The effectiveness of neck strengthening exercises on jaw mobility and clicking in anterior disc displacement with reduction of temporomandibular joint: A randomized controlled trial

Background: The studies in the literature have focused on the biomechanical and neurophysiological aspects of cervical and temporomandibular joint function. Addressing the cervical spine correlation with the temporomandibular joint may lead to long-term improvement in the derangement. This study desired to deduce the effectiveness of deep neck muscle strengthening exercises on jaw motion and clicking sounds in anterior disc displacement with reduction of the temporomandibular joint. Methods: This controlled clinical trial was conducted using a single-blinded design in a tertiary care teaching hospital affiliated with The University of Lahore- from March 2020 to January 2021. A count of 68 patients were enrolled each with 34 patients. The inclusion criteria were being 18-50 years old, suffering from temporomandibular joint pain and disc displacement with reduction, medical referral for temporomandibular disorders by a dentist or a maxillofacial surgeon, and having symptoms for more than one month before the first treatment. The exclusion criteria were having a tumor, fracture, or trauma in recent medical history, systemic, rheumatic diseases, degenerative changes, and history of surgery of the cervical spine or temporomandibular joint. The control group (Group A) was only given temporomandibular joint mobilization and soft tissue release. The Intervention group (Group B) did neck strengthening exercises in addition to the temporomandibular joint mobilization. The subjects were assessed twice. Results: To analyze the data, SPSS version.21 was used. To assess the frequency of qualitative factors like clicking, the chi-square test was employed. The mean scores of quantitative factors such as mandibular lateral deviation and maximal mouth opening were approximated between the two categories of subjects using the Mann-Whitney test. The findings demonstrated that there was no change between the groups' pre- and post-treatment means for jaw mobility and clicking sounds. Nonetheless, the Intervention group's mandibular lateral deviation significantly improved (P-value <= 0.037)*. Conclusion: The findings revealed that neck strengthening exercises in addition to routine physical therapy of the temporomandibular joint do not affect clicks and mobility between the two groups. The exercises were found out to be effective only in improving the lateral deviation of the mandible.