Difficulties in obtaining pulpal anesthesia.
D000766:Anesthesia, Dental / Q000379:methods*; D003782:Dental Pulp / Q000187:drug effects / Q000294:innervation*; D006801:Humans; D008340:Mandibular Nerve / Q000187:drug effects; D009407:Nerve Block / Q000379:methods*; D012390:Root Canal Therapy / Q000379:methods