• 作者： 洪志遠
• 作者服務機構： 國立臺灣大學醫學院牙醫學系
• 中文摘要： 在建立樹脂結合固定義齒時，金屬與牙齒表面的微機械性鍵結力是最關鍵的。為了要得到一個有固持力的金屬表面，酸蝕技術可以用來建立微倒凹。在這個方法裡，合金表面連接到工作電極，而低壓直流供電器（DC Power Supply）連接到一個不銹鋼的相對電極（Counter Electrode）。兩個電極均浸在酸液中，並通以一適當時間的電流使合金產生所需的電解。 本研究不再採用上述傳統兩個電極酸蝕的技術（2-Electrode Electrolytic Method），而加入一個定電位儀（Poten-tiostat）以及基準電極（Reference Electrode）來研究三個電極酸蝕的技術。定電位儀可以用來控制通過另外二個電極的電壓，無論被電解金屬面積多大，試片（即工作電極）與相對電極之間的電位在任何時間均保持穩定，而使電流可以自動的調整。 研究中，工作電極電位是由電位循序增加時視電流密度差異來決定的，根據五個試片的極化曲線（PotentiostaticAnode Polarization Curves）發現約1.3 Volt是最適合的電位。 為了要找出上述系統中最適合的酸蝕暴露時間，35個樣本分成7組，各組酸蝕時間以一分鐘增量，從2分鐘增至8分鐘，最適合的酸蝕時間由掃瞄電子顯微鏡（SEM Microphotograph）和抗張強度測試（Tensile Strength Test）來決定，結果發現4分鐘組中，其片柱狀樹突（Lamellar Interdendritic Eutectics）最深，樹枝狀突起（Dendritic Ridges）最高，同時平均張力鍵結強度也是各組中最高的。
• 英文摘要： Since a good retention of direct bonded retainers onto abutment teeth is the primary requirementfor the fabrication of etched fixed partial dentures, successful formation of a micromechanical retentivearchitecture on the bonding surface is one of the most important procedures. For creating such a retentive dendritic pattern on nonprecious metal, a 2-electrode electrolyticmethod has been used. This equipment consists of a low-voltage DC power supply and two electrodes,namely, a working and a counter one. However, the current and voltage should be monitored during theentire processing time and the etching area must be pre-estimated. A potentiostat has been used to automatically stabilize the voltage across the working electrode andreference electrode by adjusting the current, as commonly employed in electro-chemical technology. A3-electrode corrosion device originally developed for laboratory research was adapted for dental retaineretching in this study. The results revealed that the etching of dental nonprecious metal (Ni-Cr-Be alloy) could successfullybe performed by using the system with a potentiostat. Moreover, the working potential was found to beapproximately 1.3 volts by taking the midpoint between the breakdown and the critical potentials forpassivation on the potentiostatic anode polarization curves. The optimal exposure time has been found tobe in a range of 3 to 5 minutes and 4 minutes to be ideal as determined by SEM microphotographic obser-vation which showed a uniform dendritic pattern with regular lattice form of alternating ridges and valleys.The results from tensile strength testing also supported such a conclusion as the highest strength wasobtained after a 4-minute etching. The present study demonstrates that the 3-electrode etching system is apredictable and convenient method for etching dental nonprecious metal.
• 中文關鍵字： adhesive prosthodontics; resin-bonded retainers; dental alloy etching; potentiostat
• 英文關鍵字： --