Microbial evaluation of zirconia and titanium implants in the anterior mandibula: a randomized controlled clinical...

To evaluate the effect of the implant material-either titanium or zirconia-on the development of bacterial deposits. In this one-year prospective split-mouth study, 20 patients with an edentulous lower jaw were treated with two zirconia and two titanium implants. Clip attachments were used for the removable denture. During the follow-up period, fluid samples were taken from around each patient's implants and natural teeth to analyze the microbiota using DNA isolation, amplicon sequencing, and downstream analysis. Between the different time points, for the titanium material, the relative abundance of Actinomyces israelii increased significantly (p = 0.009) after 12 months when compared with the baseline. When comparing the different time points for each material, a significant decrease in the phyla Fusobacteria (p = 0.03) and Proteobacteria (p = 0.03) after six months versus baseline was detected for only zirconia, whereas the abundance of Firmicutes was significantly increased (p = 0.03). When comparing the different materials at each time point, the phylum Actinobacteria was found to be less abundant after 12 months on the zirconia implants than on the titanium implants (p = 0.04). By contrast, on the zirconia material, the relative abundance of the genus Leptotrichia decreased significantly after six months when compared with the baseline, while no significant changes in terms of this genus were found for the titanium implants or teeth over time. Zirconia tended to show less abundant bacterial deposits over time. The microbial diversity was lower on the titanium implants than on the ceramic material after 12 months. In addition, after 12 months of evaluation, neither the teeth nor the implants showed similar prevalences or levels of the target species.