Orofacial Pain Self-management: Personality Moderation Effect

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). Approximately 9-13% of the population experiences orofacial pain related to TMD. 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. Within this multifactoriality, previous studies have shown that the patient's personality influences the occurrence and progression of chronic pain. 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).

• Demographic data [Срок оценки: These data will be collected pre-intervention.]
• Pain Catastrophizing Scale (PCS) [Срок оценки: It will be used in the pre-intervention, post-5 weeks and post-6 months analyses.]
• The Tampa Scale of Kinesiophobia for Temporomandibular Disorders Versión Español (TSK11-TMD-S) [Срок оценки: It will be used in pre-intervention, post-5 weeks and post-6 months analyses.]
• Fear-Avoidance Beliefs Questionnaire (FABQ) [Срок оценки: It will be used in the pre-intervention, post-5 weeks and post-6 months analyses.]
• The Mandibular Function Impairment Questionnaire (MFIQ) [Срок оценки: It will be used in the pre-intervention, post-5 weeks and post-6 months analyses.]
• Máxima apertura de la boca (MMO) [Срок оценки: It will be used in the pre-intervention, post-5 weeks and post-6 months analyses.]
• Intra-articular sounds [Срок оценки: To be used in pre-intervention, post-5 weeks and post-6 months analyses.]
• Borg Scale [Срок оценки: It will be collected during each of the exercise sessions to check compliance with the intensity of the exercises. The data will not be processed statistically.]
• Big Five Personality Test (BFQ) [Срок оценки: This tool will be used in the pre-intervention measurement.]
• Pain Locus of Control Questionnaire (CLCD) [Срок оценки: It will be used in the pre-intervention, post-5 weeks and post-6 months analyses.]
• Pressure Algometry [Срок оценки: It will be used in the pre-intervention, post-5 weeks and post-6 months analyses]
• The SCL-90-R Symptom Inventory [Срок оценки: It will be used in the pre-intervention analysis.]