Available online 7 December 2023

Author links open overlay panel, , , , , , ABSTRACTStatement of problem

The use of intraoral scanners (IOSs) correlates with clinical outcome and patient satisfaction. While the accuracy of IOSs has been well evaluated, studies on the effect of scanning duration on data accuracy are limited.

Purpose

The purpose of this in vitro study was to investigate the relationship between different scanning durations and the accuracy of the scanned data.

Material and methods

Two experienced operators used the same intraoral scanner (TRIOS 3; 3Shape A/S) to scan a gypsum cast, but with 5 different scanning durations (30 seconds, 60 seconds, 90 seconds, 120 seconds, and 180 seconds), and the trueness of the scanned data was assessed. Ten scans for each duration group were performed, and all the acquired data were evaluated for precision analysis. In addition, each scanned complete arch cast was divided into anterior and posterior regions at the canine teeth, and the 3-way ANOVA test was used to assess the scanning trueness and precision of the scanned anterior and posterior dental arch.

Results

The intraoral scanning results between the 2 operators were highly consistent. The data of the 30-second group showed the lowest trueness and precision (P<.001), whereas no significant difference was found among the other groups (P>.05). The trueness and precision of the scanning data in the posterior region was inferior to that in the anterior region (P<.001).

Conclusions

The duration time of the intraoral scanning (ranging from 60 seconds to 180 seconds) did not influence the accuracy of the acquired data, while excessively rapid scanning adversely affected accuracy.

Section snippetsMATERIAL AND METHODS

The experimental design is shown schematically in Figure 1. Type IV gypsum (Die-Stone; Kulzer GmbH) was mixed according to the manufacturer's instructions and used to pour a maxillary cast. A high-precision laboratory scanner (D2000; 3Shape A/S) was calibrated to scan the gypsum cast and generate a reference file for the accuracy comparisons. Accuracy, as defined in the International Organization for Standardization (ISO) 5725–1 standard, comprises 2 components:18, 19 trueness, which denotes

RESULTS

The number of images captured by the IOS increased uniformly with the increase in scanning duration (Fig. 3). Two-way ANOVA indicated that the trueness of the IOS was affected by scanning duration (P<.001) (Fig. 4). Specifically, the T1 group showed the lowest trueness compared with the T2 to T5 groups (P<.001) (Fig. 4). Figure 5 showed the 3D distortion of the complete arch scans in different groups. In terms of scanning precision, the T1 group showed the lowest precision (P<.001) (Fig. 6),

DISCUSSION

The intraoral scanning duration for a single arch was reported to range from 60 seconds to 180 seconds in previous studies.20, 21, 22 Wu et al20 compared 3 scanning strategies with different scanning time ranging from 72 ±17–130 ±24 seconds. Al Hamad et al21 reported that the duration for a maxillary scan was 106 ±40 seconds. Resende et al22 conducted a comparative study of the scanning duration among operators with different levels of experience, and the results showed that the moderately and

CONCLUSIONS

Based on the results of this in vitro study, the following conclusions were drawn:

1.

The accuracy of the IOS was not affected by scanning durations (ranging from 60 seconds to 180 seconds). For TRIOS 3 scanners, 60 seconds is recommended to finish a complete arch scan.

2.

The scanning accuracy of the anterior region was higher than that of the posterior region.

CRediT authorship contribution statement

Cunliang Zhang: Methodology, Formal analysis, Data Curation, Writing - original draft. Xin Zhan: Investigation, Validation. Fanghuan Wang: Investigation, Validation. Ying Wu: Resources, Supervision. Yingjie Yi: Formal analysis, Investigation. Jiali Meng: Software. Guofeng Wu: Conceptualization, Methodology, Writing - review and editing.

Acknowledgments

The authors thank all manufacturers for their equipment and materials, and the Nanjing Stomatological Digital Engineering Center for their digital technical support.

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W.Y. Lam et al.Dental students’ preference and perception on intraoral scanning and impression making

BMC Med Educ

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