钇稳定氧化锆全瓷冠与贵金属烤瓷冠抗折强度对照研究

Flexural strength of Y-TZP all-ceramic crowns and precious metal ceramic restorations.

目的研究氧化锆全瓷冠与贵金属烤瓷冠抗折强度的差异。方法在精密车床上模拟磨牙牙体预备制作金属基牙代型15个,分为3组。根据代型分别铸造金钯合金和金合金基底冠各5个,氧化锆全瓷冠5个。全部试件均黏固于代型上。采用电子万能测力仪测试试件抗折强度,即用直径5 mm的圆形加载头,以0.5 mm/min速度垂直加载于烤瓷冠牙合面中央至瓷层碎裂,记录瓷裂时强度值。采用单因素方差分析(One-way ANOVA)对各组数据进行分析。结果金钯合金抗折强度为(3.932±0.27)kN,金合金为(2.280±0.20)kN,氧化锆为(2.08±0.18)kN,金钯合金组抗折强度明显高于其他两组,差异有统计学意义(P<0.05);金合金组和氧化锆组抗折强度值相近,差异无统计学意义(P>0.05)。结论研究条件下,金钯合金烤瓷冠抗折强度明显大于金合金烤瓷冠和氧化锆全瓷冠,而金合金烤瓷冠与氧化锆全瓷冠抗折强度则无明显差异。

Objective To compare the flexural strength of Y-TZP all-ceramic crowns and two other different precious metals porcelain crowns. Methods Fifteen master tooth analogs were prepared resembling a molar crown preparation using the precision lathe and were divided into 3 groups.Five wax patterns were made from the mold and cast in a Au-Pd alloy,from which five Au-Pd metal-ceramic crowns were fabricated. Another 5 high-noble alloy metal-ceramic crowns and 5 ZrO2 all-ceramic were made from the same metal die.Each crown group were made in accordance with the specific manufacture’s instructions.All specimens were cemented on the analogs.Their fracture resistance was tested in a universal machine.A stainless steel rod with a 5-mm diameter stainless-steel ball was vertically placed on the occlusal surface of the crowns and at a speed of 0.5mm/min.Fracture was de？ned as occurrence of chipping.The loads at fracture were registered,and differences between the groups were calculated using One-way ANOVA. Results Au-Pd（3.932 ± 0.27）kN;Au（2.280 ± 0.20）kN;ZrO2（2.08 ± 0.18）kN. Significant differences in flexural strength between Au-Pd and other two groups were observed（P 〈 0.05）,while there was no significant difference between the ZrO2 and high-noble group（P 〉 0.05）.Conclusion Au-Pd group shows significantly greater flexural strength than high-noble and ZrO2 ceramic restorations（P 〈 0.05）,while there＇s no significant difference between the ZrO2 and high-noble（P 〉 0.05）.