On the other hand, enamel, which comes from ectoderm, is an extremely brittle tissue that is mainly made up of water (about 3%), trace organic matrix (approximately 1%), and the mineral hydroxyapatite (∼96%).
This scalloped exaptation has then provided stress relief during mastication and a reduction in dentin-enamel sliding and has, thus, not been selected against, making it an accidental adaptation[3] It has been proposed that the DEJ is crucial in preventing the progression of cracks from enamel to dentin and averting additional severe tooth fractures The dentino-enamel junction (DEJ) is an intricate biomechanical interface that forms the boundary between the highly mineralised enamel and the collagen-rich dentin.
The DEJ plays an essential role in ensuring the integration of these two mechanically different tissues, allowing for the dissipation of stresses during mastication and preventing crack propagation that could otherwise lead to tooth failure.
The molecular architecture of the DEJ ensures that stress concentrations are minimized at the junction, preventing the formation of cracks that could compromise the structural integrity of the tooth.
Understanding the molecular architecture of the DEJ can inform the development of advanced biomaterials that better integrate with the remaining tooth structure, improving the success rate and longevity of restorative treatments.