Effects of denture wearing on coordinated features of jaw and neck muscle activities during chewing in partially edentulous elderly patients

Abstract

This study was performed to examine how denture wearing improves jaw and neck muscle coordination during chewing in partially edentulous elderly patients. Methods: Sixteen patients classified as Eichner's index B2 or B3 and 16 young dentate subjects were enrolled. Jaw and neck muscle activities during chewing were recorded using electromyography with and without denture wearing, then analyzed using intermuscular Electromyography (EMG)-EMG transfer and EMG-EMG coherence function analyses to clarify quantitative, temporal, and functional coordination of jaw and neck muscle activities while chewing. Occlusal force and masticatory scores were also determined. Results: Denture wearing increased the power values for jaw closing muscle activities, and improved occlusal area and force, and masticatory score. Gain values for jaw closing and opening muscle activities were decreased in those wearing dentures compared to those not wearing dentures. Denture wearing resulted in equivalent gain values for jaw closing and opening muscle activities as compared to the young subjects. Coherence values for chewing and non-chewing side neck muscle activities were increased as compared to not denture wearing. Conclusions: The suitability of denture wearing can be evaluated from the viewpoint of gain as a quantitative parameter showing coordination between jaw closing and opening muscle activities. Such evaluation can be performed from the viewpoint of coherence as a parameter of functional coordination between jaw and neck muscle activities during chewing in partially edentulous elderly patients. The gain parameter in regard to jaw muscle activities may be compensated to a state equivalent to that seen in young subjects by wearing an appropriate denture.

Association of Jaw and Neck Muscle Coordination with Jaw Opening Activity while Chewing in Healthy Individuals

“…The healthy individuals of this study presented the standard values in dental occlusion of area and force, similar to that in previous studies (20,21) , as well as jaw opening activities (22 -25) . Further, vales in power, peak frequency, and coherence in EMG spectrums of jaw and neck muscle activities in this study also presented similar to previous studies (9,10,26) , and these corresponded to chewing rhythm generation. From these, it could be considerable that the subjects of this study may maintain the healthy jaw movement and jaw and neck muscle activities while chewing.…”

“…Concerning the associations between jaw and neck muscle activities while chewing, previous qualitative study suggested from the viewpoints of simultaneous acceleration of head and jaw movement activities while chewing in healthy individuals (2,5) . This study quantitatively presented the further association between jaw opening activity and jaw and neck muscle coherence while chewing in healthy individuals and which approach may be more suitable for evaluation of jaw and neck functionality than were muscle coherence while chewing (9,10,26) .…”

Coherence Analysis of Jaw and Neck Muscle Coordination during Chewing in Healthy Adults

“…Coherence analysis revealed that the frequency of the chewing rhythm closely aligns with that in previous studies using other existing methods. In adults with normal teeth, coherence analysis revealed an average first peak frequency of the jaw and neck muscles during gum chewing of 1.15 to 1.25 Hz [3,14,22]. For denture wearers, this peak was observed at 1.37 Hz [22].…”

“…In adults with normal teeth, coherence analysis revealed an average first peak frequency of the jaw and neck muscles during gum chewing of 1.15 to 1.25 Hz [3,14,22]. For denture wearers, this peak was observed at 1.37 Hz [22]. Ishii et al [14] reported that this initial peak in the power spectrum is consistent with the chewing rhythm, providing insights into the power, temporal, and synergistic relationships between the jaw and neck muscles in healthy subjects.…”