Impression accuracy at the implant level is believed to have a higher degree of accuracy, compared to abutment-level impressions [20]. However, studies reporting on impression accuracy in implant dentistry may vary, and there are several possible explanations for these variations. One reason is the splinting together of copings for pick-up impressions compared to the non-splinting of copings. Secondly, the edentulous spans evaluated may differ between studies; thirdly, marginal discrepancy evaluation may use magnifying visual assessment as in the current investigation, or a superimposition of digital models as in Stimmelmayr et al. [9]. One variant that might have an impact is the impression material used. In one study, the impression material had the most considerable effect size on accuracy in terms of the 3D shift, and the implant axis inclination [21].

Most of the data on implant impression accuracy is from in vitro studies, with a small number conducted in a clinical setting. The limited number of clinical studies was highlighted in a systemic review by Papaspyridakos et al., where from the 76 studies reviewed, only 4 were in a clinical setting [22]. Baig, also in a report on the accuracy of multiple implants impressions of edentulous arches, found only 3 of the 56 studies reviewed to be in a clinical setting [7]. Also, when the same author conducted a systematic review, only 1 study out of the 34 selected for the systematic review was a clinical study [23].

This prospective clinical investigation found no significant differences between open and closed tray techniques, in agreement with Gallucci et al. [24]. In our in vitro study, we also found that the open and closed tray implant impression techniques showed a similar level of accuracy [8]. In that study, all the impressions were in the posterior maxillary region, while the current study had variations of anterior, posterior, maxillary, and mandibular. However, the current study is in disagreement with Stimmelmayr et al., where they found that the splinted implants in the open tray were more accurate than that in the closed tray technique [9].