Using Crown and Bridge Technology in the Dental Sleep World
The relationship patients have with their sleep appliances is well documented. Patients have come to rely on their particular appliance and when they need a crown made, they are hesitant to give up their appliance, let alone have a new one made. In some cases, dentists can adjust the existing appliance to fit the crown, however not all appliances are easily adjusted.
Using digital crown and bridge technology, Dental Prosthetic Services (DPS) has developed a protocol for retrofitting a new restoration under an existing sleep appliance, allowing your patient, in many cases to continue wearing his or her appliance, and avoid the cost of a new appliance. This process also helps you build value in your practice. Patients like knowing their dentist is state of the art, designing the crown and appliance to work together instead of just “making it fit.”
“From a clinical and patient satisfaction perspective, the ability to retrofit a crown under an existing appliance saves time and expense,” said Dr. Laura Fauchier of Marion Dental. “I recently had a patient who needed a restoration under her appliance. She was concerned about purchasing another appliance because this one would be out of pocket. It was a relief to her to know that we would be able to make the restoration work with her current appliance.”
The process begins with the clinician using PVS bite material to fill the area in the sleep appliance where the tooth is being restored, creating a “positive” of the existing dentition. Enough material to fully capture the tooth and tissue around the tooth being restored should be used. After the material sets up, remove it from the appliance and send it along with the prescription, impression of the crown prep, pre-operative study models, and bite. If the patient is having multiple crowns done, it may be necessary to send the sleep appliance to the lab.
“For the best outcome, in addition to the positive of the tooth being restored, we require a pre-operative study model of the arch. If the appliance is not well adapted to the tooth because of undercuts or ball clasps, it is difficult to achieve a good fit with just the positive. We use both the model and the positive in our digital design and manufacturing process to mimic the existing dentition,” said David Stricker, Research and Development Specialist for DPS.
The fit of the appliance on the new crown may be more passive than the previous fit. The crown is designed to fit under the appliance, but not fully engage it. Just as you would not want a pontic to bear the full occlusal load on a bridge, you do not want the new crown to bear the majority of the retention of the appliance. “If the tooth that is being restored is the primary source of retention for a quadrant of the sleep appliance, the retrofitting process is not ideal and I generally recommend a new appliance,” said DPS’s Dental Sleep Medicine Supervisor, Colleen Digmann.
Due to retention concerns, the retrofitting process is indicated for single tooth restorations only. Stricker also suggests that monolithic crowns, like zirconia, work best under oral appliances, “Because we are milling solid crowns and not hand-stacking porcelain, the monolithic crowns tend to have a more consistent fit.”
The retrofitting process can be used with almost all sleep appliances. However, those appliances that have more room for adjustment work best.
By using advanced crown and bridge technology to retrofit crowns under sleep appliances, your patient does not have to be without his or her appliance while a new crown is being made, nor do they have the expense of purchasing another appliance, saving them frustration and continuing to build value for the service you provide with oral appliance therapy.
