# Clinical Outcomes of Single-Piece Zirconia Implants Compared With Tooth-Supported Fixed Dental Prostheses: A Retrospective Study

## TL;DR

This study compares single-piece zirconia implants and tooth-supported bridges for replacing missing teeth, finding implants offer better long-term results despite longer treatment times.

## Contribution

The study provides new mid-term clinical evidence on complication-free survival of single-piece zirconia implants versus traditional FDPs.

## Key findings

- Single-piece zirconia implants had significantly longer treatment times and more visits than FDPs.
- Implants showed higher complication-free survival rates over three years compared to FDPs.
- Restoration type was not an independent predictor of complications once they occurred.

## Abstract

Introduction: Replacement of a single missing tooth with evolving treatment alternatives remains a common clinical challenge. This retrospective cohort study aimed to compare the treatment duration and prosthetic/biological complication rates between single-piece zirconia implants and conventional tooth-supported three-unit fixed dental prostheses (FDPs) over a minimum three-year follow-up.

Materials and methods: This study included 200 patients (100 per group) treated between 2018 and 2022 for a single missing mandibular premolar or molar. The implant group received one-piece zirconia implants with immediate/early restoration, whereas the FDP group received porcelain-fused-to-metal or monolithic zirconia three-unit bridges. The treatment duration, number of visits, and complications were retrieved from clinical records. Complication-free survival was analyzed using Kaplan-Meier curves and Cox regression.

Results: Single-piece implants required significantly longer treatment times (157.1 ± 48.3 vs. 46.6 ± 18.9 days; p<0.001) and more clinical visits (5.2 ± 1.1 vs. 3.0 ± 0.8; p<0.001) than FDPs. Overall, prosthetic complication rates were similar (p=0.689), but complication-free survival was significantly higher in the implant group according to the log-rank test (p=0.028), with 56 (56%) implant patients versus 36 (36%) FDP patients remaining complication-free throughout follow-up. The mean time to the first complication or censoring was longer for implants (680.4 vs. 592.3 days; p = 0.024). Multivariate Cox regression analysis showed that restoration type was not an independent predictor of complication risk (p = 0.346) once complications occurred.

Conclusion: Single-piece zirconia implants, despite requiring a longer treatment duration and more appointments, offered superior mid-term complication-free survival compared with conventional three-unit FDPs for replacing a single mandibular posterior tooth. When the preservation of sound adjacent teeth is prioritized, single-piece zirconia implants represent a biologically favorable option for suitable patients.