Dental Materials Laboratory, School of Dentistry, Porto Alegre, RS, Brazil.
Int Endod J. 2013 Mar;46(3):205-10. doi: 10.1111/j.1365-2591.2012.02107.x. Epub 2012 Aug 11.
To evaluate the influence of several niobium pentoxide (Nb(2) O(5) ) concentrations on the radio-opacity, flow, film thickness, microhardness and degree of conversion of an experimental root canal sealer.
An experimental dual-cured root canal sealer was produced with a methacrylate-based comonomer blend. Nb(2) O(5) was added at four different concentrations: 0, 80, 100 and 120 wt%. Radio-opacity was evaluated according to ISO 6876 using a digital system (n = 5). Flow and film thickness were determined in accordance with ISO 6876 (n = 3). Microhardness was evaluated with 50 g for 15 s (n = 5). Degree of conversion was evaluated with FTIR immediately after photocuring and after 1, 7 and 14 days. The data were analysed using anova and Tukey's test. The degree of conversion over time was evaluated using RM-anova (α = 0.05).
The groups with 80 wt% and 100 wt% of filler showed no significant difference in radio-opacity from that of equivalent 2 mmAl (P > 0.05). The addition of 120 wt% resulted in radio-opacity values higher than 2 mmAl (P < 0.05). The flow was not significantly different amongst the different groups (P > 0.05). All groups had a film thickness of <50 μm (ISO 6876). All groups with Nb(2) O(5) were associated with higher values of microhardness than the control group. The group with 0 wt% was associated with a higher degree of conversion at all times. All groups except those with 80 wt% had higher values for degree of conversion after 14 days than immediately after photocuring.
The addition of Nb(2) O(5) increases radio-opacity and microhardness; this material may be a promising filler for the production of a new endodontic sealer.
评估几种五氧化二铌（Nb(2) O(5) ）浓度对一种实验性根管封闭剂的射线不透明度、流动性、膜厚度、显微硬度和转化率的影响。
使用基于甲基丙烯酸酯的共聚单体混合物制备了一种实验性双固化根管封闭剂。以四种不同浓度（0、80、100 和 120 重量%）添加 Nb(2) O(5)。根据 ISO 6876 使用数字系统评估射线不透明度（n = 5）。根据 ISO 6876 确定流动性和膜厚度（n = 3）。用 50 g 进行 15 s 的显微硬度评估（n = 5）。立即在光固化后以及 1、7 和 14 天后使用 FTIR 评估转化率。使用方差分析和 Tukey 检验分析数据。使用 RM-方差分析（α = 0.05）评估随时间的转化率。
填充剂含量为 80 重量%和 100 重量%的组与等效 2 mmAl 的射线不透明度没有显著差异（P > 0.05）。添加 120 重量%的 Nb(2) O(5) 导致射线不透明度值高于 2 mmAl（P < 0.05）。不同组之间的流动性没有显著差异（P > 0.05）。所有组的膜厚度均<50 μm（ISO 6876）。所有添加 Nb(2) O(5) 的组的显微硬度值均高于对照组。0 重量%组在所有时间点的转化率均较高。除 80 重量%组外，所有组在 14 天后的转化率均高于光固化后立即的转化率。
添加 Nb(2) O(5) 可增加射线不透明度和显微硬度；这种材料可能是生产新型根管封闭剂的有前途的填料。
