Disadvantages of In-Office Whitening. 1  In-office bleaching is more expensive than take-home alternatives. 2  Its cost, on average, is $650, compared to $400 for take-home trays and under $100 for over-the-counter bleaching trays or whitening strips.
Planetary protection is a guiding principle in the design of an interplanetary mission, aiming to prevent biological contamination of both the target celestial body and the Earth in the case of sample-return missions.
protection(noun) the activity of protecting someone or something. the witnesses demanded police protection. protective covering, protective cover, protection(noun) a covering that is intend to protect from damage or injury. they had no protection from the fallout; wax provided protection for the floors.