Hmam. Keltjens et al., FIT OF DIRECT RETAINERS IN REMOVABLE PARTIAL DENTURES AFTER 8 YEARS OF USE, Journal of oral rehabilitation, 24(2), 1997, pp. 138-142
In a cross-sectional study the fit of direct retainers was assessed af
ter 8 years of use. A total of 101 metal frame removable partial dentu
res (RPD) were investigated, including 54 extension base prostheses wi
thout any tooth supported replacement and 47 tooth supported prosthese
s that replaced only premolars and molars. Of the frameworks studied,
about 60% of the clasps showed a space between retainers and abutments
. Logistic regression analyses demonstrated that the age of the RPD an
d the type of opposing dentition significantly influenced the fit of t
he clasps. The relative risks and a backward regression analysis revea
led that the variable nonrigid extention base RPD had the greatest inf
luence on clasp fit. It was concluded that in extension base RPDs a ri
gid design should be preferred.