In Vivo Complete Arch Implant Impressions: Comparison of the Linear Precision of Digital and Conventional Techniques

The aims of this in vivo study were to determine which implant impression technique has the best in-mouth precision and to analyse whether the maxillary or mandibular position of the implants and the increase in the interimplant distance affect the precision.

A fully edentulous patient rehabilitated with 8 implants in each arch was included in this in vivo study. Five impressions per technique and arch were obtained using 6 impression techniques: closed tray (IT), unsplinted direct technique (UDT), acrylic resin-splinted direct technique (ASDT), metal-splinted direct technique (MSDT), stereophotogrammetry (PIC system), and intraoral scanning (Trios). Precision was evaluated by comparing 28 Euclidean interabutment distances per impression. A threshold of 75 μm was used as a reference value based on previously published implant misfit studies.

Within the limitations of this study, the PIC system showed the highest precision among the evaluated techniques with 95% of the values <75 μm for the mandibular arch and 99% for the maxillary arch. The IT technique did not result in differences in the precision between the maxillary and the mandibular arches (P = .663); the other techniques showed statistically significant differences between the maxillary and the mandibular positions of the implants (P < .001).

Significant differences were observed when comparing the precision of the 6 techniques, with the PIC system tending to show the highest precision within the limitations of this study. Statistically significant differences were also obtained between the maxillary arch and the mandibular arch within each technique and the precision decreased as the interimplant distance increased, particularly for the T technique.