Frequency of daytime tooth clenching episodes in individuals affected by masticatory muscle pain and pain-free controls during standardized ability tasks.
OBJECTIVE
Tooth clenching has been suggested to be related to temporomandibular pain. However, the electromyographic characteristics of daytime clenching episodes have been minimally investigated. This study aimed to analyze the frequency, amplitude, and duration of daytime clenching episodes in patients with masticatory muscle pain and pain-free individuals.


METHODS
Fifteen women with masticatory muscles myalgia (MP group, mean ± SD age = 26.4 ± 7.6 years) matched for age to 18 pain-free women (CTR group, mean ± SD age = 25.3 ± 2.8 years) were submitted to three different ability tasks (filling out questionnaires for 40 min, reading for 20 min, and playing a videogame for 20 min). The electromyographic activity periods (AP) of the right masseter greater than 10 % (AP10), 20 % (AP20), and 30 % (AP30) of the maximum voluntary contraction were analyzed.


RESULTS
The mean frequencies of AP10, AP20, and AP30 were greater in MP than in CTR individuals (all p < 0.05). The mean duration of AP10 was higher in MP group than CTR group only while filling out the questionnaires (p = 0.0033). CTR group had an increased frequency and duration of AP10 while playing the videogame than while reading a magazine. The ability tasks did not affect the muscle activity in the MP group.


CONCLUSIONS
Individuals with masticatory muscle pain have an increased frequency of both high and low-intense daytime clenching episodes. The type of ability task affects the frequency and the duration of clenching episodes only in pain-free individuals.


CONCLUSIONS
Clinicians should recognize that the frequency and intensity of daytime clenching are noticeably increased in individuals with masticatory muscle pain in order to better tailor treatment.
Department of Orthodontics, Faculty of Dentistry, University of Toronto, Center for The Study of Pain, Toronto, ON, Canada. iacopo.cioffi@dentistry.utoronto.ca.|Department of Neurosciences, Reproductive and Oral Sciences, Section of Orthodontics and Temporomandibular Disorders, University of Naples Federico II, Naples, Italy. iacopo.cioffi@dentistry.utoronto.ca.
Iacopo
I
Cioffi
Department of Neurosciences, Reproductive and Oral Sciences, Section of Orthodontics and Temporomandibular Disorders, University of Naples Federico II, Naples, Italy.
Donatella
D
Landino
Department of Neurosciences, Reproductive and Oral Sciences, Section of Orthodontics and Temporomandibular Disorders, University of Naples Federico II, Naples, Italy.
Valeria
V
Donnarumma
Department of Surgical Sciences, School of Orthodontics, Dental School, University of Turin, Turin, Italy.
Tommaso
T
Castroflorio
Department of Oral Kinesiology, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, The Netherlands.
Frank
F
Lobbezoo
Department of Neurosciences, Reproductive and Oral Sciences, Section of Orthodontics and Temporomandibular Disorders, University of Naples Federico II, Naples, Italy.
Ambrosina
A
Michelotti
D000328:Adult; D002012:Bruxism / Q000503:physiopathology*; D016022:Case-Control Studies; D004576:Electromyography; D005157:Facial Pain / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008410:Masticatory Muscles / Q000503:physiopathology*; D063806:Myalgia / Q000503:physiopathology*; D010147:Pain Measurement; D011932:Reading; D011795:Surveys and Questionnaires; D013647:Task Performance and Analysis; D018910:Video Games
Awake bruxism; Daytime tooth clenching; Masticatory muscles; Orofacial pain; Surface electromyography; Temporomandibular disorders