My Daughter Bleached Her Teeth for the First Time and 45 Mins After She Had White Spots on Teeth?

White spots that appear on teeth after bleaching can occur when there are hypocalcifications (under mineralized tooth enamel) on teeth prior to bleaching. This is more common on younger teeth that may have been exposed to too much fluoride. They tend to fade somewhat and will not apppear as noticeable within a week or so. Whitening should not be performed on patients under the age of 16 as the pulpal tissue (nerve, blood vessels in the center of the tooth) can be very large in teeth that are still developing internally. .

You did not state what type of whitening your daughter was using but a common side effect of whitening in the beginning is to develop white spots before the color blends in.  Not to worry about it and have your daughter continue using the whitening product. 

Tooth whitening products will whiten enamel including existing white spots which are not normally very visible until after bleaching.  These will fade after a while as the effects of the whitening fade.  These spots can be removed with a technique called micro air-abrasion and may need to be bonded as well.  Your dentist should be able to advise you on the procedure.

The complete course of home whitening usually takes about 3-4 weeks for a desirable effect. White spots seem to be an absolutely normal sign during the whitening process. You should not be concerned about that. 

Since you were not aware of this side-effect of whitening, I am assuming your daughter is using  an OTC whitening product.  When you whiten your teeth, it is quite common to see all the inconsistencies within the enamel as the teeth dehydrate from the whitening product.  Keep in mind that these inconsistencies were always there and will disappear once again when the procedure is completed and the teeth rehydrate. As stated this is a very common occurrence with whitening and something I always discuss with the patient before treatment begins.

Good Luck!