Abstract
Purpose:
To evaluate the clinical outcome of 2 implants versus 4 implants placed
flapless in fully edentulous mandibles and immediately restored with
metal-resin screw-retained cross-arch prostheses. Materials and methods:
Sixty patients from two different centres were randomised: 30 to the
allon- 2 group and 30 to the all-on-4 group. To be immediately loaded,
implants had to be inserted with a minimum torque of 40 Ncm. Outcome
measures were prosthesis and implant failures, and biological and
biomechanical complications. Results: Flaps were raised in 18 patients.
Two implants in 2 patients did not reach the planned insertion torque
and were immediately replaced by larger diameter ones. Four months after
loading, no drop-out or implant failure occurred. One biomechanical
complication occurred in the all-on-2 group versus 4 in the all-on-4
group. There were no statistically significant differences between
groups for complications. There were no differences between centres.
Conclusions: These very preliminary results, just 4 months after
loading, suggest that immediately loaded mandibular cross-arch fixed
dental prostheses can be supported by only 2 dental implants. Longer
follow-ups (around 10 years) are needed to understand whether cross-arch
mandibular prostheses can be successfully supported by only 2 dental
implants.
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