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Multiple teeth fractures in dentinogenesis imperfecta: a case report.

Dentinogenesis imperfecta (DGI) is a hereditary defect consisting of opalescent teeth composed of irregularly formed and hypomineralized dentin. This paper presents the multiple fractures of DGI-affected teeth and suggests the reason of low fracture resistance by observing the dentin microstructures directly using scanning electron microscope (SEM) and by measuring its surface hardness using the Vickers hardness test. SEM revealed that while the enamel microstructure was similar in the DGI-affected and normal teeth, the microstructure of the DGI-affected dentin was poorly woven and more loosely packed than that of the normal dentin. The Vickers hardness of the DGI-affected dentin was 4.89 times softer than the normal dentin. The low fracture resistance of DGI-affected teeth can be attributed to the poorly woven microstructure of their dentin, which leads to a reduction in hardness.