The International Journal of Prosthodontics
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Int J Prosthodont 31 (2018), No. 2     29. Mar. 2018
Int J Prosthodont 31 (2018), No. 2  (29.03.2018)

Page 171-175, doi:10.11607/ijp.5535, PubMed:29518813


Precision and Accuracy of a Digital Impression Scanner in Full-Arch Implant Rehabilitation
Pesce, Paolo / Pera, Francesco / Setti, Paolo / Menini, Maria
Purpose: To evaluate the accuracy and precision of a digital scanner used to scan four implants positioned according to an immediate loading implant protocol and to assess the accuracy of an aluminum framework fabricated from a digital impression.
Materials and Methods: Five master casts reproducing different edentulous maxillae with four tilted implants were used. Four scan bodies were screwed onto the low-profile abutments, and a digital intraoral scanner was used to perform five digital impressions of each master cast. To assess trueness, a metal framework of the best digital impression was produced with computeraided design/computer-assisted manufacture (CAD/CAM) technology and passive fit was assessed with the Sheffield test. Gaps between the frameworks and the implant analogs were measured with a stereomicroscope. To assess precision, three-dimensional (3D) point cloud processing software was used to measure the deviations between the five digital impressions of each cast by producing a color map. The deviation values were grouped in three classes, and differences were assessed between class 2 (representing lower discrepancies) and the assembled classes 1 and 3 (representing the higher negative and positive discrepancies, respectively).
Results: The frameworks showed a mean gap of < 30 μm (range: 2 to 47 μm). A statistically significant difference was found between the two groups by the 3D point cloud software, with higher frequencies of points in class 2 than in grouped classes 1 and 3 (P < .001).
Conclusion: Within the limits of this in vitro study, it appears that a digital impression may represent a reliable method for fabricating full-arch implant frameworks with good passive fit when tilted implants are present.
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