Dental implants have been a major advancement in replacing missing teeth. When placed correctly, titanium implants have incredibly high success rates and are the standard for tooth replacement. Dental implants can be used to replace a single tooth or can be strategically placed to support multiple missing teeth or a whole arch of teeth. The great benefit of dental implants is that they eliminate a removable denture and provide the function and appearance of natural teeth.
Over the past couple years, patients have become concerned about the idea of having metal titanium implants placed in their body. Some patients are not comfortable with the idea of having a “foreign metal object” placed into their jawbone. I can understand their concern especially if they are unsure of the science, materials used and potential risks. So much information is available on the internet and it is difficult to find answers to these questions. Because of this, some patients are more comfortable with the idea of non-metal zirconia implants as an alternative. So, are zirconia dental implants healthier than titanium dental implants?
Composition of titanium dental implants
Titanium (Ti) is a metallic element with the atomic number 22 and has a silvery color. It is the ninth most abundant element in the earth’s crust. The alloy Ti-6Al-4V (Titanium, 6-aluminum, 4-vanadium), which was originally used for aerospace applications, is currently the most frequently used material for medical and dental implantation. Titanium alloys are widely used for orthopedic implantation (joint replacements) because of their lightweight, high biocompatibility and favorable strength/density ratios. Titanium alloys are superior to stainless steel and cobalt-chrome (Co-Cr) alloys with regard to biocompatibility and corrosion resistance.
Titanium plays a pivotal role for dental implants because the roughened surface of these implants attract bone cells to deposit bone and fill the space between the jawbone and the implant surface. This process is called osseointegration and is critical for implant stability. Titanium dental implants quickly form a layer of titanium dioxide on the surface and this layer forms a boundary between the metal surface and the body, preventing corrosion and deterioration of the material. This is the reason for the high biocompatibility.
Can titanium dental implants cause an allergic reaction?
Exposure to titanium from implants is common, but reports on clinical allergy are rare. Titanium dioxide on the surface of dental implants is more stable than pure titanium. It is possible that titanium ions could be released from the surface and sometimes into distant tissue. However, evidence for the possible toxic effects and risk of allergic reactions is weak (1). One study showed that titanium allergy can be detected in dental implant patients, even though its estimated prevalence is very low (0.6%) (2). It should be noted that no material, including any dental implant, can be considered universally biocompatible. As mentioned above, the Ti-6Al-4V alloy is the preferred choice for dental implants. Small amounts of other elements associated with titanium alloys can act as “impurities.” Titanium alloys can contain very small amounts of beryllium, cobalt, chromium, copper, iron, nickel and palladium. These impurities may be causative factors for different allergic reactions in patients with dental implants, but the likelihood is low.
It is therefore advisable to test for titanium allergy in patients with a history of multiple and/or severe allergies. These include allergy to jewelry, nickel and cobalt. Furthermore, patients with previous unexplained implant failure could be tested. In the rare situation that a patient is allergic to titanium, it is preferable to use alternative treatment options or to use an alternative dental implant material such as zirconia (3).
What are zirconia implants?
The idea of an alternative to titanium dental implants has been growing for years due to the questions regarding sensitivity to titanium that was discussed above. Another drawback of titanium is its grey color. When a titanium implant is placed in an area with very thin gingival tissue, there is a risk that a dark grey shadow may be visible.
Zirconium dioxide (zirconia) has been introduced as an alternative to titanium dioxide. Zirconia was first used for the fabrication of dental crowns and implant abutments. Currently, tetragonal zirconia poly-crystal is the ceramic of choice for dental implants. The white, opaque color of zirconia along with the good biocompatibility, favorable mechanical properties and low affinity for bacterial plaque, make it a good potential material for dental implants.
Are zirconia implants as successful as titanium implants?
Osseointegration is a major factor in the success of modern dental implants. Titanium remains the material of choice for obtaining and maintaining osseointegration. Early studies show that zirconia implants have similar 1 and 2 year survival rates when compared to titanium implants. More clinical long-term studies providing detailed information about implant failures, biological and technical complications, and prosthetic and esthetic outcomes are urgently needed (3).
Potential implant abutment and crown complications
Once a dental implant has integrated and healed with the jawbone, an implant abutment and crown are then made to complete the replacement of the tooth. The abutment and crown is held into the implant by a screw. These 3 components are shown in the picture below.
When titanium is used for the implant and abutment, this connection is incredibly strong and stable with very few mechanical complications from chewing. On the other hand, zirconia is a more brittle material compared to titanium. When zirconia is used for the implant and abutment, more mechanical complications (breakage of the abutment) have been reported, see picture below. This has been reported in studies and I have also experienced this in my practice. The challenge with zirconia is the strength and stability of the connection between the abutment and implant. So far, this connection is not as reliable as titanium. When implant abutments break, this expensive abutment and crown needs to be replaced and has the possibility of breaking again.
Conclusions
- Titanium is still the material of choice for dental implants and the replacement of missing teeth. Long term studies demonstrate very high success rates for this treatment.
- Exposure to titanium could cause an allergic reaction but the likelihood is very low. The estimated prevalence of titanium allergy in dental implant patients is less than 1%.
- Zirconia is now used as a dental implant material for patients that might be concerned about a titanium allergy. Long term studies are needed to better understand the success, function and esthetic outcomes of zirconia implants.
- If zirconia implants are used to replace a missing tooth, the patient needs to be aware of the potential complications such as breakage of the implant abutment and crown. This leads to additional expense for replacement.
References
- Fage S. et al. Titanium: a review on exposure, release, penetration, allergy, epidemiology, and clinical reactivity. Contact Dermatitis, 2016:74:323-345.
- Sicilia A. et al. Titanium allergy in dental implant patients: a clinical study on 1500 consecutive patients. Clin Oral Impl. Res, 2008:19:823-835.
- Singh R. et al. Prevalence of titanium hypersensitivity in patients with titanium implants: A systematic review and meta-analysis. Journal of Pharmacy and Bioallied Sciences, 2021:13(2):1345-1349.
- Roehling S. et al. Performance and outcome of zirconia dental implants in clinical studies: A meta-analysis. Clin Oral Imp Res, 2018:29(16):135-153.
At Geach Dental in Downtown Los Angeles and Laguna Niguel, Orange County our team has extensive experience in dealing with dental implant issues. If you are concerned about your dental implants or are considering having an implant placed, we encourage you to contact Geach Dental at (213) 622-3339, or click here to schedule a consultation. You deserve the best care.
ABOUT THE AUTHOR: Meet Dr. Adam Geach, distinguished prosthodontic specialist and owner of Geach Dental. His education includes Harvard School of Dental Medicine and The University of Connecticut, where he earned a DMD and MDSc in Prosthodontics, respectively. Dr. Geach holds Diplomate status with the American Board of Prosthodontics, underscoring his exceptional expertise in dental care.
