Abstract
<p>The human body is home to trillions of microorganisms, including bacteria, fungi, viruses, and other microbes. Together with their genetic material, these microorganisms form the microbiome. Microbial communities live in different parts of the body, including the gut, skin, vagina, and mouth. They contribute to important functions such as metabolism, immune regulation, and protection against harmful microorganisms. The microbiome begins developing early in life and can be influenced by factors such as diet, medications, health conditions, and how a person is born.The oral microbiome is one of the most diverse microbial communities in the human body. It contains hundreds of different types of microorganisms that live in specific areas of the mouth, including the tongue, teeth, gums, and cheeks. A healthy oral microbiome exists in a balanced relationship with the host and helps maintain oral health by controlling the growth of potentially harmful microorganisms.When this balance is disrupted, a condition known as dysbiosis can occur. Rather than being caused by a single harmful microorganism, diseases such as periodontitis may develop because of broader changes in the microbial community and its interaction with the body's immune system. Periodontitis is a chronic inflammatory disease that affects the tissues supporting the teeth and may also be associated with health conditions beyond the mouth.Research on the oral microbiome and periodontitis has produced varying results because studies differ in their populations, sampling methods, laboratory techniques, and approaches to analyzing microorganisms. A systematic review and meta-analysis can bring these findings together to identify patterns that are more consistent across studies.Understanding how the oral microbiome differs between health and periodontitis may help researchers identify microbial patterns associated with disease risk, progression, or treatment response. In the future, this knowledge could contribute to more personalized approaches to preventing, diagnosing, and treating periodontitis while supporting restoration of a healthy microbial balance.</p>