Effect of assistive devices on the precision of digital impressions for implants placed in edentulous maxilla: an in vitro study.

Purpose: To examine the effect of assistive devices on the precision of digital impression for multiple implants placed in the edentulous maxilla.

Methods: A reference model representing an edentulous maxilla with four implants was developed. The digital impression group included three settings: Type 0, without an assistive device; Type 1, with an assistive device connecting only neighboring implants; and Type 2, with an assistive device connecting not only neighboring implants but also the two posterior implants, with perpendicular branches from this bar towards the anterior implants.