Influence of the Size of Incisors on the Occurrence of Crowding

The size of teeth is one of the crucial factors affecting occlusion formation. In the occurrence of the crowding of dental strings, the size of teeth has a significant role. The aim of the study was to determine the influence of the size of permanent frontal teeth (bicuspids) on the appearance of the crowding of the frontal segment of dental strings. The study included 140 subjects, aged 15-20 years. All the examinees were divided into two groups. The first group comprised 90 subjects (39 males and 51 females) who had marked symptoms of crowding, especially in the frontal segment. The second group comprised 50 subjects (20 males and 30 females) with normal occlusion. The measurement was performed using a digital nonius, 0.01mm of accuracy. The following parameters were examined: mesiodistal (MD) and vestibulolingual (VL) diameter of the maxillary and mandibular incisors. The index of the crown of the tooth was calculated using the formula MD-VL × 100. The results of the study show that males have significantly wider teeth both in the upper and the lower jaw. The same results were obtained for subjects with crowding and subjects with normal occlusion. The vestibulolingual diameter of the maxillary and mandibular incisors in subjects with normal occlusion is greater in males. The vestibulolingual diameter of permanent incisors in subjects with crowding shows a sex-related dimorphism only with lateral incisors in the upper jaw. A statistically significant difference at a lower level of significance of the tooth crown index for upper incisors was observed in females, while the index of the crown of lateral incisors in the lower jaw did not show significant sex-related differences.