【公開日：2023.07.28】【最終更新日：2023.04.28】
課題データ / Project Data
課題番号 / Project Issue Number
22CT0126
利用課題名 / Title
Evaluation of Enamel Remineralization Potential of Borate Bioactive Glasses
利用した実施機関 / Support Institute
公立千歳科学技術大学 / Chitose IST
機関外・機関内の利用 / External or Internal Use
外部利用/External Use
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）物質・材料合成プロセス/Molecule & Material Synthesis（副 / Sub）計測・分析/Advanced Characterization
【重要技術領域 / Important Technology Area】（主 / Main）次世代バイオマテリアル/Next-generation biomaterials（副 / Sub）-
キーワード / Keywords
走査型電子顕微鏡,透過型電子顕微鏡,熱重量分析,電子顕微鏡/Electron microscopy,走査プローブ顕微鏡/Scanning probe microscopy,電子顕微鏡/Electron microscopy,生分解性材料/ Biodegradable material,抗菌・抗ウイルス材料/ Antibacterial/antiviral materials,細胞・組織再生誘導材料/ Materials for inducing cell and tissue regeneration
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
スニガエレディア エンリケ エズラ
所属名 / Affiliation
北海道医療大学歯学部歯学科
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
利用形態 / Support Type
（主 / Main）機器利用/Equipment Utilization（副 / Sub）,技術代行/Technology Substitution
利用した主な設備 / Equipment Used in This Project
CT-011：電界放出形走査電子顕微鏡（FE-SEM）
CT-012：透過型電子顕微鏡（TEM）
CT-020：熱重量測定装置（TGA）
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
Aim: This study aimed to evaluate the enamel remineralization potential of bioactive glass with varying network modifiers content (Sodium (Na) Calcium (Ca), Strontium (Sr)).Content: Bioactive glasses (BG) have gained attention for their multifunctional properties, suitable for biomedical applications, such as bone tissue engineering, wound healing, and dental applications. This study synthesized six types of bioactive glasses nanoparticles nBG using sol-gel synthesis with varying components, including borate glass. The enamel remineralization potential was assessed using the EDX technique to evaluate chemical composition and the nanoindenter to evaluate the mechanical properties. The results showed that all samples immersed in artificial saliva + nBG solution improved mechanical properties, indicating the effectiveness of bioactive glasses in enamel remineralization. Borate-BG exhibited superior performance in enamel remineralization potential compared to Silicate-BG. However, the borate glasses containing Sr showed a reduction in the remineralization effect in the short term due to the boron anomaly. The study provides valuable insights into the potential use of borate glass for enamel remineralization, which could pave the way for the development of new dental materials with enhanced remineralization properties.
実験 / Experimental
Experimental: Six different types of bioactive glasses were synthesized using sol-gel synthesis with varying components: nBG( nBG1 : Si-Ca-P, nBG2 : Si-Ca-Na-P, nBG3 : Si-Ca-P-Sr, nBG4 : Si-Ca-Na-P-Sr, nBG5 : B-Ca-Na-P, nBG6 : B-Ca-Na-P-Sr). The EDX technique was used to evaluate the chemical composition, while the morphology and size of the bioactive glass nanoparticles were evaluated using FE-SEM and TEM, respectively. The bioactive glass nanoparticles were dispersed in artificial saliva solution for immersion of the enamel slices. Each experiment was repeated five times (N=5) to ensure the reproducibility of the results.The mechanical properties of the enamel slices were evaluated using a nanoindenter at 28ºC with a load of 100mN. The data obtained were analyzed using one-way ANOVA followed by Tukey's post-hoc test to determine the significant differences between the groups. The level of significance was set at p＜0.05
結果と考察 / Results and Discussion
The experimental composition of all bioactive glasses is presented in Table 1. The average size of the nBG was found to be 20 nm with an asymmetric shape, as observed using FE-SEM and TEM(Fig. 1). All samples immersed in artificial saliva + nBG solution showed improved mechanical properties, indicating the effectiveness of the bioactive glasses in enamel remineralization. Notably, Borate-BG exhibited superior performance in enamel remineralization potential compared to Silicate-BG (Fig. 2). However, the Borate-BG containing Sr in the borate glasses showed a reduction in the remineralization effect in the short term. This observation can be attributed to the boron anomaly, wherein the increase of earth alkaline metal in the Borate-BG structure could enhance connectivity, decrease solubility, and hence reduce ion release. This can lead to a decrease in the formation of a hydroxycarbonate layer, which is crucial for the remineralization process. In SEM evaluation, native enamel had a uniform, smooth surface, while the etched samples with phosphoric acid showed a honeycombed surface. Samples treated with BG exhibited a smoother surface, indicating their potential use in enamel remineralization (Fig. 3). The boron anomaly is a well-known phenomenon in borate glass chemistry, where the increase in the concentration of earth alkaline metals such as calcium or strontium in the glass structure leads to a decrease in ion release upon dissolution. This is because the addition of these modifiers enhances the connectivity of the glass network, making it more rigid and decreasing its solubility. As a result, the borate glasses containing higher concentrations of earth alkaline metals tend to dissolve at a slower rate and release fewer ions, which can reduce their ability to form a hydroxycarbonate layer on the enamel surface. This layer is crucial for the remineralization process, as it provides a nucleation site for the precipitation of calcium and phosphate ions, leading to the formation of new enamel crystals. Therefore, it is important to optimize the composition of borate glass to balance its resorption capacity and ion release for effective enamel remineralization.
図・表・数式 / Figures, Tables and Equations
Table 1. Chemical compositon of the biocative glasses (mol% )
Figure 1. The SEM and TEM images revealed that the nanoparticles of all the bioactive glasses had an average size of 20 nm and displayed an asymmetric morphology.
Figure 2. Changes in hardness and elastic modulus of enamel samples immersed in artificial saliva containing various types of bioactive glasses over a period of 3, 7, and 14 days. The data presented in the graph demonstrates the effect of the bioactive glasses on the mechanical properties of the enamel samples and highlights any trends or changes over time.
Figure 3. SEM images of the enamel slices after immersion in artificial saliva solution containing bioactive glass for 14 days. The images clearly show a smoother surface for enamel treated with nBG5 and nBG6 as compared with the other nBGs.
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
Others: The authors would like to express their gratitude to Ms. Masayoshi Isezaki, Ms. Mari Sakurai, and other staff members of the Nanotechnology Support Project of the Chitose University of Science and Technology for their technical assistance in the FE-SEM and TEM observations. This study provides valuable insights into the potential use of borate glass for enamel remineralization, which could pave the way for the development of new dental materials with enhanced remineralization properties. Further studies are required to determine the optimum composition of borate glass for enamel remineralization and to assess its long-term effectiveness.
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
- 江上由華, Zuniga-Heredia EE,1 Arteaga-Arteaga F, 澤村正也,飯嶋雅弘,生体活性ガラスのエナメル質再石灰化能. 第81回日本矯正歯科学会学術大会＆第9回日韓ジョイントシンポジウム,Osaka,Japan,2022/10/5-7
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件