Five studies were included in the review, with at least 89 participants (range 14 to 28); two were prospective cohort studies, one was a retrospective cohort study, and two were retrospective controlled studies. The mean follow-up was five years in three studies and 9.4 and 10.5 years in the other two studies.
Implant and prosthesis survival (five studies): The survival rate for implants at five years was 98.5% (95% CI 97.1 to 99.3) and at 10 years was 97.1% (95% CI 94.3 to 98.5). The survival rate of implant-supported cantilever fixed dental prostheses at five years was 94.3% (95% CI 84.1 to 98.0) and at 10 years was 88.9% (95% CI 70.8 to 96.1). There was significant heterogeneity for comparisons of the survival rate of prostheses (p=0.02).
Biological complications (two studies): Five-year estimates for peri-implantitis were 5.4% (95% CI 2.0 to 14.2) for implants and 9.4% (95% CI 3.3 to 25.4) for prostheses with 10-year estimates for peri-implantitis of 10.5% (95% CI 3.9 to 26.4) at implant levels and 17.9% (95% CI 6.4 to 44.3) at prosthesis levels. There was no significant heterogeneity for these comparisons.
Technical complications: The most frequently reported complications at five years were: veneer fracture (10.3%; 95% CI 3.9 to 26.6; five studies); screw loosening (8.2%; 95% CI 3.9 to 17.0; four studies), loss of retention (5.7%; 95% CI: 1.9 to 16.5; two studies) and abutment or screw fracture (2.1%; 95% CI 0.9 to 5.1; five studies). There was significant heterogeneity for veneer fracture and abutment or screw fracture. Implant fracture was rare (five-year estimate 1.3%; 95% CI 0.2 to 8.3; four studies) and there were no reports of framework fracture. There was significant heterogeneity for this comparison (p=0.004).
Radiographic bone level changes: Non-significant differences in radiographic bone loss were observed at either the prosthesis, or implant levels, when comparing short-span implant-supported cantilever fixed dental prostheses with short-span implant-supported end-abutment fixed dental prostheses.