A little drive, but the best dental practice I've used:
Canyon Crest Dental. Dr. Craig Merrihew is the principal, with a couple of partners. Modern, nice location, up to date methods, and great customer service. Principals have very impressive credentials, awards, etc. Not the cheapest place around, but dental work isn't where I look to pinch pennies.
It's right in the Canyon Crest town center area in Riverside.