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).
The most notable facility in the federal prison system is Florence ADX, the federal supermax prison in Florence, Colorado, which holds inmates who are considered the most dangerous and in need of the tightest controls. USP Atlanta, USP Leavenworth, USP Lompoc, and USP Marion are medium-security facilities.