以溶膠-凝膠技術研發孔洞材料應用於治療牙本質過敏症

Development of Sol-Gel Porous Materials for the Treatment of Dentin Hypersensitivity

康舒涵(Shu-Han Kang)

指導教授 ： 林俊彬

共同指導教授 ： 藍萬烘

國立臺灣大學/醫學院/臨床牙醫學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.10298

摘要

牙本質過敏症為臨床上常遭遇的問題，目前以封閉牙本質小管為主要治療方式之一。市售牙本質黏著劑及去敏感劑號稱效果卓著，但在臨床使用上仍無法達到持久之療效。然而本團隊研發之DP-bioglass已證實可有效進入並封閉牙本質小管，惟其反應需三天以上，於臨床應用上有其困難。應用奈米技術可製成粒徑小具有孔洞之材料，藉由高表面積可提升材料反應能力，因此我們以溶膠-凝膠(sol-gel)法及含浸法(impregnation)製成材料，以期達到縮短反應時間、方便臨床使用之目標。本研究之第一部份將測試市售之黏著劑及去敏感劑對於牙本質小管之封閉效果。結果發現，除了DP-bioglass以外，其他三種材料Xeno R III、One coat R bond、Seal&Protect R都與管周牙本質之間有縫隙之產生，且無論在封閉深度及百分比方面，DP-bioglass都優於其他三種材料。第二部分則是運用溶膠-凝膠技術，控制催化劑（硝酸、氫氧化鈉、磷酸）及溫度（熱重分析法評估鍛燒溫度）等製成條件以合成生醫玻璃，藉由掃描式電子顯微鏡的觀察、X光繞射分析、能量散射光譜儀元素分析等研究方法，分別進行材料性質分析，評估材料與磷酸混合後之製劑對於封閉牙本質小管的效果，進而推測材料的作用機轉。材料分析部分：硝酸催化之溶膠-凝膠生醫玻璃其化學組成與加入之原料比例相似，表示化學反應完全，其結構為具有200nm~1μm之孔洞，而氫氧化鈉、磷酸催化組之化學組成與加入之原料比例不完全相同，表示化學反應未臻完全，其結構前者為棉絮狀鬆散之外型，後者為顆粒聚集之外形。溶膠-凝膠生醫玻璃粉末與30%磷酸作用後有結晶物質產生，以Ca(H2PO4)2•H2O為主要結晶相，此化合物之水中溶解度高容易滲透進入牙本質小管，反應性高。此外將硝酸、氫氧化鈉、磷酸催化之溶膠-凝膠生醫玻璃及DP-bioglass與30%的磷酸以1:2（g/ml）的比例混合調拌，分別塗佈於40片牙本質切片上，十分鐘後以大量清水將表面材料移除，使用掃描式電子顯微鏡觀察材料進入牙本質小管之深度、封閉百分比與密貼程度發現硝酸催化組之表現優於其他組，最深可達104.90μm，封閉百分比達65.4%且與管週牙本質間緊密貼合。第三部分：使用溶膠-凝膠法合併含浸法锻燒製作含氧化鈣之中孔洞二氧化矽複合材料。在材料分析方面結果顯示為具有排列整齊均勻之40nm中孔洞二氧化矽，其內含有鈣離子，此材料屬非結晶性，其粉末與磷酸作用後有結晶物質產生，由濃度為20%、30%的磷酸所調配之生醫玻璃製劑以Ca(H2PO4)2•H2O為主要結晶相，而由濃度為10%的磷酸及蒸餾水所調配者則以CaHPO4•2H2O為主要結晶相，Ca(H2PO4)2•H2O溶解度較CaHPO4•2H2O高容易滲透進入牙本質小管，反應性高。由牙本質小管封閉效果之觀察，以30%磷酸混合之氧化鈣中孔洞二氧化矽之表現最佳，深度最深可達105.26μm，封閉百分比為75.6%且與管周牙本質間緊密貼合。結論：應用溶膠-凝膠法以硝酸作為催化劑製成之生醫玻璃與合併含浸法製成含氧化鈣之中孔洞氧化矽複合材料，皆為具有奈米等級孔洞之材料，可於10分鐘內有效封閉牙本質小管，具有治療牙本質過敏症之潛力。

關鍵字

溶膠-凝膠技術 ； 生醫玻璃 ； 中孔洞 ； 牙本質過敏症

並列摘要

Our previous studies showed that most of commercialized bonding agents used for the treatment of dentin hypersensitivity were inefficient in the persistent time. Our research group have proved that DP-bioglass mixed with 30 % phosphoric acid could form well-occlusive, recrystallized precipitants inside the dentinal tubules after 3 days. However , it is not practical for clinical use. We made materials which were nano-sized particles, high surface area and high porous in nature by nano technology. The specific aims of this study were to evaluate the efficacy of tubule occlusion with the commercialized bonding agents and a desensitizer, and to produce the porous biomaterials with shorter reaction time for treatment of dentin hypersensitivity by sol-gel and impregnation methods.
In part I, we examed the efficacy of the tubule occlusion of the commercialized bonding agents and a desensitizer as well as DP-bioglass by scanning electron microscopy (SEM) observation. In part II, we developed the sol-gel bioglass with the catalyst HNO3,NaOH or H3PO4 at 800℃ followed by mixing with 30% phosphoric acid. In part III, we produced nano@CaO mesoporous silica by modified sol-gel and impregnation methods. Four nano@CaO mesoporous silica pastes were prepared from nano@CaO mesoporous silica powder by mixing with distilled water, 10%, 20%, and 30% phosphoric acid, respectively. In part II and part III, the microstructure, phase transformation, and overall qualitative analysis of materials were conducted by SEM, X-ray diffractometer (XRD), and energy dispersive spectrometer (EDS). TEM was applied in Part III for the measurement of pore size.
The results indicated that: (1) gaps were noted between peritubular dentin and resin tags of bonding agents but no gap was found between DP-bioglass and the tubules wall. (2) HNO3 catalyzed sol-gel bioglass was the most porous under SEM observation. (3) pore size of nano@CaO mesoporous silica were 40nm. (4) The chemical compositions of HNO3 catalyzed sol-gel bioglass was similar to DP-bioglass. (5)Ca(H2PO4)2•H2O was the major crystalline phase in the HNO3,NaOH or H3PO4 catalyzed sol-gel bioglass mixed with 30 % phosphoric acid. However, the major crystalline phase in the DP-bioglass mixed with 30 % phosphoric acid was CaHPO4•2H2O. (6) Ca(H2PO4)2•H2O was the major crystalline phase observed in the nano@CaO mesoporous silica mixed with 30 % and 20 % phosphoric acid. However, the major crystalline phase of the bioglass mixed with distilled water and 10 % phosphoric acid was CaHPO4•2H2O. (7) well-occlusive, recrystalline precipitants could noted in dentin tubules after sol-gel bioglass pastes and nano@CaO mesoporous silica pastes applied on dentin surface. (8) in 10 mins, HNO3,NaOH or H3PO4 catalyzed sol-gel bioglass pastes demonstrated higher percentage of tubular occlusion and penetration depth compared with DP-bioglass. 65% of dentin tubules were occluded by the recrystalline precipitants of HNO3 catalyzed sol-gel bioglass paste and the penetration depth in dentin tubule was 104.9μm. The percentage of tubule occlusion and penetration depth of nano@CaO mesoporous silica mixed with 30% H3PO4 for 10 minutes were significantly higher than nano@CaO mesoporous silica mixed with distilled water,10% or 20% H3PO4. The maximum depth was 105.26μm and the percentage was 75%.
Conclusion: Both of the sol-gel bioglass and nano@CaO mesoporous silica were porous materials, they could occlude the dentinal tubules in 10 minutes. These new porous materials have potential for the treatment of dentin hypersensitivity.

並列關鍵字

Sol-gel technique ； bioglass ； mesoporous ； dentin hypersensitivity

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