A patient took a hard fall and fractured the porcelain of her screw-retained, implant supported, ceramo-metal “bridge”. Can it be repaired?

By William Wilson, Jr., DDS, MS and Kimberly Palladino.

Carla fell and landed directly on her face and was taken to the emergency room with a “busted lip”, bleeding from her mouth, and understandably she and her husband were more than just a little worried. Fortunately there were no fractured bones or more serious injuries. She presented to NOVA Prosthodontics after release from the hospital asking if there was anything we could do. There were more multiple porcelain fractures noted, but the full extent was not realized until the prosthesis was removed and examined under the laboratory microscope. When attempting to repair a ceramo-metal prosthesis by addition of new porcelain, there are things that need to be known. How long has the prosthesis been exposed to the oral environment? What is the supporting alloy material? What porcelain was used in the original fabrication? What are the coefficients of thermal expansion for each material and what was the highest firing temperature used in the initial fabrication? Often, we do not know the answer to each of these questions, and this is especially true if the laboratory fabrication of the prosthesis was not done in our office. There is a risk that all of the porcelain will fracture when attempting to repair in the porcelain furnace, and the substructure will need to be completely stripped of porcelain and new porcelain applied.

The first step in preparing the prosthesis for repair is removal from the mouth, disinfection prior to taking inside the laboratory, and removal of all loose and fractured material that has sustained an adhesive failure. In our example to the right you can see that we have exposed underlying metal and the porcelain has been further removed in preparation for the repair. This case is actually two separate “bridges” split at the midline. The next step is to thoroughly remove all organic materials from the prosthesis. This step is critical to avoid catastrophic failure of the remaining porcelain when fired in the porcelain furnace.

To remove the retained organic materials the prosthesis is immersed in a solution of “Porcelain Wash” in an ultrasonic cleaner. (We use “Porcelain Wash” from American Dental Supply, Inc. Allentown, PA). The material is subjected to 20-45 minutes of “Porcelain Wash” in the ultrasonic cleaner with more time if the prosthesis is several years old or seems to have retained more organic debris. There is no harm in washing for a longer period of time, but we want to do this repair the same day it is removed while the patient waits. After a thorough cleaning the prosthesis needs to be dried completely. Retained moisture that is heated too rapidly will place the existing porcelain at risk.

   

The exposed metal is opaqued and with subsequent firings in the porcelain furnace, additional porcelain is applied, fired, and shaped to restore the prosthesis to its previous condition, returning the patient to an acceptable form of esthetics and function. During the repair process the patient’s implants can be protected with healing abutments if we are repairing the same day, like this case, or alternatively could have the provisional prosthesis placed if available while the patient waits or returns to the office for return of the repaired screw-retained, implant supported, fixed dental prosthesis.

Because we found more fractured porcelain than we had initially anticipated, this repair became more extensive and complex. This required us to extend our normal office hours to finish this case the same day it presented, but Carla and her husband were very appreciative and it was a rewarding experience to provide this service for someone that had just experienced such a traumatic event. The porcelain is repaired “just like new” and in time her other wounds will heal. There are some that contend that this type of repair is not possible (and sometimes it may not be), but our experience has shown this to be a viable option for most patients.