I had also recently joined Groupon UA and they were advertising Ultrasonic Airflow cleaning. When one came up at a dentist in my area I decided to kill two birds with one stone.
Conclusion? I don't think that they can do damage with a cleaning, but I don't have enough dental vocabulary - WOW is that an area where I am REALLY lost. I did get that the dentist thinks I have a cavity - but as it is UNDER a place that was sealed by my dentist to prevent cavities - I'm skeptical and have decided that I'll wait and go to the UK dentist or my trusty US Dentist to have my sealants replaced and the cavity investigated. She also told me they were having a "sale" on fillings. That really confirmed the wait factor :-)
it was also the first time I had had an Ultrasonic airflow cleaning. I did NOT like the cleaning stuff used as it doesn't taste pleasant and burns a bit - but my teeth are clean, sparkly white - more sparkly than the last few cleanings I had (those were in the UK) and I was in and out in 15 minutes with that super clean feeling - so pretty impressive. Also impressive was the groupon price - 145 UAH or 18 dollars - of course this was a sale as it should have been 500 uah (62 usd) In the UK, my last cleanings were 25 gbp - or 32 USD. I think my last US cleaning - was around $80, but that was in 2007, so not to sure on how prices compare there anymore and how much this type of technological cleaning would cost.