偶氮化合物增強過碳酸醯胺在診間牙齒美白中的可行性研究

Abstract

牙齒染色問題主要源於飲食、生活方式和年齡等因素，近年來，愈來愈多人為了追求完美的面部表情與笑容，傾向牙醫師尋求專業的牙齒美白治療，然而，傳統的過氧化物類牙齒美白劑大多使用高濃度的過氧化氫（Hydroxy peroxide, H2O2），在其分解過程中產生的過氧化物常常導致患者牙齒敏感（Tooth sensitivity）、脫礦（Demineralization）和機械強度下降等問題。為了克服這些不良效應，本研究旨在開發一種新型的牙齒美白劑，以偶氮化合物作為關鍵成分。這種新型美白劑的設計目標在於減輕傳統美白劑中的過氧化物成分造成的副作用，同時實現有效且安全的美白效果。因此，本研究挑選偶氮二異丁腈（2,2′-Azobis(2-methylpropionitrile), AIBN）作為熱敏劑，用於引發自由基反應，偶氮二異丁腈的優點在於具有優越的氧化能力，可以針對長鏈色素分子進行氧化，達到色素降解的效果，並且預期於分解過程中的含氮自由基並不會與牙齒中的有機與無機物質發生反應，同時降低對牙齒組織的影響，並使用4 wt%之過氧化醯胺作為氧氣來源，用以引發活性氧分子循環產生，加強長鏈色素分子的氧化反應。因此本研究預期可使用偶氮化合物的牙齒美白劑能夠減輕傳統牙齒美白過程中的副作用。此外，通過比較傳統過氧化氫漂白劑和偶氮化合物漂白劑的效果，分析了新型漂白劑在牙齒美白效果上的優勢。目前實驗結果表示，偶氮化合物漂白劑在CIELAB顏色分析中的色差數值顯著上升，∆E值差異達到了25.67，與對照組有明顯差異，證實本研究製備之牙齒漂白劑可以有效地漂白牙齒。在牙齒漂白前後牙釉質表面分析中，經由SEM觀察牙齒表面形貌，可以發現不同於HP漂白處理後的牙齒表面有明顯損傷，本研究製備之牙齒漂白劑可以維持牙齒平坦的表面形貌，顯示牙齒表面仍然保持整體的完整性，降低漂白處理之脫礦現象。在細胞毒性測試中顯示，本研究所製備之牙齒漂白劑是一種低細胞毒性之材料。因此，本研究中所開發的偶氮化合物材料作為牙齒美白劑有其之優勢與前景所在。

Tooth staining is mainly caused by factors such as diet, lifestyle and age. In recent years, more and more people tend to seek professional tooth whitening treatments from dentists in order to pursue perfect facial expressions and smiles, however, most of the traditional peroxide-based tooth whiteners use a high concentration of Hydrogen peroxide (H2O2), which produces peroxides during its decomposition process. During the decomposition process, peroxides are produced, which often lead to problems such as tooth sensitivity, demineralization, and loss of mechanical strength. To overcome these undesirable effects, the present study aimed to develop a novel tooth whitening agent using azo compounds as key components. This new whitening agent is designed to reduce the side effects caused by the peroxide components in conventional whitening agents, while achieving effective and safe whitening results. Therefore, in this study, azobisisobutyronitrile (2,2′-Azobis(2-methylpropionitrile), AIBN) was selected as a thermosensitizer to trigger the free radical reaction. The advantage of azobisisobutyronitrile is that it has superior oxidizing ability, which can be oxidized against long-chain pigment molecules, and achieve pigmentation degradation, and it is expected that the nitrogenous free radicals will not be mixed with those in the teeth in the process. It is also expected that the nitrogen-containing free radicals during the decomposition process will not react with the organic and inorganic substances in the teeth, and the effect on the dental tissues will be reduced. 4 wt% of carbamide peroxide was used as the source of oxygen, which was used to trigger the cyclic generation of reactive oxygen molecules to enhance the oxidation of the long-chain pigment molecules. Therefore, it is expected that the use of azo compounds as tooth whitening agents can reduce the side effects of conventional tooth whitening processes. In addition, by comparing the effects of conventional hydrogen peroxide bleaching agents with those of azo compound bleaching agents, the advantages of the new bleaching agents in terms of tooth whitening effects were analyzed. The current experimental results showed that the azo compound bleaching agent showed a significant increase in the color difference value in the CIELAB color analysis, and the difference in the ∆E value reached 25.67, which was significantly different from that of the control group, confirming that the tooth bleaching agent prepared in the present study can effectively bleach the teeth. In the surface analysis of enamel before and after bleaching, the surface morphology of the teeth was observed by SEM, and it was found that, unlike the HP bleaching treatment, the surface of the teeth was obviously damaged, and the dental bleach prepared in this study could maintain the flat surface morphology of the teeth, which demonstrated that the surface of the teeth still retained the overall integrity, and the demineralization of the bleaching treatment was reduced. The cytotoxicity test showed that the dental bleach prepared in this study is a low cytotoxic material. Therefore, the azo compound developed in this study will be advantageous and promising as tooth whitening agents.