Clinical Efficacy of Cemented Versus Screw-Retained Zirconia Single Crowns: A Systematic Review and Meta-Analysis

Background: The choice between cemented and screw-retained zirconia single crowns remains a matter of debate, especially concerning long-term biological and prosthetic outcomes. Objective: This systematic review and meta-analysis aimed to compare the clinical and mechanical performance of cemented versus screw-retained zirconia single crowns. Methods: An extensive search of PubMed, Embase, Web of Science, and Scopus was performed until July 2025. Only randomized controlled trials (RCTs) that compared cemented to screw-retained zirconia single crowns were eligible for inclusion. Primary outcomes were marginal bone level (MBL) changes, bleeding on probing (BoP), and plaque index (PI). Secondary outcomes included probing depth (PD), modified PI (MPLI), width of keratinized (KT) mucosa, and mechanical complications (i.e., fracture and loosening). Risk of bias was evaluated using the Cochrane RoB 2.0 tool and certainty of evidence (CoE) was assessed with GRADE methods. Results: Nine RCTs involving 298 patients were included. Cemented zirconia single crowns probably result in a slight reduction in marginal bone loss compared with screw-retained crowns (mean difference [MD] = –0.04 mm; 95% confidence interval [CI]: –0.08 to –0.00; I² = 0%; moderate CoE). Cemented crowns likely result in little to no difference in BoP, PI, PD, MPLI, and width of KT mucosa. Similarly, they likely result in little to no difference in mechanical complications such as fracture (risk ratio [RR] = 0.99; 95% CI: 0.82–1.19) and screw loosening (RR = 0.94; 95% CI: 0.50–1.77). Subgroup analyses confirmed these findings, except for MBL, where cemented crowns probably result in a slight reduction in longer follow-ups and adult populations. Most included trials presented some concerns or high risk of bias, primarily related to outcome measurement and reporting. Conclusion: Cemented zirconia single crowns may lead to slightly less marginal bone loss than screw-retained ones, but no meaningful differences were found in other biological or prosthetic complications. Current evidence remains limited, underscoring the need for well-designed, long-term RCTs to provide more definitive guidance.