# Nanotomographic Analysis of Orthodontic Molar Tubes for Direct Bonding
## 2 Materials and Methods
\begin{table}
\begin{tabular}{l l l l l l l} \hline \hline
**Variable** & & **Acent (Ormco)** & **Bond Sing** & **Ortho Cast M** & **Victory** & **L LP** & **\(p\) *** \\ \hline \multirow{2}{*}{Height 5 [mm]} & mean \(\pm\) SD & 0.57 \(\pm\) 0.0 & 0.64 \(\pm\) 0.01 & 0.57 \(\pm\) 0.0 & 0.59 \(\pm\) 0.0 & 0.56 \(\pm\) 0.0 & \\ \cline{2-2} \cline{6-8} \cline{10-10}  & median & 0.57 & 0.64 & 0.57 & 0.59 & 0.56 & \(\mathrm{<}\)0.001 \\ \cline{2-2} \cline{6-8} \cline{10-10}  & Q1–Q3 & 0.57–0.57 & 0.63–0.64 & 0.57–0.57 & 0.58–0.59 & 0.56–0.56 & \\ \hline \multirow{2}{*}{Height 6 [mm]} & mean \(\pm\) SD & 0.58 \(\pm\) 0.0 & 0.63 \(\pm\) 0.01 & 0.57 \(\pm\) 0.0 & 0.57 \(\pm\) 0.01 & 0.57 \(\pm\) 0.0 & \\ \cline{2-2} \cline{6-8} \cline{10-10}  & median & 0.57 & 0.63 & 0.57 & 0.58 & 0.56 & \(\mathrm{<}\)0.001 \\ \cline{2-2} \cline{6-8} \cline{10-10}  & Q1–Q3 & 0.57–0.58 & 0.62–0.63 & 0.57–0.57 & 0.57–0.58 & 0.56–0.57 & \\ \hline \hline \The results of the present laboratory research also show that the buccal tubes manufactured by GC and Ormco are characterized by the highest accuracy as far as maintaining the declared linear and angular dimensions is concerned. The worst results were recorded for the Adenta tubes, where apart from the statistically significant differences in the dimensions of the tube channels in relation to the nominal values (\(p<0.001\)), production imperfections in the form of defects in the internal structure of the alloy were found. No metallurgical defects were found in the structure of the analyzed tubes from other manufacturers. Comparison of the tubes inspected (post hoc analysis) revealed that all mean heights in all study samples were statistically significantly (\(p<0.001\)) higher than those declared by the manufacturers:  
* The largest height 1 was found for Bond Sing and the lowest was found for Accent and Ortho Cast M.
* Height 2 for Accent and Ortho Cast M was lower than for the remaining samples. * Height 3 was the largest for Bond Sing and the lowest for Accent. * The largest height 4 was found for Bond Sing comparing to all the remaining samples. * Height 5 was the largest for Bond Sing and the lowest for L LP
* Height 6 was the largest for Bond Sing and the lowest for Ortho Cast M, L LP and Victory. The angle between the horizontal walls of the channel was significantly higher (i.e., the walls were less parallel) in the Bond Sing tubes. The most parallel walls were found in the Ortho Cast M and L LP tubes. It was visibly apparent that the angles between the inner walls of the channels slightly differed from the ideal 90 degrees:  
* Angle 1 was significantly higher for Victory Series than for Bond Sing and Ortho Cast M. Moreover, the difference between median value and the right angle was significantly higher for L LP, Accent and Bond Sing than for Ortho Cast M, where the angle was less than 90 degrees. * Angle 2 was the closest to ideal in Accent and was significantly different compared to the other samples. * Angle 3 differed from 90 degrees significantly more for L LP, Accent, and Bond Sing than for Victory Series and Ortho Cast M.
* Angle 4 was significantly higher for Bond Sing compared to all other samples; for Victory Series and L LP, the angle was less than 90 degrees; for Accent, the angle was the closest to ideal. The difference between median value and the right angle was significantly higher for Ortho Cast M than for L LP and Accent, and for Victory Series, significantly higher than for Accent. * Angle 5 was the farthest and had the greatest median value for Victory Series, and for Accent, the angle was the closest to 90 degrees. * Angle 6 was found to have a difference between median and right angle which was significantly higher for Accent than for the latter samples; moreover, for Ortho Cast M, it was significantly lower than for L LP and Bond Sing.