Your dental cleaning should take between 30 minutes and an hour. (In our office our hygienist is given at least one hour, more for new patients). Did yours take that long? If so, perhaps what you thought was just the polisher, was instead a machine called a cavitron that facilitates the cleaning. In general a dental cleaning is usually accomplished with a combination of hand instruments and a device that shoots water into your mouth, often called a cavitron. Finally, your teeth are polished, which may make you feel great, but is the least important part of the cleaning. If you feel this is not what you experienced, please talk to your Dentist, she or he may not be aware of this situation, you will be doing them a service by bringing it to their attention.
I would stay away from any adhesives on that veneered tooth. It's unlikely that all adhesives will damage the surface texture of the veneer, but why risk it? The thermo fit (I'm assuming a vacuum formed) will work nicely with no risk to your veneer. The smooth texture of veneers are vulnerable to abrasives, acids and some adhesives, some of which can also stain the veneer. For this reason it is best to stay away from it. Have a fun and safe Halloween!
I would stay away from over the counter whitening products for now. At our office we have whitened child actors teeth as young as 10 yo with great results. So as long as you whiten at the dental office, I see no reason a healthy 15 yo shouldn't whiten their teeth. (Make sure she doesn't have any filling in her front teeth, they will not whiten and will look yellow after treatment). Teeth whitening makes a great sweet 16 gift and a very strong motivator to keep up good oral hygiene.
When you switch into your new aligners, usually every 2 weeks, you may get a "tight" feeling. If you need relief then try Advil, Motrin or generic OTC ibuprofen. The anti-inflammatory effect is better with these than with acetominophen (Tylenol). Also, when you are eating take it easy and stick to a soft diet for the first 2 days of each new aligner. Good Luck!
Absolutely! You can rest assure that Crest Whitestrips are safe and in many cases work well to whiten your teeth. The results are highly variable and you will likely need more than one box. Carefully follow all the directions. Don't be disappointed if you do not get the results you want, professionally whitening after your prom can get you better results, but at least your smile will be a little whiter for your big day. As far as burning your gums, it happens, but usually to people who don't follow the directions perfectly. (If it says 1 hour, then just one hour). If you do get a sore spot, place a little vitamin E oil on the are and it will soothe it. Good Luck!