螢光劑對牙科陶瓷材料之螢光反應影響

Abstract

自然牙會散發出淺藍色之螢光，市面上許多廠牌的瓷粉亦添加螢光劑以模擬自然牙的螢光效果，但是文獻上對於自然牙和瓷粉的螢光比較並不多，而且在製作贗復物時沒有類似比色板的工具作為修復材料與自然牙之間的螢光強弱比較。因此，當前牙有裝置陶瓷假牙的人們身處舞廳等常用紫外燈照明的場所時，即表現出與他們的假牙和自然牙不同的螢光反應強度，甚至發出不同顏色的螢光。不同廠牌的瓷粉所呈現的螢光強度都不同，甚至相同廠牌的不同顏色瓷粉和不同層次的瓷粉的螢光效果也都不一樣，本實驗目的旨在檢測不同廠牌的瓷粉及相同廠牌不同顏色的瓷粉內含的螢光元素，藉以了解螢光元素比例和其燒瓷後的螢光強度之關係，並利用外添加的方式把螢光劑加入市售瓷粉，觀察其燒瓷後螢光反應和顏色之變化；最後將螢光劑加入合成的瓷粉，觀察燒瓷後的螢光反應；並假設隨著加入的螢光劑比例增加，螢光強度會增強。 實驗選用五個廠牌A1 Enamel瓷粉( Procera AllCeram, Cercon Zirconia, IPS Empress II, Noritake Ex-3以及Shofu Vintage) 及Procera AllCeram 的A1、B4 Body 和Shofu Vintage的B4 Enamel、Body瓷粉，總共為九種瓷粉樣本， 利用感應式偶合電漿(ICP-MS)進行檢測。把Empress II A1 Enamel 瓷粉分成10組，第一組不加入螢光劑，第二組到四組分別加入CeO2 1~3%，第五組到第七組分別加入Eu2O3 1~3%，第八組加入Eu2O3 1%和CeO2 1%，第九組加入Eu2O3 1.5%和CeO2 0.5%，第十組加入Eu2O3 0.5%和CeO2 1.5%，每一組均燒製三個方形樣本樣本，並利用光譜儀內進行激發光譜以及放射光譜的測量與記錄，觀察加入螢光劑後瓷塊螢光效果的變化；利用數位比色機(ShadeEye-NCC)進行電腦比色，計算加入螢光劑和未加螢光劑的瓷塊兩者顏色的差異。另將螢光劑加入合成的瓷粉中，觀察其燒結後之螢光現象。 實驗結果與結論：(一) 五個市售廠牌之瓷粉，其內含的主成份均相同，其中內含的螢光元素均是鑭系元素，如：鈰(Ce)、銪(Eu)、釓(Gd)、釔(Y)等，且大多廠牌含有不只一種的螢光元素。(二)同廠牌或不同廠牌瓷粉燒結後的螢光強度，和其所內含的螢光元素含量並不成正比，因為螢光劑有其最佳濃度，即濃度淬滅效應。(三) 加入CeO2使放射光譜波峰之波長偏移至400 nm，螢光強度亦會降低。加入Eu2O3螢光強度會隨加入的Eu2O3增加而有上升的趨勢，此現象符合我們預期的假設。而添加CeO2或Eu2O3螢光劑對於瓷粉燒瓷後的顏色影響都在肉眼無法區別的範圍之內。(四)添加CeO2至合成瓷粉中，並沒有呈現螢光效果；添加Eu2O3至合成瓷粉則呈現粉紅色螢光。

The natural teeth emit a light blue fluorescence under the exposure to ultraviolet and many commercial dental porcelains added the chemical activators for mimic the fluorescence of the natural teeth. But the literature to the fluorescence of the teeth and dental porcelains were few, also there is no guide for comparing the fluorescence of restorative materials to natural teeth. People with anterior prostheses may present different fluorescence from their natural teeth when they go to nightclubs or discotheques with ultraviolet illuminations. Neither the different dental porcelain systems nor the different layers or colors of the same system present the same fluorescence. The purposes of this experiment were to identify the chemical activators in commercial dental porcelains, to analyze the relationship between the fluorescence intensity and the proportions of the chemical activators in the dental porcelains, and then adding the chemical activators into commercial dental porcelains and observing the changes in fluorescence after firing sequence. Nine dental porcelains, including: A1 enamel porcelain of the five systems (Procera AllCeram, Cercon Zirconia, IPS Empress II, Noritake Ex-3 and Shofu Vintage) , A1 and B4 body of the AllCeram system, B4 enamel and body of the Shofu system, were used as the samples for the ICP-MS testing. Set up ten groups and each group had 2g of the Empress II A1 enamel powders. Added the CeO2 into second to fourth group with different percentage from 1~3% and added the Eu2O3 into fifth to seventh group with different percentage from 1~3%. Added Eu2O3 1% and CeO2 1% into eighth group, Eu2O3 1.5%and CeO2 0.5% into ninth group, Eu2O3 0.5% and CeO2 1.5% into ten group. Each group made into three sample disks, then the excitation and the emission spectrum of the samples were recorded by using the spectrofluorometer. All the samples were also scanned by spectrophotometer (ShadeEye- NCC) and calculated the differences in the color by adding chemical activators. Experimental results: (1)The main inclusions with the five commercial porcelain systems were similar revealed by the resulted of ICP-MS. The chemical activators of the porcelains were all rare earth oxides such as: Ce, Eu, Gd and Y. More than one chemical activator of fluorescence were observed in most commercial dental porcelain systems. (2) The fluorescence intensity did not show a direct relation with the proportions of the chemical activators in the commercial dental porcelains. (3) Adding CeO2 into the Empress II shifted the emission spectrums to 400 nm and decreased the fluorescence intensity and adding Eu2O3 into the Empress II increased the fluorescence intensity. The color changes of the samples after adding the chemical activators were visually acceptable. (4)Adding CeO2 into our synthetic dental porcelain did not show the fluorescence and adding Eu2O3 showed the pink fluorescence. Conclusion: Different proportion of chemical activators can be identified in commercial dental porcelains. Adding chemical activator into commercial porcelains may affect the fluorescence intensity without changing the shade visually. Further investigations are needed.