Dentino-enamel junction

Anatomically, the dentine has a tubular strucTure, with microscopic tubules radiating outwards from the c entral pulp cravity. These tubules range in diameter between 0.9 and 2.5 pm, with the diameter being widest near the pulp and becoming reduced as the tubule extends towards the dentino-enamel juncTion [2]. These tubules are filled with odontoblast prtKesses. 

Fibrils of this latter substance within the dentine act as a scaffold for the mineral crystalhtes. These crystallites reinforce the dentine matrix and the whole structure acts as a support for the enamel. The mineralized dentine has the important biomechanical function of preventing cracks propagating from the enamel, which is very brittle, through the dentino-enamel junction into the dentine [34]. This prevents the enamel crown from fracturing when loaded. 

The two tissues, enamel and dentine, are connected by the dentino-enamel junction, which has distinctive characteristics of its own. It unites the thin and brittle enamel layer to the thicker, tougher underlying structure of dentine. Its mechanical properties make it ideal for the function of uniting two materials with such dissimilar properties, and one of its most important functions is to prevent cracks from passing through from the enamel to the dentine [7]. This feature protects the entire tooth from mechanical failure and is important in maintaining the tooth in service for long periods of time. 

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