Purpose: The purpose of this study was to compare the effect of enhancement by different shape retention nails on the anterior region resin denture base through shear strength measurements.
Methods: 24 specimens with the same size and thickness were divided into 4 groups by the shape of retention nails. Three experimental groups of the resin denture base specimen were placed a retention nail with different shape, Δtype, V type and I type. Another group of 6 specimens without nail was used as control. All the samples' shear forces were tested by universal mechanical testing machine, and the data was statistically analyzed by SPSS 10.1 software package.
Results: The shear forces of Δtype group, V type group, the I type group and control group, were respectively (326.80±64.17) N, (225.07±31.76) N, (182.85±15.18) N, and (116.67soil 4.35) N. According to the statistical results, the difference of shear forces had no significant difference (P>0.05) between I type and V type, although the shear forces of these two groups were significantly greater than the control group (P<0.05). The shear forces of Δ type group were significantly greater than the other three groups (P<0.05).
Conclusions: The retention nail of Δ shape can significantly enhance the anti-shear ability of resin denture base.