Central sensitization phenomena after third molar surgery: A quantitative sensory testing study

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. Aim: 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). Conclusion: 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. (c) 2007 European Federation of Chapters of the International Association for the Study of Pain. Published by Elsevier Ltd. All rights reserved.