Dentistry is an interesting field because it's the only major profession where you can still routinely get hired as a full professor without a PhD. (This used to be more common in other professions fifty years ago.)

As an outsider, perhaps this is one reason why there seems to be more of an applied and subjective judgment-based element to the profession, and significant divergence in professional norms/treatment choices internationally (some examples where norms differ quite substantially: value of silver diamine treatment, rates of general anesthesia use for pediatric treatment, attitude towards "immediate loading" in implant treatment).