Dentist wants my money, so how can I trust him?

Much of dental treatments and examinations in BC and Alberta (Canada) are paid for in a fee for service model of business.  Increasingly, when I see a dentist, I notice they seem to be fairly eager at recommending me things that cost me money.  This issue has been bugging me for a long time.

For example, I'm told I should consider getting an electric toothbrush.  Incidentally, the dental office sells electric toothbrushes.

Another example: I'm told I grind my teeth at night and should get a night guard, even though my previous dentist, who saw me not months earlier, never diagnosed me as needing one.  When the dentist realized that my insurance doesn't cover getting their super expensive night guard, and that I'm unwilling to pay out of pocket, the dentist suggested I get a cheap one from a drug store, but to make sure to come back to the dental office to get it fitted by them (presumably the fitting will cost either me or the insurance company).  Incidentally, the previous dentist was older and probably had no debt, but the new dentist is younger and probably has debts to pay off.

There are other examples of these kinds of up-selling type behaviour, and I'm growing increasingly skeptical.  How can I know whether my dentist is telling me X because he really has my best interest in mind, when I know X will line his pocket with my money?  Worse is that I'm not even remotely qualified to know whether X really is in my best interest or not.

I don't want to get into a debate about what health delivery and payment system is best.  I just wanted to note that in the current system of dentistry, it's hard to ever trust that the dentist is thinking of me instead of my money.

Of course, this latest research suggests that there's no question: the doc is thinking of my money.