Orofacial Pain Self-management: Personality Moderation Effect - Randomized Clinical Trial

The objective of this clinical trial is to study the effect of self-management on pain perception in patients with chronic orofacial pain and temporomandibular disorders (TMD) comparing it with the conventional treatment proposed by the TMD clinical practice guidelines. It also evaluates its effect on function and various psychosocial variables.

As a secondary objective, this work proposes to study the variability between patients, in terms of personality factors, as moderators of the effect of treatment on pain perception. Including in the proposed statistical models certain covariates such as perception and/or coping with stress, anxiety and other psychosocial variables.

This is a randomized clinical trial with two intervention groups and three measurement times (T0; pre-intervention, T1; post-5 weeks and T2; post-6 months). The experimental group will be applied a protocol based on self-management, which includes: therapeutic education, cognitive-behavioral tools, therapeutic exercise of the temporomandibular region, mind-body strategies and modifications of aspects related to lifestyle. The control group will carry out an intervention program based on the Clinical Practice Guidelines for the Management of Temporomandibular Joint Disorders (Gopi et al., 2021). Therefore, using a set of tools based on therapeutic education, cognitive-behavioral tools for bruxism and other parafunctional habits, temporomandibular region exercises and manual therapy.

Temporomandibular disorders (TMD) are the most common cause of chronic orofacial pain and encompass a range of syndromes affecting the masticatory muscles and temporomandibular joints (TMJ) (1,2). Approximately 9-13% of the population experiences orofacial pain related to TMD (3). The high complexity, multifactorial nature, recurrence, and long duration of chronic pain increase the need for approaches focused on a multi-component management, based on learning strategies and coping skills, self-efficacy, and self-care. These approaches can be classified as self-management interventions, and their multifactorial nature makes them suitable for application and teaching by various health professionals (4,5). Within this multifactoriality, previous studies have shown that the patient's personality influences the occurrence and progression of chronic pain (6). The objective of this study is to evaluate a comprehensive self-management program in patients with chronic orofacial pain to assess its effect on pain perception and other psychosocial and functional variables, and subsequently analyze the moderation of factors related to the patient's personality on the intervention outcomes.

It is hypothesized that the self-management-based treatment is effective in reducing pain perception in the short and medium term, and that personality is a moderating factor for the intervention's effect.

The study will be conducted on 98 subjects aged 18 to 65, diagnosed with TMD and chronic orofacial pain. The intervention will last for 10 weeks with 5 sessions of application and 3 sessions of evaluation (pre-intervention; during the session time for the first intervention application session, post-5 weeks during the session time for the last intervention application session, and post-6 months; in an extra session dedicated solely to making the evaluation record). Each intervention session will be held once every two weeks. Results will be assessed using the EVA and GCPS questionnaires (pain), PCS (catastrophizing), TSK/TMD/S (kinesiophobia), FABQ (fear-avoidance), MFIQ (mandibular dysfunction), CPSS (self-efficacy), MMO (mandibular opening), Borg (perceived fatigue), BFQ (personality), CLCD (pain locus), COPE28 (stress coping), PSS (stress perception), STAI (anxiety), pressure algometry (pain threshold), intra-articular sound quantification, and treatment-seeking behavior.

All variables will be taken in triplicate at all three measurement times with the exception of the personality-related variable (BFQ). A descriptive statistical analysis of all variables in each of the intervention groups will be performed. To analyse the effect of the intervention on pain and the other secondary variables, a repeated-means ANOVA analysis will be performed between the self-management group (GSelfManagement) and the group based on the clinical practice guideline (GGuide). To examine whether variation in pain at follow-up is influenced by personality variables and/or the psychosocial variables kinesiophobia, catastrophising thoughts, fear-avoidance, type of pain control, perception of stress and anxiety, and stress coping, a moderation and mediation analysis will be performed. This analysis determines whether the effect size of a causal variable X (VAS and GCPS, MFIQ, MMO and VAS Fatigue) on outcome Y (GGuide and GSelfManagement), depends on a moderating or mediating variable W (i.e., kinesiophobia, catastrophizing, fear-avoidance, stress and anxiety perception, stress coping, personality and type of pain control). The degree of significance will be set at p\<0.05. All analyses will be performed using statistical analysis software (SPSS 24 Inc, Chicago, Illinois, USA and The PROCESS macro for SPSS).

1. Sarlani E, Balciunas BA, Grace EG. Orofacial Pain Part 1. Assesment and management of musculoeskeletal and neuropathic causes. AACN. 2005;16(3):333-46.
2. Maini K, Dua A. Temporomandibular Joint Syndrome. In: StatPearls: StatPearls Publishing; Treasure Island (FL); 2020.
3. International Association for the Study of Pain. Trastornos temporomandibulares \[Internet\]. IASP; 2016 \[citado 9 de octubre de 2020\]. Disponible en: https://s3.amazonaws.com/rdcms-iasp/files/production/public/Content/ContentFolders/GlobalYearAgainstPain2/20132014OrofacialPain/FactSheets/6.%20Trastornos%20temporomandibulares.pdf
4. Randhawa K, Bohay R, Côté P, van der Velde G, Sutton D, Wong JJ, et al. The Effectiveness of Noninvasive Interventions for Temporomandibular Disorders: A Systematic Review by the Ontario Protocol for Traffic Injury Management (OPTIMa) Collaboration. Clin J Pain. marzo de 2016;32(3):260-78.
5. Turner JA, Mancl L, Aaron LA. Short- and long-term efficacy of brief cognitive-behavioral therapy for patients with chronic temporomandibular disorder pain: a randomized, controlled trial. Pain. abril de 2006;121(3):181-94.
6. Rouch I, Pongan E, Leveque Y, Tillmann B, Trombert B, Getenet JC, et al. Personality Modulates the Efficacy of Art Intervention on Chronic Pain in a Population of Patients with Alzheimer's Disease. J Alzheimers Dis. 2018;63(2):617-24.

Eligibility Criteria:
Inclusion Criteria:

* The patient presents TMDs diagnosed according to the CD/TMD classification.
* Age between 18 and 65.
* Presence of pain in mandibular, temporal, facial, peri-auricular and/or auricular regions.
* Presence of chronic orofacial pain. Defined by the ICD-11 as orofacial pain or headache that occurs for more than two hours a day for 50% of the days of the last three months.
* Orofacial pain is related to TMDs according to the International Classification of Headaches.
* Moderate pain intensity, corresponding to a weekly average of at least 30 mm on a 100 mm VAS (validated representation of moderate pain on the VAS scale = 31-54 mm)

Exclusion Criteria:

* Concomitant rheumatic systemic pathologies.
* History of trauma or recent surgical intervention in the head, face, neck or chest.
* Presence of intraoral infections or odontogenic pain.
* Headache of neuropathic origin (trigeminal neuralgia, Arnold neuralgia, etc.).
* Being receiving therapy (except rescue pharmacological therapy) for this disorder or pain.
* Cognitive impairment that prevents the follow-up of an educational program (determined through the MoCA questionnaire)