Background: Dens invaginatus is a developmental abnormality originating from tooth development, including coronal invaginatus and radicular invaginatus. The reported incidence varies greatly due to diagnostic techniques, classification criteria and race. The incidence of dens invaginatus in China was not clear, and the impact of dens invaginatus on periodontal support tissue were rarely reported. This study aims to clarify the incidence of maxillary lateral incisor dens invaginatus and its impact on periodontal supporting tissues.
Methods: From the cone-beam computed tomography database, images of 212 maxillary lateral incisors from 106 Chinese patients were selected. Teeth that met the Oehlers classification criteria for coronal invaginatus were recorded as coronal invaginatus, and teeth with radicular cystoid invaginatus or radicular groove were classified as radicular dens invaginatus. The complexity of radicular groove was determined by Gu's classification standard. Both of coronal invaginatus and radicular dens invaginatus were recorded as dens invaginatus. For 15 patients with unilateral radicular dens invaginatus, the periodontal ligament area of the affected teeth and the corresponding natural teeth in the same jaw were measured and compared.
Results: The overall incidence of maxillary lateral incisor invaginatus in China is 25.0%. The incidence of coronal invaginatus is 12.3%, and the incidence of radicular dens invaginatus is 14.6%. No significant differences were observed between genders or sides. In this study, all radicular dens invaginatus exhibited as radicular groove, of which 87.1% were Gu type I, 9.7% were Gu type II, and 3.2% were Gu type III. Although the difference was not statistically significant, the average periodontal ligament area of the maxillary lateral incisor with radicular dens invaginatus was 148.93 ± 35.62mm2, smaller than that of the control teeth (152.28 ± 40.22mm2).
Conclusions: The dens invaginatus of the maxillary lateral incisor is common. There is no significant difference in the incidence between genders or between sides. The main manifestation of the radicular dens invaginatus is the radicular groove (Gu's type I). This anatomical abnormality may reduce the periodontal ligament area. The presence of the additional root of the maxillary lateral incisor is not rare and was supposed to be highly concerned by dentists.
Keywords: Cone beam computed tomography; Dens invaginatus; Endo-perio lesion; Radicular groove.
© 2024. The Author(s).