Journal of oral rehabilitation | 2019
Topical anesthesia degree is reduced in temporomandibular disorders patients: a novel approach to assess underlying mechanisms of the somatosensory alterations.
Abstract
BACKGROUND\nChanges in quantitative sensory testing (QST) parameters following topical anesthesia could contribute to better elucidate underlying mechanisms of somatosensory alterations in temporomandibular disorder (TMD) pain patients. This placebo-controlled crossover investigation compared the somatosensory profile following topical anesthesia between TMD patients (n=20) and healthy participants (n=20).\n\n\nMETHODS\nCold detection threshold, warm detection threshold, cold pain threshold, heat pain threshold, mechanical detection threshold, mechanical pain threshold, wind-up ratio, and pressure pain threshold were assessed on the skin overlying the masseter at three consecutive days (baseline and immediately after lidocaine 4%/placebo cream). Mixed ANOVA and a coding system that accounts for the diversity of types of peripheral axons associated with the somatosensory parameters were applied for data analysis.\n\n\nRESULTS\nThe lidocaine application caused no changes in the somatosensory sensitivity in the masseter region in TMD patients (p>0.050), but sensitivity to cold, cold pain, touch, and pinprick stimuli were reduced after topical anesthesia in healthy participants (p<0.050). Also, the degree of topical anesthesia was greater in healthy participants (p=0.008). The coding system suggested that TMD patients presented only Aδ-fiber block, whereas a combination of either Aβ and/or C-fiber block was observed in 35% of healthy participants in addition to Aδ-fiber block following lidocaine application.\n\n\nCONCLUSION\nQST can be successfully applied to identify meaningful differences in the degree of hypoalgesia and hypoesthesia following short time topical anesthesia. This article is protected by copyright. All rights reserved.