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Published on: December 20, 2024
A 3-Year Split-Mouth Randomized Non-Inferiority Controlled Trial Comparing Cement-Retained Monolithic CAD-CAM
Xiaosong Yi1, Donghao Wei1, Shuman Quan1
1Department of Oral Implantology, Peking University School and Hospital of Stomatology & National Clinical Research Center for Oral Disease & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing, China.
Objectives:
To evaluate whether monolithic CAD-CAM lithium disilicate (LS2) crowns are non-inferior to monolithic CAD-CAM zirconia (ZrO2) crowns with respect to clinical and radiographic outcomes in single posterior implant restorations.
Materials And Methods:
Patients with bilateral single-tooth implants at homologous posterior sites were enrolled. Each implant was randomly assigned to receive either a monolithic CAD-CAM ZrO2 crown (Control) or a LS2 crown (Test), both cemented onto customized titanium abutments. Marginal bone level change (ΔMBL) was the primary outcome. Non-inferiority of LS2 relative to ZrO2 was evaluated using a prespecified margin of -0.5 mm for the paired difference in ΔMBL (LS2-ZrO2). Implant and prosthesis survival, biological and technical complications, periodontal parameters, and FIPS were assessed as secondary outcomes.
Results:
A total of 40 patients completed the 3-year follow-up. The survival rates were 97.5% for ZrO2 and 100% for LS2, with one implant loss in the ZrO2 group. Biological complication rates were 5% for ZrO2 and 15% for LS2 (p = 0.219), while technical complication rates were 2.5% and 5% (p = 1.000), respectively. No crown fractures, chipping, or debonding were found in either group. The ΔMBL was -0.62 ± 1.22 mm for ZrO2 and -0.36 ± 1.07 mm for LS2. The paired mean difference in ΔMBL (LS2-ZrO2) was 0.26 mm (95% CI: -0.17 to 0.70 mm). The lower confidence limit remained above the prespecified non-inferiority margin of -0.5 mm, demonstrating non-inferiority of LS2 with respect to ΔMBL. No statistically significant differences were observed in mSBI, mPLI, or FIPS between the two groups (p = 0.106, 0.201, 0.825).
Conclusions:
Monolithic CAD-CAM LS2 crowns exhibit non-inferior clinical and radiographic outcomes to ZrO2 crowns over a 3-year follow-up period. Customized titanium abutments with cemented monolithic all-ceramic crowns represent a reliable treatment option for single posterior implant-supported restorations in the medium term.
Trial Registration:
Chinese Clinical Trial Registry (chictr.org.cn): ChiCTR2200062023.