Objectives

(1) To investigate the genotoxicity of a glass ionomer cement (GIC) and GIC incorporated with titanium dioxide nanopoarticle (TiO₂NPs) and with microparticle (TiO₂MPs) on DNA double-strand breaks of human gingival fibroblast cells (HGFs). (2) To compare the genotoxic differences between GIC and two modified cements.

Methods

TiO₂NPsGIC and TiO₂MPsGIC were prepared by adding 10% w/w of TiO₂NPs and TiO₂MPs to the GIC powder and hand-mixed followed the manufacturer instruction. Dulbecco’s Minimum Essential Medium (DMEM) was used as a culture medium for HGFs and eluate preparation. Eluates from all groups were collected for XTT cell viability assay to obtain EC₅₀ values. γ-H2AX immunofluorescence assay was performed to detect DNA double-strand breaks (DSBs) of HGFs.

Results

EC₅₀ values were from 38% to 60% and eluate concentrations at 20% and 5% were selected for γ-H2AX immunofluorescence assay. At both concentrations, HGFs exposed to eluates from all cements groups had fewer mean foci per cell and higher percentage of free foci cells than H₂O₂ (p < 0.05). At 20% concentration, cells exposed to eluates from both TiO₂NPsGIC and TiO₂MPsGIC groups had fewer mean foci per cell and higher percentage of free foci cell than GIC and culture medium (p < 0.05).

Significance

Neither GIC nor 10% TiO₂-modified GICs had a genotoxic effect on HGFs. Both TiO₂NPsGIC and TiO₂MPsGIC demonstrated less genotoxic effect than GIC. When comparing between the two modified cements, there was no genotoxic difference between the modified cements from different particle sizes (nanoparticle and micro-particle) of TiO₂.

中文翻译：

---

二氧化钛改性的玻璃离聚物水泥的洗脱液在人牙龈成纤维细胞中诱导DNA双链断裂

目标

（1）为了研究玻璃的离聚物粘固剂（GIC）和GIC用二氧化钛nanopoarticle掺入的遗传毒性（的TiO _2个纳米颗粒），并用微粒（氧化钛₂个DNA双链成纤维细胞（HGFS）人牙龈的断裂MPS）。（2）比较GIC和两种改性水泥之间的遗传毒性差异。

方法

TiO ₂ NPsGIC和TiO ₂ MPsGIC的制备方法是，将10％w / w的TiO ₂ NPs和TiO ₂ MPs加入GIC粉末中，并按照制造商的说明进行手工混合。Dulbecco的最低必需培养基（DMEM）用作HGF和洗脱液制备的培养基。收集所有组的洗脱液用于XTT细胞活力测定以获得EC ₅₀值。进行了γ-H2AX免疫荧光检测，以检测HGF的DNA双链断裂（DSB）。

结果

EC ₅₀值从38％到60％，洗脱液浓度选择为20％和5％进行γ-H2AX免疫荧光测定。在两种浓度下，暴露于所有胶结物组洗脱液的HGF与H ₂ O ₂相比，每个细胞的平均病灶更少，游离病灶细胞的百分比更高（p <  0.05）。在浓度为20％的情况下，暴露于TiO ₂ NPsGIC和TiO ₂ MPsGIC组的洗脱液的细胞比GIC和培养基具有更少的每细胞平均病灶和更高的游离病灶细胞百分比（p  <0.05）。

意义

GIC或10％TiO ₂改性的GIC均未对HGF产生遗传毒性作用。TiO ₂ NPsGIC和TiO ₂ MPsGIC均显示出低于GIC的遗传毒性作用。在两种改性水泥之间进行比较时，不同粒径（纳米颗粒和微粒）的TiO ₂改性水泥之间没有遗传毒性差异。