Research Review By Dr. Robert Rodine©

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Date Posted:

May 2012

Study Title:

Intraoral myofascial therapy for chronic myogenous temporomandibular disorder: A randomized controlled trial

Authors:

Kalamir A, Bonello R, Graham P et al.

Author's Affiliations:

Macquarie University, Sydney, Australia; Anglo-European College of Chiropractic, Bournemouth University, England.

Publication Information:

Journal of Manipulative & Physiological Therapeutics 2012; 35: 26-37.

Background Information:

Temporomandibular dysfunction (TMD) is a troublesome condition for many. A common affliction, TMD signs or symptoms are reported in 40% of the general population (1). Additionally, there is a high frequency of co-morbid conditions such as headache and fibromyalgia in TMD patients, suggesting greater burden for sufferers (2).

It is thought that TMD most commonly has a myofascial origin, and also that arthrogenous forms of TMD include associated myofascial components. As such, the authors of the presented study propose an intraoral myofascial therapy (IMT) approach to management.

They tested such a program in a randomized controlled trial, comparing IMT to a control group. However, the authors also wish to highlight the self-management aspect of TMD aimed at improvement of the patients’ coping ability. They propose that addressing anatomy, biomechanics, pathophysiology and the natural history of TMD would improve outcomes, as sufferers might experience less anxiety due to increased knowledge. Given that psychosocial overlay is a poor prognostic factor for TMD, creating understanding of the disorder was felt to reduce the effect of these factors.

Pertinent Results:

  • Only one subject dropped out of the study - a member of the control group.
  • There were no significant baseline differences noted between groups for pain ratings. Opening range, however, was significantly greater for the IMTESC group, with no known reason other than chance effect.
  • For the control group, the mean age was 35, opening range of motion was 36.3 mm, resting pain was 3.85/10, opening pain was 4.76/10 and clenching pain was 5.05/10.
  • For the IMT group, the mean age was 34, opening range of motion was 37.4 mm, resting pain was 4.46/10, opening pain was 5.15/10 and clenching pain was 6.21/10.
  • For the IMTESC group, the mean age was 35, opening range of motion was 39.89 mm, resting pain was 4.26/10, opening pain was 5.09/10 and clenching pain was 5.36/10.
  • At all time points, both treatment groups demonstrated statistically significant differences compared to the control group.
  • At 6 weeks and at 6 months, there were no statistically significant differences between treatment groups. However, at 1 year the IMTESC group demonstrated a statistically significant difference compared to the IMT group.
  • When looking at mean pain score changes at 1 year, the IMT group showed resting pain of 3.1, opening pain of 1.9 and clenching pain of 1.7. In this group, only resting pain levels were reduced by a clinically significant amount. In comparison, the mean score changes at 1 year for the IMTESC group were as follows: resting pain was reduced by 4.0, opening pain by 4.1 and clenching pain by 3.6. All of these outcomes showed clinically significant change.

Clinical Application & Conclusions:

This study succeeded admirably in demonstrating that an RCT of manual methods for TMD can be performed, while following a patient population over the course of 1 year.

From a clinical perspective, any therapist who has treated patients with TMD fully understands the burden to patients, the recalcitrance of this condition to many treatment methods/options, and the apparent overlay of general stress and anxiety that can complicate matters further.

Within this paper, Kalamir and colleagues have provided a generous framework to apply an intraoral myofascial approach to TMD and combined this with a guideline for an education program directed at fostering patient understanding. Here, the goal of patient education is to provide patients with as much information as possible about their disorder, hoping that increased awareness and understanding will improve coping mechanisms and reduce repetitive strain. It would be interesting if a future study included a group solely receiving an education program to adequately determine the impact this may have.

The outcomes of this study were promising, demonstrating that both treatment groups responded favorably over the short term as well as at 6 month follow-up. However, the impact of combining education with intra-oral myofascial treatment only became apparent at the 1 year mark. Here, the difference in outcomes was identified as the myofascial treatment group experienced a regression while the combined education group maintained its status. The reason for this is unclear, nonetheless it remains an important piece of clinical information clinicians should bear in mind.

It should be recognized that this paper received third prize at the 2011 World Federation of Chiropractic Congress in Rio de Janeiro in Brazil!

Study Methods:

Design and Subjects
  • Subjects were recruited based on referrals from local dental clinics, over a period spanning 1 year
  • Subjects were required to have a history of daily periauricular pain (with or without joint sounds) for a period of at least 3 months, and to be between the ages of 18-50 years
  • Subjects were excluded if severe depression was identified upon psychosocial assessment
Recruitment generated 221potential subjects, which was narrowed down to 134 applicants following the initial assessment. A total of 93 subjects were enrolled and randomized into three equal groups.
  1. Intraoral myofascial therapy (IMT)
  2. IMT + education and self-care (IMTESC)
  3. No-treatment, wait-list control (Control)
All data was collected by an independent assessor, blinded to group allocation. The treating practitioner was blinded to the randomization schedule and assessment outcomes until the study’s completion.

Interventions:

IMT:Was delivered twice per week for 5 weeks. Therapy was delivered in the following manner:
  • Temporalis Muscle: With the therapist positioned on the side of treatment, a finger of the caudad hand was placed on the coronoid process of the mandible, with posterior-caudad pressure. Meanwhile, fingers of the cephalad hand are used to apply superior pressure along the temporalis muscle fibers while the subject opens the mouth to a maximum range (see picture below).
  • Pterygoid Muscle: With the therapist positioned on the side of treatment, a finger is used to place posterior-cephalic pressure overlying the tissues on the lateral wall of the pharynx, posterior to the back teeth. Avoid the hamulus. Pressure is sustained for 5 seconds. (NOTE: Here the authors comment that in those suffering from TMD, functional deficiencies makes any differentiation between the lateral and medial pterygoids an academic exercise only.)
  • Sphenopalatine Ganglion: Here, the little finger of the caudad hand is used to apply pressure posterior to the occluded teeth, along the buccal surface. Subjects are asked to alternate between contracting and relaxing while the finger is worked behind the medial pterygoid and masseter, attempting to reach the infratemporal fossa, at the anterior aspect. This technique proposes parasympathetic neurologic effects.
intraoral temporalis release
IMTESC:
Was delivered so that subjects received the same treatment as the IMT group, however also received a scripted 2 minute lecture at the end of each of the first four treatments. This lecture included information on anatomy, biomechanics, TMJ disc dysfunction and the role of psychoemotional health. Exercises were also provided, as described below, to be performed twice daily:
  • Post-isometric relaxation stretches of laterotrusion and opening, with isometric resistance held for 10 seconds, followed by a short duration stretch (see picture below).
  • The Macquarie University ‘’Mandibular body-condylar cross-pressure chewing technique’’ suggests the subject apply contact to the ipsilateral mandibular condyle and the contralateral ramus, with even pressure exerted on both sides while the jaw is opened and closed through 5 cycles. This is then repeated with reversed contacts (see below).
pir_laterotrusionmandibular_body_cross_pressure
Outcome Measures
:

An 11-point self-reported pain scale was used by the patient rating:
  1. Jaw pain at rest
  2. jaw pain upon maximal active opening; and
  3. jaw pain upon clenching.
The minimum clinically important change was considered to be 2 points. A secondary outcome measure was interincisal range of opening, measured in millimeters. Outcomes were collected at baseline, after a 6 week assessment, a 6 month assessment and a 1 year assessment.

Study Strengths / Weaknesses:

This study demonstrated a strong design. Outcome measures were properly chosen, using objective measures such as range of motion, as well as a variety of patient-centered outcomes such as the numerical pain rating scale.

The follow-up period was of excellent duration, assessing patient outcomes at the end of the treatment cycle, at 6 months and a 1 year time frames.

In my opinion, the recruitment process could have improved upon by expanding the subject draw from a greater population than dental referrals alone. It is possible that this subset of TMD sufferers may present with a different severity of pain and dysfunction, compared to a subset who initially presents to a family physician, physiotherapist, massage therapist, chiropractor etc.

The most notable flaw within the study design is that the treating clinician was not properly blinded to the two treatment groups. Given that the clinician was also performing the patient education seminars at the end of each treatment session, bias could have been introduced creating an uneven manual intervention between groups.

The most notable strength of this paper was the excellent description of manual methods used to treat myofascial TMD. The authors have made it very easy for the average clinician to translate this protocol directly into practice with little additional training.

Additional References:

  1. Conti et al. A cross-sectional study of prevalence and etiology of signs and symptoms of temporomandibular disorders in high school and university students. J Orofac Pain 1996;10:254-62.
  2. Aaron et al. Overlapping conditions among patients with chronic fatigue syndrome, fibromyalgia and temporomandibular disorder. Arch Intern Med 2000;160:221-7.