Title: 3058 - Gender Difference in Motor Strategy in Response to Jaw-opening Resistance


Birgitta Haggman-Henrikson (Presenter)
Malmö University

Birgitta Wiesinger, Faculty of Odontology
Anders Wänman, Clinical Oral Physiology
Catharina Osterlund, Faculty of Odontology


Objectives: There is a close functional integration between the jaw and neck motor system as well as comorbidity between jaw and neck disability. Studies have shown that normal jaw function involves both jaw and neck muscles, and with larger head movements when performing larger jaw movements. The aim of this experimental study was to evaluate the effect on jaw-neck motor function when a resistance load is applied to the lower jaw.

Methods: Lower jaw and head movement amplitudes were registered during a jaw opening-closing task in 12 healthy young men (mean age 22.5 years; SD 2.2) and 14 women (mean age 22.0 years; SD 2.0), using a 3-D movement recording system (MacReflex®). Jaw-opening was performed with and without load to the mandible. A helmet connected to a hydraulic system provided a resistance of 1600 g during the jaw-opening phase. Differences in jaw and head movement amplitudes between jaw-opening with and without load were analyzed with Wilcoxons matched pairs test and differences between men and women with Mann-Whitney U-test.

Results: A significantly lower jaw movement amplitude was found in the load tests for females (p=0.005), but not for males (p=0.077). For head movement amplitudes, females had no significant difference (p=0.077) between tests, whereas men showed larger amplitudes with load (p=0.034), compared to without load. Movement amplitudes for the head in relation to jaw (head/jaw ratio) showed a significant increase in the load tests for both males (15% vs 7%; p=0.023) and females, (17% vs 9%; p=0.009) compared to tests without load.

Conclusions: The results show that increased resistance load during jaw-opening will affect integrated jaw-neck motor function with an increase in the proportional involvement of the neck. Furthermore, our results show differences between women and men in motor strategies in response to increased load on the jaw-neck motor system.

Student Presenter

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE