Fixed denture repair contraindications mainly include the following: 1, the patient missing teeth area is generally 1-3 teeth, not too much when you can do fixed denture, missing teeth area is too large, the abutment teeth support strength is not enough, you can not do, this is the problem of how many missing teeth; 2, there is a free end missing can not do, free end missing 1-2 more if you choose porcelain fixed bridge, is a single end, single end has leverage, on the Too much damage to the abutment teeth can not do; 3, the occlusal gap is too small can not do, because the bridge abutment teeth cross-sectional area is not enough, easy to fold after doing; 4, patients with night grinding disease can not do, because night grinding teeth bite force, and night grinding teeth bite force is very large, bite force may exceed the limit of fixed dentures, will cause some damage to fixed teeth; 5, periodontal disease without treatment can not do, because No treatment there is inflammation, periodontitis patients do not treat fixed, will aggravate the development of periodontitis; 6, more than 3 months after tooth extraction, to fixed porcelain dental repair. Because this time the extraction sockets alveolar bone will reach the absorption of stable, after doing the alveolar bone will not continue to absorb deformation, at this time to repair the bridge tissue surface and the mucosa will not have gaps between and lead to food embedding.