Results.
The type of post present in each tooth was identified radiographically prior to removal and then confirmed upon removal. Posts were classified as being cast posts/cores, preformed parallel-sided posts, threaded posts or Flexiposts. The cast post/core group included all customized posts made by casting the entire unit with either gold or a non-precious metal. The preformed parallel-sided post group comprised cases where commercially available parallel-sided posts had been used and where there was no evidence of a cast core; instead, the cores had been built up with either amalgam or composite resin materials. Tapered posts with a thread for screwing into the tooth root were designated as threaded posts, and one tooth had a flexible metal post, commercially known as a Flexipost (Essential Dental Systems, South Hackensack, NJ, USA). Flexiposts have a split shank with parallel sides and a thread. It was not possible to determine the manufacturer of individual posts, apart from the Flexipost, as the designs and materials used by most manufacturers were very similar. The type of post used in each tooth had been chosen by the dentists who had restored them and hence many different brands were used.
Table 1. Frequency and types of posts removed in part 2 of the study.
Table 2. Types of posts used in various tooth groups.
Table 3. Frequency of use of various post removal devices and techniques.
When analysing the time taken to remove posts, those posts that were removed along with the crown in one unit were designated as taking 0 min, and for all other posts the time taken included the time required to remove the core filling material surrounding the post, or the time taken to shape cast cores to allow application of the post removal device. The mean time required to remove the 234 posts was 6.5 min, the mode was 3 min and the range was 0–30 min.
Table 4. Methods and devices used to remove each particular type of post.