Titanium implants work fairly well in most situations. What can we do better?
“No differences in osseointegration have been found between titanium and zirconia”
Various aspects of osseointegration have been studied: biomechanics has been evaluated by measuring removal torque; histological factors have been researched by looking at bone-to-implant contact in animal experiments. Results of these assessments were similar for titanium and zirconia implants (Manzano et al. 2014).
Peri-implant soft tissue has also been evaluated, and the authors of an experimental study reported similar soft tissue integration around titanium and zirconia implants (Thoma et al. 2015). In both types of implant, it was found that peri-implant mucosa was not influenced by the material. The factors which had the most influence on the soft tissue were implant design and the position of the microgap. This conclusion is in accordance with other studies on zirconia implants and with previous experimental studies on different abutment materials (Abrahamsson et al. 1998; Welander et al. 2008).
“It was found that peri-implant mucosa was not influenced by the material”
Regarding the clinical performance of zirconia implants, according to a recent meta-analysis, the one-year survival rates amount to 95.6% (Pieralli et al. 2017). An ongoing five-year follow-up study found a 98.4% survival rate in a cohort of 53 patients and 63 one-piece zirconia implants (Balmer et al. 2018.). These findings are summarised in Figure 1.
The majority of zirconia implants have been fabricated as one-piece (Figures 2 and 3) and the clinical limitations of this design are well-documented. In fact, because of their design, one-piece implants have reduced surgical versatility and prosthetic flexibility, and the removal of cement can be difficult, especially in anterior areas. Two-piece zirconia implants are now available, mostly with a tissue-level design (Figures 4 and 5).