Dental crowns are recommended when your tooth has a large filling that exceeds the natural tooth structure, your tooth had root canal therapy, a combination of large filling and root canal, or cosmetic reasons. 

Numbing the Tooth

The first step of the dental crown procedure involves using local anesthetic to numb the tooth and surrounding tissues. Even if you’ve had a root canal, your dentist will still likely choose to use anesthetic, because the instruments come very close to the gingival tissue.

Preliminary Impressions and Shade

The dental laboratory that fabricates your crown requires accurate models of both your maxillary and mandibular arches. If you have chosen a ceramic or porcelain fused to metal crown, your dentist will also require the exact shade of your tooth before they begin preparations.

Alginate Impresions

The dental assistant will take alginate impressions of both your upper and lower dental arches. These impressions will be poured in stone to create a model of your teeth. 

A small impression of the teeth in the same quadrant of the tooth that requires the crown and the opposing arch is also taken before the tooth is prepared. 

After the impressions have been finished, the dentist will then use a shade guide to record the exact color of your tooth. If your crown involves one of your front teeth, your dentist may ask you to visit the dental laboratory for the lab technician to take a custom shade of the surrounding teeth.

Preparing the Tooth

In order for the finished crown t fit correctly, the remaining core underneath the crown needs to be reduced. A crown is designed to fit securely to the tooth, keeping bacteria out from underneath the vulnerable tooth structure.

Once the tooth and tissues become numb, the dentist may decide to place a rubber dam over the teeth involved. This is used to prevent old filling material, tooth structure, and water from falling into your mouth.

While precisely removing amounts of tooth and filling material your dentist may find tooth decay or other complications. If that is the case, all the decay is removed and a composite core is placed on the tooth.

Once the core is complete, your dentist will continue to shape the tooth, creating a fine margin around the entire core of the tooth, like a shelf, and continue reducing the biting surface until sufficient tooth and filling have been removed. This step is crucial and is commonly the longest portion of the procedure.

Taking the Final Impression

Once the tooth has been prepared, your dentist may decide to use a gingival retraction cord to gently push your gum tissue away from the margins of the prepared tooth. A gingival retraction cord is a thin piece of cord, similar to a piece of yarn, that is gently inserted around the tooth, into the gingival sulcus.

When the tooth is ready for the impession, your dentist will begin by applying a polyvinyl siloxane impression material around the prepared tooth. The dental assistant will begin filling the impression tray with a corresponding impression material. It is important to remain biting into the impression until the material is fully set. Once set, your dentist will remove the tray from your mouth and inspect the impression for any air bubbles or another void in the impression. It may be necessary to repeat this process several times to obtain accurate impressions.

Preparation for the Crown

Using the small impression taken prior to preparing the tooth for the crown, the dentist or assistant will fill the impression tray with an acrylic resin material, in a shade appropriate for your case, and place it over the prepared tooth. Once the material has set, generally after one to two minutes, the impression is removed from your mouth. This creates a temporary crown, which is then secured with temporary dental cement. Your dentist will check for correct bite and ensure there are no rough or sharp edges around the crown. This will ensure the prepared tooth will not shift or alter position, while protecting it from infection.

Cementing the Permanent Crown

When you return to the dental office to have your permanent crown cemented, the dentist will begin the appointment by numbing the prepared tooth and surrounding tissues with local anesthetic. Even though the tooth is already prepared, the dentist needs to thoroughly clean the tooth before cementing the permanent crown. If you had a root canal performed on the prepared tooth, you will likely not require any local anesthetic.

Once the prepared tooth is completely numb, your dentist will remove the temporary crown from the tooth. All of the temporary cement is removed from the tooth, and the tooth is completely dried. Your dentist will then fit the permanent crown on the tooth.

Using a piece of dental floss, your dentist will also check the contacts in between the crown and adjacent teeth to ensure there is an ideal contact between the teeth. Contacts that are too tight or no contact at all pose a problem for you in the long run.

When your dentist is satisfied with the fit of the crown, the final cementation process begins. This process involves keeping your tooth completely isolated from any saliva or water in your mouth. Cotton rolls may be placed on both sides of the tooth to keep the area dry.

Your dentist will then place a bonding material onto the prepared tooth. Some bonding agents require a curing light to set the material. Once the bonding agent has been set, the dental assistant will fill your permanent crown with dental cement. Your dentist will place the crown on your tooth and remove some of the excess cement.

Checking the Bite

Approximately 10 minutes after applying the dental cement, your dentist will check the integrity of your bite. Any high spots on the crown will be reduced on the opposing tooth. It is very important for the bite to be correct because a high bite can lead to tooth sensitivity and pain.

Post Operative Instructions

Once the bite is accurate and your tooth has been cleaned from any excess cement, your dentist will give you very specific post-operative instructions for your new crown. It is important for you to follow these instructions to the letter. Most specifically, what you eat with your new crown is the biggest change you will make due to your new crown. For example, candy and nuts are very destructive to crowns and should be avoided at all costs.