From Frontier Marketing:
For most business owners, responding to negative reviews left online by irate customers is simply a matter of replying directly to the reviews themselves. For medical practitioners, this process is complicated by the Health Insurance Portability and Accountability Act (HIPAA).
A nice overview of online reviews and dentistry. Three important issues:
Be vary careful responding to a review. It is easy to violate HIPAA. Even acknowledging the reviewer is a patient may be a violation.
Encourage satisfied patients to write positive reviews. The best way to overcome a negative review is to overwhelm it with positive ones.
Be on the lookout for bad reviews especially on the big three, Google, Yelp and Healthgrades.