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Randomized Controlled Trial
. 2024 Dec;35(12):1669-1675.
doi: 10.1111/clr.14346. Epub 2024 Aug 22.

A 7.5-year randomized controlled clinical study comparing cemented and screw-retained one-piece zirconia-based implant-supported single crowns

Riccardo D Kraus  1 , Jenni Hjerppe  1 , Nadja Naenni  1 , Marc Balmer  1 , Ronald E Jung  1 , Daniel S Thoma  1
Affiliations
Randomized Controlled Trial

A 7.5-year randomized controlled clinical study comparing cemented and screw-retained one-piece zirconia-based implant-supported single crowns

Riccardo D Kraus et al. Clin Oral Implants Res. 2024 Dec.

Abstract

Objectives: To compare marginal bone levels, biological, and technical outcomes of screw-retained versus cemented all-ceramic implant-supported zirconia-based single crowns after an observation period of 7.5 years.

Methods: Forty-four single implants in the esthetic zone in 44 patients (22 females, 22 males) were randomly assigned to two types of restorations: SR (screw-retained); veneered one-piece zirconia abutment and CR (cement-retained); veneered lithium disilicate crown intraorally cemented on a one-piece zirconia abutment. Patients were recalled annually up to 7.5 years and survival rates, biological, and technical parameters assessed.

Results: A total of 31 patients attended the 7.5-year follow-up visit (17 SR group, 14 CR group). The survival rate on the restorative level was 77.5% (74.0% CR, 81.0% SR, p = .6399). Median marginal bone loss (MBL) values yielded -0.073 mm (-0.305; 0.238) in the CR and -0.215 mm (-0.500; 0.555) in the SR group (intergroup p = .6194). Mean bleeding on probing (BoP) values were significantly in favor of group SR with 20 ± 17% compared to 40 ± 22% in group CR (p = .011). The overall biological complication rate amounted to 27.5% (42.1% CR, 14.3% SR, p = .0775), whereas the technical complication rate was 32.5% (42.1% CR, 23.8% SR, p = .314). In total, CR restorations showed significantly more complications (84.2% for CR, 38.1% for SR, p = .0041).

Conclusion: One-piece zirconia-based single crowns on two-piece dental implants exhibited a high rate of technical and biological complications at 7.5 years of follow-up. Cemented restorations revealed significant higher rates of bleeding on probing and total complications compared to screw-retained restorations.

Keywords: biological complications; cemented; ceramic abutments; implant abutments; screw‐retained; single crowns; technical complications; zirconia.

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Conflict of interest statement

The authors report no conflict of interest.

Figures

FIGURE 1
FIGURE 1
Kaplan–Meier cumulative survival rates for cement‐retained (CR) and screw‐retained (SR) zirconia‐based implant crowns.
FIGURE 2
FIGURE 2
All‐ceramic implant screw‐retained restoration SR at baseline (a) and at 7.5‐year follow‐up (b). Site 21.
FIGURE 3
FIGURE 3
All‐ ceramic implant cemented restoration CR at baseline (a) and at 7.5‐year follow‐up (b). Site 24.
FIGURE 4
FIGURE 4
Cumulative frequencies of implants showing bone‐level changes over time (every 0.5 mm, from BL to FU‐7.5), with no significant differences between the groups (cement‐retained (CR) and screw‐retained (SR) implant crowns).
See this image and copyright information in PMC

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