Nowadays crowns and bridges are often provided to patients as prosthodontic care, which indicates the improvement of endodontic treatment and rebuilding of abutment teeth.
It also makes us use nonvital teeth as abutment teeth.
Although the opportunities are increasing, it's hard to say that all rebuilding of abutment teeth is carried out under ideal conditions. Therefore, we investigated the present conditions with X-ray film.
A study was made of 2, 543 posts which were fabricated for patients at the Department of Oral Radiology at Matsumoto Dental College from 1988 to 1989.
Some of the result were as follows:
1. Most of the length of the posts were 2-6mm.
2. 13.7% of posts in the upper jaw and 6.2% of posts in the lower jaw were 2/3 to 3/4 the ratio of post the length to root length.
3. In both upper and lower jaw, the ratio of clinical post length to clinical root length was less than 1/2 in most of the cases.
4. In most of the cases, the number of the posts for multirooted teeth were 1-2 posts.
5. In 70% of the cases, cast posts were fabricated.
6. In less than 10% of the cases, it was less than 1 mm in the minimum tooth substance width.
