Retentive properties of attachment sleeves for a new cast-post system

This study determined the retentive values of various size sleeves and their corresponding post heads when these were cemented with zinc phosphate cement. The experiment was divided into four groups of 10 samples each, except for group 3, which had eight samples. In each instance, the retentive values (measured in pounds) were obtained using a universal testing machine. In all samples studied, the retention of the sleeve was greater than 110 pounds. As the post number increased from 0 to 3, there was a corresponding increase in the retentive force needed to dislodge each sleeve. A maximum of 170.5 pounds was found for the No.3 cast-post sample. Comparison shows that the retention of the sleeve (for this cast-post system) onto the post head is in the same range as crown-to-tooth retention values shown by other investigators.