CUPPING LESIONS on CANINES ARE ASSOCIATED WITH PRISMATIC ENAMEL TRAITS

Objectives: This exploratory study aimed to describe early (diameter ≤ 0.5 mm) natural cupping lesions at incisal edges of human permanent canines and investigate their association with enamel prismatic traits (concentric circles of Hunter-Schreger bands, HSB-c, and hypomineralized subsurface prismatic cones, PC-h)
Methods: Twenty-nine extracted canines presenting 38 cupping lesions were analyzed under 3D microcomputed X-ray tomography (microCT) and optical coherence tomography (OCT). Selected samples were also analyzed under SEM and optical profilometry.
Results: All lesions were surrounded by enamel walls, with 22 presenting the bottom on dentine and 16 on enamel. OCT detected that 20 lesions were located in the center of a HSB-c vortex (prevalence = 53%; IC 95%: 37%-68%%), and microCT detected that 13 out 16 lesions (OR = 127; p = 0.002) with the bottom in enamel presented a deep subsurface PC-h. SEM and profilometry revealed that cupping lesions were surrounded by concentric circles whose surface alternated between smooth to rough textures with honeycomb-like etching pattern.
Conclusions: In conclusion, early cupping lesions with eroded-like enamel surface texture, located at the center of concentric HSB, were found at incisal edges of permanent canines, associated with a deep subsurface cone with low mineral content.