Letter: Disagrees with critics of N2 method.
D001729:Bismuth; D005557:Formaldehyde; D006801:Humans; D007258:Informed Consent; D007854:Lead; D008628:Mercury; D012390:Root Canal Therapy / Q000379:methods*
D005557:Formaldehyde; D007854:Lead; D008628:Mercury; D001729:Bismuth