Ruka Ohkubo

Hokkaido University, Sapporo, Hokkaidō, Japan

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Publications (2)3.37 Total impact

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    ABSTRACT: To determine the association between temporomandibular disorders (TMD) and experiences of jaw injury, third molar removal, and orthodontic treatment, controlling for confounding factors such as age, sex, emotional stress, and oral parafunction. First-year university students (n = 2,374) were instructed to answer a questionnaire regarding symptoms of TMD, jaw injury, third molar removal, orthodontic treatment, stress, and parafunctional habits. All subjects were classified according to the level of TMD symptoms. Logistic regression was applied to assess the associations of experiences of jaw injury, third molar removal, and orthodontic treatment with presence of TMD symptoms after controlling for age, sex, stress, and parafunctional habits. Of the 2,374 students, 715 students were TMD symptom-positive. They were classified into 7 groups consisting of those with only clicking (group 1), only pain in the temporomandibular joint (group 2), only difficulty in mouth opening (group 3), clicking and pain (group 4), clicking and difficulty in mouth opening (group 5), difficulty in mouth opening and pain (group 6), and all 3 symptoms (group 7). TMD symptoms were significantly associated with jaw injury. Odds ratios were 2.25, 2.47, 3.38, and 2.01 for groups 2, 3, 6, and 7, respectively. Experience of third molar removal was significantly associated with TMD (odds ratio = 1.81 for group 1). No association was found between orthodontic experience and TMD. Experiences of jaw injury and third molar removal might be cumulative and precipitating events in TMD.
    No preview · Article · Feb 2008 · Journal of orofacial pain
  • R Miyake · R Ohkubo · J Takehara · M Morita
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    ABSTRACT: We examined whether oral parafunctions are associated with symptoms of temporomandibular disorders (TMD) in 3557 Japanese university students, aged between 18 and 26 years. Participants completed a questionnaire regarding various oral parafunctions and subjective symptoms related to TMD, and underwent a dental examination. The prevalence of temporomandibular joint (TMJ) noise, TMJ pain and impaired mouth opening was 41.7, 16.0 and 16.3%, respectively. The most prevalent parafunction was sleeping on one side (60.2%), followed by supporting the jaw by leaning on the palm of the hand (44.8%). Mean age, decayed, missing and filled teeth, and number of teeth were not significantly different between TMD positive and negative groups according to unpaired t-test. The chi-squared test revealed that the ratio of females was significantly higher among students with TMD than without TMD. Multiple logistic regression models adjusted for age and gender demonstrated that chewing on one side caused an increased risk of TMJ noise [odds ratio (OR) = 1.52, P < 0.001], TMJ pain (OR = 1.54, P < 0.001), and impaired mouth opening (OR = 2.00, P < 0.001). Tooth clenching also increased the risk of TMJ noise (OR = 1.86, P < 0.001), TMJ pain (OR = 1.79, P = 0.001) and impaired mouth opening (OR = 1.88, P < 0.001). Further prospective cohort studies, including other potential risk factors, are required to clarify these relationships.
    No preview · Article · Jun 2004 · Journal of Oral Rehabilitation