Dental patients are becoming increasingly concerned with the materials coming into contact with their bodies and the impact this can have on their health. When placing dental implants, it is always ideal to use the least reactive and least toxic material possible. It is also important to evaluate the strength, clinical success, and other relevant factors of such materials.
Over the years, the trend has been towards avoiding putting metals in our body. An alternative material to titanium exists in the form of zirconia for dental implants. Health conscious patients frequently ask, “Are zirconia dental implants better than titanium?” The answer to this question is not simple, as it is important to understand the potential benefits, limitations, risks, and other factors.
What are zirconia implants
Dental implants are medical devices used to replace missing teeth. Since the 1960s, titanium implants have been the industry standard. With decades of clinical success and innovation, titanium implants have become one of the most successful medical devices in all of medicine with long-term success rates of 94-97%.
Zirconia implants are an alternative to titanium implants. They were released in 1987 and have recently gained more attention along with holistic dentistry and are being researched.
What are zirconia implants made of
Zirconia dental implants are typically marketed as a non-metal, “ceramic” material that is white in color like natural teeth and has all the same advantages as traditional titanium implants. Interestingly enough, Zirconium has an atomic number of 40 making it a transitional METAL. Zirconia implants come in the form of Zirconium Oxide (which is often referred to as Zirconia). Every ceramic has a crystal structure containing both metallic and non-metallic atoms, but the combination is never referred to as a metal. The addition of the oxide changes its composition structure, behavior, and name.
Traditional Titanium implant surfaces are used in Titanium Oxide form, so why are they considered a metal? This is because titanium implants are a grey metal color and zirconia implants are white. The simple difference in color is one of the main reasons these implants were developed and have gained popularity from the general public. There are many claims of non-esthetic implant restoration caused by the grey color of the titanium implant. However, with proper placement through a 3D guided surgery protocol and utilizing white zirconia for the abutment material, we can repeatedly get highly-esthetic results for our patients.
Are zirconia dental implants better than titanium?
Studies have shown that titanium and zirconia implants have a very similar bone to implant contact (Manzano et al. 2014). This is the amount of bone that is in contact with the implant and determines the stability of the implant in the patient’s mouth. By this account only, the material does not make a large difference, however, there are other factors that make zirconia implants riskier.
are zirconia dental implants safe?
As we discussed above, it is important to understand the potential benefits, limitations, risks, and other factors associated with zirconia implants. Here is what you need to know when deciding between zirconia and titanium dental implants:
- Titanium AllergiesPerhaps the biggest concern patients have is if they will be allergic to titanium. In fact, it is extremely rare for people to have a true allergy to titanium. Studies have shown an extremely low prevalence rate of 0.6% of patients being allergic to titanium. Patch tests have limited use due to poor sensitivity and the test validated to detect titanium sensitization is MELISA test. This test has also been known to show false positives.
- Zirconia implants usually cannot be left to heal under the gumsThe process by which dental implant fixate to the bone is called osseointegration. This process usually takes about 6 months to complete. When dental implants are surgically placed, they must have a certain torque value or primary stability. Implants that do not have a good primary stability need to be left to heal under the gums for 3-6 months following placement. Most Zirconia dental implants cannot heal under the gums because of their “one-piece” design, meaning that they do not have a removable abutment but one that is fixed to the implant.
- When Zirconia is adjusted, microcracks form and can cause fracturesThe related literature shows that although zirconia is a very “strong” material in compressive forces, it doesn’t have much flexture and can fracture. This is especially apparent when the zirconia is adjusted with a dental bur. Unlike some other dental materials, when zirconia is adjusted, microcracks can form which can ultimately lead to fracture of the crown or even a zirconia implant. In traditional implants, the implant is never adjusted. Since zirconia implants are a one-piece design, the dentist must prepare the top of the implant in order to customize it to each patient’s mouth. This is the point when microcracks start and can propagate to even cause fracture and the implant would have to be removed.
- Zirconia implants with a small diameter are prone to fracture
As it was mentioned above, zirconia is very strong in compressive forces but somewhat brittle in elastic forces. It is for this reason that small diameter zirconia implants are contraindicated. Often times in implant dentistry, the dentist must utilize a small diameter implant in the range of 3.0mm-3.75mm due to thin bone or small spaces between the teeth. One research study showed that every implant with a diameter less then 4mm had a catastrophic fracture (Clinical Oral Implant Research, Thoma et al 2015). Another paper showed that out of 18 zirconia implants total, 7 implants fractured and one lost osseointegration because it could not be left to heal under the gums. (Journal of Clinical Periodontology, Thoma et al 2015). Similar to Thoma’s article, Roehling et al (2015) and Koch et al (2010) reported that the overall rate of zirconia implants demonstrating cracks of the implant head amounted to 22% and 30%, respectively!! This level of failure in unacceptable in clinical implant dentistry.
- Zirconia implant crowns can generally only be cementedIn traditional implant dentistry, the dental crown can either be retained by cement or by a screw. Most FDA approved zirconia implants are a “one-piece design”, meaning they must have cemented crowns. This might not sound like a problem, but it is. The tissues around teeth and around implants are very different and cement can cause a multitude of problems for the bone and tissues around implants. Dr. Wadhwani has proven in many research articles (2010-2016) that dental cement can get lodged into the tissues, causes inflammation and bone loss, harbors bacteria, and can even cause failure of a dental implant. It is for this reason that our doctors always strive to have perfectly placed implants through 3D digital guided surgery in order to be able to use screw-retained crowns and remove dental cement from the implant system.
- Full-mouth treatments cannot be completed with one-piece abutments
Many implant patients are missing all of their teeth or need all of their teeth replaced. This is a great way to restore confidence, chewing efficiency, and quality of life. Often times, this is life changing for dental implant patients. This type of treatment takes a great amount of planning and execution by the dentist to have superior esthetic and functional results. Custom abutments and screw-retained restorations are a requirement for full arch or full mouth implant treatment. Because of zirconia implants one-piece design, it would be impossible to do this.
Conclusion on zirconia dental implants
Both titanium and zirconia are very bioinert materials, meaning that they do not cause local inflammation and are not rejected by the body. It is because of this reason that these are the two materials of choice for the abutment portion of the implant system. The abutment is the piece of the implant system that connects the dental crown or the tooth in the mouth to the implant that is in the jawbone. We do not need to use zirconia implants to achieve safe, predictable, and natural-looking restorations. Furthermore, we can avoid many long-term complications associated with using zirconia implants by placing titanium implants using 3D guided surgery. However, there are certain indications where zirconia implants can be used for patients that prefer zirconia over titanium.