新型纳米含氟树脂中氟水平对其机械性能的影响

目的:研究含氟量对新型纳米树脂的挠曲强度、弹性模量和微拉伸粘结强度(μTBS)等机械性能的影响。方法:选取Z350和4种含氟量不同(质量分数为0%、10%、20%和30%)的新型纳米树脂,将5种树脂制作成规格为(25.0±2.0)mm×(2.0±0.1)mm×(2.0±0.1)mm的挠曲强度试验标准试件,每组5个,万能测试机三点弯曲法测试挠曲强度和弹性模量。取25颗人第三磨牙,随机分到各组,每组5颗。制备成截面为(1.0±0.2)mm²的条柱状试件,每组10个,使用微拉伸测试仪测试件的μTBS,低倍镜观察粘结面断裂方式。结果:挠曲试验,各组试件挠曲强度比较差异无统计学意义(P>0.05);含氟量20%组试件弹性模量明显大于其他各组(P<0.05)。微拉伸试验,与含氟量0%组比较,含氟量10%和含氟量20%组试件μTBS差异无统计学意义(P>0.05);含氟量30%组试件μTBS明显小于含氟量0%、10%和20%组(P<0.05);与Z350组比较,含氟量0%和10%组试件μTBS差异无统计学意义(P>0.05);含氟量20%和30%组试件μTBS明显小于Z350组(P<0.05)。所有试件均为粘结面断裂。结论:树脂中含氟量不超过20%时,其对μTBS无影响;含氟量超过20%时,μTBS明显降低。

Effects of fluoride level on mechanical properties of new nano-fluoride-containing resin

Objective To study the effects of fluoride level on the mechanical properties,such as flexural strength,elastic modulus and micro-tensile bond strength(μTBS),of new nano-fluoride-containing resin.Methods Z350 and four composite resins (containing 0%,10%,20% and 30% fluoride)were selected. Five kinds of resins were used to make standard samples with the size of (25.0±2.0)mm×(2.0±0.1)mm×(2.0±0.1)mm,and there were 5 specimens in each group. The flexural strength and elastic modulus of the specimens were assessed using a three-point bending test on a universal test machine. Twenty five human molars were randomly divided into five groups,and there were 5 molars in each group. The teeth were sectioned with a cross-section of (1.0±0.2)mm²,and there were ten specimens in each group,and the μTBS of specimens were detected by Micro Tensile Tester. The fracture modes of specimens were observed under low magnification microscope.Results The flexural test results showed that there was no significant difference of the flexural strength of specimen among all groups(P>0.05);the elastic modulus of specimens in 20%F group was higher than those in the other groups(P<0.05).The micro-tensile test results showed that the μTBS of the specimens in 30%F group was lower than those in 0%F group,10%F group and 20%F group(P<0.05);but there were no significant differences of μTBS between 0%F group and 10%F or 20% F groups (P>0.05).Compared with Z350 group,the μTBS of the specimens in 20% and 30%F groups were significantly decreased (P<0.05),but there were no significant differences of μTBS between 0%, 10% F groups and Z350 group (P>0.05).All specimens were broken from the adhesive surface.Conclusion When the fluoride level is lower than 20%,it has no effect on μTBS;when the fluoride level is above 20%,the μTBS is significantly decreased.