Purpose: To determine the accuracy of direct digital impressions in vivo and compare it to that of conventional impressions in order to assess whether intraoral scanners could be a legitimate alternative for the manufacturing of fixed prosthodontics. Materials and Methods: An electronic systematic search was conducted in the PubMed, Web of Science, Embase, and Cochrane Library databases using query terms such as digital impression; intraoral digital impression; intraoral scanner; intraoral digital scanner; conventional impression; analogue impression; and accuracy. The outcomes were the trueness and precision of digital impressions in comparison to those of high-precision conventional impressions in vivo. Results: Six studies matched the inclusion criteria. Four studies investigated the precision of digital impressions, while two studies focused on their trueness. Even if all the authors agreed that conventional impressions were more accurate than digital impressions in vivo, they gave different opinions on using intraoral scanners in a clinical context without causing misfit of the final restoration. Conclusion: According to the results of the present review, conventional impressions performed using high-precision impression materials showed greater accuracy than digital impressions. However, additional studies assessing the accuracy of digital impressions in a wider variety of clinical situations are highly recommended.