Development of Glass Fillers with Controlled Releasing Ability of Ions for Dental Application

以聚甲基丙烯酸甲酯（PMMA）为基体，玻璃粉为填料的复合树脂用于牙釉质的修复已得到广泛的研究。但填料的化学耐久性、硬度、透明度有待提高。此外，人们还迫切需要具有控制离子释放等功能的牙科材料。本研究旨在开发具有F^-和Sr^<2+>释放特性的玻璃填充剂，以氟化天然牙，防止蛀牙。对玻璃填料所需的其他理化性能进行了优化研究。所选玻璃体系为SiO_2-B_2O_3-BaO-SrO-AlF_3、SiO_2-B_2O_3-Al_2O_3-BaO-SrF_2、SiO_2-B_2O_3-Al_2O_3-BaF_2-SrF_2和SiO_2-B_2O_3-SrO-AlF_3-BaF_2。研究了离子萃取速率等各种性质与离子组成的关系。总结结果如下：玻璃中离子的萃取在初始阶段经过萃取反应过程后得到扩散控制。玻璃中的铝元素起到了减少离子总萃取的作用。说明富含Al^<3+>离子的保护膜的形成阻止了除4-配位Al^<3+>离子外的离子的进一步萃取，改善了玻璃结构。硼元素的加入增加了离子的总萃取量。除B-O-B结构单元在水中耐久性较差外，B_2O_3含量的增加使分相玻璃的分相倾向增加，导致富B_2O_3相在分相玻璃中的溶解性降低。综上所述，利用Al^<3+>离子的作用和选择玻璃的成分，可以控制离子从玻璃中的萃取；利用玻璃的相分离特性，也可以制备出具有离子控制释放能力的玻璃。少

Composite resins composed of PMMA as matrix and glass powders as fillers for restoration of decayd or injured teeth have been researched extensively, which are believed to be effective in cohesiveness with tooth enamel. However, the chemical durability, hardness, transparency of the fillers are to be improved. Furthermore, the dental materials having further functions such as controlled release of ions are greatly desired. This research is to develop glass fillers having F^- and Sr^<2+> releasing characteristic in order to fluorizate natural teeth for preventing tooth decaying. The optimization of required other physical and chemical properties of the glass fillers is also investigated.The selected glass systems were SiO_2-B_2O_3-BaO-SrO-AlF_3, SiO_2-B_2O_3-Al_2O_3-BaO-SrF_2, SiO_2-B_2O_3-Al_2O_3-BaF_2-SrF_2 and SiO_2-B_2O_3-SrO-AlF_3-BaF_2. The dependences of various properties including extraction rates of ions on their compositions were researched. The summarized results are as foll … More ows :1. The extraction of ions from glasses was diffusion controlled after a reaction process of extraction at the initial stage.2. Aluminum element in glass playd a role of reducing the total extraction of ions. It was explained that the formation of protective films being rich in Al^<3+> ions prevented further extraction of ions besides 4-coordinaded Al^<3+> ions improved the glass structure.3. Adding of boron element increased the total extraction of ions. Besides it was due to the poor durability of B-O-B structure unit in water, the dissolvability of B_2O_3 rich phases in phase separated glasses was another reason because increased tendency of phase separation was observed due to increasing of B_2O_3.From the above results, it is concluded that the extraction of ions from glass are controllable by using the effect of Al^<3+> ions and selecting glass composition, and glasses with controlled releasing ability of ions can also be prepared by useful application of phase separation characteristic of glass. Less