Zirconia Dental Implants
Zirconia dental implants were first used globally in 1987 and were approved by the FDA for use in the United States in 2011, and, since then, they have become an increasingly popular option for many dentists and their patients. As more patients seek more holistic treatment options, the properties of zirconia increase in interest, and more innovations in zirconia implant dentistry are formulated. Evidence from their use in Europe preceding their FDA approval has demonstrated that they are highly stable and biocompatible, and their color helps them provide a natural appearance. They may not be the best option for the dental restoration needs of all patients, however. Your dentist can work closely with you to help you decide if zirconia implants are a good option for you and to give you more information about your options, but it’s important to understand their specific qualities and pros and cons associated with them, too.
The most appealing characteristic of zirconia implants for many people is that they are non-metallic; some people have an allergic reaction to some metals, and some people would just prefer to not have metal implanted in their bones. Zirconia, which is technically called zirconium dioxide, is considered a ceramic; ceramics are non-metallic solids that may contain metallic or non-metallic compounds. While zirconium itself is a metal, when it combines with oxygen, the chemical reaction that occurs changes the composition of the material, affecting its composition and its behavior. Zirconia is completely inert, meaning that it is not chemically reactive. It is corrosion-resistant and is not an effective conductor of either heat or electricity, making it a good option for people with known allergies, or even sensitivities, to metals. While patients may know that they are not allergic to titanium, the reality is that many titanium implants contain small amounts of other metals; in examining a selection of titanium implants, researchers found chromium, iron, manganese, molybdenum, nickel, niobium, tin, tungsten, vanadium, zirconium, and zinc in addition to titanium.
Zirconia implants can also help enhance the appearance of dental restorations. While any implant is designed to be completely hidden by the dental restoration, or crown, that it supports, sometimes the metallic gray color of an implant or abutment can show through the translucent surface of the crown, or through the very thin tissue at the edge of the gums. Because zirconia is a ceramic, it is white and glassine in appearance, meaning zirconia naturally occurs in a state that is visibly similar to a natural tooth, helping the implant blend perfectly with the crown and remain invisible behind the gums. This is especially helpful when the restorations are in the front of the mouth, on the teeth that are more frequently seen.
Zirconia implants are less likely to retain dental plaque and calculus than implants made from other materials, making them easier to clean and potentially healthier overall. While the first zirconia implants were made with the abutment already attached to the implant, they are now available in this original single-piece style and also in the two-piece form that includes a separate abutment that is screwed on after the implant has healed into the bone. These two-piece implants allow the dentist to place the implant at an angle different from the abutment, increasing the strength of the restoration while utilizing bone as efficiently as possible. This is sometimes necessary with more complicated restorations, and in cases where the patient has experienced extensive bone loss; while patients may undergo bone grafts to supplement the natural bone, this surgery can sometimes be avoided with carefully positioned two-piece implants. While two-piece implants clearly offer more versatility and choices for the patient and their treatment options, the endurance of two-piece zirconia implants is not well-known, as they are a relatively recent innovation. Titanium dental implants have been used successfully for decades, but zirconia implants have only been observed in use for about ten years. Over this time, their success rates have been comparable with those of titanium, but only time will be able to prove their long-term success.
While zirconia implants provide multiple benefits for patients receiving dental implants, they are not without their drawbacks. The inability to observe zirconia implants over the long term also means that clinicians have not observed any inflammatory reactions, as these often take time to manifest. With titanium implants, if an excessive amount of cement is used to bond the crown to the abutment or if another irritant is present, this can cause an inflammatory reaction called peri-implantitis. Peri-implantitis has not been seen with zirconia implants, though it is unknown whether this is due to the excellent biocompatibility of zirconia, or because the implants have just not been in use long enough. However, the possibility of peri-implantitis is a potential factor to consider.
Zirconia is known to degrade at low temperatures as it ages, which may eventually lead to a reduction in strength and durability. Because zirconia implants have not been observed in clinical settings over extended periods of time, there is not sufficient evidence to indicate whether they remain successful in the long term. There is also insufficient research into the various longer-term characteristics of two-piece zirconia implants, as they have not been in use long; two-piece implants that consist of a separate implant fixture and abutment have only been in use in the United States since 2019. Because of this, some dentists prefer to only use zirconia implants when they can comfortably design a restoration that is effectively accommodated with single-piece implants. This is usually easier to do when replacing a single tooth, or very few teeth, and grows increasingly challenging when more teeth are being replaced. Especially because the implants themselves may need to be very narrow when there is not much bone present, it is important to use the strongest and most fracture-resistant material for these complex restoration procedures.
Zirconia is also more brittle than titanium. It can bear compression very well, but if it undergoes force that causes it to bend, it is more likely to fracture. Zirconia is also more likely to fracture over the long term simply due to its strength when compared to titanium. It is therefore not recommended for implant-supported dentures or complex rehabilitations, due to these material properties and also to the limited availability of components that vary in size and angulation. While zirconia is more limited than titanium for these complicated procedures, it can provide an aesthetically pleasing alternative to titanium in many cases. If you have relatively healthy bone and need to replace highly visible teeth, especially, you may be a good candidate for zirconia dental implants.