# Assessment of Dental Arch Reproduction Quality by Using Traditional and Digital Methods
## 4 Discussion
A review of relevant literature published in 2017, delivered the conclusion that the accuracy of intraoral scanners used for clinical application is satisfactory and similar to the accuracy level of conventional methods. This conclusion is based on the study of natural teeth, implants, and permanent dentures up to 4-5 points [35]. [PERSON] et al. [17] assumed that, in the case of whole-arch scans, deviations smaller than 0.14 mm can be classified as very good and below 0.25 mm as acceptable. They assessed the clinical results for Trios 3 as very good. The entire process from taking the intraoral scan to printing the model was characterized by acceptable accuracy in their examination. According to these criteria, it can be concluded that the whole process from taking the intraoral scan to printing the model was characterized by very good accuracy in the current study. Most in vitro surveys [20; 21; 22; 29] showed that intraoral scanners achieve accuracy close to or higher than conventional methods in single-point scans, in contrast to whole-arch scans, where they do not match traditional methods [23; 31]. The divergent results reported in the studies can be explained by differences in the methodology used, including differences in the reference model, scanning strategy, scanning software, and analysis program [8; 36]. No statistically significant differences were found between measurements made directly on physical models using a digital calliper and those on digital models in the research of [PERSON] et al. [37]. On this basis, researchers concluded that linear measurements on virtual models created after scanning physical models with an extraoral scanner are highly accurate and one can rely on the results obtained from measuring the width and length of the arch both in clinical practice and during scientific research. Researchers were the first to use the Geomagic program instead of the software included with the scanner to determine points and measure the distance between them, studying its accuracy at the same time. In this study, the latest version of the Geomagic Control X quality control program was used for measurement. The program automatically searches for matching points on the test model after selecting them on the reference model based on a previous 3D comparison. This eliminates human error in the selection of corresponding points on the compared models. Conventional methods (SGM) compared to digital (TPM) resulted in the smallest deviation, by a statistically significant degree, from the standard for all linear dimensions. In addition, digital methods significantly diminished each time all sections compared to traditional (LD1: \(-\)0.2040 mm; LD2: \(-\)0.2362 mm; LD3: \(-\)0.1523 mm). The linear dimension between the second molars (LD3) was reproduced with the highest accuracy by each method (SGM: 0.0982%; TPM: 0.2839%). Elastomer impression materials shrinkage of approximately 0.15% to 0.5%, is at least partly compensated by expansion of dental plaster during setting which is approximately 0.07% to 0.1% [38; 39]. Although the distance between the amines (LD1) was the shortest, it was reproduced the least accurately by each of the methods (SGM: 0.13112%; TPM: 0.6032%). Other authors reported that the shorter the distance between the points measured on the model, the greater the accuracy of linear dimension reproduction achieved by both traditional and digital methods [18]. As it is visible, this determination does not apply to the anterior segment of the dental arch in the current study. The SGM method reproduced all sections most accurately, without statistically significant differences between individual linear dimensions, while the TPM method reproduced LD1 with accuracy diminished to a statistically significant degree in comparison to the other sections. [PERSON] et al. [17], concluded on the basis of linear measurements in their in vitro study that, intraoral scanners are an alternative for scanning full arches in orthodontics, while for prosthetics, the scanning distance should be one quarter [40].