針式奈秒短脈衝低溫常壓電漿對變形鏈球菌與糞腸球菌之抗菌效應研究

Abstract

口腔疾病與微生物感染感有高度的相關性，以目前的傳統治療方式，可利用機械性清創 (mechanical preparation)以及化學性沖洗(chemical irrigation)降低細菌量，但無法達到完全殺菌之目標，同時可能產生副作用，例如使用化學藥劑意外造成的組織傷害。而電漿系統之發展，已進展到可於常溫常壓下操作之特性，其具殺菌力之產物半衰期短，不易累積毒性，故有應用於牙科之領域潛力。變形鏈球菌(Streptococcus mutans)為兼性厭氧菌，為口腔中齲齒之主要致病菌，並且存在於感染之根管內，糞腸球菌 (Enterococcus faecalis)為根管感染中持續性感染(persistent infection)以及治療失敗案例中的優勢菌種，故選定兩種細菌作為殺菌處理之標的，採用的方式為將細菌塗布於培養基後以電漿系統進行殺菌測試，記錄抑菌圈直徑 (Diameter of inhibition zone)進行效能分析。本實驗採用的新型電漿系統，特色為短脈衝電源輸出，並且能於常溫常壓下運作，選用氦氣、氦氣混合氧氣為兩種工作氣體，可調控之參數為氣體流量、測試時間以及測試距離，選定之參數範圍以臨床上可行之範圍做為限制條件，研究結果顯示: (1)流量為決定殺菌效能的最主要因素，定量方面對於抑菌圈直徑之影響大於其他條件；定性方面，若流量大於1.0slm(standard liter per minute)，則會產生抑制不全之現象，於氦氣、氦氣混合氧氣之組別皆可於抑制圈之中心發現無法抑制的菌落。(2)時間以及距離在其他條件固定之前提下，與抑菌圈直徑具有線性關係。(3)氦氣混合氧氣之組別:於流量為0.5至1.0slm之前提下，最低有效殺菌時間為15秒。(4)純氦氣組別:於流量為1.5slm之前提下，最低有效殺菌時間為60秒。(5)電漿殺菌之效能於兩個菌種間無顯著性之差異(6)以氦氣混合氧氣為輔助氣體之組別，殺菌效能明顯高於單純使用氦氣之組別。由上述之結果可得知，新型電漿殺菌系統，若以臨床上可行之參數範圍內於培養基上進行操作，可見顯著之殺菌效能，但仍需進一步完整之研究，驗證其對於生物膜(biofilm)以及實際應用於人體之效能。

Oral disease is highly related with microbiological infection. In several decades, treatment of dental infection was accomplished by mechanical preparation and chemical irrigation. However, primary goal of treatment is to decrease the total number of bacteria, but total elimination of bacteria is impossible; In addition, accident may occurred during chemical irrigation and may damage to human tissue such as skin, mucosa, periapical tissue, etc. In recent years, plasma system can operate in atmosphere condition at room temperature and pose a potential to application in dental treatment. In this study, Streptococcus mutans, and Enterococcus faecalis which are important oral pathogens were selected as a target to perform antibacterial test with plasma system. Diameter of inhibition zone was measured in each condition for the purpose of quantitative analysis. In this study, Needle Type Nano-second Pulsed Atmospheric-pressure Cold Plasma system was established and use pure helium and helium with oxygen mixture as two kinds of working gas; Controllable conditions including flow(gas flow rate), time(plasma exposure time), distance(applied distance of plasma). With respect to clinical limitation, all condition was set to a limited range. Result shows: (1)Flow is a determinant factor of antibacterial effect, quantitative study shows diameter increases with flow; but in qualitative study, with increase of flow(higher than 1.0 slm),incomplete bactericidal effect was noted over center zone of inhibition. (2)With fixed condition of flow, linear correlation is significant between time and diameter also significant between distance and diameter. (3)Group of Helium with oxygen mixture: with limited condition of flow(0.5~1.0 Standard Liter per Minute), minimum effective time is 15 seconds.(4)Pure helium group :with limited condition of flow(1.5 Standard Liter per Minute), minimum effective time is 60 seconds (5) No significant difference between two species of bacterial in bactericidal effect(6)With addition of oxygen into Helium, obvious higher bactericidal effects was noted compared with groups of pure helium. In conclusion, this new plasma system has an effective bactericidal effect on oral pathogen within limited conditions which are applicable in clinical treatment. Further study is indicated with biofilm condition and experiment in vivo.