## 3 Results  
The dimensional trueness of both tested printing systems was statistically different from the reference measurement (\(p<0.05\)) at both time points. MAX UV demonstrated median deviation of 108 \(\upmu\)m and 99 \(\upmu\)m whilst Form 2 yielded 117 \(\upmu\)m and 118 \(\upmu\)m at two- and six-weeks post-printing, respectively. The study found no significant difference from the reference model (\(p>0.05\)) for either 3D printer at both two- and six-weeks post-printing in terms of full-arch trueness.  
Comparison of the dimensional accuracy between the two printing systems resulted in a statistical difference (\(p=0.005\)). MAX UV had a lower median deviation (108 \(\upmu\)m) and greater precision (27 \(\upmu\)m) when compared to Form 2, which had trueness of 117 \(\upmu\)m and precision of 59 \(\upmu\)m after two weeks post-printing (Figure 2). Similarly, a statistical difference (\(p=0.000\)) was also present for full-arch accuracy, with MAX UV having a smaller error (26 \(\upmu\)m) and higher precision (32 \(\upmu\)m) (Figure 3).  
Figure 2: Boxplot for the median error and precision of the sphere diameter at T1 and T2 for MAX UV and Form 2 3D printed models. \({}^{\circ}\) Denotes outliers more than 1.5 IQR but less than three IQR from the end of the boxplot. \({}^{\star}\) Denotes outliers more than three IQR from the end of the boxplot.  
When the models were stored for an additional four weeks after the initial measurement, no statistical differences were found for the dimensional deviation between the two time points for both printers (\(p>0.05\)). However, statistical differences were detected for full-arch accuracy for both MAX UV samples (\(p=0.003\)) and Form 2 samples (\(p=0.000\)) between two- and six-weeks post-printing indicating a progressive contraction with time (Figures 2 and 3).  
The analysis of the individual arch segments did not identify significant differences (\(p>0.05\)) in the deviation between the left and right posterior arch for both printers. Similarly, no statistical difference (\(p=0.117\)) was found between the anterior and posterior arch for MAX UV. However, Form 2 showed significant (\(p=0.000\)) posterior cross-arch shrinkage when the anterior (vectors V\({}_{12}\), V\({}_{13}\), V\({}_{16}\)) and posterior arch (vectors V\({}_{5}\), V\({}_{6}\), V\({}_{10}\), V\({}_{11}\)) segments were compared (Table 3). The Form 2 models also showed a large anteroposterior (vector V\({}_{3}\), V\({}_{18}\)) contraction with a median deviation of 212 \(\upmu\)m from the reference measurement with low precision of 124 \(\upmu\)m.  
The tested DLP system was more than twice as efficient as the SLA system with similar resin consumptions. MAX UV required approximately 37.7 mL of resin for the fabrication  
Figure 3: Boxplot for the median error and precision of the full-arch parameter at T\({}_{1}\) (two weeks post-printing) and T\({}_{2}\) (six weeks post-printing) for MAX UV and Form 2 3D printed models. \({}^{\text{o}}\) Denotes outliers more than 1.5 IQR but less than three IQR from the end of the boxplot.  
\begin{table}
\begin{tabular}{c|c c c c c c} \hline \hline
**Printer** & **Measurements** & **Left Posterior** & **Right Posterior** & **Posterior** & **Anterior** & **Anterioroposterior** \\ \hline Max UV & Median deviation (\(\upmu\)m) & 20 & 9 & 49 & 27 & 23 \\  & IQR (\(\upmu\)m) & 31 & 12 & 47 & 27 & 31 \\  & \(p\)-value & 0.152 & & 0.117 & \\ \hline Form 2 & Median deviation (\(\upmu\)m) & 94 & & 114 & 278 & 56 & 212 \\  & IQR (\(\upmu\)m) & 76 & 157 & 94 & 88 & 124 \\  & \(p\)-value & 0.576 & & 0.000 & & \\ \hline \hline \end{tabular}
\end{table}
Table 3: Median deviation and interquartile range (IQR) of arch segments: left posterior; right posterior; posterior; anterior; anteroposterior of MAX UV and Form 2 3D printed models at T\({}_{1}\).  
of two models in 1 h and 48 min. On the other hand, Form 2 required 37.3 mL to fabricate two models in 4 h.