年輕女性罹患顳顎關節內部紊亂症與身體質量指數、骨密度、顱顏面形態關聯之研究

Abstract

目的： 由於顳顎關節內部紊亂症在一般人口有高達32%的盛行率，不但發生臨床上常見之關節雜音、張口疼痛、咀嚼困難等症狀，其衍生的顳顎關節退化性病變又與顏面形態異常、咬合不正等問題有相關。由我們先前的研究發現，不可復位的顳顎關節內部紊亂症竟然與全身性之低骨質密度、低身體質量指數有明顯相關。因為顳顎關節內部紊亂症的高盛行率及其它相關問題，我們面對的將會是一個攸關全民的國民健康問題。 但由於臨床理學檢查不容易察覺顳顎關節的結構紊亂症，因此臨床上診斷率遠被低估。另外，若每個病人都用磁振掃描為黃金標準去檢查診斷，將是非常可觀的醫療支出，有實際上實行的困難，我們需要是更貼切實際且簡單的篩檢方式。 因此，本研究的目的是分析顳顎關節內部紊亂症與顱顏形態及全身性之危險因子之間的相關性。並試圖找出臨床上簡單易用的篩檢顳顎關節內部紊亂症方法。 實驗材料與方法： 本實驗採用橫向截面(cross section)的實驗設計。實驗對象為128位18至28歲的年輕女性，三群實驗對象：國立台大醫院牙科部顳顎關節障礙特別門診病人、齒顎矯正科門診病人、與隨機挑選無任何抱怨顳顎關節疾病及症狀的平常年輕女性。以靜態及動態顳顎關節磁振掃描影像以作為顳顎關節內部紊亂症診斷，並測量顳顎關節髁頭面積大小與下顎上升枝長度；以側面及後前向測顱X光影像，作顱顏面形態之分析；以雙能量式X光骨質密度偵測儀（DXA）測得腰椎之骨質密度；並取得身高、體重資料，以計算身質質量指數（BMI）。統計方法是以卡方統計、多變量迴歸分析，以分析顳顎關節內部紊亂症之相關預測因子。 結果： 三個族群之間的顳顎關節內部紊亂症之診斷及分布有明顯之不同，齒顎矯正科門診女性病人，有64.10%的個體至少一側罹患顳顎關節結構性紊亂，50%的關節罹患內部紊亂症；顳顎關節障礙特別門診女性病人，有96.43%的個體至少一側罹患顳顎關節結構性紊亂，83.04%的關節罹患內部紊亂症；無症狀的平常年輕女性，有45.45%的個體至少一側罹患顳顎關節結構性紊亂，34.85%的關節罹患內部紊亂症。有關節症狀主訴病人，明顯在顳顎關節罹患內部紊亂比例高於需要接受齒顎矯正病人，需要接受齒顎矯正病人又高於沒有關節及齒列不整主訴之人。 迴歸分析的結果發現，顳顎關節髁頭面積愈小、髁頭寬度、長度愈小，罹患顳顎關節結構性紊亂可能性愈高，而且可能進展為較嚴重之不可復位性關節盤異位。骨性三級及二級顎間關係罹患顳顎關節結構性紊亂的發生率較高，而且水平覆咬較大的骨性二級顎間關係，更容易與較嚴重之不可復位性關節盤異位有關。上下顎的不對稱亦容易與顳顎關節結構性紊亂有關，且患側通常較小。 結論： 不同來源的樣本，顳顎關節內部紊亂症之診斷及分布有明顯之不同。而顳顎關節內部紊亂症，與特定的顱顏面形態特徵有關。因此，在各科間應該注意這些顳顎關節內部紊亂的顱顏形態危險因子，以促進病人健康。

Objectives: Prevalence of TMJ internal derangement (ID) in general population is relatively high (up to 32%). TMJ ID is often associated with joint noise, pain during mouth opening, and difficulty in chewing. Problems in TMJ ID possibly include changes in craniofacial morphology and malocclusion. From our previous study, disc displacement without reduction (DDNR) is significantly correlated with low bone mineral density and low body mass index. Therefore, high prevalence rate of TMJ ID and other associated changes may cause major health problems and needs our attention. Diagnosis rate of TMJ ID is under estimated because there is no general physical examination which can evaluate TMJ ID precisely. MRI, being used for correct diagnosis of TMJ ID, costs much and therefore, is not practical to apply on every patient. Thus, an easier and convenient method but with less cost should be developed for diagnosis of TMJ ID. The aim of this study was to explore correlations of TMJ ID and morphological differences of craniofacial structure, and to explore systemic risk factors of TMJ ID. A screening method for TMJ ID with different variables was derived for three populations of patients. Materials and methods: A total of 156 young females (18 to 28 years old) participated in this cross-sectional study. Samples were collected from: 1) TMD department, 2) orthodontic department of NTUH, and 3) general young females without any symptoms of TMD. Both static and dynamic TMJ MRI was used for the correct diagnosis of TMJ ID. Condylar head area (CHA) and ascending ramus height (ARH) were measured on the images from static TMJ MRI. The craniofacial morphology of the subjects was assessed by using both lateral and PA cephalograms. The bone mineral density in the lumbar spines was obtained by using dual energy X-ray absorptiometry (DXA). BMI was calculated using the body height and weight (height/weight2). Chi square and multivariate regression analysis were used for the statistical analyses. Results: There was significant difference in diagnosis and distributions TMJ ID among three populations. In orthodontic department, 64.10% of population was diagnosed with ID at either side of TMJ and 50% of total condyles were diagnosed as TMJ ID. In TMD department, 96.43% of population was diagnosed with ID at either side of TMJ and 83.04% of total condyles were diagnosed as TMJ ID. In general young female population, 45.45% was diagnosed with ID at either side of TMJ and 34.85% of total condyles were diagnosed as TMJ ID. Prevalence of TMJ ID was highest in the population from TMD department, subsequently followed by the population from orthodontic department. The prevalence of TMJ ID in general young females were the lowest but still with one third of the joints affected. Multivariate regression model showed that small condyle head area, narrow condyle width, and short condyle length were associated with higher risks for TMJ ID. The smaller the condyle head was with higher possibility for TMJ ID. Patients with class II and class III skeletal jaw relationships were much prone to have TMJ ID than those with normal one. Especially, asymmetry in upper and lower jaws was with higher risks for TMJ ID. In addition, skeletal class II with large overjet was highly associated with disc displacement without reduction. Conclusion: There were significant differences in diagnosis and distribution of TMJ ID among three populations. TMJ ID was associated with specific changes in craniofacial morphology. Therefore, the characteristics of craniofacial morphology associated with higher risks for TMJ ID should be notified in different clinics for patient health benefits.