![]() ![]() Many studies in the literature have used the ATOS Core 80 (GOM GmbH, Braunschweig, Germany) industrial scanner as the reference scanner, similar to the present study. When evaluating the trueness scores of digital scanning systems, it is necessary to use a scanner with superior features. Trueness and precision refer to total accuracy. Precision refers to the closeness of agreement between test results. 16 According to this, trueness refers to the closeness of agreement between the arithmetic mean of a measured subject and a known or true value. The terms, accuracy, trueness, and precision, are frequently mentioned when testing digital scanning systems. 10, 11, 12, 13, 14, 15 In particular, knowing the accuracy of new generation IOS is clinically important for achieving passive fit in full-arch implant-supported restorations. 9 However, digital systems for implant-supported restorations are still controversial because of scanning strategies and technologies, implant depth and angles, and scan body materials and shape. 4, 7, 8 The use of scan bodies with digital impressions enables intraoral scanners (IOS) to be used in implant restoration. 5, 6Īlthough conventional impression materials are acceptable for implant-supported full-arch restorations in terms of passive fit, there are disadvantages, such as dimensional change, patient discomfort, time, cost, and technical difficulties. 4 Although, in the literature, passive fit ranges between 10 µm and 150 µm, it has been stated that this value should range between 30 µm and 50 µm to avoid mechanical and biological complications. 3 Passive fit starts from the impression and requires high precision in the clinical and laboratory stages. The success of implant-supported full-arch fixed restorations, such as the All-on-4 treatment concept, largely depends on the passive fit. 1, 2 This technique can be used to avoid additional surgical interventions in patients without sufficient bone distance due to the maxillary sinus and mandibular nerve or to make a fixed prosthesis with a single surgical procedure in elderly patients whose systemic condition is unfavorable. The All-on-4 concept has been developed as a treatment alternative for edentulous patients with difficulties due to anatomical limitations.
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