Masticatory muscle activity assessment and reliability of a portable electromyographic instrument.
BACKGROUND
Masticatory muscle hyperactivity is thought to produce muscle pain and tension headaches and can cause excessive wear or breakage of restorative dental materials used in the treatment of prosthodontic patients. The quantification and identification of this type of activity is an important consideration in the preoperative diagnosis and treatment planning phase of prosthodontic care.


OBJECTIVE
This study investigated the quantification process in complete denture/overdenture patients with natural mandibular tooth abutments and explored the reliability of instrumentation used to assess this parafunctional activity.


METHODS
The nocturnal EMG activity in asymptomatic complete denture/overdenture subjects was assessed with and without prostheses worn during sleep. Because of the large variance within and between subjects, the investigators evaluated the reliability of the 3 instruments used to test nocturnal EMG activity in the sample.


RESULTS
Electromyographic activity data of denture/overdenture subjects revealed no differences between prostheses worn versus not worn during sleep but demonstrated a very large variance factor. Further investigation of the instrumentation demonstrated a consistent in vitro as well as in vivo reliability in controlled laboratory studies.


CONCLUSIONS
The portable EMG instrumentation used in this study revealed a large, uncontrollable variance factor within and between subjects that greatly complicated the diagnosis of parafunctional activity in prosthodontic patients.
Kuwait University Health Sciences Center, Jabriya, Kuwait. johnbowley@hsc.kuniv.edu.kw
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D000704:Analysis of Variance; D002940:Circadian Rhythm; D000044:Dental Abutments; D003766:Dental Occlusion; D003824:Denture, Complete; D003826:Denture, Complete, Lower; D003827:Denture, Complete, Upper; D003828:Denture, Overlay; D004576:Electromyography / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008409:Mastication / Q000502:physiology; D008410:Masticatory Muscles / Q000502:physiology*; D009991:Oscillometry / Q000295:instrumentation; D012890:Sleep / Q000502:physiology