Study Year of
publication 		Study
design 		Follow-up Population Patients Gender Control and test group
N Male/
female
Benic et al. [14] 2013 Prospective randomized clinical trial 1 year Patients in need of an implant-supported crown 40 NR Control group: Ti 4.1 mm diameter implant.
Test group: Ti-Zr 3.3 mm diameter implant
Bienz et al. [15] 2021 Prospective randomized clinical trial 6 months Prerequisite were two missing adjacent teeth 42 8/12 Control group: Zr implants.
Test group: Ti implants
Hassouna et al. [16] 2022 Prospective cohort study 5 years Replacement of a single-tooth in the maxillary premolar area 28 NR Control group: one-piece Ti implant.
Test group: one-piece Zr implant
Ioannidis et al. [17] 2015 Prospective randomized clinical trial 3 years Patients in need of an implant-supported crown 40 NR Control group: Ti 4.1 mm diameter implant.
Test group: Ti-Zr 3.3 mm diameter implant
Koller et al. [18] 2020 Prospective randomized clinical trial 6.5 years Patients had edentulous space ≤ 3 missing teeth as well adequate horizontal and vertical bone for implants ≥ 10 mm in length and 4 mm diameter 22 13/9 Control group: two-piece implants made of yttria-stabilized Zr.
Test group: standard two-piece Ti implants
Müller et al. [19] 2015 Prospective randomized clinical trial 5 years Patients who had completed the core study were invited to participate in the follow-up study to collect long-term data 47 24/23 Control group: Ti implants.
Test group: Ti-Zr implants
Osman et al. [20] 2014 Prospective randomized clinical trial 1 year Patients with functional problems in their use of complete dentures 24 15/4 Control group: one-piece Ti implant.
Test group: one-piece Zr implant
Payer et al. [21] 2015 Prospective randomized clinical trial 2 years Patients providing tooth gaps up to three missing units with a sufficient amount of horizontal and vertical bone for the placement of implants 22 13/9 Control group: two-piece standard Ti implants.
Test group: two-piece yttria-stabilized Zr implants
Siddiqi et al. [22] 2015 Prospective randomized clinical trial 1 year Patients involved surgical and prosthodontic rehabilitation of 24 completely edentulous participants with implant overdentures 24 15/4 Control group: implants were made from Ti.
Test group: Zr implants were used
Tolentino et al. [23] 2016 Prospective randomized clinical trial 1 year Patients for single-unit prosthetic rehabilitation in contra lateral molar sites of the mandible were included in the study 12 4/8 Control group: cpTi implants.
Test group: Ti-Zr implants

N = number; NR = not reported; Ti = titanium; Zr = zirconia.