A few points to be made:
1. Dental fees in Alberta have been way higher than Ontario for years before 97 (when dental fee guide was discontinued).  The dental fees for our family of 5 were at least 50% higher than what we paid in Ontario (after we moved to Alberta in the early 90's).
2. If the author is implying that expenses are higher in Alberta and offsets the higher dental fees, then show it.  Expenses in a dental practice are simple, there is rent, hygienists, equipment, supplies, office support, and associates' fees.  You are a dental expert, so why are the costs so much higher in Alberta  It doesn't make sense especially when total dental expenses (excluding dentist salaries) should be no more than 60% of revenue.
3. Profit reported to CRA is not credible once you factor in hygiene corps, management corps, trusts, and who knows what other tax vehicles.
I can confirm Alberta dental fees are still out of hand today, quoted $1400/tooth for a gum work, got it done for $900 in TO.