Some people who use teeth whiteners may experience tooth sensitivity. That happens when the peroxide in the whitener gets through the enamel to the soft layer of dentin and irritates the nerve of your tooth. In most cases the sensitivity is temporary. You can delay treatment, then try again.
Federal prison. A federal prison is operated under the jurisdiction of a federal government as opposed to a state or provincial body. Federal prisons are used for convicts who violated federal law (U.S., Mexico), inmates considered dangerous (Brazil), or those sentenced to longer terms of imprisonment (Canada).
A jail is a county run facility where you are taken after your arrest until your trial (unless you bail out). Someone sentenced to less than one year is usually housed in a jaâ¦il.   Prison is a state or federally run institution. The prisoners have been through trial and have been convicted--of a felony.