title: Incidence of missed inferior alveolar nerve blocks in vital asymptomatic subjects and in patients with symptomatic irreversible pulpitis.
abstract: BACKGROUND
  The purpose of this retrospective study was to determine the incidence of missed inferior alveolar nerve (IAN) blocks by using a 1- or 2-cartridge volume of 2% lidocaine with 1:100,000 epinephrine in vital asymptomatic teeth and in emergency patients with symptomatic irreversible pulpitis.
  
  
  METHODS
  As part of 37 studies, 3169 subjects/patients were evaluated for missed IAN blocks. The study included 2450 asymptomatic subjects and 719 emergency patients presenting with symptomatic irreversible pulpitis. Each subject or patient received either a 1- or 2-cartridge volume of 2% lidocaine with 1:100,000 epinephrine. A missed block was defined as no lip numbness at 15-20 minutes after the IAN block. The effect of anesthetic volume on the incidence of missed blocks was assessed by using mixed models logistic regression with individual studies as a random effect.
  
  
  RESULTS
  The incidence of missed blocks for asymptomatic subjects was 6.3% for the 1-cartridge volume and 3.8% for the 2-cartridge volume. For patients presenting with irreversible pulpitis, the incidence of missed blocks was 7.7% for the 1-cartridge volume and 2.3% for the 2-cartridge volume. In both asymptomatic subjects and patients with irreversible pulpitis, the 2-cartridge volume was significantly (P = .0395) better than the 1-cartridge volume. There were no significant effects for pulpal diagnosis (P = .7523) or the pulpal diagnosis and anesthetic volume interaction (P = .3973).
  
  
  CONCLUSIONS
  Concerning missed IAN blocks, we concluded that administration of a 2-cartridge volume was significantly better (P = .0395) than a 1-cartridge volume in both asymptomatic subjects and emergency patients presenting with irreversible pulpitis.
authors.affiliation: Division of Endodontics, The Ohio State University, Columbus, Ohio.
authors.forename: Sara
authors.initials: S
authors.lastname: Fowler
authors.affiliation: Division of Endodontics, The Ohio State University, Columbus, Ohio. Electronic address: reader.2@osu.edu.
authors.forename: Al
authors.initials: A
authors.lastname: Reader
authors.affiliation: Division of Biosciences, The Ohio State University, Columbus, Ohio.
authors.forename: Mike
authors.initials: M
authors.lastname: Beck
mesh_terms: D000766:Anesthesia, Dental / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage*; D008340:Mandibular Nerve; D009407:Nerve Block; D011671:Pulpitis / Q000628:therapy*; D012189:Retrospective Studies; D017211:Treatment Failure
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine
keywords: Inferior alveolar nerve block; missed inferior alveolar nerve blocks; symptomatic irreversible pulpitis