# Cost Effectiveness of Two Short Implants Versus One Short Implant With a Cantilever in the Posterior Region: 7.5‐Year Follow‐Up of a Randomised Controlled Trial

## TL;DR

A 7.5-year study compared the effectiveness and cost of using one short implant with a cantilever versus two short implants in the posterior region, finding similar outcomes but higher early complications with the cantilever approach.

## Contribution

This study provides long-term clinical and cost-effectiveness data comparing two dental implant strategies in posterior regions.

## Key findings

- Both treatment approaches showed comparable clinical and radiographic outcomes over 7.5 years.
- Short implants with a cantilever restoration were more cost-effective but had higher early complication rates.
- Implant survival rates were 83.3% and 86.6% for the one-implant and two-implant groups, respectively, with no significant difference.

## Abstract

To compare long‐term clinical and radiographic outcomes of a single short implant (6 mm) supporting a cantilevered restoration versus two adjacent short implants with non‐splinted single crowns over a 7.5‐year follow‐up and determine which approach is more cost effective.

A total of 36 patients with at least a two‐tooth gap in the posterior region were randomised to receive either one short implant with a cantilever prosthesis (ONE‐C) or two short implants with individual crowns (TWO). Fixed restorations were placed 3–6 months post implantation, and patients were evaluated at baseline and at 6 months and 1, 3, 5 and 7.5 years. Kaplan–Meier curves, mixed‐effects models and cost‐effectiveness models were used to compare the groups.

Twenty‐five patients (15 in ONE‐C, 10 in TWO) completed the 7.5‐year follow‐up. Implant survival was 83.3% in group ONE‐C and 86.6% in group TWO, with no significant differences between the groups (p = 0.772). No statistically significant differences were found between groups for marginal bone levels (mean difference −0.16 [95% CI: −0.7 to 0.3] p = 0.57), probing depth (mean difference −0.13 [95% CI: −0.5 to 0.3] p = 0.58), bleeding on probing (mean difference 0.0 [95% CI: −0.0; 0.2] p = 0.31) or plaque levels (mean difference −0.0 [95% CI: −0.1 to 0.1] p = 0.93). Technical complications were more frequent in the ONE‐C group (64%) than in the TWO group (36%).

Both treatment approaches showed comparable clinical and radiographic outcomes. Short implants supporting cantilever restorations were generally more cost effective than two short implants but exhibited higher early complication and failure rates, likely related to mechanical overload.

ClinicalTrials.gov Identifier: NCT01649531