Impact of Superstructure Type on Interleukin-1β and Interleukin-6 Levels in Peri Implant Crevicular Fluid: Screw Retained Zirconia Crowns Versus Cement Retained Metal Ceramic Crowns in Healthy and Peri Implantitis Sites

Abstract

Background: The effect of configuration of implant superstructure, namely screw-retained zirconia crowns versus cement retained metal-ceramic crowns on local inflammatory biomarker profiles is not yet fully characterized although emerging evidence demonstrates the effects of superstructure material or retention mechanism on peri-implant health outcomes. Objectives: The aim of this study was to investigate whether the concentrations of IL-1β and IL-6 in PICF were different between screw-retained zirconia crowns and cement-retained metal-ceramic crowns, as well as correlate these inflammatory biomarkers with peri-implant conditions. Methods: A comparative study in cross-sectional design was performed from May 2025 to January 2026 on 66 adult patients with single-tooth implant-supported restorations. Patients received an SLA implant and were randomly assigned into either Group 1 (n=24) with screw-retained monolithic zirconia crowns or Group 2 (n=42) cement-retained metal-ceramic crowns. Peri-implant crevicular fluid samples were obtained from the mesiobuccal aspect of each implant and quantified for IL-1β and IL-6 using enzyme-linked immunosorbent assay (ELISA). Recording of clinical parameters including probing depth and bleeding on probing. Patients were categorized in accordance with peri-implant health status as healthy implants or peri-implantitis sites. Results: The cohort had 56% healthy implants and 44% peri-implantitis systems. Screw-retained zirconia crowns (34.8 ± 7.6 pg/mL) exhibited significantly lower levels of IL-1β compared to cement-retained metal-ceramic crowns (45.7 ± 9.2 pg/mL); t-value = 4.52, p <0.004. Likewise, levels of IL-6 in the cement-retained metal-ceramic group (30.8 ± 7.5 pg/mL) were significantly higher than levels in the screw-retained zirconia group (19.6 ± 5.4 pg/mL), with a t-value of 5.18 and p<0.002 found to be statistically significant as well. In general, IL-1β (48.6 ± 10.1 pg/mL vs. 28.9 ± 6.5 pg/mL, p<0.005) and IL-6 (32.4 ± 8.3 pg/mL vs. 16.7 ± 4.8: Healthy implants p<0·003) levels were significantly higher for peri-implantitis sites in comparison to healthy implants. Conclusion: Screw-retained zirconia crowns have significantly lower IL-1β and IL-6 levels in the peri-implant crevicular fluid than cement-retained metal-ceramic crowns, indicating that superstructure configuration is an important modifiable determinant of peri-implant inflammatory burden.