Study of the Relationship Between Microstructural Alterations and Elastic Properties in Teeth with Dentinogenesis Imperfecta

Dentinogenesis Imperfecta (DI) is a rare genetic disease (1 in 8,000 to 6,000 births) characterized by hypomineralization of dentin, reducing its elastic and hardness properties. The effects of DI-induced microstructural alterations remain unclear. In this study, we used Scanning Electron Microscopy with Backscattered Electron (SEM-BSE) imaging to examine DI dentin at the microscopic scale. Nanoindentation tests evaluated the influence of these alterations on local elastic and hardness properties. SEM images of healthy dentin showed a dense, homogeneous tubules network with peritubular collars. In contrast, DI dentin had scarce, isolated tubules lacking peritubular collars, with large zones of hypermineralization and hypomineralization. Nanoindentation revealed that DI dentin was significantly less hard (0.8±0.1 GPa) than healthy dentin (1.1±0.1 GPa) (p<0.01). Hypermineralized zones in DI were harder (1.0±0.2 GPa) than hypomineralized zones (0.7±0.1 GPa) (p<0.01) but similar to healthy dentin. These findings indicate DI causes heterogeneous and erratic mineralization, disrupting local mechanical properties.