Assessment of different types of intra oral scanners and 3D printers on the accuracy of printed models: An in vitro study

Abstract

Background: 3D printing technology is a reality in Dentistry and presents several ways to obtain a printed model. The aim of this study was to verify the influence of different types of intraoral scanners and 3D printers on the accuracy of printed models in comparison to plaster models obtained from conventional impressions.

Material and methods: A dental study model was used as the reference model and was molded with polyvinyl siloxane to produce the plaster models. It was also scanned with two types of intraoral scanners and the digital files were printed by two types of 3D printers. The plaster and printed models formed five groups (n=50), which were analyzed using linear measurements at six dimension sites. In order to test the equivalence in the precision of the measurements made in the reference model and in the different models of the experimental groups, the Schuirmann Two-One Sided t-test was applied. The trueness of the measurements of the experimental models was tested in comparison to those of the reference model by applying tests for paired data. In all statistical tests, the significance level of 5% (α = 0.05) was adopted.

Results: In relation to precision, all five groups presented similar and acceptable results. The trueness analysis indicated that both the printed and the plaster models had average measurements that were different from the reference model.

Conclusions: It was concluded that the accuracy of printed and plaster models was impaired due to the trueness of the models. The type of printer influenced the accuracy of the printed models, while the type of scanner did not. The standardization of the method of obtaining printed models must be carried out in order to provide the production of quality models. However, there will be differences between the technologies. Key words:Dental models, three-dimensional printing, dimensional accuracy.

Figure 1

Dimension sites. A: dimension site 1 e 2; B: dimension sites 3 e 4; C: dimension site 5; D: dimension site 6.

Figure 2

Average of the difference calculated between the measurements made in the reference model and in the TrEd, OmEd, TrMi and OmMi experimental models (confidence limits of the mean (95%) and tests for selected paired data).

Figure 3

Average of the difference calculated between the measurements made in the reference model and in the Pl experimental models (confidence limits of the mean (95%) and tests for selected paired data).