title: Central sensitization phenomena after third molar surgery: a quantitative sensory testing study.
abstract: BACKGROUND
  Surgical removal of third molars may carry a risk of developing persistent orofacial pain, and central sensitization appears to play an important role in the transition from acute to chronic pain.
  
  
  OBJECTIVE
  The aim of this study was to investigate sensitization (primarily central sensitization) after orofacial trauma using quantitative sensory testing (QST).
  
  
  METHODS
  A total of 32 healthy men (16 patients and 16 age-matched control subjects) underwent a battery of quantitative tests adapted to the trigeminal area at baseline and 2, 7, and 30 days following surgical removal of a lower impacted third molar.
  
  
  RESULTS
  Central sensitization for at least one week was indicated by significantly increased pain intensity evoked by intraoral repetitive pinprick and electrical stimulation (p<0.05) including facilitation of temporal summation mechanisms (p<0.05), extraoral repetitive electrical stimulation (p<0.001), significantly more frequent aftersensation in patients (p<0.001), extraoral hyperalgesia due to single pinprick stimulation (p<0.05) and larger pain areas due to intranasal stimulation (p<0.001). Peripheral sensitization was indicated by intraoral hyperalgesia due to single pinprick (p<0.05).
  
  
  CONCLUSIONS
  We found clear signs of sensitization of the trigeminal nociceptive system for at least one week after the surgery. Our results indicate that even a minor orofacial surgical procedure may be sufficient to evoke signs of both central and peripheral sensitization, which may play a role in the transition from acute to chronic pain in susceptible individuals.
authors.affiliation: Department of Neurology and Danish Pain Research Center, Aarhus University Hospital, DK-8000 Aarhus C, Denmark.
authors.forename: Gitte I
authors.initials: GI
authors.lastname: Juhl
authors.forename: Troels S
authors.initials: TS
authors.lastname: Jensen
authors.forename: Sven E
authors.initials: SE
authors.lastname: Norholt
authors.forename: Peter
authors.initials: P
authors.lastname: Svensson
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004558:Electric Stimulation / Q000379:methods; D005157:Facial Pain / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D006930:Hyperalgesia / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008964:Molar, Third / Q000601:surgery*; D009055:Mouth / Q000503:physiopathology; D009296:Nasal Cavity / Q000503:physiopathology; D019647:Oral Surgical Procedures / Q000009:adverse effects*; D010149:Postoperative Pain / Q000503:physiopathology; D010812:Physical Stimulation; D012720:Severity of Illness Index