## 5 Conclusions  
In this paper we evaluated the trueness and precision of 3D printed occlusal devices with different height and volumes ([2.5_TOTAL] and [4.5_TOTAL]) obtained from a DLP printer using a transparent resin. The occlusal devices [2.5_TOTAL] were less voluminous than the [4.5_TOTAL]. The applied layer thickness of 50 \(\upmu\)m was representative of a high detail level. We can draw the following conclusions from the results:  
Figure 4: Orientations of the occlusal devices on the building platform (a) 2.5 (b) 4.5.  
The printing and post-processing process were accompanied by a minimal shrinkage. The volume of the printed objects was between 2.11% and 2.35% less in comparison to the CAM files, which served as blueprint;
* Within their groups, the [2.5_TOTAL] and [4.5_TOTAL] devices showed identical dimensional deviations in comparison to their corresponding stl references. However, between the two groups different deviation patterns were observed. The [2.5_TOTAL] were wider in the posterior region and compressed in the anterior area. The [4.5_TOTAL] showed a compression of the posterior area;
* These observations confirmed that deviation patterns are not rigidly associated with the specific printer system but with different parameters. The different platform orientations specified by the CAM software for [2.5_TOTAL] and [4.5_TOTAL] and the different volumes could be identified as such influential variables;
* The results revealed a high precision. The absolute mean deviation values were 19 \(\upmu\)m for [2.5_TOTAL] and 26 \(\upmu\)m for [4.5_TOTAL]. The high precision was underlined to be the more outlier sensitive RMSE value which revealed 34 \(\upmu\)m for [2.5_TOTAL] and 42 \(\upmu\)m for [4.5_TOTAL];
* The absolute mean trueness was 68 \(\upmu\)m for [2.5_TOTAL] and 90 \(\upmu\)m for [4.5_TOTAL]. The median RMSE results were 88 \(\upmu\)m for [2.5_TOTAL] and 122 \(\upmu\)m for [4.5_TOTAL]. Thus, the results were comparable with previously published printer results;
* There were statistically significant differences between [2.5_TOTAL] and [4.5_TOTAL] and between [2.5_TNTERNAL] and [4.5_TNTERNAL] with respect to trueness and precision values.  
The orientation of the printed parts on the building platform could be a decisive co-factor influencing accuracy.  
A higher volume of printed objects resulted in increased deviations regarding trueness and precision.  
Trueness and precision values of the tested digital light processing printer were competitive to the results published for other printers when occlusal devices were evaluated.  
Conceptualization, S.B., H.H. and S.R.; data curation, S.B. and H.H.; investigation, S.B., H.H. and S.R.; methodology, S.B., H.H. and S.R.; project administration, S.R.; supervision, S.R.; visualization, S.B., H.H., S.R. and C.K.; writing--original draft, S.B., H.H. and S.R.; writing--review & editing, S.B., H.H. and S.R. All authors have read and agreed to the published version of the manuscript.  
The research was funded by Dentsply Sirona.  
Not applicable.  
The data presented in this study are available on request from the corresponding author.  
Thanks to [PERSON] for giving advice.  
The author [PERSON] has or had commercial relationships with the following companies including consulting, presentation activities, and third party-funded research: 3M OralCare, 3 Shape, Amann Girrbach, Camlog, Oral Reconstruction Foundation, DCS, Dentaurum, Dentsply Sirona, Ivoclar Vivadent, Straumann, Vita Zahnfabrik. S.B, and H.H. declare no conflict of interest.