###### Abstract  
Proper torque is an important element of orthodontic treatment. There are many factors affecting effective torque expression, e.g., the interplay between an archwire and a bracket, the precision during bracket positioning, and the morphology of the crown vestibular surface (CrVS) of the tooth. Our study focused on the impact of the maxillary incisor CrVS morphology on the torque exerted by the archwire-bracket interplay. Three-dimensional models of 50 patients acquired through the use of an intraoral scanner were used to examine the four maxillary incisors. A total of 200 teeth were examined. The influence of the tooth crown shape on the bracket position and the related torque change was analyzed with Ortho Analyzer software 2015 (3 Shape, Copenhagen, Denmark). All calculations were made for full size archwires. Central incisors showed less variability in their vestibular surfaces than lateral incisors. For the central incisors, the mean values of the additional palatal root torque ranged from 0.6\({}^{\circ}\) to 1.6\({}^{\circ}\). For the laterals, the mean values ranged from 1.4\({}^{\circ}\) of additional vestibular root torque to 3.5\({}^{\circ}\) of additional palatal root torque. The results showed essential morphological differentiation of the CrVS of the maxillary incisors. Therefore, when the bracket is positioned, the individual variation in the tooth surface should be considered and evaluated.  
b 2024 14 3D 2024 12 2024 1  
its base [6]. However, even with sophisticated, contemporary brackets, torque expression may be affected by many factors, such as adopted treatment mechanics, variability of the mechanical properties of orthodontic wires and/or brackets, varying mechanical properties of the tooth surrounding structure, as well as variability of the tooth morphology [6; 7; 8; 9; 10; 11; 12; 13; 14]. Tooth morphology diversity has been proven in many studies [6; 7; 8; 9; 10; 11]. Although the maxillary incisors show the smallest variability in shape [9], these teeth are also differentiated. Differences between the right and left central incisors have been demonstrated even in the same patient [6]. The morphology of the tooth crown vestibular surface (CrVS) has been examined using various approaches.  
The study builds on the premise that individual tooth morphology can significantly influence orthodontic treatment outcomes, particularly in terms of the root torque control. Previous research has demonstrated variability of tooth morphology, but the application of three-dimensional scanning technology to analyze this variability is novel. The use of high-precision intraoral scanners, such as the TRIOS(r)3, represents a significant leap from traditional methods, offering sub-millimeter accuracy that is critical for assessing the complex geometries of the dental structures. Conventionally, CrVS was examined by means of a circle or a system of coordinates based on a cross-section of the teeth from plaster models [4; 8; 10; 11; 12; 15; 16]. To date, no modern 3D technologies have been used for this purpose. Therefore, the aim of this study was to apply intraoral scans to analyze the maxillary incisor CrVS morphology and to determine whether this anatomy affects the prescribed torque values.