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Failed Crowns


Crown Failure – Replacements and Repair


Crown failure happens for many reasons, but product failure is almost never the true cause. For the most part crowns fail because of two technical reasons. The first technical error deals with cementation and bonding of the post, buildup, or crown itself. The second technical error deals with occlusion and crown type selection. The proper selection of a crown is imperative because biting forces can exceed the properties of some kinds of crowns. Also, tooth preparation that subjects the crown to over excessive biting forces can in turn cause the need for a root canal on that tooth.
Different types of crowns and locations require different preparation, bonding and cementation techniques. This is why Dr. Koeppel has a vast array of cementation and bonding agents, to fit each case specifically.


Loose Crowns - Sometimes crowns become loose or fall off due to the bonding process, materials used, or fit 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, it is technique sensitive.   Over-preparation or under-preparation may also be the culprit. If this is the problem, then 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. A little decay is mistakenly left under the crown during preparation or an ill-fitting crown can leak, where bacteria can work itself in.  Some of the older cements wash, causing a space between the crown and tooth where bacteria and decay could migrate. The bacteria by products 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 lava 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 boding 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) to enable occlusal experts to gather the data needed for an optimal fitting crown. Because Dr. Koeppel and his ceramists use articulators, this common error is always avoided.


Replacement of Failed Crowns


Replacement of a failed crown is a fairly easy and straightforward process. The old crown is removed and decay is excavated (removed). A crown build (repair of the tooth structure) up 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.




Call our office at (631) 318-0000 to arrange a consult with Koeppel Dental Group to learn more about how to get the best restorations. You can also use our Consult Request form to arrange an appointment.


Patients seeking specific answers or information related to the material on this page can also choose to contact Koeppel Dental Group directly with our Ask The Dentist form. Our Doctors will reply to you directly with the information you are seeking.




Before Removal of Leaky Wash
Out Cement Crowns

Green Black Slime Under Crowns

Leaky Ugly Dark Margin
Crowns Before Treatment Upper Arch

Cosmetic Enamel Replacement
After Treatment Upper Arch