## 4 Discussion
The authors suggest that additional well-designed and adequately powered studies, preferably randomized controlled trials with well-defined primary and secondary outcome variables and long-term follow-up (of at least 12 months) are required to determine whether the orthodontic treatment mode (CAT versus fixed OT) has any impact on the esthetic and functional outcome in patients after OS. A BMI ranging between 18.5 and 24.9 Kg/m\({}^{2}\) is considered normal [26]. In a prospective volumetric analysis, [PERSON] et al. [27] used three-dimensional photographs to quantify post-operative FS after OS (L1O and/or BSSO) in relation to BMI. The results showed that patients with a higher BMI experience a greater amount of FS and fastest rateof its resolution in initial postoperative weeks compared with individuals with a lower BMI [27]. In the present systematic review, two studies [10; 12] reported the mean BMI of patients that underwent CAT or fixed OT after OS, which ranged between approximately 24 and 25 \(\mathrm{Kg/m^{2}}\). Due to the divergent results observed in these studies [10; 12] concerning facial symmetry (FS) and the limited range of average BMI, establishing a direct correlation between FS and BMI is challenging. Moreover, the severity of post-surgical edema/FS is influenced by factors such as operator(s') skills and the complexity and duration of the intervention [28]. Based on the methodology of the included studies [10; 11; 12; 13], all surgical and post-operative orthodontic interventions were performed by experienced operators. The mean duration of intervention (operating time [OT]) and follow-up was reported in 50% of the studies [10; 12] which ranged between approximately 180 and 300 min and 7 and 24 weeks, respectively. Despite variations in OT and duration of follow-up, these studies [10; 12] reported conflicting results in terms of post-operative FS. There were limited results regarding the surgical duration and total treatment duration with CAT versus fixed OT. From a clinical perspective, CAT has allowed clinicians to plan presurgical decompensatory tooth movements in digital platforms such as Invisalign\({}^{\prime}\)s ClinCheck and virtually simulate the surgery through a bite jump. A study by [PERSON] et al. evaluated presurgical orthodontic decompensation with CAT and reported that common tooth movements for decompensation were highly accurate with the use of CAT [29]. Despite the results in this study, it is incumbent on clinicians to approach the virtually planned tooth movements with caution as the planned tooth movements made by the technician may not be predictable or attainable clinically. Moreover, the use of aligners instead of fixed orthodontic appliances (brackets, wires and surgical hooks) during the operative and postoperative phases of treatment may pose challenges to orthognathic surgeons and orthodontists particularly regarding the use of intermaximillary elastics for occlusal stabilization and settling during and after the OS, respectively [30]. Nonetheless, this perceived deficiency in CAT can be overcome by using auxiliaries such as buttons, brackets, Ivy loops, Erich arch bars and intermaximillary fixation screws, amongst others, in conjunction with the conventional clear aligners. Another important consideration regarding the use of CAT in OS, is that in the postoperative phase, OS patients oftentimes have limited mouth opening from stripping of muscles intraoperatively and from postoperative edema. In the setting of these postoperative limitations, rescanning for ordering finishing and detailing aligners can be challenging. It was noted by [PERSON] that a presurgical scan of patients, that has been fully decompensated, can be used to order more aligners to have immediately after surgery for finishing and detailing [31]. However, [PERSON] noted that this is not recommended in multi-piece LeFort osteotomies due to aligners not fitting properly postoperatively [31]. Regarding postoperative stability, a study by [PERSON] et al.