**Tooth Decay and pH Level in the Mouth**

To understand why tooth decay starts when the pH of the mouth is lower than 5.5, it is important to delve into the relationship between pH, oral bacteria, and dental health.

**What is pH?**
pH is a measure of the acidity or alkalinity of a substance. It is determined on a scale from 0 to 14, where 0 is highly acidic, 7 is neutral, and 14 is highly alkaline. The pH level of the mouth plays a crucial role in maintaining oral health.

**The Role of Oral Bacteria**
The mouth contains numerous bacteria, some of which are beneficial, while others can be harmful. One such harmful bacterium is Streptococcus mutans, which is primarily responsible for tooth decay. These bacteria feed on the sugars and carbohydrates present in our diet. As they metabolize these sugars, they produce acids as byproducts.

**Acid Formation and Tooth Decay**
When the pH level in the mouth drops below 5.5, it becomes acidic, creating an ideal environment for the growth of harmful bacteria like S. mutans. At this acidic pH, the minerals that make up the tooth enamel, such as calcium and phosphate, start to dissolve. This process is known as demineralization.

**Demineralization and Enamel Erosion**
Demineralization weakens the tooth enamel, which is the protective outer layer of the tooth. Over time, the acid produced by oral bacteria can erode the enamel, leading to the formation of cavities or dental caries. If left untreated, these cavities can progress deeper into the tooth, affecting the dentin and potentially reaching the pulp, causing pain and infection.

**Prevention and Maintenance**
Maintaining a pH level above 5.5 is essential to prevent tooth decay. This can be achieved through proper oral hygiene practices, including:

1. Brushing teeth twice a day using fluoride toothpaste: Fluoride helps in remineralizing tooth enamel and making it more resistant to acid attacks.
2. Flossing daily: This helps remove food particles and plaque from between the teeth, where bacteria thrive.
3. Limiting sugary and acidic foods and beverages: These contribute to acid formation and demineralization.
4. Regular dental check-ups: Professional cleanings and examinations can detect early signs of tooth decay and prevent its progression.

By maintaining a balanced pH level in the mouth and adopting good oral hygiene habits, individuals can reduce the risk of tooth decay and maintain optimal dental health.

Tooth decay starts when the pH of the mouth is lower than 5.5. Tooth enamel, made up of calcium phosphate is the hardest substance in the body. It does not dissolve in water, but is corroded when the pH in the mouth is below 5.5. Bacteria present in the mouth produce acids by degradation of sugar and food particles remaining in the mouth after eating....