Neck Exercise Training for Temporomandibular Disorders: A Randomized Controlled Trial

A review

Introduction

Temporomandibular disorders (TMDs) affect the jaw, neck, and associated musculature, leading to chronic orofacial pain, impaired jaw function, and reduced quality of life. With more than 70% of TMD cases occurring in women, there is a critical need for targeted, conservative treatment options. Traditional approaches include manual therapy, occlusal splints, medications, and exercise interventions. This study evaluates whether an eight‐week neck motor control exercise program can effectively reduce pain and improve jaw function and oral health-related quality of life (OHRQoL) in women with chronic TMD.

Date Posted

• Published: March 12, 2024

Authors and Affiliations

• Authors: Ana Izabela Sobral de Oliveira-Souza, Laís Ribeiro do Valle Sales, Alexandra Daniele de Fontes Coutinho, Daniella Araújo de Oliveira, Susan Armijo-Olivo

• Affiliations:

  • Federal University of Pernambuco, Brazil

  • University of Applied Sciences, Germany

  • University of Alberta, Canada

Publication Information

• Published in: Journal of Oral & Facial Pain and Headache, Volume 38 (Issue 1), Pages 40-51

• DOI: 10.22514/jofph.2024.005

• Journal Impact Factor: 1.9

Methods and Study Design

PICO Framework

• Population: Fifty-four women (aged 18–45) with chronic myofascial or mixed TMD diagnosed by the RDC/TMD criteria.

• Intervention: Eight-week supervised neck motor control training program with a daily home exercise component.

• Comparison: Manual therapy (active control) and a placebo intervention.

• Outcome Measures:

  • Primary: Orofacial pain intensity (Visual Analog Scale)

  • Secondary: Jaw function (Mandibular Function Impairment Questionnaire), OHRQoL (OHIP-14), and jaw range of motion (ROM)

Exercise Protocol

Phase 1 (Weeks 1–6) – Deep Neck Stabilization

• Exercise: Craniocervical flexion (“nodding”) in a supine relaxed position using a pressure biofeedback device (Chattanooga Stabilizer) placed under the occipital region.

• Progression: Incremental increases in pressure from 20 mmHg to 30 mmHg in 2 mmHg steps.

• Repetitions: 10-second holds, 10 repetitions per set.

• Additional Exercise: Low-load isometric extension in a prone position on elbows, progressing from one set of 10 repetitions (3-second holds) to three sets of 15 repetitions.

Phase 2 (Weeks 7–8) – Strengthening

• Exercises:

  • Cranio-cervical flexion followed by cervical flexion (head lift) in supine.

  • Cervical extension in a quadruped position.

• Progression: Similar increases in set and repetition count with appropriate 2-minute rest intervals.

Home Exercise Program

• Protocol: Daily sessions lasting 15–20 minutes performing the same exercises.

Key Findings and Assessment

Pain Reduction

• Neck Exercise Training Group (NTG):

  • Pre-intervention: 5.69 ± 1.95

  • Post-intervention: 5.20 ± 1.81

  • Difference: 0.49-point reduction (p < 0.001)

• Placebo Group (PG):

  • Pre-intervention: 5.44 ± 2.67

  • Post-intervention: 5.58 ± 2.59

  • Difference: 0.14-point increase (p = 0.013)

• Intergroup Comparison: Statistically significant pain reduction in NTG versus PG (p < 0.001) with a small effect size (Cohen’s d = 0.427).

Jaw Function (Mandibular Function Impairment Questionnaire)

• NTG showed significant improvements compared to PG at all follow-ups.

• NTG outperformed manual therapy at the three-month follow-up.

Oral Health-Related Quality of Life (OHIP-14 Score)

• NTG demonstrated greater improvements in OHRQoL than both manual therapy and placebo.

• The largest improvement was noted at the three-month follow-up.

Jaw Range of Motion (ROM)

• No significant differences were observed between groups.

• Minor improvements in protrusion and lateral excursions were noted in NTG.

Clinical Applications and Recommendations

Neck Training as a Primary Treatment for TMD

• Recommendation: For patients with concurrent TMD and neck dysfunction.

• Program Structure: Include six weeks of deep neck stabilization followed by two weeks of progressive strengthening.

• Home Exercise: Essential for reinforcing clinical benefits.

Manual Therapy as a Complementary Treatment

• Role: Provides short-term symptom relief.

• Usage: Best used as part of a multimodal treatment plan.

Neuromuscular Influence on TMD Pain

• Insight: Deficits in neck motor control may contribute to TMD pain via the trigeminocervical complex.

• Rehabilitation: Incorporate targeted neuromuscular retraining for optimal outcomes.

Risk-Benefit Analysis

Potential Risks

• Study conducted exclusively on female participants may limit generalizability.

• The placebo intervention may not fully account for non-specific effects such as therapeutic attention.

Potential Benefits

• Non-invasive, cost-effective intervention.

• Provides long-term functional benefits and enhances quality of life.

• Aligns with current best practices in musculoskeletal rehabilitation.

Limitations and Future Research

Study Limitations

• Exclusively focused on women aged 18–45, limiting broader applicability.

• Long-term sustainability beyond a three-month follow-up was not assessed.

• No direct comparison with other treatments such as occlusal splints.

Future Research Directions

• Long-term studies to evaluate adherence and sustained effectiveness.

• Inclusion of male and older adult populations.

• Evaluation of combined treatment strategies (e.g., exercise therapy with splint or cognitive-behavioral therapy).

Conclusion

An eight-week neck motor control training program significantly reduced orofacial pain, improved jaw function, and enhanced oral health-related quality of life in women with chronic TMD. These findings support integrating targeted neck exercises into conservative treatment protocols for TMD. Further research is nee