三级硅基填料的构筑及其对牙科复合树脂性能的影响

Construction of trimodal silica-based filler and its effects on properties of dental resin composites

为提高无机填料在牙科复合树脂中的堆积密度,采用八乙烯基多面体低聚倍半硅氧烷(OV-POSS)作为第三级填料,填充双模SiO2填料(SiO2纳米粒子&SiO2纳米团簇)型复合树脂中的空隙。用高分辨率透射电镜(HR-TEM)和动态光散射仪(DLS),研究了OV-POSS的形貌和粒径,并利用UV-vis-NIR分光光度计、万能实验机和MTT比色法,研究了三级填料的组成对复合树脂性能的影响。结果表明:OV-POSS形貌为近球形,粒径为(4.0±2.9)nm;当OV-POSS的添加量≤5wt.%时,复合树脂的性能逐渐得到改善,尤其当OV-POSS的质量分数为5%时,复合树脂的透光率和细胞活性优于商品化纳米团簇型树脂Z350 XT,且其弯曲强度(112.3 MPa±5.6 MPa)、弯曲模量(6.6 GPa±0.2 GPa)和压缩强度(217.8 MPa±5.3 MPa)达到最大值,较未添加OV-POSS的树脂分别提高了7.2%、4.8%和5.8%。但是,随着OV-POSS含量增加(≥10wt.%),OV-POSS易聚集且散射更多的光,导致复合树脂性能下降。

To increase the packing density of inorganic fillers in dental resin composites, octavinyl-polyhedral oligomeric silsesquioxane(OV-POSS) was used as tertiary filler to fill the voids in the bimodal silica fillers(SiO2 nanoparticles & SiO2 nanoclusters) based dental composites. Morphology and size of OV-POSS were studied by using high-resolution transmission electron microscopy(HR-TEM) and dynamic light scattering(DLS). It was found that OV-POSS exhibited a close-to-spherical morphology with a size distribution of 4.0 nm±2.9 nm. Subsequently, UV-vis-NIR spectrophotometer, universal testing machine, and MTT colorimetric assay were used to investigate the effect of filler composition on the properties of dental composites. The properties of the dental composites were improved by partially substituting the bimodal silica fillers with OV-POSS(≤ 5 wt.%). Specifically, with the incorporation of 5 wt.% of OV-POSS, the composite exhibited improved light transmittance and cell activity compared with commercial Z350 XT. In addition, this composite displayed its highest flexural strength(112.3 MPa±5.6 MPa), flexural modulus(6.6 GPa±0.2 GPa), and compressive strength(217.8 MPa±5.3 MPa), providing the respective improvements of 7.2%, 4.8%, and 5.8% with respect to those without OV-POSS. However, more OV-POSS(≥10 wt.%) resulted in the formation of aggregates and more light-scattering, which led to the deterioration in the properties of dental composites.