Odermatt Reto, Par Matej, Mohn Dirk, Wiedemeier Daniel B, Attin Thomas, Tauböck Tobias T
Department of Conservative and Preventive Dentistry, Center for Dental Medicine, University of Zurich, 8032 Zurich, Switzerland.
Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, 10000 Zagreb, Croatia.
J Clin Med. 2020 Mar 12;9(3):772. doi: 10.3390/jcm9030772.
Bioactive resin composites can contribute to the prevention of secondary caries, which is one of the main reasons for failure of contemporary dental restorations. This study investigated the effect of particle size of bioactive glass 45S5 on chemical and physical composite properties. Four experimental composites were prepared by admixing the following fillers into a commercial flowable composite: (1) 15 wt% of micro-sized bioactive glass, (2) 15 wt% of nano-sized bioactive glass, (3) a combination of micro- (7.5 wt%) and nano-sized (7.5 wt%) bioactive glass, and (4) 15 wt% of micro-sized inert barium glass. Hydroxyapatite precipitation and pH rise in phosphate-buffered saline were evaluated during 28 days. Degree of conversion and Knoop microhardness were measured 24 h after specimen preparation and after 28 days of phosphate-buffered saline immersion. Data were analyzed using non-parametric statistics (Kruskal-Wallis and Wilcoxon tests) at an overall level of significance of 5%. Downsizing the bioactive glass particles from micro- to nano-size considerably improved their capability to increase pH. The effect of nano-sized bioactive glass on degree of conversion and Knoop microhardness was similar to that of micro-sized bioactive glass. Composites containing nano-sized bioactive glass formed a more uniform hydroxyapatite layer after phosphate-buffered saline immersion than composites containing exclusively micro-sized particles. Partial replacement of nano- by micro-sized bioactive glass in the hybrid composite did not impair its reactivity, degree of conversion ( > 0.05), and Knoop microhardness ( > 0.05). It is concluded that downsizing bioactive glass particles to nano-size improves the alkalizing potential of experimental composites with no negative effects on their fundamental properties.
生物活性树脂复合材料有助于预防继发龋，继发龋是当代牙科修复失败的主要原因之一。本研究调查了生物活性玻璃45S5的粒径对复合材料化学和物理性能的影响。通过将以下填料混入市售可流动复合材料中来制备四种实验复合材料：（1）15 wt%的微米级生物活性玻璃，（2）15 wt%的纳米级生物活性玻璃，（3）微米级（7.5 wt%）和纳米级（7.5 wt%）生物活性玻璃的组合，以及（4）15 wt%的微米级惰性钡玻璃。在28天内评估磷酸盐缓冲盐水中的羟基磷灰石沉淀和pH值升高情况。在试件制备后24小时以及磷酸盐缓冲盐水浸泡28天后测量转化率和努氏显微硬度。使用非参数统计（Kruskal-Wallis和Wilcoxon检验）在5%的总体显著性水平上分析数据。将生物活性玻璃颗粒从微米级减小到纳米级可显著提高其提高pH值的能力。纳米级生物活性玻璃对转化率和努氏显微硬度的影响与微米级生物活性玻璃相似。与仅含有微米级颗粒的复合材料相比，含有纳米级生物活性玻璃的复合材料在磷酸盐缓冲盐水浸泡后形成更均匀的羟基磷灰石层。在混合复合材料中用微米级生物活性玻璃部分替代纳米级生物活性玻璃不会损害其反应性、转化率（>0.05）和努氏显微硬度（>0.05）。得出的结论是，将生物活性玻璃颗粒减小到纳米级可提高实验复合材料的碱化潜力，且对其基本性能无负面影响。
