How does brushing and flossing prevent cavities

Okay, so I know brushing and flossing are supposed to prevent cavities. My dentist tells me every six months! But I’m not really sure how it works, like the specific science behind it. I understand it removes food, but is that all it does?

Is it literally just physically removing food particles, or are there other reasons it helps? Does the toothpaste I use matter? Does the type of floss matter? Is it more about the bacteria in my mouth than the food itself? I’m curious about the entire process of cavity formation and how brushing and flossing interrupts that process. I want to understand it well enough to explain it to my kids so they actually understand why they need to brush and floss. Thanks!

Answer

Brushing and flossing are the primary methods of preventing cavities, also known as dental caries. They achieve this by disrupting and removing dental plaque, a sticky biofilm that forms on teeth. Plaque harbors bacteria, and these bacteria are the main culprits in the cavity-formation process.

Here’s a detailed breakdown of how brushing and flossing work to prevent cavities:

1. Disruption and Removal of Plaque:

• Plaque Formation: Plaque begins to form within hours of brushing and flossing. It consists of bacteria, saliva, and food debris. The bacteria adhere to the tooth surface, creating a matrix that protects them.
• Brushing Action: Brushing physically disrupts the plaque matrix. The bristles of the toothbrush, along with the abrasive action of toothpaste, loosen and dislodge the plaque from the tooth surface. The mechanical action is key to removing the bulk of the plaque.
• Flossing Action: Flossing reaches areas that the toothbrush cannot, primarily between the teeth and under the gum line. The floss scrapes against the tooth surface, removing plaque from these hard-to-reach areas. Without flossing, plaque accumulates in these interproximal spaces, increasing the risk of cavities forming between teeth.

2. Reduction of Bacterial Load:

• Bacteria in Plaque: Plaque contains various types of bacteria, including Streptococcus mutans, which is particularly adept at producing acid.
• Brushing and Flossing’s Impact: By physically removing plaque, brushing and flossing significantly reduce the number of bacteria present in the mouth. This decrease in bacterial load directly translates to a reduction in the amount of acid produced.

3. Acid Neutralization and Prevention of Enamel Demineralization:

• Acid Production: When bacteria in plaque metabolize sugars and carbohydrates from food and drinks, they produce acids as a byproduct. These acids, such as lactic acid, lower the pH of the oral environment.
• Enamel Demineralization: Tooth enamel is primarily composed of hydroxyapatite, a mineral susceptible to acid. When the pH in the mouth drops below a critical level (around 5.5), a process called demineralization occurs. Acids dissolve the calcium and phosphate ions from the enamel, weakening its structure. This is the initial stage of cavity formation.
• Brushing and Flossing’s Role: Brushing and flossing, by removing plaque and reducing acid production, help to maintain a higher pH level in the mouth. This reduces the amount of time that the enamel is exposed to acidic conditions, minimizing demineralization. Furthermore, fluoride toothpaste plays a crucial role here.

4. Fluoride’s Protective Action:

• Fluoride in Toothpaste: Most toothpastes contain fluoride, a mineral that strengthens tooth enamel and makes it more resistant to acid attacks.
• Fluoride Incorporation: During brushing, fluoride ions are incorporated into the enamel’s crystal structure, forming fluorapatite. Fluorapatite is more resistant to acid dissolution than hydroxyapatite.
• Remineralization: Fluoride also promotes remineralization, a process where dissolved calcium and phosphate ions are redeposited onto the enamel surface. Fluoride helps to rebuild weakened enamel, effectively reversing the early stages of cavity formation.
• Inhibition of Bacterial Activity: Fluoride can also interfere with the metabolism of bacteria in plaque, further reducing acid production.

5. Removal of Food Debris:

• Food as Fuel: Food particles, especially sugary and starchy ones, serve as fuel for the bacteria in plaque.
• Brushing and Flossing’s Action: Brushing and flossing remove food debris from the mouth, depriving bacteria of their primary energy source. This reduces the amount of acid they can produce.

In summary: Brushing and flossing are effective cavity prevention strategies because they work synergistically to:

• Physically remove plaque and food debris.
• Reduce the number of acid-producing bacteria in the mouth.
• Neutralize acids.
• Strengthen tooth enamel with fluoride.
• Promote remineralization of weakened enamel.

Regular and thorough brushing and flossing, combined with a balanced diet and regular dental check-ups, are essential for maintaining good oral health and preventing cavities. The recommended frequency is brushing at least twice a day (especially before bed) and flossing at least once a day.