A, local contraindications: 1, poor occlusal relationship: such as occlusal relationship is not normal, should not do implant restoration. Can correct the occlusal relationship can be carried out. (Severe jaw anomalies, such as misalignment, tight bite, night grinding, lateral chewing and other bad habits of patients, due to imbalance of bite or excessive force may cause trauma to the bone tissue around the implant and lead to failure; 2, alveolar bone has pathological changes: such as root stumps, inflammation, etc., after eliminating pathological changes can be considered for implant restoration. Patients with jaw bone lesions, osteomyelitis, bone cysts, sinusitis; 3, the jaw bone after radiation therapy; 4, progressive periodontitis, oral infection; 5, patients with restricted mouth opening; 6, psychological disorders mental tension, can not cooperate with the physician; serious alcoholism, smokers. Second, systemic contraindications: patients with systemic diseases and immune dysfunction, such as heart disease, blood disease, diabetes, kidney disease, bone metabolic disease, mental and neurological disorders can not cooperate with the doctor and pregnant women.