Scuba diving can induce stress of the temporomandibular joint leading to headache

In ordinary recreational scuba diving, many anatomical parts can be involved in disorders of cranial regions: ears and eyes are involved but also sinuses. Dental problems are generally involved in barotraumas because of bad dental fillings or other matters of interest to the general dental practitioner.¹ Very few papers have looked at the articular and periarticular problems of the temporomandibular joint (TMJ).²

Local factors such as joint laxity, anatomical factors, capsular or muscular inflammation, and articular stress of long duration resulting from holding the regulator mouthpiece in scuba diving or the snorkel mouthpiece in skin diving can lead to TMJ disorders including headaches and myalgic symptoms.³

We examined the biomechanics of the TMJ (fig 1) in relation to diving, particularly looking at the disc-condylar position during mouthpiece biting and with the mouth closed and wide open (submaximal opening). The aim was to see if during scuba diving the TMJ is maintained in a stressed position leading to pathology (myalgia, headaches, discal subluxations) under certain conditions.

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Figure 1

Diagram illustrating the structure of the temporomandibular joint.

Methods

To measure condylar and discal displacement in divers, we studied 30 TMJs in a population of 15 divers aged 18–55, including six women. None had symptoms of TMJ disorder such as joint noise, pain, or luxations. All were fully informed about the experimental paradigm and agreed to have magnetic resonance imaging (MRI) of both TMJs.

MRI was used so that the intra-articular disc and condyle body could be viewed in the same image and scale to allow angular measurements. Six sagittal and parasagittal slices were viewed on each side (T1 weighted sequences, performed with a 6.5 cm circular coil at each side of the head). All the procedures were consistent with actual TMJ MRI techniques. Measurements were made on the same subject in three standard mouth positions:

1. Closed mouth (biting position)

2. Mouth holding regular diving mouthpiece

3. Mouth submaximally opened holding a 40 mm uncompressible non-magnetic plastic tube (fig 2)

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Figure 2

(A) Radiograph of a diver with a large plastic tube (40 mm diameter) inserted in the mouth. (B) The same diver with a standard mouthpiece inserted.

The different angles calculated for the whole samples were computed for statistical analysis by standard procedures including mean, standard deviation, median, and analysis of variance after the Kolmogorov Smirnoff test for normality. Post-discriminant tests included Tukey-Kramer and Bonferroni.

Results

Figure 3 shows that there was a significant difference between the closed mouth position and the two other standard mouth positions (wide open, p<0.001; holding a standard mouthpiece, p<0.05), but no difference was found between the two latter positions.

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Figure 3

Angular variations between the condyle axis and the medial part of the disc. ***p<0.001; *p<0.05 compared with the closed mouth position.

Conclusions

From the results we cannot reject the hypothesis that the prolonged position of the TMJ during scuba diving may induce pain as the result of stress to the retrodiscal portion of the joint, which is near neurovascular elements. It is recommended that divers should be taught not to overstress the TMJ to avoid headache and other myalgic syndromes. The reader is referred to the paper on temporomandibular dysfunction in scuba divers by Aldridge and Fenlon (p ??).