Signs, Symptoms, and Causes of Tooth Decay
- Appearance of a chalky white spot on the tooth surface
- Brown discoloration indicating demineralization
- Formation of a cavitation (cavity)
- Softening of affected areas of the tooth
- Exposed dentinal tubules leading to pain and sensitivity
- Presence of tooth surface (enamel or dentin)
- Caries-causing bacteria, such as Streptococcus mutans and Lactobacillus species
- Fermentable carbohydrates (sucrose, fructose, glucose)
- Time for the disease process to occur
- Sheltered environment promoting development of cariogenic biofilm

Bacteria and Complications of Tooth Decay
- Mutans streptococci, particularly Streptococcus mutans and Streptococcus sobrinus
- Lactobacilli
- Cariogenic bacteria present in dental plaque
- Shift in bacterial balance due to sugar intake or inadequate biofilm removal
- Role of Streptococcus mutans in biofilm formation and acid production
- Inflammation of tissue around the tooth
- Tooth loss
- Infection or abscess formation
- Bad breath and foul tastes
- Spread of infection to surrounding soft tissues, leading to life-threatening complications

Prevalence, Prevention, and Socio-economic Factors of Tooth Decay
- Approximately 3.6 billion people (48% of the population) have dental caries in their permanent teeth
- Nearly all adults experience dental caries at some point
- Dental caries affect about 620 million people (9% of the population) in baby teeth
- More common in developed countries due to higher sugar consumption
- Prevention includes regular teeth cleaning, low-sugar diet, and fluoride use
- Poverty is a significant social determinant for oral health
- Dental caries are linked to lower socio-economic status
- Dental caries can be considered a disease of poverty
- Intrauterine and neonatal lead exposure promote tooth decay
- Exposure to certain ions, such as cadmium, may promote tooth decay

Factors Affecting Tooth Decay
- Dietary sugars: Bacteria in the mouth convert glucose, fructose, and sucrose into acids through fermentation.
- Exposure: The frequency of exposure to acidic environments affects the likelihood of caries development.
- Teeth: Certain diseases and disorders can increase the risk of cavities.
- Other factors: Reduced salivary flow rate, medications, medical conditions, radiation therapy, altered metabolism, tobacco use, and exposure to secondhand smoke increase the risk of caries.

Pathophysiology and Classification of Tooth Decay
- Pathophysiology: Microbe communities attach to tooth surface and create a biofilm, leading to acid production and demineralization.
- Enamel: Bacteria produce lactic acid, causing demineralization of enamel crystals.
- Dentin: Dentin reacts to the progression of dental caries, with odontoblasts producing dentin and defense mechanisms including sclerotic and tertiary dentin.
- Cementum: Cemental caries increases in older adults with gingival recession and can result in tooth loss.
- Classification of Caries: G. V. Black Classification of Restorations categorizes caries by location, etiology, rate of progression, and affected hard tissues. Early Childhood Caries is a specific type affecting young children. Rate of progression can be acute, chronic, recurrent, incipient, or arrested. Caries can involve enamel, dentin, or cementum.