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Fig. 1 — Premolar tooth with minimal tooth structure remaining requires a post and pins to ensure connection of the coronal build-up to the remaining root structure. |
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Fig. 2 — A fiber-reinforced resin-based composite post and two pure titanium pins (Filpins) have been placed in the premolar shown in Fig. 1 to ensure retention of the build-up material. |
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Fig. 3 — Radiograph from endodontist showing well done endodontic treatment, but minimal tooth structure remaining. |
| Fig. 4 — Tooth shown in Fig. 3 was built up with two fiber-reinforced resin-based composite posts and bonded composite. |  |
| Fig. 5 — Often, endodontically treated teeth with minimal tooth structure remaining, such as the second molar shown, can be built up adequately to provide long-term service. |  |
| Fig. 6 — Preoperative view of patient with gross caries in both maxillary and mandibular anterior teeth. Several of the teeth were treated endodontically and posts, build-ups, and tooth-colored crowns were placed on the teeth. Assuming adequate oral hygiene is practiced, teeth restored in such manner will serve for many years. |  |
No tooth structure remaining coronal to the gingival tissue
There are clinical situations in which these teeth should be retained, including if the practitioner plans to extrude the tooth orthodontically. However, when considering the clinical success of dental root-form implants compared to questionable teeth, it is often better to extract the teeth and place implants. In the debatable event that a decision is made to restore such teeth, a post in single-rooted teeth or more than one post in multirooted teeth should be placed. Even with adequately placed posts present, the long-term success of such teeth is very questionable.
No tooth structure coronal to the bone
These teeth should usually be extracted. The only procedure, infrequently accomplished, that may allow teeth with long roots to be retained is orthodontic extrusion of the tooth. However, the cost of orthodontic extrusion and the time involved in waiting for the tooth to extrude and stabilize make the procedure questionable unless there is some major reason to retain the tooth.
Quality of remaining tooth structure
Assuming that there is a significant amount of coronal tooth structure remaining, the quality of the remaining tooth structure should be considered. Often, remaining tooth structure has discolored areas, slightly demineralized areas, cracks, undermined areas, or other negative characteristics. Removal of tooth structure with these characteristics allows a realistic and necessary appraisal of the amount of viable tooth structure remaining. After removing the affected areas, the same suggestions stated in the previous section on quantity of tooth structure remaining apply. Posts are often indicated.
Remaining adjacent teeth
If an endodontically treated tooth stands alone without adjacent teeth present, it will receive significantly more occlusal forces on it when compared to a tooth that has sound adjacent teeth. When restoring a tooth that has no or few surrounding teeth, it is appropriate to use a post or posts to augment the strength of the endodontically treated tooth, and to ensure that the remaining coronal tooth structure is strongly connected to the root portion.
Occlusion
One of the most important factors relative to the question of post placement in an endodontically treated tooth is the nature of the patient’s occlusion. Patients with bruxing or clenching habits place far more stress on teeth than those patients with normal occlusion. Usually, bruxers move their mandibles in left-right and forward-back movements, grinding off canine rise and incisal guidance. Enormous lateral stresses are placed on the teeth of these patients. Clenchers place forces in an apical direction with intense load and frequency. A logical decision is to place posts in bruxing and clenching patients.
Planned restoration to be placed on the tooth
An endodontically treated tooth planned to receive a single crown has minimal stress when compared to a tooth that is planned to be an abutment for a fixed prosthesis or an abutment for a removable partial denture. If an endodontically treated tooth is expected to have significant load placed on it in service, posts should be placed.
In summary — YES, posts are often needed, and there are many clinical factors related to whether or not they should be used, in addition to just how much tooth structure is remaining. Clinical judgment is still critical in deciding whether or not to use posts.