Metal-Free Zirconia Ceramic Dental Implants

Dental implant therapy has become the standard treatment method to replace missing teeth. Titanium dental implants demonstrate excellent biocompatibility and offer numerous treatment possibilities to improve patient’s quality of life.  The most scientifically researched and documented dental implants are made out of titanium combined with alloys. A recent systematic review states that osseointegrated implants (made out of titanium) are safe, present high survival rates, have minimal marginal bone resorption with clinical documentation over a period of at least 10 years.1

Clinicians and researchers are constantly striving to improve on the success of dental implants.  The notion of an alternative to titanium dental implants has been growing for the last 30 + years.  The main reason is that some patients have a true sensitivity to titanium. The true allergy reported in the literature is estimated at 0.6%,which is very low and varies depending the specific test. Patch tests have limited use due to poor sensitivity and the test validated to detect titanium sensitization is a MELISA test. This test has also been known to show false positives. The other main reason is to achieve a more desirable esthetic result.  Due to the grayish color of titanium, if the implant is not placed in the correct position with favorable bone and gum tissue around the implant, a dark shadow may be visible through the gum tissues (Fig. 1). To overcome this challenge, a white abutment could be placed  to mask the grey color visible through the gum tissues. In fact, in 1992, Drs. Abe Ingber and Vince Prestipino invented,  obtained a FDA 510k patent (Fig. 2) for the first ceramic (white) abutment  to achieve a more desirable esthetic result with dental implant crowns. The white abutment was made out of Aluminum oxide. This was a landmark invention because it led to the development of the currently used ceramic abutment, Zirconia.

Zirconia dental implants are typically marketed as a non-metal, “ceramic” material that is white in color like natural teeth and shares similar advantages as traditional titanium implants. Interestingly enough, Zirconium has an atomic number of 40 (periodic table) making it a transitional METAL. Zirconia implants come in the form of Zirconium Oxide (which are referred to as Zirconia).  Zirconia ceramic dental implants  are a favorable due to their white color, compressive strength and are compatible with  bone and gum tissues.  However, there are some concerns about the use of zirconia dental implants. Early research focused on the copying the design principles of titanium implants and applying them to Zirconia implants. This was not successful because Zirconia is not a true metal and does not behave like titanium.  Additionally, the manufacturing imperfections or design flaws during zirconia implant fabrication and surface treatment may compromise the strength and may lead to fracture of the implant.  The fracture of the zirconia implants may not be seen until 3 -5 years after the implant is restored.3   Lastly, there is limited long-term data of only 5-7 years studying the long-term clinical success rates of Zirconia dental implants.4     

When titanium dental implants are properly planned, surgically placed and restored by trained specialists, the long term results should be highly functional and esthethic(Figures 3,4 ).

The doctors at PDG feel that Zirconia is an excellent material of choice to be used for crowns and abutments on implants, however we feel that additional long-term scientific research is required to specifically understand the proper use of and clinical indications of zirconia dental implants before they become mainstream. Zirconia dental implants can be an alternative to titanium dental implants, but they are not a replacement.  The doctors at PDG stay abreast of the ever-changing dental implant technology due to their unique relationships they have with many of the implant manufacturing companies.  As soon as a fully researched zirconia dental implant system is FDA cleared and brought to the US market, the doctors at  PDG will provide this alternative dental implant treatment. Stay tuned for future developments! Your partner in dental health, Dr. Tassos Sfondouris.

 

Fig. 1. Grayish color of implant crown showing through the gums.

 

Fig 2: US Patent Ceramic Abutment (Aluminum Oxide)
Fig. 3: (Left) Zirconia Abutment. (Right) Ceramic crown.
Fig. 4: Titanium dental implant restored with the above ceramic abutment and crown to replace the upper left central incisor.

References

1.Moraschini, L. A. da C. Poubel, V. F. Ferreira, E. dos S. P. Barboza: Evaluation of survival and success rates of dental implants reported in longitudinal studies with a follow-up period ofat least 10 years: a systematic review.Int. J. Oral Maxillofac. Surg. 2015; 44: 377–388

2. Stejskal J, Stejskal V. The role of metals in autoimmunity and the link to neuroendocrinology. Neuro Endocrinol Lett; 1999; 20: 351–366.

3. Reham B. Osman  and Michael V. Swain.. A Critical Review of Dental Implant Materials with an Emphasis on Titanium versus Zirconia. Materials; 2015. 8(3), 932-958.

4. Hashim D, Cionca N, Courvisier DS, Mombelli A. A systematic review of the clinical survival of zirconia implants. Clin Oral Investig. 2016 Sep;20(7):1403-17.

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