Recent medical research has once again emphasized the critical importance of oral health, warning that poor oral hygiene not only leads to common dental issues but is also closely linked to the development of various systemic diseases. As the starting point of the human digestive system, the mouth is a breeding ground for bacteria. Inadequate daily cleaning and care can easily trigger a series of health problems.  The study shows that poor oral hygiene first causes oral diseases such as dental caries, gingivitis, and periodontitis. These conditions not only lead to discomfort such as toothache, gum bleeding, and bad breath but can also result in loose teeth or even tooth loss in severe cases, affecting chewing function and facial aesthetics. For example, pathogenic bacteria from periodontitis can enter the bloodstream, damage vascular endothelial cells, increase blood viscosity, and raise the risk of blood clots. This significantly elevates the likelihood of cardiovascular diseases such as coronary atherosclerosis, myocardial infarction, and stroke. Data indicates that periodontitis patients are far more likely to develop cardiovascular diseases compared to those with healthy gums.  There is also a bidirectional relationship between oral health and diabetes. Patients with diabetes have higher blood sugar levels and weakened immunity, making them more susceptible to periodontal disease, which tends to be more severe and harder to control. Conversely, periodontal inflammation can exacerbate insulin resistance, cause blood sugar fluctuations, and hinder diabetes management. Individuals with moderate to severe periodontitis are 2-3 times more likely to develop diabetes than healthy people.  Additionally, oral health is closely tied to respiratory health. People with poor oral hygiene are 4.5 times more likely to suffer from chronic respiratory diseases. Bacteria in the mouth, such as *Streptococcus pneumoniae* and *Haemophilus influenzae*, can be aspirated into the lungs, triggering pneumonia or acute exacerbations .