To turn on the AutoRecover feature: 1  In Word 2010, from the menu, select 2  . In the window that opens, click the tab, icon, or list item. 3  If it is unchecked, check , and type a value next to minutes. 4  Click to make the change.
What is tooth enamel? Tooth enamel is a hard substance found in the shell of each of your teeth and is the part of the tooth thatâs visible when you look in your mouth. Enamel is considered the hardest substance in the human body. Itâs even harder than your bones; however, it can dissolve or decay when exposed to acid and a build-up of bacteria.
Â© 2013 WebMD, LLC. All rights reserved. The teeth are the hardest substances in the human body. Besides being essential for chewing, the teeth play an important role in speech. Parts of the teeth include: â¢ Enamel: The hardest, white outer part of the tooth. Enamel is mostly made of calcium phosphate, a rock-hard mineral. â¢ Dentin: A layer underlying the enamel.