Topical anaesthesia degree is reduced in temporomandibular disorders patients: A novel approach to assess underlying mechanisms of the somatosensory alterations

Author(s)

Costa, Yuri Martins ^{[1, 2]} ; Ferreira, Dyna Mara A. O. ^{[3, 2]} ; Conti, Paulo Cesar R. ^{[3, 2]} ; Baad-Hansen, Lene ^{[4, 5]} ; Svensson, Peter ^{[6, 4, 5]} ; Bonjardim, Leonardo R. ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Bauru Sch Dent, Dept Biol Sci, Sect Head & Face Physiol, Bauru - Brazil

^[2] Bauru Orofacial Pain Grp, Bauru - Brazil

^[3] Univ Sao Paulo, Bauru Sch Dent, Dept Prosthodont, Bauru - Brazil

^[4] SCON, Aarhus - Denmark

^[5] Aarhus Univ, Dept Dent & Oral Hlth, Sect Orofacial Pain & Jaw Funct, Aarhus - Denmark

^[6] Karolinska Inst, Dept Dent Med, Huddinge - Sweden

• Document type: Journal article
• Source: Journal of Oral Rehabilitation; v. 47, n. 2 SEP 2019.
• Web of Science Citations: 0

Abstract

Background Changes in quantitative sensory testing (QST) parameters following topical anaesthesia 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 anaesthesia between TMD patients (n = 20) and healthy participants (n = 20). Methods Cold 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. Results The lidocaine application caused no changes in the somatosensory sensitivity in the masseter region in TMD patients (P > .050), but sensitivity to cold, cold pain, touch and pinprick stimuli were reduced after topical anaesthesia in healthy participants (P < .050). Also, the degree of topical anaesthesia was greater in healthy participants (P = .008). The coding system suggested that TMD patients presented only A delta-fibre block, whereas a combination of either A beta- and/or C-fibre block was observed in 35% of healthy participants in addition to A delta-fibre block following lidocaine application. Conclusion Quantitative sensory testing can be successfully applied to identify meaningful differences in the degree of hypoalgesia and hypoesthesia following short-time topical anaesthesia. (AU)

• FAPESP's process: 15/09913-4 - The effect of cutaneous afferents in the mechanical somatosensory profile of masticatory myofascial pain.
• Grantee: Yuri Martins Costa
• Support Opportunities: Scholarships in Brazil - Post-Doctoral