生物活性玻璃盖髓剂的理化性质

目的：研究生物活性玻璃（bioactive glass, BG）盖髓剂的理化性质。方法：BG盖髓剂由粉剂和液剂组成，粉剂为溶胶 凝胶法制备的亚微米BG（化学组成：82.36% SiO2，15.36% CaO和2.28% P2O5）。液剂有两种，一种为磷酸盐缓冲溶液（phosphate buffer solution, PB），调拌而成的盖髓剂命名为BG PB；另一种在磷酸盐缓冲溶液中添加1%（质量分数）的有机物海藻酸钠（sodium alginate, SA），调拌而成的盖髓剂命名为BG-PB-SA。采用固化时间加荷仪测量BG盖髓剂的固化时间、力学试验机测量抗压强度，采用独立样本t检验对实验数据进行统计学处理，比较差异是否有统计学意义（α=0.05）。采用pH计测定BG盖髓剂、三氧化矿化物凝聚体（mineral trioxide aggregate, MTA）硬固后pH值，染料渗透法检测BG盖髓剂与MTA的封闭性。采用单因素方差分析对实验数据进行统计学处理，并应用LSD事后多重比较，比较各组之间差异是否有统计学意义（α=0.05）。结果：（1） 固化时间：BG-PB的初凝时间为（7.2±0.3） min，终凝时间为（12.7±0.9） min，BG-PB-SA的初凝时间为（7.5±0.3） min，终凝时间为（13.6±1.6） min，BG-PB与BG-PB-SA差异无统计学意义（P>0.05）。（2） 抗压强度：BG-PB、BG-PB-SA在1 d时抗压强度分别为（16.5±1.8） MPa、（26.6±6.3） MPa，28 d时分别下降到（14.1±3.7） MPa、（21.6±5.6） MPa，BG-PB-SA抗压强度高于BG-PB，且差异具有统计学意义（P<0.05）。（3） pH： BG-PB、BG-PB-SA在模拟体液中可使得pH显著升高，最高可达8.07，但显著低于MTA的最高pH值8.47（P<0.05）。（4） 封闭性：BG-PB、BG-PB-SA具有良好的封闭性，且与MTA差异无统计学意义（P<0.05）。结论：BG盖髓剂具有良好的理化性质，固化时间较短，有望成为效果理想的新型盖髓剂。

Physical and chemical properties of pulp capping materials based on bioactive glass

Objective： To investigate the physical and chemical properties of pulp capping materials based on bioactive glass (BG). Methods: Novel BG pulp capping materials were composed of powder and fluid. The powder was BG (82.36% SiO2, 15.36% CaO, and 2.28% P2O5) synthesized by using the sol-gel method combined with template technology. Two kinds of fluid were provided: (1) phosphate buffer (PB) solution and (2) phosphate buffer solution with 1% sodium alginate (SA) addition. After mixing the powder and fluid, BG-PB and BG-PB-SA were prepared. Setting time and compressive strength of the BG pulp capping materials were tested by setting time loading system and mechanical testing machine. Statistical analysis was performed using the independent sample t test, with the significance set at 0.05. pH meters was used to test the pH of the BG pulp capping materials and mineral trio-xide aggregate (MTA). The sealing ability of the BG pulp capping materials and MTA was tested by methylene blue dye leakage model. Statistical analysis was performed using one-way ANOVA analysis and LSD multiple comparison, with the significance set at 0.05. Results: (1) Setting time: the initial and final setting time of BG-PB were (7.2±0.3) min and (12.7±0.9) min, respectively. And the initial and final setting time of BG-PB-SA was (7.5±0.3) min and (13.6±1.6)min. There was no significant difference between BG-PB and BG-PB-SA groups (P>0.05). (2) Compressive strength: the compressive strength of BG-PB was (16.5±1.8) MPa at 1 day and (14.1±3.7) MPa at the end of 28 days. However, the compressive strength of BG-PB-SA was (26.6±6.3) MPa on day 1 and (21.6±5.6) MPa on day 28, which was significantly higher than that of BG-PB (P<0.05). (3) pH: the pH of BG pulp capping materials’ bulk immersed in simulated body fluid (SBF) went up to 8.06, and the highest pH of MTA was 8.47. Significant difference was observed between the BG pulp capping materials and MTA (P<0.05). (4) Sealing ability: the optical density (D) in positive control group was significantly higher than ln BG-PB, BG-PB-SA and MTA groups (P<0.05). And BG-PB and BG-PB-SA showed the similar favorable sealing ability with MTA, and no significant difference was observed among the three groups (P>0.05). Conclusion: The novel BG pulp capping materials showed good physical properties, especially BG’s setting time was short; BG pulp capping materials are promising.