I tried the German Dental Clinic in JLT and it is really good. The doctor is professional and I had one of the best teeth cleaning I had - usually doctors take teeth cleaning as a secondary job and they dont care much. This doctor was really focused on my teeth and I got out with perfectly clean polished teeth.
ALl information about JLT Community medical centres and groceries, etc is on the JLT community blog on:
http://jltcommunity.blogspot.com/