臺灣博碩士論文加值系統

　　在當今牙科材料中，由於純鈦金屬具有優異生物相容性及抗腐蝕、低比重、高強度，以用低熱傳導率等特性，使純鈦及其合金已廣泛運用於牙科領域中，並成為牙科修復體中一新的替代金屬。本實驗目的乃探討－理想的純鈦金屬厚度與陶瓷－純鈦金屬鍵結強度之關係。本實驗方法中有三種金屬試片，分別是Grade II、Grade III純鈦金屬試片及鎳鉻鈹金屬試片，在Grade II、GradeIII純鈦金屬試片又有4種不同厚度，為0.3、0.5、0.7、1.0mm，在鎳鉻鈹金屬試片則有兩種厚度為0.3、0.5mm，故本實驗共分成10組，每一組有15個金屬試片，並放置陶瓷於金屬試片正中央位置，而其陶瓷厚度為1.0mm，純鈦金屬使用“Tibond”陶瓷，而鎳鉻鈹金屬使用“Williams”陶瓷，將已燒結完成之金屬試片經過三點變曲測試，並記錄金屬與陶瓷剝離時的荷重，並計算其撓屈強度，再經過二因子變異數分析（Two-way ANOVA）以及薛費氏事後比較分析（Scheff's analysis）。結果發現Grade II、Grade III純鈦金屬在撓屈強度比較下，並無明顯差異（P>0.05），金屬厚度不同的Grade II、Grade III純鈦金屬在撫屈強度下，有顯著差異（P<0.05），而厚度0.7、1.0mm之Grade II純鈦金屬與厚度0.7、1.0mm之Grade III純鈦金屬，其撓屈強度在統計上無顯著差異（P<0.05），在厚度0.7、1.0mm之Grade II、Grade III純鈦金屬試片之撓屈強度與厚度0.3mm之Grade II、Grade III純鈦金屬強度有明顯差異。厚度0.5mm　之鎳鉻鈹金屬撓屈強度較厚度1.0、0.7mm之Grade II、Grade III純鈦金屬強度高，但在統計上無顯著差異（P<0.05）。界面分析方面，鎳鉻鈹金屬介面間在錨點形成，且錨點處有擴散現象，而純鈦金屬無錨點形成，且無擴散現象。在斷裂面方面，鎳鉻鈹金屬其斷裂是屬於合併cohesive/adhesive的情形，而純鈦金屬其斷裂是屬於adhesive的情形。結論是，在臨床上，使用鈦金屬作為捕綴物之金屬支架，其厚度至少需要0.5mm。

　　Titanium and its alloys have been widely used in dentistry because of their excellent biocompatibility and corrosion resistance. In addition, its low specific gravity, high strength, low thermal conductivity have made this metal as an alternative metal used for dental prostheses. The purpose of this study was to evaluate the effect of metal thickness of cp titanium on the flexural bond strength of ceramic to cp titanium. In cast specimens of cp titanium Grade II (Group I) and Grade III (Group II), wax patterns of different thickness (subgroup: 0.3, 0.5, 0.7 and lmm) were made and in Ni-Cr-Be alloy (Group III) cast specimens, those of different thickness (subgroup: 0.3 and 0.5mm) were prepared. Fifteen specimens were made in each thickness of metal. The fired square-shaped porcelain layer covered a central portion of one side of a metal surface for a total thickness of 1.0mm ceramic thickness achieved. Titanium specimens/Tibond ceramic (Dentsply DeTrey GmbH, Greieich) and Ni-Cr-Be alloy specimens/Will-Cream ceramic (Williams, Ivoclar North America Inc, USA) combinations were used. The specimens were subjected to Three-point bending test, and the load of bond failure was recorded. The surface of each debonded specimens were examined and photographed to determine the mode of bond failure. A two-way ANOVA followed by a Scheff's analysis was to analyze the data. There was no statistically significant difference of flexural bond strength between Ti II and Ti III specimens (P>0.05). The metal thickness of cp titanium, either Grade II or Grade III, do effect the flexural bonding strength of c.p. titaniumceramic(P<0.05). There were no statistically significant difference (P>0.05) of the metal-ceramic flexural bonding strength among Ti II, III (10.mm) and Ti II, III(0.7mm) specimens,but Ti II, III(1.0 and 0.7mm) were significantly stronger than Ti II, III (0.3mm) specimens (P>0.05). The flexural bonding strength of Ni-Cr-Be (0.5mm) specimens were stronger than Ti Grade II, III (0.7mm) specimens but there was no statistically significant difference (P>0.05). The study of the interfaces between ceramic and alloys was done by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS). It is observed that the anchor points were found in the Ni-Cr-Be alloy-ceramic interface, and the both fracture types, i. e., cohesive and adhesive type, were coexistent in its fracture surface. Compared to the Ni-Cr-Be alloy, the fracture of c. p. titanium-ceramic interface after bending test revealed that the fracture is adhesive type dominantly. It was concluded that metal thickness of cp titanium, either Grade II or Grade III, will effect the flexural bond strength of cp titanium, either Grade III, will effect the flexural bond strength of cp titanium-ceramic and the minimum of metal thickness was recommended as 0.5mm to be used on cp titanium-ceramic system.