When a dentist has decided on an implant crown or bridge (or an overdenture) as the preferred course of action for teeth replacement, one of the next decisions to make is the retention method. Implants themselves are effective, standardized, and safe, and deciding between the two most popular retention methods—screw-retained implants vs. cement-retained implants—is a source of debate among many clinicians.
The good news: both cement- and screw-retained implants have low complication rates, and both methods are pervasive and ubiquitous enough such that there’s adequate experience, training, and common knowledge. Fixed dental restorations are always going to come with their benefits and limitations, the decision really boils down to a patient’s specific teeth, tooth, and case. Let’s compare factors like performance, durability, esthetics, and more to help you decide which implant retention method might be the best for your patients.
Screw-retained implant crowns and bridges
For a single implant crown restoration or an implant bridge, an impression or digital scan is necessary before a prosthetic implant is surgically inserted. If you’re choosing a screw-retained implant, you will physically attach the implant abutment to jawbone, where after healing, it will provide a sturdy, rigid base for your crowns to–as the name implies—screw into.
Dentists who prefer screw-retained implants typically do for more than one reason, but a main benefit is retrievability. The technical complications that may happen when cementing a crown to an abutment are nonexistent, as application and installation is a cinch. But if something does happen, it is much easier than a cemented crown for removal, repair, cleaning, and even directly observing the soft tissue or implant underneath. It is all-around easier to diagnose and treat a complication. And, while wear and tear happens, it is easy enough to just retighten a screw, especially compared to removing and replacing cement.
With digital dentistry options like CAD/CAM and intraoral scanning, impressions are eliminated while the precision of screw-retained crowns continues to increase.
One negative (by comparison to cement-retained implants) of screw-retained implants is esthetics. Even when covered with composite, the hole for the screw can sometimes be visible or uneven, though precision design can allow you to avoid some of these visibility issues.
Cement-retained implant crowns and bridges
Many dentists opt for cement-retained implants. The more esthetic choice, cement retention is as described by the name: the abutment is attached to the jawbone, but instead of simply being screwed into the abutment, the implant crown is cemented.
As a standard crown always sits above the gumline, this method’s main benefit is the less-visible border. The crown blends in and sits below the gumline — which also increases the fixture’s durability, damaging a patient’s existing teeth less than regular crowns.
Cement-retained implants are, of course, not retrievable in the same way a screw-retained implant crown is. Cement is more permanent, and so if the abutment becomes loose, the final restoration becomes ruined, because it can’t be removed without damage. Another (albeit small) risk is what’s called late implant failure, which covers a variety of reasons an implant may fail in the first few years — infection, stress, grinding, shortage of bone. Late implant failure is more common in cement-retained than screw-retained implants because cement can act as a medium for bacteria to grow, damaging the ability of an abutment to osseointegrate (attach to bone). Implant failure can be painful and frustrating, not to mention costly.
That said, cement advancements are always on the horizon, and so the quality of cement-retained implants may, as a result, also improve. This won’t come without increased cost, but for situations where esthetic quality is a major concern, cement-retained have remained a quality, safe, and industry-standard approach to implant crowns.
Choosing your implant retention method
So: how should you choose between screw-retained implants and their counterpart, cement? It often comes down to dentist’s preference, your confidence with both prosthetic quality and their competency cementing. But both methods have the same level of safety and (low) failure rate, so the decision is the clinician’s.
Cementation is the more common method, because of its flexibility at installation. If an implant is ever-so-slightly misaligned or inclined, the malleability of the process allows for clean lines and better control of occlusion. It is also stronger. The advent of CAD/CAM technology also allows for the design and fabrication of more-precise prostheses, meaning that screw-retained are easy to install and increasingly as aligned as cemented. They also allow for mishaps to be more easily corrected, avoiding the miserable patient experience of implant failure.
According to a study published by Dove Press: “No significant difference was found between the screw-retained and cemented-retained implant supported reconstructions. However, Screw-retained implant-supported reconstructions were found to pose less biological and technological complications. Retention of the tooth is more stable and functional when implantation is selected based on the efficiency of a treatment procedure.”
But given any variables, it comes down to the dentist. There will always be cases (and patients) that call for a specific process, but in general, the method a dentist is most comfortable performing (and teaching and training staff to do) is the procedure more likely to result in positive outcomes. Dental technology has advanced so sufficiently as to allow for more than one really-darn-good way of doing something.
Dental implants with Dandy
Which brings us to us, Dandy. You can learn about how Dandy provides custom abutments with either method: screw-retained or cement-retained implants. The differences, advantages, and which is better all come down to preference. But for cement-retained, intraoral scanning gives you the option to secure your process against excess cement. And for screw-retained, the precision of Dandy’s CAD/CAM technology both for digital impressions and lab fabrication of prostheses means that patients will end up happy with the incline, occlusion, and alignment of the slightly more difficult-to-fabricate screw-retained implant. Whichever you decide, your patients’ smiles are in good hands when you’re working with a digital lab like Dandy.