Abstract: PURPOSE: CBCT was used to measure and analyze the relationship between dental crowding degree and basal bone morphology, dental arch and alveolar arch morphology in adult female maxillary anterior teeth. METHODS: A retrospective analysis was conducted on the medical records of 122 adult female patients with maxillary anterior dental arch crowding who received orthodontic treatment at Qingdao Haici Hospital, Affiliated to Qingdao University, from December 2019 to December 2022. The patients were divided into two groups based on the degree of dental arch crowding: group I(mild crowding,maxillary dentition crowding degree ≤ 4 mm, n=62) and group II(moderate to severe crowding,maxillary dentition crowding degree 4-8 mm, n=60). The lengths and widths of the alveolar bones, dental arches and alveolar arches were compared between the two groups. The correlation between dental arch crowding and alveolar bone morphology, dental arch and alveolar arch morphology was analyzed. SPSS 26.0 software package was used for statistical analysis of the data. RESULTS: In group I (mild crowding), the maxillary basal bone length, mandibular basal bone length, maxillary basal bone width at the root apex and root bifurcation,mandibular basal bone width at the root apex and root bifurcation were significantly higher than group II(P<0.05). The maxillary dental arch length, mandibular dental arch length, maxillary dental arch width,mandibular dental arch width on the mesial and distal sides were significantly higher in group I than group II(P<0.05). The maxillary alveolar arch length and mandibular alveolar arch length in group I were significantly higher than group II (P<0.05). There was no significant difference in maxillary alveolar arch width and mandibular alveolar arch width between the two groups(P>0.05). The crowding degree of the dental arch was negatively correlated with the length of the maxillary and mandibular bases, the width of the maxillary and mandibular bases at the root bifurcation,and the width of the proximal maxillary and mandibular arches(P<0.05). The length of the maxillary base bone(OR=0.283, 95% CI: 0.128-0.625), the width of the maxillary base bone at the root bifurcation (OR=0.182, 95%CI: 0.083-0.402), the width of the proximal maxillary arch (OR=0.347, 95%CI: 0.158-0.766) and the width of the mandibular arch(OR=0.304, 95% CI: 0.137-0.669) were the influencing factors of dental congestion in the aesthetic area of adult female maxillary anterior teeth(P<0.05). CONCLUSIONS: The reduction of basal bone, dental arch and alveolar arch are associated with crowded dentition in the maxillary anterior aesthetic zone of adult females.

Key words: Dental crowding, Cone beam CT, Adult female, Basal bone, Dental arch, Alveolar arch