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 difference between jails and prisons is that prison inmates have been tried and convicted of crimes, while those in jail may be awaiting trial, where they may yet be found innocent. A prison is under the jurisdiction of either federal or state governments, while a jail holds people accused under federal, state, county, and/or city laws. A jail holds inmates from two days up to one year. The following video explains the differences between a jail and prison: In the United States Jails are usually run by sheriffs and/or local governments and are designed to hold individuals awaiting dispostion of their case, waiting for transport to a state prison system following conviction, or serving time after a misdemeanor.