Clear aligners (CAs) have emerged as a widely accepted alternative to conventional fixed orthodontic appliances due to their aesthetic appeal, comfort, and removability. Despite their increasing use, the precise biomechanical behavior of CAs—particularly in relation to maxillary arch expansion and torque control—remains incompletely understood. This scoping review aims to synthesize and critically examine the recent body of evidence derived from finite element analysis (FEA) studies investigating the performance of clear aligners in managing transverse discrepancies and controlling tooth movement. It considered studies published up to April 2025. All included FEA studies assumed dental and bone tissues as linearly elastic, homogeneous, and isotropic, unless otherwise specified. Five in silico studies were included, all employing three-dimensional FEA models to assess the influence of various clinical and design parameters, such as aligner thickness, movement sequence, attachment configuration, and torque compensation. The findings consistently show that movement protocols involving alternating activation patterns and specific attachment designs can significantly improve the efficiency of maxillary expansion, while reducing undesired tipping or anchorage loss. Additionally, greater aligner thicknesses were generally associated with increased force delivery and more pronounced tooth displacement. Although FEA provides a powerful tool for visualizing stress distribution and predicting mechanical responses under controlled conditions, the lack of standardized force application and limited clinical validation remain important limitations. These findings underscore the potential of optimized aligner protocols to enhance treatment outcomes, but they also highlight the need for complementary in vivo studies to confirm their clinical relevance and guide evidence-based practice.

Hemifacial Microsomia (HFM) is the second most common craniofacial malformation after clefts and it is characterized by mandibular hypoplasia and facial asymmetry. This retrospective study aimed to evaluate mandibular morphology in growing HFM patients using three-dimensional (3D) computed tomography (CBCT), focusing on volumetric asymmetries. A total of 26 patients aged 5-13 years with unilateral HFM were analyzed. They were stratified into two age groups (5-8 and 9-13 years) and classified according to Pruzansky-Kaban system in two severity categories (mild/severe deformity). CBCT data were processed to reconstruct 3D mandibular models, segmenting the condylar, coronoid and gonion regions. Volumetric differences between affected and unaffected sides were compared across age and severity subgroups. Results showed that all the three functional units were significantly smaller on the affected side, especially in severe HFM cases. However, no statistically significant differences were found between the two age groups, suggesting that mandibular asymmetry remains substantively unchanged over the two consecutive time points examined. Multivariable regression confirmed that HFM severity was strongly associated with condylar and gonial volume discrepancies. This study highlights the value of CBCT-based 3D reconstruction for precise assessment of mandibular morphology and supports its role in individualized diagnosis and treatment planning for HFM patients.