類陶瓷薄膜技術應用於乳牙成型冠基材表面修飾之研究

Abstract

本研究旨在開發以電漿輔助化學氣相沉積 (Plasma-Enhanced Chemical Vapor Deposition, PECVD) 技術，應用有機矽烷化合物於兒童乳牙用不鏽鋼成 型牙冠表面進行改質，以提升其生物相容性與抗菌性能。實驗採用兩種有機矽前驅物──四甲基矽烷 (Tetramethylsilane, TMS) 與六甲基二矽胺烷 (Hexamethyldisilazane, HMDSZ)，於不同壓力與處理時間條件下，將奈米級類陶瓷薄膜沉積於不鏽鋼 試片及臨床牙冠樣品表面。 本研究分三階段進行。第一階段為成膜參數優化，針對不同壓力與時間條 件下所製備之薄膜，以傅立葉轉換紅外線光譜（FTIR）、水接觸角（WCA）、X光繞射（XRD）、掃描式電子顯微鏡（SEM）及能譜分析 （EDS）等物理性質評估。由實驗結果顯示，TMS以100 mTorr、15分鐘為最佳鍍膜 參數，WCA達107.3°；HMDSZ則以100 mTorr、5分鐘為最優，其WCA為 100.8°，皆展現出顯著疏水性。 第二階段以上述最佳參數組別進行生物學性能評估。細胞毒性試驗中，以NIH-3T3小鼠纖維母細胞為模型，鍍膜樣品顯示與對照氧化鋯冠相當的細胞活性，無明顯毒性反應。抗菌試驗使用大腸桿菌進行抑菌圈與SEM觀察，顯示鍍膜樣品具有減少菌體附著之效果。電化學極化測試結果顯示，HMDSZ 與 TMS 鍍膜樣品皆能有效提升不鏽鋼之抗蝕性能。HMDSZ 組具最高腐蝕電位，展現出優異的初期電位穩定性，能延緩腐蝕反應啟動；TMS 組則具最低腐蝕電流密度與較高極化電阻，顯示其阻隔效果良好，有助於長期抑制腐蝕進程。整體而言，兩種鍍膜皆展現良好防護效果，具備應用於生醫金屬表面改質之潛力。 第三階段將上述最佳參數應用於臨床市售不鏽鋼乳牙冠，經表面處理後進行SEM觀察。結果顯示膜層覆蓋均勻，無裂縫與剝離現象，證實PECVD鍍膜技術具備應用於複雜立體牙冠結構之可行性。 綜合以上結果，PECVD技術能在不改變不鏽鋼冠結構的前提下，賦予其優異的表面疏水性、抗菌性、生物相容性與耐腐蝕性，顯示其具備作為臨床不鏽鋼冠表面功能性改質的潛力。此研究提供一創新方向，有望改善兒童口腔修復材料之臨床表現與長期健康效益。

This study aimed to develop a surface modification technique for preformed stainless steel crowns (SSCs) used in pediatric dentistry by employing plasma enhanced chemical vapor deposition (PECVD) with organosilicon precursors. The goal was to enhance the biocompatibility and antibacterial properties of SSCs, thereby mitigating gingival inflammation and reducing bacterial adhesion commonly observed in clinical applications. Two types of organosilicon precursors—tetramethylsilane (TMS) and hexamethyldisilazane (HMDSZ)—were selected to fabricate nanostructured ceramic-like films under varied pressure and treatment time conditions. The study was conducted in three phases. In the first phase, optimization of deposition parameters was performed. Stainless steel specimens were coated with thin films under different PECVD conditions and evaluated through Fourier-transform infrared spectroscopy (FTIR), water contact angle (WCA) measurement, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Results indicated that the optimal parameters for TMS were 100 mTorr and 15 minutes, yielding a WCA of 107.3°, while those for HMDSZ were 100 mTorr and 5 minutes, with a WCA of 100.8°, both showing significant hydrophobicity and surface morphology alterations. In the second phase, the selected coatings were subjected to biological performance evaluations. Cytotoxicity tests using NIH-3T3 fibroblast cells revealed that coated specimens exhibited comparable biocompatibility to zirconia crowns, iii without apparent cytotoxic effects. Antibacterial tests using Escherichia coli demonstrated the presence of inhibition zones and reduced bacterial adhesion on coated surfaces. Electrochemical polarization tests revealed that both HMDSZ and TMS-coated samples exhibited improved corrosion resistance on stainless steel substrates. The HMDSZ coating demonstrated superior electrochemical stability, effectively delaying the onset of corrosion reactions. In contrast, the TMS coating showed excellent barrier properties, significantly reducing the corrosion rate over time. These findings suggest that both coatings hold strong potential for surface protection applications in biomedical metal devices. In the third phase, the optimal PECVD conditions were applied to commercially available stainless steel pediatric crowns. Post-treatment SEM analyses showed uniform film coverage without cracks or delamination, confirming the feasibility of PECVD coatings on complex crown geometries. In conclusion, the application of PECVD using TMS and HMDSZ precursors successfully imparted favorable surface characteristics—hydrophobicity, antibacterial activity, biocompatibility, and corrosion resistance—without compromising the structural integrity of SSCs. This technique offers a promising strategy for functional surface enhancement of pediatric crowns, with potential to improve clinical outcomes and long-term oral health in children.