Abstract The in vitro bioactivity and in vivo bone neoformation in critical-size bone defects of a glass-ceramic material containing strontium ions (Sr2+) were evaluated in the present study as well as the antimicrobial effect against oral pathogens. A glass-ceramic bioactive material in powder (CP), based on the composition of S53P4 bioactive glass, was produced by partially replacing calcium with SrO using the sol-gel route. The amount of SrO added was 2.2 wt% (CPSr12.5) and 5.0 wt% (CPSr25). The amount of Sr2+ ions released by the CP increase with time achieving 18 mg/L at 6 h and the release rate decreased at longer times. pH values higher than 10 were obtained in the first 6 h, in agreement with an inhibitory microbial effect. These materials showed in vitro bioactivity, with total surface coated by hydroxyapatite (HA) after 7 days of immersion in simulated body fluid (SBF). The pH of SBF increased rapidly after immersion of CP, reaching a maximum value of 8.72 after 168 h. HA formation was observed in vitro for all samples. On microtomography and histomorphometric analysis, CPSr25 showed higher values than CP without Sr2+ (CPSr0) for bone volume (p = 0.016), density (p = 0.016) and neoformation area (p = 0.025) at 28 days. Histological analysis revealed higher degree of vascularization after 28 days for CPSr25 when compared to CPSr0 (p = 0.003). In addition, CP showed an inhibitory effect on oral pathogens. Substitution of CaO by SrO (CPSr25) presented the best results on the healing of critical-size bone defects, as evidenced by microtomographic and histological analyses. These data confirmed that higher concentrations of Sr2+doped CP materials are potential alternatives to improve bone healing and regeneration in critical-size bone defects.

中文翻译：

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锶掺杂微晶玻璃材料在严重缺损骨再生中的应用：体外和体内分析

摘要 本研究评估了含有锶离子 (Sr2+) 的微晶玻璃材料在临界尺寸骨缺损中的体外生物活性和体内骨新生，以及对口腔病原体的抗菌作用。基于 S53P4 生物活性玻璃的组成，粉末状玻璃陶瓷生物活性材料 (CP) 是通过使用溶胶-凝胶路线用 SrO 部分替代钙来生产的。SrO 的添加量为 2.2 wt% (CPSr12.5) 和 5.0 wt% (CPSr25)。CP 释放的 Sr2+ 离子的量随时间增加，在 6 小时时达到 18 mg/L，释放速率在更长的时间内下降。在前 6 小时内获得高于 10 的 pH 值，这与抑制微生物作用一致。这些材料显示出体外生物活性，在模拟体液 (SBF) 中浸泡 7 天后，整个表面涂有羟基磷灰石 (HA)。浸泡CP后SBF的pH值迅速升高，168小时后达到最大值8.72。在体外观察到所有样品的 HA 形成。在显微断层扫描和组织形态计量学分析中，CPSr25 在第 28 天的骨体积 (p = 0.016)、密度 (p = 0.016) 和新形成面积 (p = 0.025) 方面显示出高于不含 Sr2+ 的 CP (CPSr0) 的值。组织学分析显示，与 CPSr0 相比，CPSr25 28 天后血管化程度更高（p = 0.003）。此外，CP对口腔病原体显示出抑制作用。显微断层扫描和组织学分析证明，用 SrO (CPSr25) 替代 CaO 对临界尺寸骨缺损的愈合效果最好。