Author’s Note: This is Part 1 in my series on preexisting implants in full-arch reconstructions. The introduction article, “How to Use Preexisting Implants in Redesigning a Full-Arch Reconstruction,” was published first.
Let me begin by stating that in it of itself, not only is there absolutely nothing wrong conceptually with a removable implant assisted solution.
Some of the undisputable benefits of a removable implant assisted solution are:
- Facilitated hygiene access.
- It provides ideal lip support in those patients with advanced ridge resorption.
The benefits of removable, implant-assisted dental protheses
When providing a fixed hybrid or an implant-supported fixed dental prosthesis, patients need to be diligent with their home care efforts that often require some level of dexterity.
When a patient is physically impaired or has conditions such as Parkinson's disease, home care can be challenging. Utilizing a removable implant-assisted solution provides a much easier access for hygiene, as well as maintaining the intraoral components like locators or telescopic crowns.
For those patients where there is an accentuated bone resorption, providing lip support via a flange in a removable solution is often recommended, since doing so with a fixed solution may potentially become a plaque trap for a patient, which would impede proper hygiene.
Normally the maintenance for these types of restorations has to do with replacing the retentive element, such as the nylon housing of a locator, or a plastic clip of a bar, which truly makes it extremely straightforward to maintain.
Usually the price tag associated to a removable implant-assisted solution is considerably lower compared to a fixed solution.
Why transition the patient from a removable solution to a fixed one?
In previous digest article, we outline what are the five factors to consider in recommending a given prosthetic solution.
As previously stated, a removable appliance is a fantastic alternative for patients with terminal dentition or those fully edentulous patients that had been denture-wearers but are in need for additional retention. However, treatment success is ultimately dependent on patient satisfaction.
For some patients, having a removable appliance has a significantly higher psychological impact, as these prosthetic solutions are usually associated with aging. Furthermore, it normally leads to cultural stereotyping from many younger patients which makes them anxious and wanting to avoid a removable appliance at all costs.
That's why selecting the right prosthetic solution needs to be part of a broad and detailed conversation that the treating team requires to have with the patient in order to ensure that they are fully committed. Not confirming this may lead to frustrated patients who feel slighted or ignored.
This happened to be the case with the following patient, who had been treated elsewhere and received an implant-assisted maxillary overdenture on five locators. The patient had six implants placed but one of the implants was not utilized and it had a cover screw.
The patient came to see us and appeared quite disappointed and frustrated because she was promised a fixed reconstruction and the previous dentist gave her a removable prosthesis as a final restoration (Figures 1-4).
During the initial analysis it was evident that the patient had six implants in the maxilla that are very shallow and buccal (Figures 5-6), the first thing we did was utilize the intraoral scanner to scan the existing removable prosthesis, scan bodies on the implants, occlusal relationship and lower arch (Figures 7-9), once we had this information in the virtual world, we planned for a screw-retained implant supported provisional prosthesis, and as you can see in the virtual plan some of the anterior screw access holes of the implants are extremely buccal.
At this time we were not overly concerned about the direction of the access holes, because the idea was to essentially evaluate if it was even possible to transition the patient to a fixed temporary and then to test drive and evaluate its performance. The provisional was milled in PMMA and tried in the patient's mouth (Figures 10-12). We figured out that the provisional looked very long both incisally and gingivally so we adjusted the incisal length by shortening it with a rubber wheel.
Once the desired incisal edge position was validated, we added wax to the gingival area and developed more ideal tooth proportions (Figures 13-14), this was tried in the patient's mouth to make sure the esthetics were closer to ideal (Figure 15), once we were happy and it was approved by the patient we converted the wax into pink acrylic resin (Figures 16-17), the access holes were then obliterated utilizing Teflon tape and composite resin and the occlusion was adjusted and polished (Figure 18).
In these cases, it becomes crucial to shoot a video with the temporary in the patient's mouth to carefully analyze the dynamics of the upper lip and assess if the transition line between the temporary and the gingiva is safely concealed underneath the lip (Figure 19).
We also need to assess in a sagittal view, if the lack of a longer buccal flange does not affect lip support.
Both of these aspects turned out to be adequate, and both the patient and our team were very satisfied with the result and it was decided with the patient that she would test-drive the provisional for 4-6 months before deciding on the final prosthesis (Figure 20).
Final considerations on the case
This patient was new to our practice. We had previously seen her only once for consultation and scanning, and basically at her second appointment we provided a fixed, screw-retained, full-arch provisional restoration. So, we were unaware of her level of compliance and based on how she expressed disappointment toward the previous dentist, we were a bit skeptical about our treatment design's success.
While we had concerns about the patient's ability to keep impeccable hygiene, and on the other hand being that this was a PMMA provisional without any type of metal reinforcement, we were equally skeptical about the provisional's performance and not fracturing prematurely.
For these types of situations, the recommendation is to utilize the adage of “under-promise and over-deliver.”
Perhaps one of the more relevant aspects that we have showcased in this case is the straightforward technique we utilized to fabricate a fixed, screw-retained implant provisional restoration utilizing digital technology.
Getting to this point utilizing analog conventional technology would have taken us four appointments.
Another important aspect that is worth discussing is the fact that we did not alter the “hardware” the patient presented with (locators and a removable overdenture) assuming the patient would have been dissatisfied with the solution we provided her with, then we could've easily and safely return to her original situation.
This in essence becomes a useful contingency plan.
In my next article, Part 2, we will see how the patient held up with the provisional restoration and how we were able to ultimately transition here into a more definitive prosthesis.
Ricardo Mitrani, D.D.S., M.S.D., is a member of Spear Resident Faculty