Table 3 Baseline characteristics of systematic reviews

Elnayef [15]

Partially and fully edentulous patients

Zirconia dental implant

Titanium dental implant

(edentulous jaw[MeSH terms]) OR jaw, edentulous, partially[MeSH terms]) OR edentulous mouth[MeSH terms]) AND dental implantation, endosseous[MeSH terms]) OR dental implant[MeSH terms]) OR dental implantation, endosseous[MeSH terms]) AND zirconium[MeSH terms]) OR zirconia[all terms] Filters: Clinical Trial; Humans; English

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health

Upto July 2015

Clinical trial

Two reviewers designed and assessed the proposal for the present project to make sure the STROBE statement and PRISMA guidelines were followed to avoid risk of bias and provide a high level of evidence. The STROBE statement consists of a 22-item checklist that should be fulfilled in a systematic review. PRISMA consists of a 27-item checklist and a four-phase flow diagram. 35 The authors used the NOS to assess the risk of bias in nonrandomized studies. Cohen’s kappa coefficient was used to assess interrater agreement. The authors used the randomized clinical trial checklist of the Cochrane Center and the CONSORT to evaluate the quality of RCTs

Comisso [14]

adult subjects partially edentulous in the upper-anterior sector

Zirconia dental implant

titanium dental implant

(partially edentulous OR aesthetic sector OR upper maxilla OR upper anterior maxilla) AND (zirconia dental implants OR zirconium oxide OR dental implants) AND (titanium implants OR dental implants) AND (gingival index OR bleeding on probing OR peri-implant bleeding OR peri-implant health index OR peri-implant PD OR pink aesthetic score OR white aesthetic score)

MEDLINE via Pub-Med and Cochrane Central

until January 2020

experimental, epidemiological studies, quasi-experimental or analytical studies (cohort studies) and intervention (clinical trial, field trial, community trial) in humans

A judgment (high, low, or uncertain) was used to assess bias for specific aspects across five domains: Bias resulting from the randomization procedure; bias resulting from variations from planned interventions; bias resulting from incomplete outcome data; bias resulting from bias in outcome assessment; and bias resulting from preference in chosen reported result. When a trial is deemed to have a low risk of bias across all domains, it is often regarded as having a low risk of bias

Unclear if the test is decided to raise some concerns in at least one area for this result, but not to be at high risk of bias for any domain and High

Risk of preference if the study is judged to be at high risk of bias in at least one area for this result or the trial is decided to have some concerns for multiple domains in a way that substantially lowers confidence in the result

Fernandes [16]

partially and fully edentulous patients

zirconia or titanium-zirconium implants

titanium implant

((“Dental Implants” (MeSH Terms)) OR (Dental Implant† (Supplementary Concept))) AND ((“Zirconium” (MeSH Terms)) OR (Zirconium Oxide (Supplementary Concept)) OR (Zirconia (Supplementary Concept)) OR (Yttria Stabilized Tetragonal Zirconia (Supplementary Concept)) OR (“Ceramics” (MeSH Terms)))

MEDLINE/PubMed and Web of Science

January 2010 and December 2020

RCTs

The randomization procedure, baseline-similar groups, blinded group assignment, random housing, blinded interventions, random and blinded outcome evaluation, dropout reporting, and other funding-related biases were all taken care of

One red box or two yellow boxes indicated the presence of bias for the particular study that was included. It could only be declared that there was no prejudice if every box was green

Sales [17]

edentulous patients

Zirconia dental implant

titanium dental implant

until march 2022

RCTs

2 independent reviewers assessed the study, none of the study had risk of bias

Duan [18]

Partially and fully edentulous patients

Zirconia dental implant

Titanium dental implant

Cochrane Central Register of Controlled Trials (CENTRAL), Medline via Ovid, EMBASE,

and Web of Science were searched

From Inception to August 2022

RCTs

Two authors manually searched the reference lists of the included papers to find possible related studies

Using RevMan software, the Cochrane Risk of Bias Assessment Tool was used to assess the bias of the included RCTs. Due to substantial loss during follow-up or baseline incomparability between the control and experimental groups, two studies were deemed to have an elevated risk of bias. Furthermore, it was unclear whether this study had a bias risk

Morena [22]

partially and fully edentulous patients

Zirconium implants

Titanium dental implant

Dental implants AND Zirconia implants OR zirconium implants OR

titanium implants OR zirconium oxide OR Yttria Stabilized

Tetragonal Zirconia

; Dental implants AND Zirconia implants OR zirconium implants OR

titanium implants OR zirconium oxide OR Yttria Stabilized

Tetragonal Zirconia

; (ALL = (Dental implants AND Zirconia implants OR zirconium

implants OR titanium implants OR zirconium oxide OR Yttria

Stabilized Tetragonal Zirconia)) AND ALL = (Randomized

Controlled Trial)

MEDLINE/PubMed and Web of Science, Scopus

Last 10 years -upto April 2024

Randomized controlled trial (RCT)

studies, and exclusively clinical and human studies involving adult patients

Two independent authors (T.B. and D.M.) conducted the electronic search on three

databases: Medline/PubMed, Scopus, and Web of Science (WoS). In case of disagreement, a

tie-break was performed by a third author (G.V.O.F.). The PICO question guided the search

parameters, and search filters were applied

The quality of the conducted study was independently assessed by two authors (T.B

and D.M.). In the case of disagreement, a third author was consulted (G.V.O.F.). The risk

of bias in the considered RCTs was evaluated using a Cochrane risk-of-bias assessment

tool specifically designed for randomized trials (RoB2)