- 學位論文
鍶離子濃度梯度對於牙釉質去礦化之影響：體外實驗
Effect of Concentration Gradient of Strontium Ion on Enamel Demineralization: an in vitro study
摘要
目的：牙齒去礦化問題隨盛行率上升日益受到重視，本實驗目的在於以體外實驗探討不同酸度下鍶離子濃度梯度對於降低牙釉質去礦化程度的影響。 材料與方法：使用檸檬酸當作酸性來源，並以檸檬酸鈉滴定成pH 2.5、pH 3.5、pH 4.5、pH 5.5 四種酸度，分別調配成鍶離子濃度為 10-2 M、10-3 M、10-4 M等三種濃度的含鍶溶液，與一組不含鍶者當成實驗對照組，總共16組，使用48片人類牙釉質樣本。樣本浸泡30毫升溶液3分鐘後，使用去離水沖洗樣本25 秒，以感應耦合電漿質譜儀分析溶液內磷離子含量、以維氏微小硬度計測量樣本表面硬度變化、使用雷射掃描共軛焦顯微鏡以及電子掃描顯微鏡觀察表面影像、以能量色散光譜儀偵測對照區及實驗區的牙釉質表面元素含量。 結果：在 pH 3.5以及pH 5.5下鍶離子濃度10-2 M的組別，溶液中檢出磷離子析出量顯著減少，在pH 2.5以及pH 4.5下鍶離子濃度10-2 M的組別，溶液中檢出磷析出量有減少但未達到顯著差異。在各組 pH 值下，添加10-2 M鍶離子能降低牙釉質表面硬度下降量，且在pH 2.5以及pH 4.5下達到顯著差異。在各組pH下，添加鍶的各組牙釉質表面之鍶元素含量有微量的上升，隨著酸性溶液中添加的鍶離子濃度增加，牙釉質表面鍶元素量並未隨著增加。 結論：在本實驗發現，在酸性溶液中添加一定濃度的鍶離子，能有效降低酸性溶液對牙釉質所造成的影響。鍶離子降低酸性環境對牙釉質之影響，可能是經由史吞層以及再礦化作用來達對於牙釉質的保護效果。
並列摘要
Objectives: With the rising prevalence, tooth decalcification has attracted more attention gradually. The aim of this study was to evaluate the effect of concentration gradient of strontium ion on tooth decalcification in vitro. Materials and methods: Citric acid was chosen as acid source in the present study. The pH value was adjusted by Sodium citrate to pH values of 2.5, 3.5, 4.5 and 5.5. Strontium chloride dehydrate was added to the former solutions to achieve a strontium concentration of 10-2 M, 10-3M, 10-4M. No strontium chloride dehydrate was added to the control groups. Forty-eight enamel discs made of human extracted teeth were divided into sixteen groups. Each enamel samples was then exposed to 30 ml of the appropriate solution for 3 minutes individually. After the exposure, the solution was tested by inductively coupled plasma mass spectrometer (ICP-MS) to detect the concentration of phosphorus and the samples were rinsed in gently running distilled water for 25 seconds. The samples were then analyzed of surface hardness change and surface structure by confocal laser scanning microscope, Vickers’ hardness tester and SEM. Energy dispersive spectrometer was used for the elemental analysis of the samples. Results: At pH 3.5 and pH 5.5, the addition of 10-2M strontium resulted in significantly decreased detection of phosphorus in the solution. At pH 2.5 and pH 4.5, the addition of 10-2M strontium resulted in less phosphorus released in the solution. At each of the pH values, the addition of strontium ion decreased the amount of surface hardness loss, especially at pH2.5 and pH4.5. At each of the pH values, the addition of strontium ion result in small increase of strontium element on enamel surface. The amount of strontium element on enamel surface not increase when add more strontium ion. Conclusion: By adding strontium to acid solution, the acid solution showed less effect on enamel samples. The protection mechanism of strontium ion on enamel against acid solution was due to Stern layer and precipitation of strontium ion and ion released from dissolved enamel.