What are some indications to cement a permanent crown with temporary cement?

I usually choose to cement most crowns initially with permanent rather than temporary cement. When might I choose a temporary cement instead? If  I want to have the patient try it out and see how it works.  Last week, for example, a patient came in with angry looking "overgrown gums" that were making it difficult  to properly seat and cement the crown with permanent cement. If gums are bleeding when a crown is cemented it can cause a compromised result. Also if tissue becomes trapped under the crown when it is cemented this can cause the crown to not fit as it is intended. I cemented my patients crown for one week and then removed it. Now her gums were well adapted, pink and perfect. It was easy to cement her crown with a permenent cement and I was now certain of its fit.

In some other instances if some feature of a crown may still possibly need adjusting later, a temporary cementation can be a good idea. For example, the patient is uncertain whether they like the shade of a crown. Sometimes I am not sure if the bite  is perfect, a temporary cementation may be utilized as well.

Another reason to temporarily cement a crown is to make sure that a tooth will be "happy" with the crown. Many patients complain of sensitivity after a tooth is prepared and temporized. While the great majority are fine after the permanent crown is cemented, a small minority need to have a root canal. If a patients tooth is symptomatic prior to the tooth preparation and remains so afterwards I usually choose to temporarily cement a permanent crown, just in case he or she will need a root canal. Once a crown is permanently cemented a root canal specialist will need to make a hole in it to perform a root canal. Although this is usually not a big problem, sometimes the porcelain adjacent to the hole can chip or break while the endodontist is preparing their access hole. If he is able to remove a temporarily cemented crown he has no need to make an access hole in the patients crown. After the root canal is completed I then cement the crown in with a permanent cement.

A good question to ask is: "Why  not cement all my crowns with temporary cement?" The answer is simple- Some temporarily cemented crowns can be difficult to remove . Using too much force when removing a temproarily cemented crown can cause the a crowns porcelain to crack or can damage the underlying tooth. .  In that event that I am unable to remove a crown easily, with a small  judicious use  of force, my temporary cemention will have to serve as a "final" cementation. Since the vast majority (over 95%) end up without any long term problems, it seems a good idea to routinely cement my patients crowns with permanent cement. It not only saves the patient a visit but it may be the safest alternative as well.