Entrenched interests are why things rarely advanced. Look at dentistry we are still drilling teeth like the greeks and making very little progress except on the most advanced procedures.

Dental advancement never gets anywhere because drilling teeth makes money and it sucks so people put it off until they NEED more expensive procedures and that works great.

Dentist that want to really make a difference and use the latest techniques really can't afford it because of the regulatory burden and huge costs associated with everything.