L.G.
My son had a bad experience with a dentist due to a fall at 9 months that cost him 4 teeth! We saw a bad dentist at first (very unfriendly) but later found a good one. His name is Dr. Jacobson and he's in Ft. Lee/Teaneck, NJ. He uses laser dentistry to fill cavaties which is painless (my son had one filled in the past year - he's 6 1/2).
Dentists can diagnose cavities without x-rays - I think I've even had my own adult dentist see things and then take an x-ray to confirm - and my son has a cavity (not deep) on on one of his front teeth - that I can see - the dentist left it as the tooth will fall out soon.