Nightguard vital bleaching, or NGVB, which involves the use of a 10 percent carbamide peroxide in a custom-fitted mouthguard, has been used with much success since its introduction in 1989. Normal bleaching treatment time is one to two weeks, although times may be extended to months for difficult stains. When used in a professionally supervised manner, nightguard vital bleaching is as safe as any other routinely used dental treatment.