Evaluation Of Bond Characteristics Between Porcelain And Ti2448 Alloy

Ti2448 alloy is a newβ-type titanium alloy which has been developed by Chinese researchers. It belongs to the third-generation titanium alloy. It has high strength, high toughness and high fatigue strength. It also has good corrosion resistance and biological properties. Especially, the alloy has the lower elastic modulus (forging 33 GPa, casting 42 GPa) than other titanium alloys. So the bio-mechanical compatibility is better. In a word, Ti2448 alloy has good application prospects in the dental field.The aims of our research are to know the feasibility that using Ti2448 alloy to product PFM crown, evaluate the usual combination between Ti2448 alloy and titanium porcelain, and apply commonly methods of surface treatment on its surface so as to know which methods can improve the combination. Finally, we want to provide the experimental basis that using Ti2448 alloy in production of PFM.Method:1. Ti2448 specimens were fabricated by conventional casting system. The coefficient of thermal expansion (CTE) of Ti2448 was evaluated. The bond strength was analyzed with three-point-bonding test according to IS0 9693(1999)Amd.1 2005 (E) standard.2. The surface roughness (Ra), surface energy (E) and bond strength of titanium/porcelain were evaluated just after using the different sizes of Al₂O₃ (50μm, 120μm, 250μm) to rough the Ti2448 surface.3. The surface roughness (Ra), surface energy (E) and bond strength of titanium/porcelain were evaluated just after using the different solutions (10%HF, 50%NaOH) to modify the Ti2448 surface.4. The surface roughness (Ra), surface energy (E) and bond strength of titanium/porcelain were evaluated just after using the different preoxidation temperatures (700℃, 750℃, 800℃) to modify the Ti2448 surface.Results:1. The result of CTE test showed that the Duceratin Kiss porcelain was 8.7×10^-6·K^-1. and the Ti2448 was 9.51×10^-6·K^-1. The difference between porcelain and Ti2448 was 0.81×10^-6·K^-1. The bond strength of porcelain and Ti2448 was 31.51 MPa which is above the lowest limit value in the IS0 9693(1999)Amd.1 2005 (E) standard (25MPa) .2. As the size of Al₂O₃ become larger, the value of Ra increased but the value of E decreased . The bond strength of Ti2448 and porcelain was higher after using 120μm Al₂O₃ sandblasting than using 50μm and 250μm Al₂O₃ sandblasting under the same pressure.3. The value of Ra was increased after treated with 10% HF but the value of E decreased, The value of E was significantly increased after treated with 50% NaOH(38.86±2.51 MPa). Bond strength between porcelain and Ti2448 can be largely increased by using a 50% NaOH caustic bath prior. 4. The roughness was decreased and the surface energy was increased after preoxidation. When titanium subjected to preoxidation treatment at 750°C(39.94±1.63 MPa), the bond strength was higher when compared to treatment at 700°Cand 800°C .Conclusion:1. The result of CTE test showed that the Duceratin Kiss porcelain had a good thermal compatibility with Ti2448.The bond strength of porcelain and Ti2448 was above the lower limit value in the ISO9693 Standard (25MPa).2. The bond strength after treated with 120μm Al₂O₃ sandblasting was higher than using 50μm and 250μm Al₂O₃ sandblasting under the same pressure.3. The treatment of 50%NaOH caustic bath prior significantly increased the bond strength of porcelain and Ti2448.4. The treatment of 750°C preoxidation significantly increased The bond strength of porcelain and Ti2448.