## 4 Discussion
### Tooth Movement Produced and Clinical Implications  
The biomechanics behind molar uprighting are often coupled with unwanted effects, including molar extrusion or uncontrolled tipping when using different molar uprighting methods [32; 33]. Thus, a detailed analysis is necessary to better control the clinical outcomes of molar uprighting. The present study evaluated the efficiency of a conventional molar uprighting spring in achieving the desired correction for a tilted molar. The presented results indicate that the molar experienced some distalization during the uprighting process, which may be attributed to the distal location of the C\({}_{\text{Rot}}\), influenced by the molar's angulation and the line of action of applied forces [34]. Additionally, the vertical extrusion of the molar also occurred due to the uprighting spring's short lever arm producing a higher force component on the mesial upper corner of the buccal tube slot, which is an expected outcome when using this type of appliance [6]. However, the 2.15 mm of molar extrusion observed is considered clinically significant, as each millimeter of posterior extrusion is estimated to open the bite anteriorly by 1.5-2.5 mm [35]. Therefore, the use of such uprighting springs might not be recommended for cases requiring the strict control of vertical dimensions. The achieved partial molar uprighting of about \(\sim\)22\({}^{\circ}\) suggests that the further activation of the spring may be needed in order to achieve full molar uprighting. Furthermore, adding a vertical control component to this activation, such as an intrusion bend, could help mitigate the molar extrusion [7]. The anchoring teeth showed varying amounts of vertical intrusion, with the highest intrusion located on the second premolar, which can be attributed to the spring's point of engagement with the anchorage wire being between the two premolars. This tilting in the occlusal plane indicates that, although the square 0.016-inch stainless steel consolidating wire is considered theoretically rigid, it still undergoes slight bending, therefore affecting the vertical position of the anchoring segment even when they are tied together. Incorporating a larger dimension consolidating wire or possibly adding a bonded retainer can reduce this unwanted effect on the anchorage teeth [13; 36]. Although limited, the literature includes quantitative FE analysis and clinical data related to molar uprighting [13; 15; 31; 32; 37]. Table 3 illustrates a comparative overview of prior findings in relation to the current study's outcomes. It also highlights the proximity of the achieved simulation results to common clinical observation. While the assumptions of the current model were designed to be standard and reproducible, they closely resemble routine clinical practice. Sectional mechanics are highly predictable in comparison with a continuous arch \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Author** & **Study Type** &
\begin{tabular}{c} **Molar** \\ **Angular Correction (\({}^{\circ}\))** \\ \end{tabular} & **Forces Used** & **Treatment Duration** \\ \hline Present Study & FEA & 21.9\({}^{\circ}\) & 0.6 N & 12 Weeks \\ [PERSON] et al., 2007 [13] & FEA & 22\({}^{\circ}\) & 0.66 N & - \\ [PERSON] et al., 2024 [15] & FEA & - & 0.5 N & - \\ [PERSON] et al., 2021 [31] & Clinical Case Series & 24.5\({}^{\circ}\) & - & 10–12 Weeks \\ [PERSON] et al., 2010 [32] & Clinical Study & 18\({}^{\circ}\) & - & 9 Weeks \\ [PERSON] and [PERSON], 2022 [37] & Case Report & - & 50 g & 12 Weeks \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Current study’s simulation outcomes compared to previous FE analysis (FEA) and clinical data. Corresponding values that were not reported in some of the listed studies; these are marked with (-). a controlled environment where variables can be set and assessed individually [7]. The present arcnwire setup and the second molar tilt of 30\({}^{\circ}\) with a missing first molar were chosen to mimic the nature of cases usually encountered in daily practice.