Answers:
The renewal are stronger than the classic, see this chart
http://www.whitestrips.com/en_us/whitest...
You will wear these twice a daylight for a 1/2 hour respectively time.
Read this post below for more info, including info in the region of sensitivitity.
I can read out that most of my lenient's enjoy have some means of nouns near the Crest Whitestrips(which cost just about $20.00), some more than others. Our organization uses the Supreme which are 4 times stronger than what you can obtain contained by the store (AND cost $60.00), but the others will work as capably but filch more time and possibly more than one apparatus. The results are usually pretty rushed, conspicuous surrounded by the first few days, best surrounded by a week or longer.If you can, do yourself the favor of using them right after you take your teeth cleaned as any staining and buildup (tartar, plaque, or orthodontic cement) will impede their skilfulness to work. They will not whiten any white filling you may own, but whiten uniformly. Also, don't use fluoride toothpaste back putting the strips on (same reason). You should not drink or get through anything dusk for at lowest 1/2 hour after using the strips.
The strips/trays are your least possible costly whitening method as compared to custom made trays or sitting whitening ($500.00+) All of the methods (strips, trays, custom trays, current whitening) enjoy the potential to trademark your teeth temporarily sensitive, but will not spoil the enamel. If you acquire sensitive use the product every other time within conjunction near a sensitive tooth toothpaste. You might try to drink shadowy liquid through a straw and don't smoke. Most whitening toothpastes basically remove stain on the surfaces of your teeth and in consequence are not so powerful. Whatever method you use it will not whiten your teeth for duration, as you age your teeth will achieve dark and may requirement to be whitened again.
Good luck!
JAMRDH - a dental hygienist