## 4 Discussion
Men are probably at less risk in this respect, but more research is needed on this topic. Similar results were seen in women aged 40 to 49 years and men aged 30 to 39 years. When planning the treatment of upper incisor protrusion, the structure of the palatal canal should be taken into account, especially in connection with the posterior rotation of the mandible. Studies have shown that individuals with posterior mandibular rotation have a narrower maxillary alveolar ridge [8]. Analysis of canal width and distance between the most mesial point of the root and the tangent passing through the most anterior point of the incisive canal showed a negative correlation in all age groups of men. The wider the canal, the shorter the distance between the roots and the canal. This may be related to the convergence of the incisors in the case of larger canal widths. The strongest correlation at the L1 level again confirms the increased risk of contact and possible resorption in the pericervical region in men. At L2, boys aged 13 to 20 years were most at risk. In women, the correlation at the level of L1 and L3 occurred in the age group of 40 to 49 years. The roots here were located closer to the canal, which had a reduced width. In women in this age group, there was an increased risk of excessive movement of the incisors within the tongue, e.g., in the case of decompensation of class III malocclusion. Different results were obtained by [PERSON] et al. [8]. They found no gender-dependent relationship between the interroot distance of the upper central incisors and the anterior border of the incisal canal or the sagittal or vertical skeletal patterns. Regarding the width of the canal in the aspect of gender, this research confirmed the results obtained by [PERSON] [8]. Men had greater canal widths compared to women. Similar results were previously obtained [7; 25; 26]. Our research has confirmed the sexual dimorphism of the incisive canal. At the same time, it was noted that the incisive canal had a cross-sectional shape similar to a circle at the L1 level and an ellipse at the L3 level with a larger transverse dimension. These findings suggest that incisor retraction after maxillary expansion should be performed with care. The increasing AP dimensions of the canal in women over 40 years of age at the L3 level suggests a greater risk in the case of axial retraction of the incisors, especially after maxillary osteodistraction, during which the width of the canal increases. On the other hand, increasing the width of the incisive canal in relation to the length of the anteroposterior with age in women up to 40 years of age also increases the potential risk of incisor resorption after maxillary expansion. This is due to the high risk of greater canal width than the interroot distance. Various complications can occur during orthodontic treatment. Root resorption is mild in most cases and does not adversely affect the prognosis of the affected teeth. Unfortunately, some patients experience extensive root reduction, which may even lead to tooth loss. The etiology of resorption is not fully understood. In this place, contact of the roots with the vestibular or palatal cortical bone of the alveolar process is increasingly indicated. Similarly, the probability of resorption as a result of contact with the cortical bone surrounding the incisal canal can be assumed [1; 2; 3; 4; 5]. According to [PERSON], the risk of severe resorption is highest in the case of the upper incisors and amounts to 3%, while the same risk increases 20 times when the roots are moved into contact with the palatal cortical plate of the alveolar process [27]. Similarly, contact with the cortical plate of the incisive canal may also increase the risk of resorption, which is discussed in detail in a systematic review on this topic [5]. Incisor retraction, excessive labial or lingual movement, and intrusion or extrusion are high-risk factors for resorption.