牙科常規術式誘發三叉神經心臟反射之風險與機制探討：以李宋迷你豬模型為基礎

Abstract

背景與目的： 三叉神經心臟反射（Trigemino-cardiac reflex, TCR）是一種腦幹反射，當三叉神經受到機械性或化學性刺激時，可能引發一連串生理反應，包括心律不整、心搏暫停、動脈血壓下降、呼吸暫停，以及腸胃蠕動增加等。此反射可能導致顯著的血壓下降與心搏徐緩，嚴重時甚至可能造成昏厥，乃至心跳停止，危及患者生命。儘管TCR在神經外科與眼科等領域中已有廣泛記載，其於牙科處置中的作用與臨床意義仍未被充分釐清。因此，本研究旨在達成以下兩項主要目標： 1. 建立以李宋豬牙科用動物模型，替代因實驗倫理爭議而難以執行的米格魯犬牙科動物模型。 2. 透過李宋豬牙科動物模型來探討常見牙科處置與TCR之關聯性，並評估其風險，提供做為未來臨床醫療之參考。 材料與方法： 本研究分析本研究團隊於2016年至2023年間所執行之一系列實驗性牙科手術所蒐集之生理監測數據。研究對象包括兩隻雄性米格魯犬與六隻李宋迷你豬，旨在評估牠們於接受常見牙科治療期間（如洗牙、根管治療、拔牙與植牙），心跳（Heart Rate, HR）與平均動脈血壓（Mean Arterial Blood Pressure, MABP）之變化情形，藉此系統性的探討牙科常規術式誘發三叉神經心臟反射之風險與機制。 結果： 洗牙過程中未觀察到HR或MABP的顯著變化，屬於TCR低風險治療。相較之下，根管治療的TCR誘發風險最高，其中9.6%的案例出現HR與MABP同時下降超過15%，另有5.8%發生同時下降超過20%。拔牙處置中，在47例中有2.1%案例出現HR與MABP同時下降超過15%，但並無HR與MABP同時下降達20%之情況發生。在植牙手術期間雖未觀察到HR與MABP同時下降超過15%的情況，但手術期間出現超過20%的HR劇烈波動則偶有出現。 結論： 本研究針對四種常見牙科術式（洗牙、根管治療、拔牙與植牙）進行TCR之系統性評估。結果顯示，洗牙過程中生理指標穩定，為TCR風險最低之低風險處置。根管治療則因同時涉及物理性與化學性刺激，為TCR發生率最高之術式，尤以次氯酸鈉沖洗階段最具誘發TCR之風險。拔牙手術亦因機械性刺激導致TCR，雖發生率較低，但仍具臨床意義；而植牙雖未出現符合TCR標準之事件，惟部分個案仍觀察到心跳劇烈波動，顯示潛在風險不可忽視。 此外，TCR之發生具有明顯的生理進程，初期多表現為HR單獨下降；若未能及時中止操作，反應可能進一步惡化，導致HR與MABP同時下降達20%。研究結果顯示，若能於HR單獨下降或HR與MABP同時下降達15%時即時停止操作，多數情況下生理參數可自然恢復；然而，一旦下降幅度同時達20%，則往往無法自行回復，需進行醫療介入處理。 綜合上述發現，建議臨床操作中應於HR下降超過15%時即啟動強化監測機制；若HR與MABP同時下降超過15%，則應立即中止手術操作，待生理參數穩定後再行後續處置。此預警與介入策略有助於降低TCR相關之急性生理風險，進一步提升牙科處置之整體安全性。

Background/purpose: The trigemino-cardiac reflex (TCR) is a brainstem reflex characterized by sudden reductions in heart rate (HR) and mean arterial blood pressure (MABP) following trigeminal nerve stimulation. Although well-documented in other surgical fields, its role during dental procedures remains unclear. This study had two primary objectives: 1. To establish a dental animal model using Lee-Sung miniature swine as an alternative to the Beagle dog model, which has become increasingly difficult to implement due to ethical concerns in animal experimentation. 2. To investigate the association between standard dental procedures and the occurrence of TCR using the Lee-Sung pig model, and to assess the associated risks as a reference for future clinical applications. Materials and methods: This study analyzed physiological monitoring data collected by our research team from a series of experimental dental procedures conducted between 2016 and 2023. The study subjects included two male Beagle dogs and six Lee-Sung miniature swine. The aim was to evaluate changes in heart rate (HR) and mean arterial blood pressure (MABP) during standard dental procedures, including dental scaling, root canal therapy, tooth extraction, and dental implantation. Through this analysis, we sought to systematically investigate the risk and underlying mechanisms of TCR induced by routine dental procedures. Results: No significant changes in HR or MABP were observed during dental scaling, indicating that it is a low-risk procedure for triggering TCR. In contrast, root canal therapy presented the highest risk, with 9.6% of cases showing a simultaneous decrease in HR and MABP exceeding 15%, and 5.8% exhibiting a simultaneous reduction greater than 20%. Among the 47 tooth extraction procedures, 2.1% resulted in a concurrent drop in HR and MABP greater than 15%, but no cases exceeded a 20% simultaneous decrease. During dental implantation, although no instances of simultaneous HR and MABP decrease beyond 15% were recorded, episodes of HR fluctuation exceeding 20% were occasionally observed throughout the procedure. Conclusion: This study systematically evaluated the occurrence of TCR during four standard dental procedures: dental scaling, root canal therapy, tooth extraction, and dental implantation. Physiological monitoring revealed that dental scaling maintained stable HR and MABP, indicating minimal TCR risk. In contrast, root canal therapy showed the highest incidence of TCR, particularly during sodium hypochlorite irrigation, due to combined physical and chemical stimulation. Tooth extraction also induced TCR in a small proportion of cases through mechanical stimuli. Although no definitive TCR events were recorded during dental implantation, transient HR fluctuations exceeding 20 % were occasionally observed, suggesting potential physiological responses. The onset of TCR followed a progressive pattern, typically beginning with HR reduction alone. If the procedure continued, simultaneous reductions in HR and MABP could reach 20 %, often requiring medical intervention. Early termination of the procedure when HR or both HR and MABP decreased by 15 % allowed for spontaneous recovery in most cases. Based on these findings, it is recommended to initiate enhanced monitoring when HR decreases by more than 15 %, and to suspend treatment if both HR and MABP decrease beyond this threshold. This approach may help prevent acute complications and improve the safety of dental procedures.