Johannes Liebsch No peri-implantitis after 9 years A milestone: the first long-term study on two-piece zirconia implants was published. The independent prospective study at Heinrich-Heine-University Düsseldorf examined two-piece Patent™ Implants (Zirc... Patent™ Dental Implant System Peri-implantitis long-term results Mar 28, 2023 Patent™ Dental Implant System