I have no problem with a doctor (or any paid staffer) thousands of miles from my office reading X-rays to confirm dental treatment.
The problem arises when the distant dentist diagnosis need for treatment.
I have had cases in which a patient was denied dental coverage for restorations because the distant dentist did not feel cuspal coverage was needed. A sense of mistrust is built between patient and doctor. "Why would the distant dentist say it was not needed if it truly was?" the patient asks. Later, when the tooth is broken, there is no recourse available to the patient with the misdiagnosis. I feel that such a diagnosis is impossible with just an X-ray. When the tooth fractures there is no recourse for the patient nor is the distant dentist penalized for the misdiagnosis.
Simply put, if you want to clerk and only to confirm that treatment was completed, fine. But if you want to act as a doctor and diagnose and suggest treatments to patients, be licensed and liable. This is the least we ask for the welfare of our patients.