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51.金屬瓷修復體（metal-ceramic restorations）在烤瓷前，須先氧化鑄體合金，此過程稱為何者？①條件化燒烤（conditioning bake） ②除氣（degassing） ③氧化還原（oxidization-reduction）
(A)僅①②
(B)僅①③
(C)僅②③
(D)①②③
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統計： A(41), B(27), C(14), D(53), E(0) #3817646
統計： A(41), B(27), C(14), D(53), E(0) #3817646
詳解 (共 1 筆)
eric
#7436207
Most metal-ceramic systems require that the cast alloy be subjected to an initial oxidation step before the several layers of dental porcelain are fired.
(A notable exception is the palladium- copper-gallium [Pd-Cu-Ga] high-palladium alloy Freedom Plus [Jelenko Dental Alloys], in which the oxidation step does not need to be performed before firing the opaque porcelain layer.例外.鈀-銅-鎵 [Pd-Cu-Ga] 高鈀合金 ，在燒製不透明瓷層之前不需要執行氧化步驟)
This step has also been called a conditioning bake or degassing. The latter term, which is frequently used in the dental laboratory industry, is inaccurate because this procedure’s purpose is to oxidize the metal surface for subsequent adherence to the fired porcelain. Historically, some clinicians thought that the heating cycle might result in the loss of gases incorporated in the alloy during melting. However, this occurs during solidi- fication because of the much greater solubility of atmospheric gases in the molten alloy than in the solidified alloy; it results in the formation of microscopic porosity in the casting.
Contemporary Fixed Prosthodontics 6e 2023 p716
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