Background: Temporomandibular disorder (TMD) is a common and costly problem that often leads to chronic pain or dysfunction. There is moderate evidence to support physical therapy (PT) interventions for individuals with TMD, yet they continue to be an underserved population. A known relationship between TMD and the cervical spine exists with some evidence to support the use of cervical interventions for TMD. Cervical spine thrust joint manipulation (TJM) is an effective PT intervention that has been explored in a limited fashion for this population.

The purpose of this trial is to determine the immediate and short term (1 and 4 week) effects of cervical TJM delivered by a physical therapist on pain, dysfunction, and perception of change in persons with a primary complaint of TMD. The hypothesis is that all participants will improve, and those in the cervical TJM group may have a greater degree of improvement.

Design: Participants will be randomized to one of two groups and all will receive physical therapy. Forty-two willing participants, age 18-65 with TMD will complete the informed consent process and screening for eligibility before being admitted. Participants will receive a combined treatment of 1) behavioral education, a home exercise program, soft tissue mobilization, and cervical spine TJM or 2) behavioral education, a home exercise program, soft tissue mobilization, and sham manipulation. Participants will receive 4 treatments over a period of 4 weeks.

Significance: The results of this clinical trial will provide evidence relative to the impact of cervical spine TJM in the treatment of persons with TMD. Determining the effectiveness of cervical spine TJM included with a combined treatment approach has clinical implication for physical therapists and the patients they serve.

Methods: Research design following CONSORT guidelines. A blinded assessor will measure ROM and PPT. Treating therapists will know group allocation and will receive training to standardize assessments and treatments. Self-report and objective measurements will be taken at baseline, immediately after treatment one, and at one and four week follow-ups.

Data Analysis (primary): Sample size estimations were completed using G-Power, a free online downloadable program. An F-test family with ANOVA: Repeated measures, within-between interaction protocol was selected. While it is optimal to power sample size estimations around a functional outcome measure, the limited use of functional measures in this population created an obstacle. The sample size estimation for this project was powered around maximal mouth opening (MMO) as this most closely relates to function in the TMD population. In order to account for 15% attrition, and maintain equal participants in each arm of this study, the desired sample size is 42 participants.

A 2 x 4 mixed model analysis of variance (ANOVA) will be used with treatment group as the between-subjects factor and time as the within-subjects factor. Separate ANOVAs will be performed for dependent variables and the hypothesis of interest will be group by time interaction for each ANOVA.

To determine if missing data points associated with dropouts were missing at random or missing for systematic reasons, we will perform Little's Missing Completely at Random (MCAR) Test. Intention to treat analysis will be performed by using expectation maximization whereby missing data are computed using regression equations. Planned pair-wise comparisons will examine the difference between baseline and follow-up periods using the Bonferroni equality at an alpha level of 0.05.

Success will be dichotomized using the GROC scale. A cut-off score of +5 or higher on the GROC will be used as a measure of success. Correlations between outcome measures (change scores) and success will be analyzed using an independent t-test to determine if differences between groups exist. Number needed to treat (NNT) will be calculated. Correlations among dependent variables will be analyzed with Pearson/Spearman correlations. Examples include the following: correlation between NDI and jaw functional measures, correlation among PPT at various areas tested, and correlation between change in ROM and change in functional scores. Data analysis will include 95% confidence intervals, and tables, charts, or other figures will be utilized to display findings to enhance reader understanding. Effect size of primary outcome measures including jaw ROM, JFLS, and TMD Disability Index will be calculated and reported. If there is no significant difference between groups noted, a post-hoc power analysis will be performed to determine the risk of Type II error.

Data Safety Plan/Subject Confidentiality: The PI will be responsible for educating all clinicians, research assistants, and front office staff with RVPT, Bradley University, and UNLV in confidentiality measures and data safety plans. This information will be part of the live training and included in the Manuals of Standard Operating Procedures. The PI will also periodically check in with each participating clinician, blinded assessor, and clinic office staff member to review procedures and monitor recruitment and retention. This check will occur once per month over the phone.

Standard Operating Procedures: Manual developed and used in training.

Inclusion Criteria:

• 18-65 y/o
• primary complaint of TMD pain
• positive TMD screen
• proficiency in English language
• availability to attend 4 sessions
• minimum level of disability (NPRS 2 or greater)
• minimum level of disability (pain free mouth opening 50 mm or less).

Exclusion Criteria:

• traumatic onset of symptoms
• whiplash in the last 6 weeks
• prior neck surgery
• medical red flags suggestive on on-musculoskeletal origin of pain, systemic disease, or neurological disease
• contraindications to thrust joint manipulation (TJM),
• previous TJM in the last 3 months
• Worker's compensation
• pending litigation regarding pain or injury.

Participants will be blinded to group allocation. Blind assessors will be utilized to measure objective change in range of motion and pain pressure threshold.