The Impact of Mandibular Third Molars on the Anterior Teeth Crowding of the Mandible: A Case-Control Study

Background: Mandibular dental anterior crowding (MAC) (twisted, overlapped or displaced teeth) is extremely prevalent among adults and adolescents, as roughly ۴۰% of the population is experiencing moderate to severe anterior crowding. The aim of this study was to analyze potential influence of third molar in advancement of lower incisors crowding. Methods: Mandibular dental plasters of ۱۵۰ (۹۰ male and ۶۰ female) pretreated patients from the year ۲۰۱۹ to ۲۰۲۱ were included in this study. The participants were aged between ۱۸ and ۲۶. They were divided into two groups: The control group with the minimum anterior crowding of the mandible according to the Little’s irregularity index (LII), the study group in which there were subjects with moderate to severe irregularity of teeth. The position of the third molars was defined by panoramic radiographs. The obtained measurements were statistically analyzed by SPSS software and student’s t-test. Results: The results represented a significant correlation between the mandibular third molars and mandibular incisor crowding (P = ۰.۰۳۳). In the control group, ۲۸% had impacted third molar, ۹% had third molar third molar hypodontia, ۵۸% had extracted third molar and ۵% had erupted third molar. While in the study group the percentages were ۴۴%, zero, ۲۳% and ۳۳%, respectively. Conclusion: A positive correlation between the eruption and impaction of mandibular third molar and mandibular incisor crowding has been observed. While, there was a negative correlation between extraction and hypodontia of mandibular third molar and mandibular incisor crowding.

Keywords:

Mandibular third molars , mandibular incisor crowding , malocclusion , Little’s irregularity index