Porcelain or composite crown restorations can fail for a variety of reasons. Product failure however is seldom the cause ... it is rare that the integrity of high grade porcelain or the fabrication process (in the dental lab) becomes suspect. Dental science and engineering has all but eliminated those types of failures.
How, when and in what fashion a crown fails is actually a function of how and where the restoration was used in the patient's treatment. Different locations involves different preparation and different bonding procedures. In many instances... even the cementation products can differ.
Loose Fitting Crowns
Bite and occlusal issues can be common causes... as well as generalized trauma to the affected tooth. Bite problems, if they are immediate, may suggest inaccurate treatment. If the bite problems occur over an extended period of time... it may be due to issues involving other tooth structures and the overall occlusal relationship.
Inadequate existing tooth structure or poor preparation of the existing tooth structure may be the culprit. In some instances, Dr. Scalzitti overcomes this issue with a build up and post to create the needed structure for a crown to adhere to.
If certain physical properties aren't monitored closely, even a brand new build up can fail, due to the inadequate relationships of physical forces (biting) and retention qualities of surface areas.
The bonding process and bonding materials can often lead to crowns becoming loose in a very short time. Issues of over-preparation or under-preparation can be the cause. Matching the ideal cement product with the type of bonding surfaces can be critical. Contamination of the bonding surfaces is a frequent cause, arising from air borne bacteria or saliva. In some instances, even a patient's breath can compromise a bonding procedure.
Leakage and Decay
Older crowns often become loose of decay occuring under the crown. Decay can become manifested through leakage between the bonding surfaces that allow bacteria ot accumulate. In other instances the preparation process did not remove 100% of the existing decay.
This decay-causing-looseness event occurs frequently in certain types of bridgework applications. Anchor teeth restorations, due to the biting forces operating on the bridge, may cause bonding surfaces to flex and eventually leak.
Discolorations - Black Line Effect
Many of the older crowns produced during earlier generations of dentistry science become discolored because of underlying metal characteristics. Errors in creating and assuring secure margins of the crown can cause the "dark line effect" on a crown. The use of all porcelain crowns or porcelain fused to gold crowns, as used in our office, overcomes this age old problem.
Sensitivity - Pain
Tooth sensitivity (reactions to hot and cold temperatures) that occurs immediately after placement of a new crown can be caused by indequate bonding procedures. Internal structures of the original tooth structure are indequately sealed due either inaccurate preparation or contamination of bonding compounds.
Articulation: Occlusal Bite Measurement and Analysis
Pain associated with biting pressure may indicate a crown treatment that may have too much height or poor match of occlusal surfaces of an adjacent tooth. In some severe instances, stories of new crowns being ground down to the point of exposing underlying metal structures are not unheard of.
Reconstruction dentists routinely use Articulators to overcome this issue. Stone models are mounted to the articulation devices which enable occlusal experts to obtain the technical data needed for fabricating the best fit of dental crown(s) that recreates or maintains a patient's normalized bite. Unfortunately, articulators are not used as often as they should be.
Doctors who readily accept and/or seek out the development of complex multifaceted treatment plans tend to have the technical know-how of overcoming what should be common error issues in dentistry.
Because of the vast experience acquired by Dr. Scalzitti in successfully treating reconstructive dental needs on a routine basis, commonplace errors in assessment due to inadequate study of articulation data rarely occur.
Replacing Bad or Failing Dental Crowns
Replacement of a ceramic crown that shows signs of impending failure can be a fairly straight forward process. If oral health disease is present there may be additional treatments needed to stabilize tissue health. Visit the Porcelain Crown page for more detailed information.