Complex Implant Treatments
Inside Dental Technology delivers updates on digital workflows, materials, lab techniques, and innovation in dental technology through expert articles and videos.
June 1, 2017
Volume 8, Issue 6, June 2017
Page(s): p. 60
The use of digital technology has been a godsend in the development of a predictable full-arch prosthesis and the ability to service this type of case in the event of any damage to the prosthesis.
The protocol we use to develop a full-arch or full-mouth prosthetic treatment involves utilizing a traditional denture setup to determine appropriate tooth position. The CBCT guide is then converted to a surgical guide and the implants are placed in the planned positions.
A traditional fixture-level impression is taken of the arches to be restored. This is the key for developing and checking optimum esthetics, function, and phonetics prior to fabricating any definitive restorations. After this verification step, the laboratory receives the approved wax try-in and proceeds with the case. After the models are scanned, the digital files can be used for designing optimally shaped custom abutments, a PMMA provisional, and, later, the final ceramic prosthesis.
This protocol allows for accurate checking of the tooth position, contours, and arch form that will minimize errors in later treatment. The abutments can be tried in along with a PMMA provisional to verify accuracy of fit and verify minor adjustments needed in the mouth. Once the provisional has confirmed the fit, then the final restoration can be fabricated in the laboratory with confidence that the final restoration will be seated with minimal chair time.
Additionally, the protocol allows for prosthesis replacement in a single appointment—meaning lower fees, less chair time, and higher confidence in the replacement’s fit.
This protocol helped us manage a very difficult patient with a history of bruxism when he broke his PFM bridge and a new zirconia bridge. Since he lived a far drive from us, our ability to deliver new bridges in one appointment was a major benefit.
For years in our dental laboratory, we were waxing our frameworks to full contour, cutting them back, and then investing, casting, and finishing. While the process delivered incredibly accurate substructures and allowed for beautiful layered ceramic, it was time consuming and made the delivery of large-scale comprehensive rehabilitations very expensive and slow.
As we adopted model scanners and digital design into our workflow, it became clear to us that once essential parameters such as the location of the teeth in a full-arch case had been established, we had a variety of options to output the restorations and the material we chose to mill became almost irrelevant. Additionally, we were looking for ways to minimize chair time for our clients, which allowed them to offer their services at a lower cost to the patient. When things go wrong—which, unfortunately, they can—we have the option of sending our client a backup restoration milled in PMMA without taking another impression.
When we fabricate a full-arch implant restoration, our starting point is a complete denture try-in. This provides the ability to secure the patient’s approval of the positioning of the teeth to optimize the functional and esthetic parameters of the smile. If we select an arch of fixed restorations, the denture is then scanned, the abutments are designed to the optimum tooth position, and then a virtual design of the final prosthesis is created.
At this time, a prototype restoration can be milled in PMMA to verify the implant impression, esthetics, and articulation of the casts. If everything goes well, the patient has a provisional to wear while the definitive restorations are being fabricated, and we know that as long as we can replicate the provisional, the predictability and profitability of these cases is dramatically improved.
