Over the last seven weeks, I have been reviewing the vast library of literature that can be discussed in relation to the implications of temporomandibular joint dysfunction (TMJD) on athletic performance.
The articles have considered the effects of increased glial cell activation & increased substance P secretion, related to the hyper-sensitisation of the trigeminal nerve, that can occur as a result of TMJD.
During the last post, I discussed what components need to be included in a thorough TMJ assessment by the various members of the multi-disciplinary team involved in the condition’s management. So, all that is left to discuss now, is what we actually need to do to resolve TMJD.
I will predominantly focus on the physical therapy approach in this article, as I that is where my strengths lie. However, as I mentioned in a couple of the posts that make up this series, effective treatment of TMJD is a multi-disciplinary sport, incorporating dentists, psychologists, dieticians & physical therapists (both physiotherapists & osteopaths).
From a dental perspective, their examination will focus on bite alignment, as impacted by the teeth. So in some instances they may look to file down dental surfaces, whilst in others, the aim may be to encourage eruption of the molars. This may be achieved in conjunction with braces or splints, which may be worn all the time or only during certain times of day or night.
The psychologists will look to identify the factors causing anxiety or stress in an attempt to put strategies in place to deal with the underlying causes of bruxism or clenching. This may be related to specific situations or a more generalised state that is impacting the TMJ during sleep.
Dieticians will want to introduce strategies to deal with eating habits, dietary preferences & managing the symptoms that have arisen as a result of symptom progression.
The physical therapy approach considers the functional relationships between the TMJ, cervical spine & cranium, addressing altered kinematics by treating myofascial (muscle & connective tissue), joint & neural structures. This can be done using both manual & exercise therapy (Furto et al, 2006).
When we consider the normal arthrokinematics that may arise at the TMJ, they may be categorised into depressions or elevations, lateral excursions or protrusions.
In mandibular depression, the initial roll-gliding of the condyle in the inferior joint space transitions to a translatory gliding motion in the upper joint space at around 25 mm of opening, the posterior & collateral ligaments are pulled taut at around 35mm of opening, with any further opening achieved by increased translation & over-rotation, further stretching of these ligaments.
This end range opening requires the lateral pterygoid (inferior head) to provide a protecting force on the condyles & discs, whist the geniohyoid & digastic muscles must affect a depressive & retractive force on the chin. Combined with the downward pull on the mandibular body by the mylohyoid muscle, the jaw is rotated & translated to achieve mandibular depression.
When the mandible is elevated, the temporalis, masseter & medial pterygoid muscles contract to provide the force of the elevation, whilst the lateral pterygoid (superior head) pulls the condyle forward in the joint to provide room for the rotation. The temporalis muscles provide a postero-superior pull to achieve congruency in the joint at the end of range.
The grinding motion of the jaw is achieved by the alternating action of the medial pterygoid muscles.
The lateral excursion of the TMJ requires the condyle and the disc on the contralateral side to be pulled forwards, downwards & medially along the articular eminence. Meanwhile the condyle on the ipsilateral side performs a small rotation around the vertical axis combined with a slight lateral shift.
The muscles responsible for this movement are the lateral pterygoids on the contralateral side of the movement direction, in combination with the temporalis muscles on the ipsilateral side, which must contract to hold the condyle in position, thus preventing anterior deviation of the mandible.
Finally, the condyle & disc complexes must achieve symmetrical anterior translation on theatrical eminence to achieve mandibular protrusion. This is performed by a collaboration between the lateral pterygoid (pulls the condyle & disc forward & down), masseter & medial pterygoid muscles (maintain the mandibular position).
Mandibular retrusion is achieved by the temporalis muscles whilst the mouth is retained in a slightly open position by the muscles responsible for depression & elevation.
So what happens when any of these muscles develop an imbalance? Well, any restrictions of the myofascial anatomy can cause a change in the normal kinematics & a variation in the stresses placed upon the TMJs. Over time, these altered kinematics will result in modifications to the joint capsular tension, the ligament tension & the wear on the condyles.
An altered resting position of the joint caused by muscular imbalance will affect dental alignment & the ability of the molars to achieve congruency, thus preventing healthy occlusion & a normal resting posture for the mandible, disc & condyle in the TMJ.
This abnormal inter molar relationship can also be brought about by changes in the dental anatomy, brought about by wear, trauma or surgical/non-surgical corrective intervention. The margins for error are tiny, with micrometers making the difference between a healthy occlusion & a pathological occlusion.
Altered occlusion can cause the mandible to be pulled forward, which increases anterior stress on the disc, in addition to increased resting tone of the muscles that originate or attach to the mandible. These changes can cause neural sensitisation of the tri-geminal nerve & increases in substance P secretion.
Whilst malocclusion can be caused by dental factors, extra-dental factors can also exacerbate or precipitate the dental factors that result in malocclusion. For example, a change in the resting position of the mandible can change the posture of the head & neck (Daly, 1982) but also a forward head posture caused by myofascial restrictions of the neck extensors, will place the mandible in a more retruded position (Darling et al, 1984), causing an altered mandibular trajectory, which pulls the mouth open at rest. As a result, the muscles involved in mastication have to work to maintain jaw closure at rest (Goldstein et al, 1984).
Daly, P. Postural response of the head to bite opening in adult males. Am J Orthodontics, 1982; 82: pp 157-160
Darling, D.W. et al. Relationship of head posture & the rest position of the mandible. J Prosth Dent, 1984; 52(1): pp 111-115
Goldstein, D.F. et al. Influence of cervical posture on mandibular movement. J Prosth Dent, 1984; 52(3): pp 421-426
So what are the types of TMJD that can occur as the result of extra- or intra-dental factors & how can they be treated?
Treatment will vary according to presentation, however, the aims of intervention will be to restore normal joint movement of both TMJ & the cervical spine, whilst improving postural awareness; restore functional capabilities (e.g. eating, talking); reduce occurrence of joint pain & associated headaches & educate patients on strategies to prevent recurrence of symptoms.
Capsulitis or Synovitis
The lateral joint condyle or posterior compartment will be painful on palpation, as well as by applying overpressure to retrusion & on accessory joint mobilisation.
Actively, biting will cause pain on the contra lateral side.
Capsular Fibrosis
Whilst there will be no history of trauma or surgery reported, the will be deviation towards the symptomatic side on opening & protrusion, accompanied by limited lateral excursion to the opposite side. This will contribute to both limited active & accessory ranges of movement at the joint, although there will not be any abnormal sounds in the joint.
Masticatory Muscle Dysfunction
The masticatory muscles will be painful on palpation & whilst there will be no abnormal joint sounds, there will be changes to the joint function & control of the mandible.
Actively, biting will cause pain on the ipsilateral side.
Joint Hyper-mobility
Whilst these presentations may not necessarily be painful, there will be a joint sound at the end range of opening, often a click, which accompanies a deviation away of the symptomatic side. This excessive range of more than 40mm opening & hypermobile accessory testing, may lead to disc displacement.
Articular Disc Displacement (with Reduction)
Whilst the range of motion at the TMJ will not be reduced, unless it occurs in combination with a capsulitis or muscle dysfunction, the action of opening will occur with an “S” curve, with the deviation towards the pathological side early & late in the range. In addition, there will be a reciprocal joint sound with both closing (as the disc displaces anteriorly, staying in this position whilst the teeth are together) & opening (as the disc relocates).
Articular Disc Displacement (without Reduction)
If the disc displacement is not reduced & the disc remains in an anteriorly displaced position, the range of motion can be markedly restricted (limited to 25mm in acute presentations).
When the jaw is opened, the mandible deviates towards the pathological side & this will be accompanied by joint sounds that may have a longstanding history.
Post-surgical TMJD
This can present as a capsulitis or synovitis & may occur in combination with an underlying TMJD.
Majwer & Swider reported significant improvements of post-surgical joint pain following dexamethason or xylocaine infiltration using iontophoresis.
Majwer, K. & Swider, M. Results of treatment with iontophoresis of post traumatic changes of temporomandibular joints with an apparatus of own design. Prochet Stomatol, 1989; 39: pp 172-176
Osteoarthritis
The TMJ will be painful on palpation & crepitus will be audible on auscultation. On imaging investigation, there will be evidence of osteoarthritis on radiograph.
So as with every other condition, now we are able to ascertain an accurate diagnosis, a treatment plan can be drawn up to address the condition, centred around the appropriate goals.
The starting points are unsurprisingly to decrease the pain (both in the TMJ & any associated head or neck referral) & improve the function at the joint, whether this is eating, talking or even laughing. This will involve a restoration of the physiological movement at both the TMJ & the cervical spine. Finally, by improving postural awareness & educating patients on what causes symptoms to arise, we can improve the chances of preventing future recurrence of the symptoms.
Pain modulation can be achieved using modalities such as iontophoresis, heat & acupuncture, with dexamethasone & xylocane being two of the favoured pharmacological agents administered in the early studies by Majwer & Swider (1989) to treat capsulitis & synovitis, along with an exercise programme.
Majwer, K. & Swider, M. Results of treatment with iontophoresis of post traumatic changes of temporomandibular joints with an apparatus of own design. Prochet Stomatol, 1989; 39: pp 172-176.
Vicente-Barrero et al (2012) investigated the efficacy of acupuncture in the treatment of TMJD in comparison to use of decompression splints in a population of 20 patients diagnosed with TMJD.
Evaluating results using analogue pain scales, jaw lateral deviation, measurement of mouth opening & assessment of sensitivity to pressure applied to pre auricular, temporal, masseter & trapezes muscle points, the patients were assessed before & after 30 days of treatment.
The authors reported reductions in pain on subjective reporting using the analogue scales as well as upon pressure applied to the temporal, masseter & trapezes muscles, also with increased mouth opening ranges post-treatment with the decompression splints. The group exposed to acupuncture treatment showed the same improvements in addition to a reported reduction of pain in the short term.
Joint manipulation & mobilisation of the TMJ is indicated in both pain modulation & ROM restoration in those conditions where there is a loss of jaw motion, limited accessory movement, capsular pattern restrictions & deviations caused by restriction through range.
Depending on the presentation of the restriction, manipulations or mobilisations can either look to glide the joint medially or laterally or aim to distract the joint in its long axis.
Similar reasoning can be employed when addressing restrictions in the cervical spine, to improve the mobility, function & posture, which will indirectly encourage a change in the resting position of the condyle.
Cuccia et al (2010) compared two groups of TMJD patients, one exposed to what is described as osteopathic manual techniques & the second which participated in conventional conservative management.
The osteopathic techniques were described as consisting of myofascial release, muscle energy techniques, balanced membranous tension, joint articulation, high velocity/low amplitude thrust & craniosacral therapy directed at the cervical & TMJ regions. The conventional conservative approach consisted of using an oral appliance, gentle stretching/relaxing, hot/cold therapy & TENS.
Results reported improvements in both groups over a course of six months, whilst the group treated with osteopathic techniques required significantly less medication, described as non-steroidal medication muscle relaxants.
Kalamir et al (2013) investigated the efficacy of intra-oral myofascial therapy in a population of patients diagnosed with myogenous TMJD, which is a technique I have personally experienced very good results with. However, whilst benefits were reported, the levels of significance were sub-clinical.
As with any other musculoskeletal condition, however, passive range of movement treatments directed at the joint should be reinforced with directed myofascial techniques along with a regularly conducted exercise programme. This may included both passive & active exercises to mobilise & stabilise the joint & its capsule, as well as postural exercises to address the relationship of the joint with the rest of the spine, thorax & pelvis.
The review by da Rocha Moraes et al (2013) discussed various stretching techniques aimed at decreasing the resting tension of the muscle fibres. Stretches can either be applied passively, or actively, with the latter being recommended to target the elevator jaw muscles when range is greatly limited in the presence of pain.
Reciprocal inhibition techniques, where the opposing muscles are contracted isometrically to actively assist the stretching movement & consequently relax the opposing muscles, are also advocated.
Nicolakis et al investigated the results of a joint mobilisation intervention, alongside soft tissue techniques & an exercise regime over a 12 month follow-up period in patients with TMJD. The study reported positive results in measures of pain at rest, incisional opening & TMJ function.
30 patients diagnosed as having an anterior TMJ disc displacement, with reduction, attended an average of 9 physiotherapy appointments, with 75% reporting significantly favourable outcomes.
Nicolakis, P. et al. Effectiveness of exercise therapy in patients with internal derangement of the temporomandibular joint. J Oral Rehabil, 2002; 29: pp 362-368.
Furto et al (2006) also reported overall reductions in pain & improved function after a two week physical therapy management programme for 15 patients with TMJD.
In this study, exercises were aimed at neuromuscular re-education of the musculature surrounding the TMJ, by improving the co-contraction of the posterior temporalis, deep masseter & superior lateral pterygoid muscles to facilitate joint stabilisation.
Furto et al’s exercise programme included the use of a piece of cylindrical tubing, which was placed between the incisors, which was rolled between the teeth in a series of controlled motions, combined with biting & gentle isometrics. Exercises were performed every 2 hours for 6 repetitions (lasting less than 60 seconds in total).
The theory behind incorporating the isometric & co-contraction work was to increase the natural stability & the convexity of the joint structure, thus retraining the joint to maintain normal condylar alignment during movement. This is particularly indicated in TMJD where hyper mobility is an issue.
A presentation by Olson & Furto provided a simple summary of treatment approaches according to TMJD classification & I have based the table below on this, whilst supplementing it with my own approaches.
|
Classification |
Treatment Allied to Education |
|
Capsulitis |
Mobilisation Exercises Proprioceptive Exercises Iontophoresis Acupuncture Intra-oral Myofascial Therapy |
|
Hyper-mobility |
Stabilisation Exercises Proprioceptive Exercises |
|
Capsular Fibrosis |
TMJ Mobilisation & Manipulation Mobility Exercises Sustained Stretch Acupuncture Intra-oral Myofascial Therapy |
|
Muscles of Mastication Disorders |
Mobility Exercises Stability Exercises Proprioceptive Exercises Soft Tissue Manipulation Acupuncture |
|
Post Surgical |
TMJ Mobilisation Mobility Exercises Stability Exercises Proprioceptive Exercises Acupuncture |
|
Disc Dislocation w/ Reduction |
Mobility Exercises Stability Exercises Proprioceptive Exercises TMJ Mobilisation Intra-oral Myofascial Therapy |
In addition to the exercise programmes & treatment, education is crucial in maximising compliance & reinforcing the importance of a 24 hour approach to addressing TMJD.
Education should cover postural elements (avoiding sleeping in prone, not resting chin in hands, neck/head position), anatomical alignment (tip of the tongue resting at the ridge of the roof of the mouth, one third of the tongue on the roof; teeth 2 to 3mm apart at rest; lips lightly together when breathing through the nose; tongue on the roof of the mouth when yawning), diet (avoidance of hard, crunch foods & cutting food into small bites) & limitation of parafunctional activities (nail-biting, gum chewing, clenching & grinding teeth).
Olson, K. & Furto, E. Examination & Treatment of Temporomandibular Disorders - An Evidence-based Manual Physical Therapy Approach. Student Sessions, 2010.
Whilst this article may not be exhaustive in its investigation of the efficacy of the available techniques used in the management of TMJD, this covers many of the approaches I have had great success with over the years. As such, I hope it provides some value in the reflection of how other people address the same issues.
I am still learning & strongly believe that collaboration between physical therapists (physiotherapists, osteopaths, chiropractors etc.), dentists, psychologists & dieticians is key to addressing the presentation of TMJD in a thorough & co-ordinated manner.
