Four techniques for the cementation of cast post restorations were compared in extracted single-rooted teeth. The techniques used were the lentula spiral, endodontic explorer, paper point, and direct post application. Evaluation was based on the presence of voids in the cement and retention of the post. The lentula spiral technique was performed without voids. The other techniques produced voids in increasing numbers in the following order: the endodontic explorer, direct application, and the paper point. The voids were commonly located along the shaft of the post, but there was no correlation between the number of voids and the retention of the posts.