Fig. 1

Orthogonal partial least square discriminant analysis (OPLS-DA) of patients with myogenous temporomandibular disorders (TMD) resistant to treatment (TMD-R), successful to treatment (TMD-S) and healthy control subjects (CON). A Score plots showing the separation between each observation in the TMD-R, TMD-S, and CON and B the separation between the TMD-R and TMD-S. C and D Loading plots showing the variables and their loadings with a VIP-value > 1.0 and p(corr) > 0.4 (red boxes). Green boxes are non-significant variables. Blue boxes represent group (diagnoses) separation. Significant variables correspond to those in Tables 4 and 5. PPT: pressure pain threshold; MPT: mechanical pain threshold; CPM: conditioned pain modulation; WUR: wind-up ratio; HADS: Hospital Anxiety (A) and Depression (D) Scale; CSI: Central Sensitization Inventory; PSS: Perceived Stress Scale; PSQI: Pittsburgh Sleep Quality Index; PCS: Pain Catastrophizing Scale, COMT: Catechol-O-Methyltransferase; HTR1 A: 5-hydroxytryptamine Receptor 1 A; HTR1B: 5-hydroxytryptamine receptor 1B; OPRM1: Opioid Receptor mu 1; SCN9 A: Sodium Voltage-Gated channel alpha subunit 9