The mouth contains both good and bad bacteria. Good bacteria help to maintain a healthy balance in the mouth, while bad bacteria can lead to oral health problems such as tooth decay, gum disease, and bad breath.

Good bacteria, also known as beneficial or probiotic bacteria, help to protect the mouth by competing with harmful bacteria for nutrients and space. They also produce acids that help to neutralize the pH levels in the mouth, which can prevent tooth decay and gum disease.

Some examples of good bacteria found in the mouth include Streptococcus salivarius, Lactobacillus acidophilus, and Bifidobacterium bifidum.

On the other hand, bad bacteria, also known as pathogenic bacteria, can cause oral health problems. They can produce harmful acids that erode tooth enamel, cause inflammation and infection in the gums, and lead to bad breath.

Some examples of bad bacteria found in the mouth include Streptococcus mutans, Porphyromonas gingivalis, and Prevotella intermedia.

Maintaining good oral hygiene practices, such as brushing and flossing regularly, using mouthwash, and visiting the dentist for regular cleanings, can help to keep the balance of good and bad bacteria in the mouth and promote oral health.