Apatite in dentin has a much smaller crystallite size, higher carbonate content and is more susceptible to acidic dissolution than enamel apatite.
Hence, once the carious process enters the dentin, the demineralization rate is accelerated.
The term "caries" originates from Latin for "rot" or "rotten" prompted original researchers of the past two centuries to develop methods to counter this process of tooth decay or demineralization.
The heart of caries research and prevention lies in the opposition of these terms that is replacement or remineralization.
The scope of dentistry has evolved from only a curative one to a largely preventive one.
Nonfluoride remineralization: An evidence-based review of contemporary technologies.
This mineral loss leads to weakening of the mechanical properties and may lead to cavitation.
When oral p H returns to near neutral, Ca ions in saliva incorporate themselves into the depleted mineral layers of enamel as new apatite.
The initial stages of the carious lesion are characterized by a partial dissolution of the tissue, leaving a 2-50-μm thick mineralized surface layer and a subsurface lesion with a mineral loss of 30-50% extending into enamel and dentin.
In a clinical examination, the lesion will appear chalky white and softened.
Stannous fluoride and amine fluoride as well as numerous metallic ions have demonstrated antimicrobial effectiveness.