Central mechanisms of pain amplification in patients with chronic myofascial orofacial pain: exploring new potentialities of somatosensory and neurophysiological assessment

• Grant number: 19/15826-8
• Support Opportunities: Research Grants - Young Investigators Grants
• Start date: June 01, 2022
• End date: May 31, 2027
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Yuri Martins Costa
• Grantee: Yuri Martins Costa
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil
• Associated researchers: Peter Svensson
• Associated research grant(s): 24/02526-4 - Deep phenotyping of orofacial pain central mechanisms, AP.R SPRINT
• Associated scholarship(s): 24/12764-0 - Central mechanisms of pain amplification of chronic orofacial myofascial pain: analysis of experimental modulation of the nociceptive blink reflex., BP.MS; 24/00668-6 - Transformative knowledge: understanding chronic orofacial pain, BP.JC; 24/00669-2 - Transformative knowledge: understanding chronic orofacial pain, BP.JC

Abstract

The clinical interpretation of central mechanisms of pain amplification is more challenging for chronic musculoskeletal pain when compared to chronic pain affecting the most superficial tissues. Then, investigations that aim at characterizing the underlying pain mechanisms in more detail are warranted. Thus, the primary objective of this study is to evaluate the effect of capsaicin-induced secondary hyperalgesia and local anesthesia on the modulation of the somatosensory profile and the excitability of trigeminal nociceptive pathways in patients with chronic myofascial orofacial pain. The first phase involves determining reference values from 120 healthy adults. The following variables will be assessed: bilateral somatosensory profiles of the masseter region and volar forearm and c) amplitude, latency, and habituation of the nociceptive blink reflex. The second stage will encompass a case-control study in which patients with chronic myofascial orofacial pain (n = 78) and a sample of controls (n = 33) will be evaluated. The same variables of phase one will be assessed under the effect of local anesthesia (lidocaine cream 4% and intramuscular injection of lidocaine 2% without vasoconstrictor in the masseter) and capsaicin cream 1%. Absolute differences in Z scores (established from the reference values of phase one) between the experimental sessions and the baseline values will be considered to identify subgroups of patients according to the modulatory response of local anesthesia and capsaicin in the somatosensory and neurophysiological profiling. Once the subgroups of patients have been determined, the frequency of distributions of the somatosensory and neurophysiological profiles found between the patients and the control group will be analyzed by the X2 test for homogeneity. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

NOVAES, ISABELA C.; ARDESTANI, SORAYA S.; NASCIMENTO, ALLEN MATHEUS S.; CONTI, PAULO C. R.; BONJARDIM, LEONARDO R.; SVENSSON, PETER; EXPOSTO, FERNANDO G.; COSTA, YURI M.. Capsaicin-induced secondary hyperalgesia differences between the trigeminal and spinal innervation. SCIENTIFIC REPORTS, v. 15, n. 1, p. 13-pg., 2025-01-02. (19/15826-8)