced diet rich in fruits, vegetables, and whole grains. 
• Fluoride:
  • Use fluoride toothpaste, mouthwashes, and consider fluoride treatments.
  • Make sure to take fluoride-containing water. 
• Dental Sealants:
  • Ask your dentist to apply sealants to deep pits and fissures. 
• Regular Dental Checkups:
  • Schedule regular visits with your dentist for checkups and cleanings.

### Management

• Restorations:
  • Fillings (composite resins, amalgam, glass ionomer) are used to repair cavities. 
• Crowns:
  • Crowns are used to cover and protect heavily damaged teeth. 
• Extractions:
  • Extractions are necessary in cases of advanced caries or non-restorable teeth. 
• Other treatment options:
  • Antibiotics: Used for severe carious infections.
  • Root canal therapy: May be required to treat caries that have infected the pulp of the tooth.
• Preventive measures and lifestyle modifications:
  • Maintain good oral hygiene.
  • Limit sugary intake.
  • Increase fluoride consumption.
  • Consult a dentist for regular checkups and cleanings.

### Conclusion

• Dental caries is a complex disease with multiple contributing factors. 
• It requires a multifaceted approach to prevention and management.
• Maintaining good oral health practices is crucial for preventing and treating dental caries.

This quiz covers the essential aspects of dental caries, commonly known as tooth decay. It delves into its definition, the disease process, and the multifactorial etiology behind this prevalent chronic condition. Gain insights into the formation of carious lesions and their implications for oral health.