Effects of Scanning Strategy and Scanner Type on the Accuracy of Intraoral Scans: A New Approach for Assessing the Accuracy of Scanned Data

Abstract

PurposeThis study aimed to determine the most reliable scanning strategy and scanner type, using a new protocol for assessing the accuracy (trueness and precision) of intraoral scan data.Materials and MethodsFive different maxillary and mandibular typodont pairs (n = 10) and 2 intraoral scanners were used for the study. A reference scan for each arch was obtained with an industrial scanner. Scanning strategies were classified into 2 continuous methods—continuous scan in horizontal direction (CH group) and continuous scan with vertical rotation in anterior region (CV group)—and 1 segmental method (S group). In the CH group, the scanner head was maintained mostly in a horizontal position. In the CV group, the scanners were rotated 180° around the anterior tooth region to allow smooth scanning through the area. The intraoral scan data were individually superimposed over their corresponding reference scan data. Raw data of the distances between paired surface points were extracted from the superimposed pairs of datasets, with (original distance values) or without consideration (absolute distance values) of the value signs. Trueness values were calculated using absolute distance values, while precision values were obtained from original distance values. Data were analyzed with a 2‐way repeated‐measures analysis of variance using α = 0.05 as the level of significance.ResultsThe CV group produced significantly inferior outcomes compared to the CH and S groups in terms of trueness (p < 0.001, F = 24.67), whereas no significant differences were observed among the 3 scanning strategies with respect to precision (p = 0.451, F = 0.83). Scanner type did not produce significant differences in terms of either trueness (p = 0.058, F = 4.72) or precision (p = 0.742, F = 0.12).ConclusionsThe segmental approach for scanning the region of interest first and continuous scanning with the scanner head held mostly in a horizontal position are both acceptable as full‐arch scanning strategies. However, vertical rotation of intraoral scanners should be minimized.

Feasibility of using an intraoral scanner for a complete arch digital scan, part 2: A comparison of scan strategies

“…In previous studies, because the IOS could scan only 1 or 2 teeth at a time in one direction in the oral cavity, many scan strategies for complete-arch scanning have been proposed to improve accuracy. [21][22][23][24][25][26][27] However, the optimum scan strategy for the most accurate scan has not yet been established. The recommended scan range of an IOS for fixed dental prostheses has been reported in the first part of the present study.…”

Effect of the volumetric dimensions of a complete arch on the accuracy of scanners

“…Because an intraoral scanner acquires information regarding the oral cavity through a small scan tip in the limited space in the oral cavity, unlike a desktop scanner, 16,17 the present study expected that the accuracy of the intraoral scanners would be the best in the volumetric dimension of a complete arch of 70%. The CS3600 and Trio3 showed the best accuracy at a volumetric dimension of a complete arch of 70%, whereas the i500 showed the best accuracy at a volumetric dimension of a complete arch of 100% (Table 3).…”

“…[12][13][14][15] In contrast to a desktop scanner, an intraoral scanner obtains information about the oral cavity through a small scan tip in the limited space of the oral cavity. 16,17 Hence, areas scanned only once are limited when using the intraoral scanner, and the virtual model is completed by stitching and aligning partially scanned areas. [18][19][20] Accordingly, with an intraoral scanner, the distortion of the dental arch occurs at the tooth from which the scanning begins.…”

Marginal and internal fit and intaglio surface trueness of interim crowns fabricated from tooth preparation of four finish line locations

“…The intraoral scanner has advantages of superior convenience, fast acquisition time of the virtual model, and superior accuracy (based on scanning for single unit) compared with the conventional method [22][23][24][25]. However, the use of an intraoral scanner for xed dental prosthesis still requires a solution from a clinical perspective [26,27].…”