研發含氧化鈣中孔洞二氧化矽治療牙本質過敏症：以液體流動模組評估效果

Development of nano@CaO mesoporous silica for treatment of dentin hypersensitivity:permeability assessment by fluid flow model

陳虹君(Hong-Jiun Chen)

指導教授 ： 林俊彬

國立臺灣大學/醫學院/臨床牙醫學研究所/碩士(2007年)

https://doi.org/10.6342/NTU.2007.00213

摘要

在牙科臨床的經驗中，牙本質過敏症是常見的主訴，並且往往無法完全消除症狀，雖然有相當多的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立即或是持久之療效。本團隊研發之DP-生醫玻璃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，於臨床應用上有困難。使用奈米技術可製成粒徑小且具有孔洞之材料，藉由高表面積可提升材料反應能力，因此我們以含浸法製成奈米孔洞材料，以期達到縮短反應時間與方便臨床使用之目標；並且使用液體流動模組測試牙本質滲透性，評估不同材料對牙本質的封閉效果。本研究首先製作含氧化鈣中孔洞二氧化矽的粉末，將之與30 %磷酸使用不同水粉比調拌，然後觀察製劑的狀態變化。經由穿透式電子顯微鏡觀察，此孔洞材料呈現均勻之圓球體，平均直徑小於50 nm，並且具有15 nm 之孔洞，的確為體積十分微小之孔洞奈米顆粒；以不同水粉比混合磷酸與含氧化鈣中孔洞二氧化矽，分別將液狀至膠狀而至固態所歷經時間，進行記錄與觀察，最後依據可操作時間長短以及磷酸使用量，選定水粉比3：1 (mL/g) 作為本研究之調配方式。接下來運用二種方法來評估去敏感材料對牙本質小管的封閉效果，第一種方式為直接測試牙本質滲透性，本團隊參考Pashley 的水力導率概念，自行架設液體流動模組，透過量測液體流速，比較不同材料減少牙本質滲透性之能力；而另一種衡量牙本質封閉程度之方式，即為大家常用的電子顯微鏡觀察法，檢視小管堵塞物質進入小管之深度，以及與管周牙本質之密合程度。本研究比較市售材料、DP-生醫玻璃及含氧化鈣中孔洞二氧化矽三種材料，其中含氧化鈣中孔洞二氧化矽表現最優異，能使牙本質滲透性降低至19.1 %，並且在掃描式電子顯微鏡觀察下，結晶可深達牙本質小管100 μm 以上，並且與管壁之間完全密合。本研究也測試牙本質小管朝外壓力存在與否，對於三種材料封閉小管能力之影響，而由結果發現，市售材料、DP-生醫玻璃和含氧化鈣中孔洞二氧化矽都沒有表現出顯著差異。
結論：(1)利用含氧化鈣中孔洞二氧化矽奈米複合材料，與磷酸混合後，能有效且快速封閉牙本質小管，具有治療牙本質過敏症之潛力。(2)在本研究中，無論模擬之牙髓腔壓力是否存在，對受測材料皆未有顯著影響，但在壓力存在下，牙本質滲透性有較高之趨勢。(3)合併使用電子顯微鏡觀察及液體流動模組測試滲透性，能使牙本質封閉效果之評估，得到更完整更明確的結果。

關鍵字

中孔洞氧化鈣 ； 生醫玻璃 ； 液體流動模組 ； 牙本質過敏症 ； 牙本質滲透性

並列摘要

Dentin hypersensitivity is a common complaint in dental clinics. The clinical experiences and investigations have exhibited the inefficiency of the commercialized dentin sealants. Our previous investigation proved that DP-bioglass mixed with 30 % phosphoric acid could form well-occlusive, recrystallized precipitants deep into the dentinal tubules. Because more than 3 days were needed for crystal formation,DP-bioglass has not been practical for clinical use.
In this research, a nano-sized biomaterial was synthesized using mesoporous silica as the carrier, and the nano@CaO mesoporous silica was prepared via an impregnation
technique. TEM observation of nano@CaO mesoporous silica showed homogenous spherical particles with about 50 nm in diameter. Because of the small size and large surface-volume ratio, the reaction time of crystal formation was shortened that made more practical for clinical use. We prepared the nano@CaO mesoporous silica paste by mixing nano@CaO mesoporous silica powder and 30 % phosphoric acid in different liquid/powder ratios. Then, we observed the changes of the conditions of these agents.
We examined the efficacy of three desensitizing materials for occlusion of dentinal tubules. We measured the fluid flow rate to compare the effects of different materials on dentin permeability with a fluid flow model. We also compared the depth and the sealing quality of the plugs or precipitants penetrating into dentinal tubules with SEM observation. The results revealed that nano@CaO mesoporous silica decreased the dentin permeability most to the lowest level (19.1 %) among three tested materials, and
the SEM showed the best sealing ability and deep penetration (> 100 μm) of the crystal precipitants. We also tested the efficacy of three desensitizing agents with or without pressure, and all of Seal & Protect, DP-bioglass, and nano@CaO mesoporous silica did not exhibit significant difference.
In conclusion: (1) The nano@CaO mesoporous silica could react with 30 % phosphoric acid quickly and occlude the dentinal tubules well. This porous material had the potential in treatment of dentin hypersensitivity clinically. (2) None of the tested materials in this research exhibited significant difference in reducing dentin
permeability whether the pulp pressure existed or not. (3) We compared the efficacy of different desensitizing agents by combination of SEM observation and dentin permeability with a fluid flow model. It provided more appropriate results to evaluate the occlusion of dentinal tubules.

並列關鍵字

mesoporous ； CaO ； bioglass ； fluid flow model ； dentin hypersensitivity ； dentin permeability

參考文獻

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