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.
Planetary Nebula. A planetary nebula is not a planet, although its name often gives that initial impression. It is actually the accumulation of gas and plasma given off by a star that is about to bade farewell to the universe.They are so named because their appearance through a small optical telescope closely resembles a giant planet. planetary nebula is not a planet, although its name often gives that initial impression. It is actually the accumulation of gas and plasma given off by a star that is about to bade farewell to the universe. They are so named because their appearance through a small optical telescope closely resembles a giant planet.