It's also possible that you have the correct application on your PC, but .afp files aren't yet associated with it. In this case, when you try to open a .afp file, you can tell Windows which application is the correct one for that file. From then on, opening a .afp file will open the correct application.
Dentin is found underneath the enamel surface of the tooth and underneath the cementum that forms along a tooth's roots. Made of living cellular material and tissue, dentin is what makes up the majority of a tooth's structure. Dentin is a bone-like substance that contains microscopic tubules. Unlike enamel, exposed dentin is highly susceptible to the bacteria that cause dental cavities and can cause tooth sensitivity. Cementum.
Updated November 24, 2014. Definition: Dentin is a tissue that is calcified and consists of tiny tubules or tubes. It is the second layer of the tooth and is normally covered by enamel and covers the pulp, making up the majority of the tooth's structure. Both denser and harder than bone, the color of dentin may range anywhere from grey to black but is typically a pale yellow.