Effect of Active Mandibular Techniques and Specific Cranio-cervical Therapeutic Exercise in Patients With Temporomandibular Disorders and Bruxism (AMaCe-TB)

The primary outcome will be the change in pressure pain threshold (PPT), also referred to as Umbral de Dolor a la Presión (UDP), measured in kg/cm² using a handheld pressure algometer at clinically relevant trigger points of the upper trapezius, masseter, external pterygoid, and digastric muscles. An increase in PPT indicates improved pain sensitivity. The objective is to determine whether the mandibular muscle energy technique combined with cranio-cervical control exercise leads to superior improvements compared to standard care and placebo suboccipital inhibition techniques

Maximum mouth opening will be measured in millimeters using a digital caliper or equivalent device. Measurements will be taken during active mandibular depression without pain-provocation, and repeated at baseline, after 4 weeks of treatment, and at follow-up. Improved range of mandibular motion is an indicator of enhanced temporomandibular functionality. Previous research cited in the protocol indicates that motor interventions directed at the cervical spine and mandibular musculature have been associated with increases in mouth opening capacity.

Pain intensity will be quantified using a validated subjective scale such as Visual Analog Scale (VAS) or Numeric Pain Rating Scale. VAS is a simple, 1-dimensional measurement tool used to assess subjective experiences like pain, fatigue, or mood, typically a 10-centimeter line with descriptive anchors (e.g., "no pain" to "worst imaginable pain") at each end, where patients mark their current feeling, and clinicians measure the distance from the start to get a score (0-10 or 0-100). The NPRS is a simple 11-point scale (0-10) where patients rate their pain intensity, with 0 being "no pain" and 10 being the "worst pain imaginable", helping clinicians track pain levels and treatment effectiveness. Pain reduction is expected as a direct result of the active mandibular and cervical therapeutic exercises, which have previously demonstrated improvements in patients with temporomandibular disorders.

Postural control of the craniocervical region will be assessed through standardized tests of cervical motor control and alignment (e.g., deep cervical flexor endurance test, joint repositioning accuracy, or similar). Baseline and post-intervention evaluations will determine whether targeting mandibular musculature in combination with cervical stabilization exercises contributes to improved neuromuscular coordination and postural balance. This is supported by previous studies showing multidirectional effects between cervical and mandibular systems.

Mandibular movements will be assessed using a digital caliper, with measurements recorded in millimeters (mm). Movements evaluated will include maximum mouth opening and left and right lateral deviation. For each movement, two to three individual measurements will be obtained, and the mean value will be calculated for analysis. Measurements will be collected pre and post intervention, allowing for evaluation of changes in mandibular mobility.

Pressure pain threshold (PPT) of myofascial trigger points in the main mandibular muscles will be measured using a pressure algometer. The algometer quantifies the pressure required to elicit pain at a specific muscular trigger point, expressed in kg/cm². Measurements will be obtained bilaterally, including both the left and right hemiface, and recorded pre and post intervention. Higher PPT values indicate lower sensitivity or pain at the trigger point, whereas lower values indicate higher sensitivity.

Cervical motor control evaluates the range of motion in flexion, extension, and right and left cervical rotation. It will be evaluated by measuring movement deviations during a motor control task. Deviations from a visual target will be recorded in centimeters (cm). Larger deviations indicate poorer motor control, while smaller deviations indicate better accuracy and control. Measurements will be collected pre and post intervention.

Fear of movement and pain-related avoidance behaviors will be assessed using the Tampa Scale for Kinesiophobia (TSK) and the Visual Analogue Scale (VAS):

TSK: A 17-item questionnaire that evaluates fear of movement and re-injury. Scores range from 17 to 68, with higher scores indicating greater kinesiophobia and fear of movement.

VAS: A 10-cm visual scale measuring perceived pain or fear associated with movement. Scores range from 0 (no fear/pain) to 10 (maximum fear/pain).

Both scales will be used pre and post intervention, allowing assessment of changes in fear and pain perception over time.