Comparison of retentive properties of dowel forms after application of intermittent torsional forces

Four different forms of cast-gold dowels (round parallel-sided, round parallel-sided with antirotational keyways, tapered, and ovoid parallel-sided) were subjected to intermittent horizontal and vertical rotational forces prior to tensile testing. The results of this experiment indicated that ovoid parallel-sided dowels were the most retentive. Tapered dowels were found to be the least retentive. The addition of antirotational features to the round parallel-sided dowel did not improve the retentive values. The retentive properties of the round parallel-sided dowels, with or without antirotational features, were not statistically different from the ovoid parallel-sided dowels. Sandblasting the finished castings prior to cementation increased retention.