磨牙症是屬於下意識的口腔異常功能性 (parafunctional) 運動，由於具有強烈的肌肉收縮，長期下來 往往對於牙齒、牙周、肌肉以及顳顎關節產生傷害。其致病因素為多因子，一般相信與壓力和咬合 以及中樞神經系統相關。臨床上最普遍採用的治療方式為咬合板治療，因此本實驗的目的在於探討 咬合板治療在短期內 (19 天 ) 對於磨牙症患者的夜間咬肌活性之影響。實驗方法使用可攜帶型肌電 圖系統 (portable EMG) ，長程記錄 10 位磨牙症患者在平時所習慣的睡眠環境下之夜間咬肌活性。
分別於咬合板配戴前 (pre-1;pre-2) 、配戴中第一星期 (S-6; S-7) 、配戴中第二星期 (S-13; S-14) 、 咬合板配戴後第一、二天 (po-1; po-2) 及二個月之後追蹤 (F/U-1; F/U-2) 共 10 天夜間測量。每晚記 錄肌電圖時並以「每日壓力感受量表」（ Daily Stress Inventory, DSI ）和受測者自覺壓力分數來評 量受測當日之壓力指數。
統計分析先以 Friedman two way analysis of ranks 和 Wilcoxon match-pairs ranks test 檢驗配戴咬合板 前、中、後、追蹤四組咬肌活性的差異；再分別以 General Estimating Equations (GEE) 分析同時以 性別及壓力和咬合板的配戴作為共同影響因素時對於咬肌活性的影響。
實驗結果顯示咬合板治療結束後 (po-1; po-2) 所測得的肌肉活性最低。而咬合板的配戴使得 2 位受 測者的咬肌活性降低， 2 位升高， 6 位無明顯變化；磨牙型態較偏向於有強烈收縮的緊咬 (clenchin g) 以及沒有側方干擾的磨牙症患者，對於咬合板的治療效果較好；男性的肌肉活性較女性為強，且 受測者日間承受的情緒壓力度與夜間磨牙頻率成正相關。
我們可以說磨牙症是由中樞神經系統主導的一種病症，與情緒壓力很有關連；咬合板治療並不能停 止或改變夜間磨牙，但它可以使得原本肌肉活性特別強烈的患者有一定程度的改善。本實驗將性別
，壓力等可能影響肌肉活性的因素一起考量，對於評估咬合板的治療效果會有較完整的呈現。
磨牙症患者在咬合板治療下的夜間咬肌肌電圖變化
Bruxism was a mandibular parafunctional behavior and had excessive occlusal forces, the long-term effect s of it were injury to the teeth, PDL, muscles and TMJ. The etiology was multifactorial and was believed to be emotional stress, occlusal factors and CNS problems. The most common treatment regime of it was spli nt therapy, so we wanted to know how the nocturnal masseter muscle activity was influenced by it.
We used portable EMG system to record bilateral masseter muscle activity of 10 bruxers under their usual sleeping environment. The recording was performed before splint treatment (pre-1; pre-2), during the first week of treatment (S-6; S-7), the second week of treatment (s-13; S-14), and immediately after the splint tr eatment (po-1; po-2). After 2 months taking-off the splint, the recording was performed as follow-up perio d (F/U-1; F/U-2). All ten recording nights before sleep, the subjects were asked to evaluate their daily stres s amount by answer the “Daily Stress Inventory; DSI” and scale their subjective feelings from 0 to 10. The special stress events were also recorded.
Friedman two way analysis of ranks and Wilcoxon match-pairs ranks test were used to evaluate the muscle activity changed before, during, after splint and follow-up period. General Estimating Equations (GEE) wa s used to evaluate whether the sex, stress and splint may influence the nocturnal masseter muscle activity. I t revealed that: 1. The lowest muscle activity was detected immediately after the splint treatment (po-1; po- 2); 2. The muscle activity of male was stronger than female; 3. The subjects’ daily emotional stress was po sitive correlated with the nocturnal muscle activity; 4. Nocturnal EMG values were reduced during use of s plints in two subjects (both male), six subjects (3 male, 3 female) had no change and two (both female) had increase in nocturnal EMG values. It seemed to have better treatment result on bruxers with extreme clench ing and without balancing side interference.
We can conclude that the bruxism was mainly controlled by CNS and highly related with emotional stress.
The effect of splint therapy was varied from one to one and it may even increase the muscle activity in som e subjects. Our study put sex, stress, and splint treatment together to evaluate the change of muscle activity could have a more complete result
The Nocturnal EMG Activity of Masseter Muscle on Bruxers during Splint Treatment
