不同厚度二硅酸锂陶瓷对后牙牙合贴面抗折强度的影响

The effect of different thickness lithium disilicate glass ceramics on the fracture resistance of posterior occlusal veneer made of the identical material

目的:探讨不同厚度和材料类型对后牙[牙合]贴面抗折强度的影响。方法:制作厚度为0.6、0.9、1.2 mm的IPS e.maxCAD(IC),IPS e.maxPress(IP)后牙[牙合]贴面,粘接树脂代型后进行抗折破坏实验,记录最大断裂载荷值,体式显微镜与扫描电镜观察并分析失效模式。双因素分析厚度及材料类型对抗折强度的影响。结果:1.2 mm厚度IC和IP组的后牙[牙合]贴面平均最大载荷值分别为(1593.59±241.13)N和(1511.86±129.01)N,均明显高于0.6、0.9 mm组(P<0.05)。统计分析显示:材料类型对贴面抗折强度的差异无统计学意义(P>0.05),不同厚度对抗折强度的差异有统计学意义(P<0.05)。结论:IC和IP的后牙[牙合]贴面厚度影响抗折强度,材料类型无明显影响。

Objective:To determine the effect of restoration thickness and material type on the fracture strength of posterior occlusal veneers.Methods:Maxillary molars composite resin dies were prepared and restored with occlusal veneer restorations fabricated from IPS e.maxCAD(IC)and IPS e.maxPress(IP)with the occlusal thicknesses of 0.6,0.9 and 1.2 mm,respectively.Restorations were adhesively bonded and subjected to compressive loading.The maximum force at fracture were compared.Stereomicroscope and SEM were used to observe the fracture mode of the failed specimens.Two-way ANOVA was used to identify the statistically significant relationship between fracture strength and thickness and material type.Results:The average maximum load(N)at fracture for the IC groups and the IP groups of the 1.2 mm thickness groups were 1593.59±241.13 and 1511.86±129.01 respectively,which were significantly higher than that of the 0.6 mm and 0.9 mm groups(P<0.05).No significant difference existed between the material type with the same thickness in terms of fracture strength(P>0.05),the various restoration thicknesses was found to be influential(P<0.05).Conclusion:The thickness of occlusal veneers of IC and IP is the main factor for the fracture resistance,but not the material type.