Failed Crowns

Loose Crowns – Sometimes crowns become loose or fall off due to the bonding process, materials used, fit of the crown, or using expired materials. Matching the proper cement to the bonding agent is critical, and keeping the area clean from saliva, blood, and water during the bonding process is imperative. Over-preparation or under-preparation may also be the culprit. If this is the problem, re-cementing the crown will not fix the problem.

Crowns that have been on for long periods of time can become loose due to decay growing underneath the crown. If a little decay is mistakenly left under the crown during preparation or an ill-fitting crown leak, bacteria can continue to grow or work itself underneath the crown. Some of the older cements wash out, causing a space between the crown and tooth where bacteria and decay could migrate. The bacteria byproducts cause the decay and discoloration around and under the existing crowns.

Discoloration – Discoloration can be described as unsightly black lines surrounding the top margins of the crown. Many crowns become discolored because of metallic defects. Newer crowns become discolored because of leaking margins. The use of porcelain, emax, or zirconia crowns with tight margins can overcome this problem, as well as handling the preparation on the tooth correctly.

Sensitivity – When a new crown is placed, and immediate sensitivity to hot or cold foods is felt, this could be the cause of inadequate bonding procedures allowing for the food or liquid to get inside of the crown. If the bite is not adjusted properly, it can also cause tooth sensitivity. Being meticulous in adjusting the bite is important.

Proper Occlusion – Pain associated with biting down or chewing may mean that the preparation of the tooth was done inadequately. The crown may have too much height and may not have been mounted on an articulator during the fabrication process. Stone models are poured and mounted on articulators (jaw simulators), or digital impressions and virtual articulators to enable occlusal experts to gather the data needed for an optimal fitting crown. Because Dr. Ira Koeppel, Dr. Nick Gianuzzi and Dr. David Gohari, and his master ceramists use articulators, this common error is always avoided.

Replacement of Failed Crowns

Replacement of a failed crown is an easy and straightforward process. The old crown is removed, and decay is excavated (removed). A crown buildup (repair of the tooth structure) is usually utilized to stabilize the tooth. A new impression is taken, and a new crown made for optimal fit is placed. During the interim the patient wears an esthetically correct temporary crown that maintains the space and gum tissue levels. If other complications exist, more treatment may be necessary.