Objective To investigate and analyse causes and law of pulp, periapical and periodontal disease of base teeth occurred in five years after finishing restoration. Methods 263 patients with defect of dentition were restored by five sorts of fixed prosthesis including single crown and fixed bridge, 582 vital base teeth of fixed prosthesis were reexamined and observed for caries, periodontitis, gingival recession and leakage form by clinic examination. To analysis causes of base teeth of prosthesis in five years following repaired. Results Above 41- year old patients had higher obviously than under 40- year old group in incidence of base teeth disease during 5 years after repaired. No relationship between base teeth that suffer from diseases and sorts of restoration had been found. Number of base teeth suffer from disease much more in first year than next four years after repaired. Pulpitis or apicitis of base teeth caused by dental caries, periodontal disease, gingival recession and leakage between body of restoration and base teeth occurred following third year after fixed restorations had been finished. Conclusion The cause of pulpitis or apicitis of base teeth was difference in different time following repaired. Dental pulp injured during the restoration may be cause of pulpitis and apicitis of base teeth in above 41- year old patients. Dental caries, periodontitis became main disease of base teeth sickened in next second or third years after completed restoration.
