MAEKAWA Kenji Okayama University, Hospital, Associate Professor, 医学部歯学部附属病院, 講師 (20304313)
KUBOKI Takuo Okayama University, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Professor, 大学院・医歯薬学総合研究科, 教授 (00225195)
|Budget Amount *help
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2004: ¥2,500,000 (Direct Cost: ¥2,500,000)
Objective : Sleep bruxism (SB) has been assessed by a self-estimated questionnaire and/or degree of tooth attrition. However these reliabilities were recognized insufficient to detect on-going SB events. One solution can be a miniature self-contained EMG detector-analyzer (BiteStrip○!R, S.L.P. Israel) that can be applied directly to the masseter muscle. Our previous study demonstrated this device has sufficient reliability to detect bruxism events with polysomnography as a golden standard (sensitivity : 0.92, specificity : 0.91); however, this device occasionally showed error message when applied in Asian subjects. This would be potentially due to skin resistance difference between Asian and Caucasians. In response, the version-up model has been developed recently to solve this problem. This study verified the improvement of this device. SB also has been hypothesized as a precipitating/perpetuating factor in TMD signs and symptoms. However, the direct relationship between the SB level
and prevalence of the TMD signs and symptoms were still unclear, because of the difficulty in measuring the SB severity epidemiologically. Therefore, the aim of this study was to investigate the relationship in an adolescent population by using a miniature SB detection device (BiteStrip○!R, S.L.P. Israel).
Methods : Six healthy volunteers (1 female and 5 males, mean age 24.5+/-0.55) who had been diagnosed as bruxisers by means of portable electromyography assessment and concomitant video recording and participated continuous 10-nights BiteStrip recordings. Each subject was applied both conventional and version-up BiteStrip on their bilateral buccal skin surface individually during continuous 5-nights. The incidence rates of error message were compared. The 1st degree students of a high school were exhaustively recruited, and 195 students (male/female : 86/109, mean age 15.4±0.5 yr) among them participated in this survey. They received clinical examination and were explained the usage of BiteStrip. Bruxism episodes were detected at their 30% MVC threshold, and total number of SB episodes was classified into 0-3 (<40, 41-74, 75-124 and ≦ 125, respectively). Relationship between their SB levels and presence/absence of the TMD signs and symptoms (clicking, limitation of mouth opening (LMO), headache, shoulder stiffness) were calculated, and odd-ratio and confidence interval (CI) were estimated by a simple regression analysis.
Results : The incidence (rates) of error message in the conventional and version-up systems were 14/30 (46.7%) and 1/30 (3.3%) and the incidence in the version-up system was significantly lower than that in the conventional systems (p<0.01, Chi-square test). Of which 195 responders, 29 subjects didn't return BiteStrip and 40 BiteStrip showed error or no indication. Severe bruxier (≧score 3) had 3.58 times higher prevalence of TMJ clicking (95% CI : 1.21-10.39, P=0.02), whereas other signs and symptoms showed no significant relation.
Conclusion : This modification made in the version-up BiteStrip was able to reduce the incidence of the error message in this system. The device appears to be clinically applicable even for Asian population. These results supported TMJ clicking can be associated with severe bruxism. However this study measured SB in one night, multiple SB recordings should be included in a further research. Less