In order to estimate the long-term clinical effects of wearing partial dentures, the authors Undertook follow-up on 2140 dentures with which 1564 patients were fitted at Tokyo Medical and Dental University.Clinical examinations were performed at the time when the dentures were inserted.Six months to five and a half years thereafter a questionnaire was sent out to each case to ask several simple questions on the dentures, and to attend for re-examination.1158 cases replied to the questionnaires, and 772 of them appeared for re examination.
As based on the results derived chiefly from the replies to the questionnaires, the following conclusions were drawn:
1.The patients were asked if they were wearing their dentures.The 28.03 percent of examined partial dentures were discarded.In these examined dentures the 21.78 percent of the dentures made of cast cobalt-chromium or gold alloy skeleton with acrylic resin saddles were discarded, and also the 32.56 percent of dentures in acrylic resin with clasps and bars in wrought metal discarded.The rate of discarded dentures in the former was remarkably higher than in the later, and the chi-square test at 5 percent level showed a significant difference between them. But in the rate of discarded dentures was no discrepancy between maxillary and mandibular dentures, among dentures provided for patients of different ages, and between those of men and women.
The rate of discarded dentures remained about 10 percent for a year and a half after the examined dentures were inserted.But afterwards it increased to 30 percent after three years and three months following their insertion. And it approached 40 percent after four years and nine months.Furthermore it increased rapidly to 64 percent after five years and three months.
In unilateral free-end posterior dentures, unilateral bounded posterior dentures and unilateral combined posterior dentures, the rate of discarded dentures reached 30 percent as early as two years after they were inserted.But in bilateral combined posterior dentures the rate increased to 30 percent after three years following their insertion, and in both bilateral free-end posterior dentures and bilateral bounded posterior dentures, it rose rather slower to 30 percent until fourth year. With the exception of unilateral combined anterior and posterior dentures in which the rate rose to 30 percent after three years, the rate of anterior and posterior dentures increased considerably slower to 30 percent. Namely the rate of bilateral combined anterior and posterior dentures reached 30 percent after four years.In both bilateral free-end anterior and posterior dentures, and bilateral bounded anterior and posterior dentures, it increased to 30 percent until fifth year. In unilateral free-end anterior and posterior dentures, and in unilateral bounded anterior and posterior dentures, the rate of discarded dentures did not reach to 30 percent within five years following their insertion, although a small number of them.
