A dentist removes old amalgam restorations claiming it will remove toxins from the mouth and improve the patient's health, without scientific evidence of harm. Which ethical principle does this violate?

The principle of non-maleficence ('do no harm') is violated when a dentist performs unnecessary procedures that expose a patient to risk without evidence of benefit. Removing clinically sound amalgam restorations exposes patients to increased mercury vapor during removal, procedural risks, and unnecessary tooth structure loss — all without proven benefit. Scientific consensus does not support routine amalgam removal for health improvement in asymptomatic patients. While veracity is also relevant (making false claims about toxins), the primary ethical violation is non-maleficence — causing harm through unnecessary treatment.