Diabetes is prone to many oral diseases: 1. Periodontal infection The risk of periodontal infection is 2 to 3 times higher in diabetic patients than in non-diabetic patients. It is manifested as gum congestion, swelling, bad taste in the mouth, pain or pressure pain in individual teeth or all teeth. In severe cases, it leads to periodontal abscesses and even loosening or displacement of teeth. 2, loose teeth because diabetic patients are often accompanied by gingivitis, periodontitis and other chronic destructive lesions, especially the alveolar ridge bone osteoporosis, often affecting the stability of teeth, resulting in loose teeth, displacement or misalignment. In turn, it induces periodontal infection and causes tooth loss in serious cases. 3.Root surface caries shows as gum atrophy, multiple teeth decay at the same time, sensitive and painful to hot and cold stimulation. 4.Candida infection (thrush) diabetic patients, the elderly, infants or weak people are easy to be infected. It is manifested as creamy white or gray-white pseudomembrane in the buccal, tongue and palate parts of the mouth, which is surrounded by narrower red halo with clear boundary.