## 4 Disscussion
According to the literature, the prevalence of severe resorption with multibracket appliances is higher than in clear aligners [9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37]; fortunately, the long-term survival of teeth with severe root resorption appears to be good. Regarding the instrumental examination, we used CBCT scan with the low dose protocol because panoramic and periapical radiographs tend to underestimate the finding of root resorption by more than 20% compared to CBCT [38]; indeed, CBCTs show high sensitivity, specificity, and reproducibility. In orthodontics, the 2D examinations, e.g. panoramic or lateral cephalometric radiographs, lack all information required during diagnosis, treatment planning, and follow-up. In contrast, CBCT scans provide detailed 3D images on skeletal tissue, root resorptions, facial muscle measurement (e.g. masseter), TMJ morphology, and upper airway status. To limit patient radiation exposure, low-dose CBCT protocols have been proposed. In the current study, we used a low-dose CBCT with a value of the effective dose of 35 \(\upmu\)Sv [17], considerably lower than that of traditional CBCT. There is a need for clinical recommendations, guidelines, or position statements from authoritative bodies regarding the use of the low-dose protocol in dentistry. The clinical recommendations issued by the American Academy of Oral and Maxillofacial Radiology (AAOMR) [39] in 2013 concern only high-dose CBCT. In addition, according to AAOMR, in orthodontics, the recommendations are \"neither rigid guidelines nor did they represent or imply a standard of care\"; therefore, the orthodontist evaluates the use of CBCT based on clinical presentation considering the patient's best interest. Recently, [PERSON] et al. [40] in their review have underlined that the low-dose CBCT undoubtedly offers greater information both at the beginning and end of the therapy in various dental medicine disciplines, such as in orthodontics to evaluate impacted teeth or alveolar bone quantity and to assess TMJs, in endodontics to detect root fractures, resorptions, and periapical bone loss, and in dental surgery to plan implant insertion and to place temporary anchorage devices. The current study was subjected to the following limitations. Firstly, we examined only non-extraction treatment. In extraction cases, the management of torque during closing extraction spaces is challenging for the orthodontist [41], and consequently, the root length loss is higher. Secondly, we excluded the use of intermaxillary elastics, so the incidence of EARR was underestimated in our study since the intermittent forces of intermaxillary elastics could lead to greater root resorption. Lastly, we considered only aligners produced by a single manufacturer, and aligner materials' clinical performances vary from manufacturer to manufacturer. Future papers are suggested to establish whether the materials of other clear aligner manufacturers show similar outcomes to those reported in the present study. We found, within study limitations, an improvement of sagittal root position and a significant increase in torque in the upper and lower incisors, canines, and first premolars, as well as the highest mean torque changes in anterior teeth. Moreover, these torque increases led to no severe root resorptions, and we observed mainly mild root resorptions following clear aligner treatment. Therefore, compared to previous papers, our study extended the assessment of root control management to all upper and lower teeth and demonstrated that the clear aligners could enhance the torque in both arches without a substantial root length loss.