Two-piece zirconia implant concepts are appropriate for clinical application
While the first generations of zirconia implants were limited to a one-piece design the preference for two-piece implants amongst clinicians has pushed the development also for two-piece ceramic designs. The European Society for Ceramic Implantology (ESCI) has recently reviewed the available scientific literature to evaluate the performance of the latest generation of two-piece ceramic implants in comparison with one-piece ceramic designs and with two-piece titanium designs.
The ESCI considered clinical studies evaluating
- the survival rate and clinical data of two-piece implants,
- the reliability and stability of screw-retained implant-abutment connections and
- the usage in clinical applications.
“Based on the currently available scientific data, the two-piece zirconia implant concept can be recommended for clinical application after correct diagnostic evaluation and appropriate patient information.”
The authors of the statement rely on studies showing that Zirconia implant survival rates have significantly increased between 2004 and 20171. The fracture incidence of zirconia oral implants has significantly reduced from 3.4% to 0.2%. Commercially available zirconia implants show survival rates of 95% at a follow-up of 5 years. 2, 3, 4, 5, 6
No statistically significant differences were found regarding the reliability and stability of the implants. The two-piece zirconia implants have been proven to withstand clinically relevant masticatory forces.24-29 Also, one-piece and two-piece micro-roughened ceramic implant concepts showed a similar level of osseointegration to their titanium counterparts. 7,8-12 The results refer to individual evaluations of studies and implant systems, as the clinical outcome depends on the material used and the type of connection.
In some indications, two-piece implant designs offer distinct advantages, for example regarding prosthetic flexibility and “reversibility”. Additionally, depending on some individual clinical situations, the ESCI concluded that the use of a two-piece implant design is beneficial compared to a one-piece design. For example:
- In a completely edentulous jaw
- In soft bone conditions
- When bone augmentations are performed simultaneously with implant placement
- When primary implant stability is hard to achieve
Ultimately, two-piece implants offer the possibility of implant axis corrections with individually designed abutments.
The choice for a one- or two-piece implant depends mainly on the patients’ clinical situation. Overall, there seems to be a trend towards two-piece implant concepts, whether ceramic or titanium is used as implant material. The evaluation conducted by ESCI presents zirconia implants as a reliable alternative to titanium with comparable results in terms of survival rates, stability and osseointegration.
At a glance
- Two-piece zirconia implants offer advantages regarding prosthetic flexibility and clinical indications.
- Two-piece zirconia implants withstand clinically relevant masticatory forces
- Manufacturing processes, material properties, implant geometries and prosthetic connection concepts may influence the fracture resistance and the mechanical stability of two-piece implants
- One- and two-piece zirconia implants show equal levels of osseointegration and biologic integrity.
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2. Gahlert M, Kniha H, Weingart D, Schild S, Gellrich NC, Bormann KH. A prospective clinical study to evaluate the performance of zirconium dioxide dental implants in single-tooth gaps. Clin Oral Implants Res 2016;27:e176-e184.
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10. Gahlert M, Roehling S, Wieland M, Sprecher CM, Kniha H, Milz S. Osseointegration of zirconia and titanium dental implants: a histological and histomorphometrical study in the maxilla of pigs. Clinical oral implants research 2009;20:1247-1253.
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12. Janner SFM, Gahlert M, Bosshardt DD, Roehling S, Milz S, Higginbottom F, et al. Bone response to functionally loaded, two-piece zirconia implants: A preclinical histometric study. Clin Oral Implants Res 2018;29:277-289.