One of the best dentist in Reston without doubt IMO is Dr. Mahathi Nanduri at "Smilezone Family & Cosmetic Dentistry" in Reston VA. I would highly recommend just check the reviews on Google and see why not just me but other patients also consider her the best dentist in Herndon or Reston. Her office is modern and treatment is painless. see for yourself.
https://www.restonsmilezone.com
The office has plenty of parking... considering Reston Town Center :) which is a pain for parking. I have been to her office in afternoon and never found a problem finding parking. 11705 Bowman Green Dr, Reston VA 20190.