RESUMO
The objective of this study was to compare the retention of three different groups of acetal resin retentive clasp arm and a group of stainless steel wrought wire retentive clasp arm. The differences in design of acetal resin retentive clasp arms were as follow: group A, 1/3 terminal clasp arm was below a survey line and engaged retentive undercut 0.02˝ ; group B, 1/3 terminal clasp arm was below a survey line and engaged retentive undercut 0.03˝ ; group C, 2/3 terminal clasp arm was below a survey line and engaged retentive undercut 0.03˝ where as group D, stainless steel wrought wire clasp arm engaged retentive undercut 0.02˝ Tensile load of each clasp arm was performed by a Universal testing machine and the retentive force for group A, B, C, and D were 1.21, 1.67, 1.51, and 6.32 N respectively. One way ANOVA and Dunnett T3 multiple comparison reveal no significant difference in retentive force between group B and C but there were significant differences between these two groups and group A and D at p \<0.05.\ Keywords:\ acetal resin retentive clasp arm, stainless steel wrought wire retentive clasp arm