Are posts really necessary in endodontically treated teeth?

Dr. Gordon Christensen addresses the most frequently asked questions.

Q

I’m confused about the necessity of using posts in endodontically treated teeth. Some publications and speakers say that posts are always necessary, and others say they are never necessary. When, if ever, should posts be used, and what type of post should be used?

A

During my career to date, I have watched the use of posts and cores for endodontically treated teeth evolve from complicated, expensive, difficult to make, custom cast posts and cores, to metal prefabricated posts made from stainless steel, to titanium or titanium alloy, to today’s popular fiber-reinforced resin-based composite. In my opinion, there have been numerous misunderstandings about the need or lack of need for posts.

In my answer, I will discuss several factors that should be considered before making a decision about whether or not to place posts in endodontically treated teeth. My conclusions about posts are based not only on the research literature, which contains many excellent but sometimes confusing in-vitro studies on extracted teeth, but also my clinical experiences over many years as a practicing prosthodontist.

Factors to be considered in making the decision to use a post

Many have stated that the main reason for placing a post is to strengthen the connection between the coronal build-up material or remaining tooth structure to the root portion of the tooth. In my opinion, that is only partially true. Additionally, the following potentially negative or positive factors should be considered in the decision to use a post. All of these factors should be observed before making the decision:

• Quantity of remaining tooth structure

• Quality of remaining tooth structure

• Remaining adjacent teeth

• Occlusion

• Planned restoration to be placed on the tooth

Quantity of tooth structure remaining

Some teeth have most of the coronal tooth structure remaining after endodontic treatment, and others have very little tooth structure remaining. What is the significance of the amount of remaining tooth structure? For simplicity, I’ll divide the discussion of remaining tooth structure into several categories, and I’ll list them in decreasing order of clinical success:

All of the coronal tooth structure present except the endodontic access hole

If other negative factors (to be discussed later) are not present, such teeth usually do not require posts. After the endodontic procedure is completed, tooth colored resin-based composite should be bonded into the pulp chamber. These teeth usually continue to serve adequately as though they were vital teeth.

At least one-half of the coronal tooth structure remaining

This situation is one of the most common. Assuming the remaining coronal tooth structure does not have any of the negative characteristics discussed next, the occlusion is not heavy, and there are other teeth contiguous with the one being treated, this tooth may not need to have a post. The coronal tooth structure can be built up, usually with retentive resin-based composite build-up material, to provide additional retention for the subsequent restoration, and these teeth have excellent potential to serve uneventfully. However, if other negative factors are present, it is prudent to place a post.

Less than one-half of the coronal tooth structure remaining (Figs. 1-6)

It is my opinion, regardless of the other factors present, that it is still advisable to place a post or posts in such teeth. Endodontically treated teeth with less than one-half of the coronal tooth structure remaining have a reduced chance of long-term service, and patients should be so advised as the treatment plan is developed.