What Causes Tooth Decay? The Key Factors That Damage Teeth

Tooth decay (dental caries) results from a combination of factors that erode tooth enamel over time. Understanding these contributors helps you protect your oral health.

Primary Causes

• Bacteria: Streptococcus mutans and other oral bacteria form plaque, a sticky biofilm on teeth. They metabolize sugars and produce acids that demineralize enamel.
• Sugar and fermentable carbohydrates: Frequent consumption of sugary foods, drinks, and refined carbs fuels acid-producing bacteria. The frequency of exposure matters more than quantity.
• Acid: Direct acid exposure from acidic foods/drinks (citrus, soda, sports drinks, wine) or conditions like acid reflux (GERD) and frequent vomiting erodes enamel chemically.
• Poor oral hygiene: Inadequate brushing and flossing allows plaque to accumulate and harden into tartar, accelerating decay.
• Dry mouth (xerostomia): Reduced saliva flow—due to medications, medical conditions, or mouth breathing—diminishes natural acid neutralization and remineralization.

Contributing Factors

• Tooth anatomy: Deep grooves and pits in molars trap bacteria and food.
• Dental work: Worn fillings, crowns, or bridges can create gaps where decay starts.
• Grinding and clenching (bruxism): These habits cause microfractures and enamel wear, increasing vulnerability.
• Trauma: Chips or cracks expose inner tooth layers to bacteria.

Prevention focuses on fluoride use, limiting sugar frequency, thorough daily plaque removal, regular dental checkups, and addressing dry mouth or bruxism if present.