# Implant-Supported Cantilever Fixed Partial Dentures in the Posterior Region: A Systematic Review and Meta-Analysis on Survival Outcomes

## TL;DR

This study reviews the success and complications of implant-supported dentures with cantilever extensions in the back of the mouth.

## Contribution

A systematic review and meta-analysis of survival outcomes and complications of posterior implant-supported cantilever dentures.

## Key findings

- Low failure rates for prostheses and implants (1%) were observed.
- Technical complications occurred in 14% of cases, with retention loss in 13%.
- Marginal bone loss was significantly associated with cantilever extensions.

## Abstract

Implant-supported partial dentures with cantilever extensions (ISPDCs) present significant biomechanical challenges when rehabilitating partially edentulous patients, especially in the posterior region, where higher complication rates are often reported. This systematic review aimed to evaluate the complications, survival rates, and marginal bone loss associated with ISPDCs in posterior areas. The review protocol was registered with the PROSPERO database (CRD42024606201) and was conducted in accordance with PRISMA-P guidelines. A comprehensive search was performed across 10 databases for studies published up until 28 January 2025. Out of an initial 2142 records, 11 clinical studies met the inclusion criteria. The analysis showed a low failure rate for both prostheses and implants, at 1% (95% confidence interval: 0–3%) across the studies evaluated. However, noteworthy complications arose from biological factors as well as technical issues. Complications related to the prosthesis and abutment occurred in 14% of cases (95% CI: 5–26%), while loss of retention was noted in 13% of cases (95% CI: 7–21%). These technical issues were particularly more frequent in extensions greater than 7 mm. A significant difference was observed in marginal bone loss when comparing the final and initial measurements to the cantilever (p < 0.0001), which was influenced by the study design. Factors such as the type of occlusal veneering material, study design related to biological complications, the number of implants, marginal bone loss (between adjacent and distant sites), and the retention system did not significantly affect the complication rate (p > 0.05). The certainty of evidence for all primary outcomes was rated as low due to study limitations, heterogeneity, and risk of bias. In conclusion, ISPDCs show favorable survival outcomes when supported by adequate planning and clinical monitoring, although longer extensions require more cautious case selection and prosthetic design.