Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region.
EaStCHEM, School of Chemistry, The University of Edinburgh, Edinburgh, UK.
J Dent. 2021 Feb;105:103581. doi: 10.1016/j.jdent.2021.103581. Epub 2021 Jan 9.
This study investigated the effects of a new strontium-doped bioactive glass and fluoride on hydroxyapatite crystallization.
We designed an in vitro experiment with calcium phosphate (CaCl·2HO + KHPO in buffer solution) with different concentrations of strontium-doped bioactive glass (1 mg/mL or 5 mg/mL), and different concentrations of fluoride (0 ppm, 1 ppm or 5 ppm). Tris-buffered saline served as negative control. After incubation at 37 ℃ for 48 h, the shape and organization of crystals were examined by transmission electron microscopy (TEM) and electron diffraction. Structure of the crystals was assessed by powder X-ray diffraction (P-XRD) and unit cell parameters were calculated. Characterization of the crystals were performed by Raman spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR).
TEM and selected-area electron diffraction revealed that the precipitates in all experimental groups were crystalline apatite. There was an interaction between strontium and fluoride with different concentrations on crystal thickness (p = 0.008). P-XRD indicated the formation of strontium-substituted-fluorohydroxyapatite and strontium-substituted-hydroxyapatite in the groups with both bioactive glass and fluoride. Expansion or contraction of crystal unit cell was influenced by the concentrations of strontium and fluoride. Raman spectra showed strong phosphate band at 960 cm in all experimental groups and displayed no obvious shift. FTIR results confirmed the formation of apatite.
The results of this study suggest that strontium-doped bioactive glass and fluoride have synergistic effects on hydroxyapatite crystallization.
Strontium-doped bioactive glass and fluoride have synergistic effects on hydroxyapatite crystallization by producing strontium-substituted-hydroxyapatite and strontium-substituted-fluorohydroxyapatite with enhanced bioactivity and reduced solubility which could be beneficial for caries management.
本研究旨在探讨掺锶生物活性玻璃和氟化物对羟基磷灰石结晶的影响。
我们设计了一个体外实验，使用不同浓度的掺锶生物活性玻璃（1mg/mL 或 5mg/mL）和不同浓度的氟化物（0ppm、1ppm 或 5ppm）处理磷酸钙（CaCl·2HO 和 KHPO 在缓冲溶液中）。三羟甲基氨基甲烷缓冲盐水作为阴性对照。在 37℃孵育 48 小时后，通过透射电子显微镜（TEM）和电子衍射观察晶体的形态和组织。通过粉末 X 射线衍射（P-XRD）和晶胞参数计算评估晶体结构。通过拉曼光谱和傅里叶变换红外光谱（FTIR）对晶体进行了表征。
TEM 和选区电子衍射显示所有实验组的沉淀物均为结晶磷灰石。不同浓度的锶和氟化物之间存在相互作用，影响晶体厚度（p=0.008）。P-XRD 表明，在同时含有生物活性玻璃和氟化物的组中形成了锶取代氟羟磷灰石和锶取代羟磷灰石。晶体晶胞的膨胀或收缩受到锶和氟化物浓度的影响。拉曼光谱显示所有实验组在 960cm 处均有较强的磷酸盐带，且无明显位移。FTIR 结果证实了磷灰石的形成。
本研究结果表明，掺锶生物活性玻璃和氟化物对羟基磷灰石结晶具有协同作用。
掺锶生物活性玻璃和氟化物通过产生具有增强生物活性和降低溶解度的锶取代羟磷灰石和锶取代氟羟磷灰石，对羟基磷灰石结晶具有协同作用，这可能有利于龋病管理。
