雷射都卜勒微流影像儀診斷外傷牙髓活性之效能分析

The efficacy assessment of laser doppler imager in diagnosing the pulp vitality after dental trauma

李惠娜(Hui-Na Lee)

指導教授 ： 莊富雄

高雄醫學大學/口腔醫學院/牙醫學系碩士班/碩士(2020年)

摘要

研究背景：牙髓狀態的檢測可分為牙髓敏感性測試與牙髓活性測試。臨床常使用的敏感性測試如電髓試驗（electric pulp test, EPT）是通過刺激受測的牙髓牙本質複合體中的Aδ神經纖維，使其迅速產生尖銳、短暫麻刺感，依靠患者自身的主觀感受對測試做出反饋，然而外傷牙齒因纖維母細胞降解而暫時性神經麻痺，常使電髓測試呈現偽陰性，造成對牙髓真實健康狀態的判讀錯誤，影響後續的診斷與治療計畫。雷射都卜勒微流影像儀（laser doppler imager）利用雷射光偵測牙髓血管，其移動的紅血球散射光束後產生頻移（doppler shift），呈現客觀的數據、波形與影像，以灌注單位(perfusion units（PU））換算訊號代表紅血球細胞的濃度及流體速度，能真實反應牙髓的活性。
研究目的：對於外傷患者，若能更精準評估外傷後的牙髓活性，避免不必要的根管治療，將有助於增進患者的生活品質和提升醫療效益。本研究即是比較雷射都卜勒微流影像儀與臨床最常使用的電髓試驗評估外傷牙的診斷效益。
材料與方法：選取2018-2019年間於高雄醫學大學體系醫院牙科門診進行牙髓活性評估患者共七人。過程為單一操作者，針對外傷患者進行常規檢查以及電髓測試與雷射都卜勒微流影像儀評估。統計方法包含Kappa一致性檢定、卡方檢定，並探討患者敘述症狀、醫師診斷分類與一年後牙髓狀態相關性，以及不同活性測試敏感度、特異性及誤診率等，進一步透過接收者操作特徵曲線分析其面積與最佳切點。
結果：不論是透過患者敘述的症狀（p=0.043）或經由醫師診斷（p=0.018）後分類，嚴重外傷組與輕微外傷組相比，雷射都卜勒流量數值都有顯著的差異：當外傷嚴重程度越高，其雷射都卜勒微流影像儀流量數值則越低。Fisher's精準檢定則顯示患者敘述、醫師診斷分類與一年後牙髓狀態皆有顯著的相關性（p=0.000）。醫師透過EPT診斷外傷牙髓的情況，Kappa係數為0.67和一年後牙髓狀態具有高度的一致性（p＜0.001）；醫師透過雷射都卜勒微流影像儀診斷外傷牙髓情況，Kappa係數為0.85，和一年後牙髓狀態幾乎一致（p＜0.001）。採用麥內瑪卡方檢定來檢定不同活性測試與一年後牙髓狀態的差異性時，使用EPT對外傷牙髓活性的預測與一年後牙髓狀態，達顯著差異（p=0.05）；而使用雷射都卜勒微流影像儀對外傷牙髓活性的預測與一年後牙髓狀態，則無顯著差異（p=0.125），表示外傷以初期雷射都卜勒微流影像儀診斷牙髓活性與一年後牙髓狀態較為一致。根據ROC曲線圖以及輸出報表，EPT曲線下面積（AUC）是0.94，雷射都卜勒微流影像儀曲線下面積（AUC）為1，最佳切點值為31.55，兩者均屬於鑑別度極佳的診斷工具。
結論：雷射都卜勒微流影像儀及電髓測試皆可做為診斷外傷牙髓壞死的工具，其中微流影像儀突破傳統敏感性測試的困境，結合臨床和X光片的檢查，更即時且準確地評估外傷的牙髓活性。有別以往的都卜勒微流儀(doppler flowmetry)，本研究是首篇將雷射都卜勒微流影像儀（laser doppler imager）應用於牙科領域的文獻，未來則需要投入更多研究與相關訓練去謹慎闡述雷射都卜勒數據，並以大樣本的資料分析其最佳切點，為治療方案的選擇提供適宜的臨床依據。

關鍵字

牙髓活性 ； 雷射都卜勒 ； 影像儀 ； 牙科外傷

並列摘要

Background: Tests for detecting the condition of the dental pulp can be divided into pulp sensitivity test and pulp vitality test. Commonly used sensitivity tests in the clinical setting, such as the electric pulp test (EPT), stimulate Aδ nerve fibers in the pulpo-dentinal complex and rapidly produce a sharp, transient numbness. The results of these tests depend on a patient’s subjective feedback. However, teeth that have experienced trauma are temporarily paralyzed due to fibroblast degradation, which often leads to a false negative result on the EPT, thereby causing misinterpretation of the actual health status of the pulp and affecting subsequent diagnosis and treatment plans. By contrast, doppler imaging measures pulp vitality by using laser light to detect blood vessels in the pulp. Moving red blood cells within the vessels scatter the laser beam, generating a Doppler shift that results in objective data and waveforms. Signals expressed as perfusion units (PU) represent the concentration and fluid velocity of red blood cells, allowing for a more accurate measurement of pulp vitality.
Research objectives: For patients who have experienced traumatic dental injuries, a more accurate assessment of pulp vitality can help prevent unnecessary root canal treatment and improve patient quality of life and treatment benefits. The purpose of this study was to evaluate and compare the diagnostic benefits of doppler imaging and the EPT in cases of dental trauma.
Materials and methods: A total of seven patients were selected for pulp vitality evaluation at the dental clinic of Kaohsiung Medical University Hospital between 2018 and 2019. Routine examination, EPT and doppler evaluation, were performed for patients with traumatic injury, and the procedures were performed by a single operator. Statistical methods utilized included the Kappa consistency test and the chi-square test. The correlation between patient self-reported symptoms, diagnostic classification by physicians, and follow-up examination findings were investigated. In addition, the receiver operating characteristic (ROC) curve, the area under the curve (AUC), and the optimal cut-off points were used to analyze the sensitivity, specificity, and rate of misdiagnosis between different vitality tests.
Results: There was a significant difference in doppler flow values between the severe trauma group and the mild trauma group, regardless of patient self-reported symptoms (p = 0.043) or physicians’ diagnostic classification (p = 0.018): Doppler flow value decreased as the severity of trauma increased. Fisher’s exact test showed a significant correlation between patient self-reported symptoms, physician’s diagnosis, and follow-up examination findings (p = 0.000). For physicians diagnosing pulp trauma using an EPT instrument, the Kappa coefficient was 0.67 and 1-year pulpal status findings were highly consistent (p＜0.001). For physicians diagnosing pulp trauma using a doppler instrument, the Kappa coefficient was 0.85 and 1-year pulpal status were nearly completely consistent (p＜0.001). When using the McNemar chi-square test to compare the difference between various vitality tests and 1-year follow-up result, prediction of pulp vitality following trauma using the EPT instrument combined with 1-year pulpal status reached the level of significance (p = 0.05). Prediction of post-trauma pulp vitality using the doppler instrument with 1-year pulpal status did not reach the level of significance (p = 0.125), indicating that prediction of pulp vitality using doppler was consistent with follow-up examination findings. According to the ROC curve plot and the report output, the AUC for EPT was 0.94, the AUC for doppler was 1, and the optimal cut-off value was 31.55, indicating that both were superior diagnostic tools.
Conclusion: Both doppler and EPT can be used as tools for diagnosing traumatic pulp necrosis. Blood flow imaging instruments overcome the problems with traditional sensitivity testing, and when combined with clinical and X-ray examinations, allow for a more timely and accurate assessment of pulp vitality in the setting of dental trauma. The present research report is the first paper evaluating the efficacy of laser doppler imager different from doppler flowmetry in dental field. In the future, ongoing research and related training are necessary for accurate interpretation of doppler data. Large data samples should be analyzed diligently to find the optimal cut-off point in order to provide an appropriate clinical basis for the selection of treatment options.

並列關鍵字

pulp vitality ； laser doppler ； imager ； dental trauma

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