CLINICAL EVALUATION OF OSSEOINTEGRATED IMPLANTS IN TOKYO DENTAL COLLEGE HOSPITAL (THIRD REPORT): LONG TERM OBSERVATION OF FUNCTIONING SURVIVAL RATE OF FIXTURES

The objective of this report was to review 365 cases of Branemark Implant Bridge including 1,444 fixtures in patients of Tokyo Dental College Chiba Hospital. The term of implantation was divided into several phases; less than 1 year, from 1 year to 3 years, from 3 years to 5 years, from 5 years to 7 years, from 7 years to 10 years, more than 10 years, and the survival rate was calculated for each phase. The removal rate of fixture after connecting the superstructure was 13% in maxillary cases and 2% in mandibular cases. The functioning survival rate in maxillary cases slightly decreased from 91% in less than 1 year to 87% after more than 10 years; however, the functioning survival rate in mandibular cases was about 99% in all periods. The removal rate of fixtures per patient was 23% in maxillary cases and 6% in mandibular ones. The average removal number of fixtures was 1.8 in maxillary cases and 1.2 in mandibular ones. The removal of the fixture occurred most frequently at less than 1 year in maxillary cases, but there was no tendency for a pattern of removal of fixture in mandibular cases.