## 4 Discussion
This current outcome is supported by various finite element model studies done in the past [40]. In group 2, the length of the power arm was increased from 4 mm to 8 mm to keep the force application near the center of resistance in the maxillary anterior segment [41]. Another reason for increasing the power arm was to keep the line of the force of applicationalmost parallel [42]. When the model of group 2 was analyzed for stress generation and distribution, it was observed that the stresses around the lateral incisors were found to be on the higher side when compared with the central incisors and canines. This may be due to the additional curve of spee in the wires during the retraction stage to avoid a deep bite [43]. Moreover, finite element models reproduce the retraction procedure, not the complex biological process. The current study showed that the stress values in the hard bones are greater than in the soft bones. The explanation for this might be hard bones having a higher Young's modulus than soft bones which sustain more loads and resists more deformation than soft bones [6]. This result also complies with the previous studies [6; 27]. The stress values for all bones are distantly lower than the 135 MPa, which is the fundamental tensile strength of the bone [31]. This signifies that the bone has adequate strength to defy retraction forces. When a comparison of stress generation and distribution was done between group 1 and group 2, it was found that higher levels of stress were generated in group 1 than in group 2. This could be due to different heights of power arms which produced different force vectors that are well supported by the previous study [40]. Thus, a methodology of orthodontic tooth movement was established in the current study by all the procedures included such as finite element modeling, model analysis, and result deduction. The current finite element model study of en masse retraction using the mini screws exhibited inconsistent distribution of stresses on teeth along with hard and soft bones. Nevertheless, stresses in the crown area are significantly greater than the stresses in the apical area of the teeth. This study explains the generation and distribution patterns of stresses in the maxillary anterior region, which need to require further clinical investigations. A previous finite element model study on stress patterns was conducted in periodontium with three different power arm heights at 3 mm, 6 mm, and 9 mm. Moreover, orthodontic mini implants were placed at two different heights: 7 mm and 10 mm [27]. This study revealed that a high orthodontic mini-implant with a lower anterior retraction hook was required for controlled lingual tipping and, in the case of retraction with root movement, a high orthodontic mini-implant with a higher anterior retraction hook was required. Orthodontic tooth movement causes more stress on the periodontal ligament than on the surrounding bony structures. Previous studies showed that compressive stresses concentrated more on the palatal side near the apex, and the labio-cervical area of the tooth was distributed by the tensile stresses [27; 44; 45]. Lateral incisors experienced more stress than central incisors due to the periodontal ligament support. The reason behind this is that lateral incisors have shorter roots than central incisors [46]. Moreover, greater stresses were observed near the higher retraction hook, irrespective of the mini-implant placement [45; 47]. However, the current study focused on the hard and soft bones only. Moreover, only two different heights (4 mm and 8 mm) of power arms were used in this study, and these different heights of power arms have no effect on stress distribution. As per literature searches, none of the studies placed power arms at a height of exactly 4 mm and 8 mm; therefore, direct comparison of the stress at these specific heights of power arms could not be possible.