# Clinical outcome and technical complications of bimaxillary full-arch implant-supported metal-resin fixed dental prostheses with or without ceramic molars: 5-year results

## TL;DR

This study compares dental implants with and without zirconium molars over 5 years, finding fewer technical issues with zirconium-supported implants.

## Contribution

The study introduces a modified metal-resin implant design with zirconium molars that reduces technical complications in long-term use.

## Key findings

- Implants with zirconium molars had significantly fewer acrylic tooth fractures and repairs.
- Technical complications increased over time in the control group but remained stable in the test group.
- No implant or denture loss occurred in either group over five years.

## Abstract

To evaluate the prevalence of prosthetic-related technical complications (PRTC) for bimaxillary implant-supported fixed complete metal-resin prostheses (ISFP) with (Zrm-ISFP) or without (r-ISFP) occlusal support by incorporation of zirconium molars.

Two cohorts of patients with bimaxillary ISFP subdivided into test group (TG; Zrm-ISFP) and control group (CG, r-ISFP) providing a 5-year follow-op program were retrospectively analyzed. For both groups the prevalence of PRTC was assessed and compared including evaluation of their occurrence in different time periods (-1 year, > 1–3-years; > 3–5-years post-loading). Additionally, implant/prosthesis survival-rates, peri-implant-marginal bone loss (MBL) and implant-related-technical complications were evaluated and compared.

For the 29 patients with bimaxillary ISFP subdivided into 14 TG [Zrm-ISFP] and 15 CG [r-ISFP]) and followed-up for 5 years no implant and denture loss was seen (survival 100%). However, the prevalence of PRTC such as acrylic-tooth fracture (p < 0.001) and acrylic-tooth repair (p = 0.015) differed significantly between TG (Zrm-ISFP) and CG (r-ISFP). For the CG, an evidently higher time-related ongoing increase (-1 yr: n = 9; > 1-3yrs: n = 23; > 3-5yrs: n = 34) of the prevalence of PRTC was noted compared to TG ( -1 yr: n = 2; > 1-3yrs: n = 3; > 3-5yrs: n = 7). In contrast, PRTC such as denture rebasing/reduction, denture cleaning, screw hole repair and implant-related technical complications and peri-implant MBL did not differ between TG and CG.

The modified metal-resin ISFPs incorporating zirconium molars/quadrants used for bimaxillary ISFP reduce the prevalence of PRTC and combine beneficial effects such as cost effectiveness and reparability of metal-resin and occlusal stability and reduced wear of complete zirconium prostheses.