Diabetes mellitus is a disorder of glucose metabolism caused by insufficient insulin secretion. There is a clear trend of increase in this disease in China. Patients mainly present with elevated blood sugar and urine sugar, and clinically present with the three symptoms of polydipsia, polyphagia and polyuria. Diabetic patients can often lead to dystrophic lesions in a variety of organs, and diabetic gingivitis and periodontitis can occur in the oral cavity. The gums are dark red, swollen, easily bleeding or exfoliated, periodontal abscesses easily occur and often recur; tartar can be formed rapidly in a short period of time, due to the deposition of calculus, the gums are stripped, the periodontal membrane is damaged, and periodontal pockets are quickly formed. This makes food debris easily embedded in the periodontal pockets, which is conducive to microbial growth and aggravates the destruction of periodontal tissues; due to the fear of gum bleeding when brushing, the quality of brushing decreases, and teeth can quickly appear loose, weak, elongated feeling and a series of other symptoms, and some patients even have the loss of the whole mouth teeth in the early stage. People with diabetes can also develop oral symptoms such as dry mouth, thirst, tongue color changing to deep red, and tongue hypertrophy. Severe diabetic patients can smell ketones (rotten apple smell) in the mouth due to fat metabolism disorder and increased ketone bodies, so some patients with bad breath can consider having a blood sugar test. The high sugar content in the tissues of diabetic patients, coupled with the patient’s reduced immune function, is conducive to bacterial growth and reproduction. As a result, purulent infections such as boils and carbuncles can often occur on the maxillofacial area. Since diabetic patients have low systemic and local resistance, the injured wounds are prone to infection and necrosis, so before performing oral surgery such as tooth extraction and deep scaling for periodontal disease, blood glucose should be controlled within 8.96 mmol/L and effective antibiotics should be used before and after surgery. In addition, anesthetics containing epinephrine should be used sparingly because epinephrine can raise blood sugar and cause local ischemia in the wound, which can lead to infection. In addition, the extraction should be completed within two hours for insulin-injected patients to prevent hypoglycemic reactions due to prolonged fasting time.