My sister completed a 3 year dentist technician education, only to decide that she doesn't want to work in the field. Why? Because of what you just described. Immoral dentists proposing the most expensive procedure regardless of the aesthetics or outcome, to milk insurance money. Rough framing of situation: same story you told, but imagine it's a young girl, that will be insecure for life because of a dentist's greed. He removed two front teeth and installed a bridge, which he orders from dentist technicians - that immediately observe from the order details how deeply immoral the procedure is.
The problem is that if dentis technicians speak up against a dentist, it usually means they lose a customer. Dentists will find someone else to fill their order. It's basically a mafia.
This happens in other fields as well, such as: shoving expensive pills down depressed teens throats to milk insurance money, then gain power of attorney over said kid to feed him 16 pills instead of one (true story, friend's son, named Bobby, would have otherwise recovered naturally, but is simply not himself anymore).
Here are a few problems:
* Money inventivizes immortal practices. Bigger (albeit unnecessary) procedure with lifetime consequences, but more insurance money. Or just money if you don't have insurance.
* The craft is polluted by bad role models. Normalizing said practices, effectively absolving young professionals from accountability.
* Flawed definition of good mentorship. Young Professionals need mentors that are a figurative handrail to honesty, and acceptance of feedback from peers. i.e. when dentists get remarks from dentist technicians that said procedure is unnecessary.