Occlusal Surface Changes in Single-Unit Versus Three-Unit Implant-Supported Zirconia Restoration: A Retrospective Observational Study
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Published on: December 20, 2024
Jay Gohil1, Shilpa Chawan2, Mukesh Singla3
1Department of Prosthodontics, K. M. Shah Dental College and Hospital, Sumandeep Vidyapeeth (Deemed to be University), Vadodara, IND.
Introduction:
Implant-supported zirconia restorations (ISZRs) are increasingly used for posterior rehabilitation; however, differences in occlusal wear and associated clinical outcomes between single-unit restorations and three-unit fixed restorations remain clinically relevant. This study aimed to compare occlusal surface wear between single-unit implant-supported zirconia restorations (single-ISZRs) and three-unit implant-supported zirconia restorations (three-ISZRs) and evaluate antagonist enamel wear, occlusal adjustment requirements, surface roughness, and restoration-related complications.
Materials And Methods:
This retrospective observational study included 120 records, comprising 64 single-ISZRs and 56 three-ISZRs. Digital records at restoration delivery and at 6 and 12 months were evaluated. Occlusal surface wear and antagonist enamel wear were quantified using digital scan superimposition. Occlusal adjustments, surface roughness, and complications were assessed from clinical records. Continuous variables were analyzed using independent-samples t-tests with Welch's correction where appropriate, while categorical variables were analyzed using Pearson's chi-square or Fisher's exact test. Statistical significance was set at p < 0.05.
Results:
Baseline characteristics were comparable between the groups. At baseline, occlusal wear was 2.1 ± 0.8 μm for single-ISZR and 2.3 ± 0.9 μm for three-ISZR (p = 0.204). At 6 months, wear was 8.4 ± 2.1 and 11.2 ± 2.8 μm, respectively (p < 0.001), increasing at 12 months to 14.6 ± 3.4 and 19.8 ± 4.1 μm (p < 0.001). The baseline-to-12-month change was 12.5 ± 3.2 versus 17.5 ± 3.8 μm (p < 0.001). Antagonist enamel wear was also lower with single-ISZR (15.2 ± 3.8 vs. 19.7 ± 4.5 μm; p < 0.001). The overall complication rate was lower for single-ISZR than for three-ISZR (9.4% vs. 25.0%; p = 0.022).
Conclusion:
Single-ISZRs demonstrated less occlusal and antagonist enamel wear and fewer overall complications than three-ISZRs during 12 months of follow-up.