Three‐Dimensional Segmentation of Dens Invaginatus: A Case Series Exploring the CARES Classification for Anatomy‐Driven Clinical Decision‐Making

INTRODUCTION: Dens invaginatus (DI) exhibits substantial 3-dimensional anatomical variability that may not be fully represented by conventional classification systems. The recently introduced CARES classification provides a CBCT-based framework incorporating communication, cross-sectional anatomy, root formation, vertical extent, and supplementary features. This case series aims to describe the clinical management of three teeth with DI using cone-beam computed tomography (CBCT) and three-dimensional segmentation for anatomical assessment and treatment planning, while illustrating the clinical application of the CARES classification. METHODS: Three maxillary lateral incisors with DI and periradicular pathosis were evaluated using CBCT and 3-dimensional segmentation of the tooth and root canal system. Anatomical features were categorized according to both Oehlers and CARES classifications. Treatment strategies were individualized according to the anatomical configuration encountered in each case. One tooth was managed using conventional CBCT-assisted access, whereas static guided endodontic access was used in 2 anatomically complex cases following unsuccessful conventional localization of the target anatomy. RESULTS: Case 1, classified as Oehlers Type II and CARES C1-A0-R2-E2-S1, presented an invagination communicating with the root canal without displacement or deformation of the canal and was successfully managed using conventional CBCT-assisted access, with complete periradicular healing after 7 years. Cases 2 and 3 were classified as Oehlers Type IIIa and CARES C2-A1-R2-E2-S3 and C2-A1-R2-E2-S2, respectively. In both cases, the invagination communicated with the periodontium but not with the root canal system and displaced or deformed the root canal, resulting in a C-shaped configuration in Case 2 and an asymmetrical, flattened configuration in Case 3. Static guided endodontics enabled access to anatomically challenging targets after conventional approaches proved insufficient. Follow-up demonstrated clinical resolution in all cases, with complete periradicular healing at 7 years in Case 1, progressive periradicular healing at 6 months in Case 2, and significant periradicular healing at 24 months in Case 3. CONCLUSION: CBCT combined with three-dimensional segmentation provided detailed characterization of DI anatomy and supported individualized treatment planning. Application of the CARES classification captured clinically relevant anatomical and disease-related features not conveyed by Oehlers classification alone, particularly communication patterns, root canal deformation, and the origin of periradicular pathosis. These cases illustrate the potential clinical value of integrating three-dimensional anatomical assessment and CARES coding when managing complex DI.