A clinical survey of removable partial dentures. --Analysis of follow-up examinations over a sixteen-year period--.

In order to carry out the proper prosthetic treatment, it is necessary to select the method of treatment on the basis of accurate information concerning the prognosis of the prosthetic appliance. The oral structures are particularly proved to change when partial dentures are being used because the structures of the partial dentures are quite complex and they are easily broken. Therefore, in an attempt to analyze the changes that occur in the oral structures and partial dentures after insertion of the partial dentures, we conducted 3 series of follow-up examinations. The author sent out questionnaires and also conducted follow-up examinations of the patients. A summary of the major findings is as follows: 1) The percentage of those patients who came for their follow-up examinations, using metal based dentures, rose sharply over time. There were only 11.99% of the patients using the metal based dentures at the time the first study was conducted, but this rose to 58.13% at the time of the second study and 73.73% at the time of the third study. 2) The proportion of the patients who had anterior partial dentures declined over time from 9.36% at the time of the first study to 8.74% at the time of the second study and finally to 5.61% at the time of the third study. 3) The proportion of the partial dentures that had fractured was 23.15% at the time of the first study and 16.37% at the time of the second study and 16.67% at the time of the third study. 4) There was a striking difference in the fracture frequency of the acrylic resin based partial dentures and that of the metal based partial dentures. The denture bases of the acrylic resin-based partial dentures fractured about four times as often as those of the metal based partial dentures. 5) In all three studies it was found that about 60% of the caries occuring on the abutment tooth occurred on the edentulous proximal side. 6) Changes in the mucous membrane, such as inflammation or development of ulcers, had occurred in 48.86% of the cases at the time of the first study. This proportion declined to approximately 47% at the time of the second and finally to 43% at the time of the third study. 7) In examining the changes in the mobility of the abutment teeth, it was found that in all three studies approximately 20 to 30% of the abutment teeth demonstrated increased mobility, and about 10 to 20% showed decreased mobility while 55 to 65% showed no change.