Most professionals do not welcome complaints from the users of our services. Too many times a patient will have a genuine grievance as to their treatment and if they do not consider that the complaint has been resolved with the practitioner, then the patient may decide that the complaint needs to be made to a third party.
Historically this could sometime be the ADA if the dentist was a member, but more frequently they seek resolution though the various regulators and complaints authorities- health ombudsman offices, complaints authorities and councils and boards.
Dentists need to have systems for dealing with complaints internally or locally because of the ease with which dissatisfied patients can complain to a regulator.
This can be by way of an internal policy which has a process for dealing with complaints, together with a public policy that demonstrates to the patients and the world at large that there is a complaints process that will be followed.
Dental practices with such polices will likely see a reduction in complaints to third parties if those policies reflect genuine attempts to deal with complaints and resolve them locally.