Abstract：
BACKGROUND: Despite the superiority of glass-ionomer cements (GICs) over composites in treating white spot lesions (WSLs), there is still a concern about their preventive and antibacterial properties. Efforts have been made to improve the strength of their bond to demineralized enamel, fluoride release and antibacterial properties by adding nanoparticles of chitosan, which seems to be a promising method.
OBJECTIVE: The aim of the present study was to assess the antibacterial effect, the microshear bond strength (μSBS) to enamel at the WSL area, and the fluoride and nano-chitosan release after modifying the polyacrylic acid liquid phase of a traditional GIC with different nano-chitosan volumes.
METHODS: A total of 120 samples were prepared, and then divided into 4 groups (n = 30): G1 - non-modified GIC, which served as a control group, while G2, G3 and G4 were modified with different nano-chitosan volumes (50%, 100% and 150%, respectively). Microshear bond strength was assessed using a universal testing machine (UTM) after storage in distilled water for 24 h. Fluoride and nanochitosan release was measured with the use of spectrophotometers at different time points (initially, and at 1 h, 24 h, 48 h, 72 h, 1 week, 2 weeks, 3 weeks, and 6 weeks) after storage in distilled water. The antibacterial effect against the Streptococcus aureus strain was assessed with the agar diffusion test. The data was statistically analyzed.
RESULTS: After 24-hour storage, G2 recorded a slight, yet non-significant, increase in the μSBS values (4.1 ±0.94 MPa) as compared to G1 (3.9 ±1.30 MPa). With regard to fluoride release, the amount recorded for G1 was significantly greater at the end of the 24-hour storage period (0.70 ±0.30 μmf/cm2) than modified nano-chitosan GIC groups; G1 was followed by G4 (0.54 ±0.34 μmf/cm2). The highest amount of nano-chitosan release after 24-hour storage was noted for G3 (0.85 ±0.00 μmf/cm2). The highest inhibition zone value was recorded for G2.
CONCLUSIONS: Glass-ionomer cement modified with 50% nano-chitosan was shown to positively affect μSBS and the antibacterial effect, while modification with 150% nano-chitosan significantly increased fluoride release.
OBJECTIVE: The aim of the present study was to assess the antibacterial effect, the microshear bond strength (μSBS) to enamel at the WSL area, and the fluoride and nano-chitosan release after modifying the polyacrylic acid liquid phase of a traditional GIC with different nano-chitosan volumes.
METHODS: A total of 120 samples were prepared, and then divided into 4 groups (n = 30): G1 - non-modified GIC, which served as a control group, while G2, G3 and G4 were modified with different nano-chitosan volumes (50%, 100% and 150%, respectively). Microshear bond strength was assessed using a universal testing machine (UTM) after storage in distilled water for 24 h. Fluoride and nanochitosan release was measured with the use of spectrophotometers at different time points (initially, and at 1 h, 24 h, 48 h, 72 h, 1 week, 2 weeks, 3 weeks, and 6 weeks) after storage in distilled water. The antibacterial effect against the Streptococcus aureus strain was assessed with the agar diffusion test. The data was statistically analyzed.
RESULTS: After 24-hour storage, G2 recorded a slight, yet non-significant, increase in the μSBS values (4.1 ±0.94 MPa) as compared to G1 (3.9 ±1.30 MPa). With regard to fluoride release, the amount recorded for G1 was significantly greater at the end of the 24-hour storage period (0.70 ±0.30 μmf/cm2) than modified nano-chitosan GIC groups; G1 was followed by G4 (0.54 ±0.34 μmf/cm2). The highest amount of nano-chitosan release after 24-hour storage was noted for G3 (0.85 ±0.00 μmf/cm2). The highest inhibition zone value was recorded for G2.
CONCLUSIONS: Glass-ionomer cement modified with 50% nano-chitosan was shown to positively affect μSBS and the antibacterial effect, while modification with 150% nano-chitosan significantly increased fluoride release.
摘要：
背景：尽管玻璃离聚物水泥（GIC）在治疗白斑病变（WSL）方面优于复合材料，人们仍然担心它们的预防和抗菌性能。已经做出了努力来提高它们与去矿质牙釉质的结合强度，壳聚糖纳米粒子的氟释放和抗菌性能,这似乎是一个很有希望的方法。
目的：本研究的目的是评估抗菌作用，WSL区域与牙釉质的微剪切粘结强度(μSBS)，以及用不同的纳米壳聚糖体积改性传统GIC的聚丙烯酸液相后的氟化物和纳米壳聚糖的释放。
方法：共制备了120个样品，然后分为4组（n=30）：G1-未修饰的GIC，作为对照组，而G2、G3和G4用不同的纳米壳聚糖体积(50%，100%和150%,分别)。在蒸馏水中储存24小时后，使用通用试验机（UTM）评估微剪切粘结强度。在不同时间点使用分光光度计测量氟化物和纳米壳聚糖的释放（最初，在1小时，24h,48h,72小时,1周,2周,3周,和6周）在蒸馏水中储存后。用琼脂扩散试验评估对金黄色链球菌菌株的抗菌作用。对数据进行统计学分析。
结果：储存24小时后，G2记录了轻微的，但不重要，与G1（3.9±1.30MPa）相比，μSBS值（4.1±0.94MPa）增加。关于氟化物的释放，在24小时储存期结束时，G1的记录量（0.70±0.30μmf/cm2）明显大于改性纳米壳聚糖GIC组；G1之后是G4（0.54±0.34μmf/cm2）。对于G3,在24小时储存后纳米壳聚糖释放量最高(0.85±0.00μmf/cm2)。记录到G2的最高抑制区值。
结论：用50％纳米壳聚糖改性的玻璃离聚物水泥显示出积极影响μSBS和抗菌作用，而150%纳米壳聚糖改性显著增加氟释放。
目的：本研究的目的是评估抗菌作用，WSL区域与牙釉质的微剪切粘结强度(μSBS)，以及用不同的纳米壳聚糖体积改性传统GIC的聚丙烯酸液相后的氟化物和纳米壳聚糖的释放。
方法：共制备了120个样品，然后分为4组（n=30）：G1-未修饰的GIC，作为对照组，而G2、G3和G4用不同的纳米壳聚糖体积(50%，100%和150%,分别)。在蒸馏水中储存24小时后，使用通用试验机（UTM）评估微剪切粘结强度。在不同时间点使用分光光度计测量氟化物和纳米壳聚糖的释放（最初，在1小时，24h,48h,72小时,1周,2周,3周,和6周）在蒸馏水中储存后。用琼脂扩散试验评估对金黄色链球菌菌株的抗菌作用。对数据进行统计学分析。
结果：储存24小时后，G2记录了轻微的，但不重要，与G1（3.9±1.30MPa）相比，μSBS值（4.1±0.94MPa）增加。关于氟化物的释放，在24小时储存期结束时，G1的记录量（0.70±0.30μmf/cm2）明显大于改性纳米壳聚糖GIC组；G1之后是G4（0.54±0.34μmf/cm2）。对于G3,在24小时储存后纳米壳聚糖释放量最高(0.85±0.00μmf/cm2)。记录到G2的最高抑制区值。
结论：用50％纳米壳聚糖改性的玻璃离聚物水泥显示出积极影响μSBS和抗菌作用，而150%纳米壳聚糖改性显著增加氟释放。
