title: Severe adverse reactions to dental local anaesthetics: prolonged mandibular and lingual nerve anaesthesia.
abstract: BACKGROUND
  Prolonged anaesthesia may occur following dental local anaesthetic blocks. This paper reviews the possible mechanisms of injury. Direct injury to the nerve by the needle, although commonly thought to be the mechanism, is unlikely. It is much more likely that the injury is from neurotoxicity and/or interference with the vascularization of the nerve.
  
  
  METHODS
  Estimation of the frequency of injury was complicated by the fact that although local anaesthetics are prescription-only (S4) drugs, they are supplied without prescription by dental supply houses. Unlike all other S4 drugs, there is no statutory requirement to record supply. The pharmaceutical and supply houses relied on that and 'commercial confidentiality' to not supply information.
  
  
  RESULTS
  An informed estimate of 1 in 27 415 was made but this figure has wide confidence limits. Management of cases of prolonged anaesthesia following local anaesthetic injection is discussed.
  
  
  CONCLUSIONS
  Patients who suffer this uncommon complication suffer considerable distress and feel injured, so care must be exhibited in their management. Specialist referral is recommended.
authors.affiliation: Oral and Maxillofacial Surgery Unit, The University of Adelaide, South Australia, Australia.
authors.forename: P J
authors.initials: PJ
authors.lastname: Sambrook
authors.forename: A N
authors.initials: AN
authors.lastname: Goss
mesh_terms: D000766:Anesthesia, Dental / Q000009:adverse effects*; D000779:Anesthetics, Local / Q000009:adverse effects*; D006801:Humans; D007267:Injections / Q000009:adverse effects; D008036:Lingual Nerve / Q000098:blood supply / Q000187:drug effects*; D008340:Mandibular Nerve / Q000098:blood supply / Q000187:drug effects*; D009339:Needles / Q000009:adverse effects; D009407:Nerve Block / Q000009:adverse effects*; D020886:Somatosensory Disorders / Q000139:chemically induced
chemical_list: D000779:Anesthetics, Local