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Abstract：
OBJECTIVE: To investigate the effects of novel bioactive glasses (BG) including PSC with high phosphorus component and FBG with fluorine-doped element on promoting remineralization of artificial dentin caries.
METHODS: (1) BGs were used in this study as follows: PSC (10.8%P2O5-54.2%SiO2-35.0%CaO, mol.%) were synthesized using phytic acid as the phosphorus precursor through sol-gel method. FBG (6.1%P2O5-37.0%SiO2-53.9%CaO-3.0%CaF2, mol.%) and 45S5(6.0%P2O5-45.0%SiO2-24.5%CaO-24.5%Na2O, mol.%) were synthesized by traditional melt method. (2) The above BGs were soaked in simulated body fluid (SBF) for 24 hours. Then X-ray diffraction (XRD) was used to analyze the formation of hydroxyapatite (HA) crystals. (3) Prepared 1 mm thick dentin slices were soaked in 17% ethylene diamine tetraacetic acid (EDTA) for 1 week to demineralize the dentin. Then the dentin slices treated by BG were soaked in SBF for 1 week. Field emission scanning electron micro-scopy (FE-SEM) was used to observe the surface morphology of the dentin slices. (4) Four cavities were prepared to 1 mm depth in each 2 mm thick dentin slice, then were treated with lactic acid for 2 weeks to form the artificial dentin caries. Wax, mineral trioxide aggregate (MTA), PSC and FBG were used to fill four cavities as blank control group, MTA group, PSC group and FBG group respectively. Then the spe-cimens were soaked in SBF for 4 weeks. The changes of depth and density of demineralized dentin were analyzed using Micro-CT before filling and after 2 and 4 weeks filling.
RESULTS: (1) PSC and FBG promoted mineral formation on the surfaces of the demineralized dentin. And the speed was faster and crystallinity was higher in PSC group than the FBG and 45S5 groups. (2) The increased mineral density of artificial dentin caries in PSC group were (185.98 ± 55.66) mg/cm3 and (213.64 ± 36.01) mg/cm3 2 and 4 weeks after filling respectively, which were significantly higher than the control group [(20.38 ± 7.55) mg/cm3, P=0.006; (36.46 ± 10.79) mg/cm3, P=0.001]. At meanwhile, PSC group was also higher than MTA group [(57.29 ± 10.09) mg/cm3; (111.02 ± 22.06) mg/cm3], and it had statistical difference (P=0.015; P=0.006). The depth of remineralized dentin in PSC group were (40.0 ± 16.9) μm and (54.5 ± 17.8) μm 2 and 4 weeks respectively, which were also statistically different from the control group (P =0.010;P=0.001). There were no statistical differences between the control group and MTA group. The above effects of FBG group were between PSC and MTA.
CONCLUSIONS: PSC has advantages in the speed, quality and depth of mineral deposition in the demineralized layer of artificial dentin caries. It would be expected to be an ideal material to promote the remineralization of dentin caries.
METHODS: (1) BGs were used in this study as follows: PSC (10.8%P2O5-54.2%SiO2-35.0%CaO, mol.%) were synthesized using phytic acid as the phosphorus precursor through sol-gel method. FBG (6.1%P2O5-37.0%SiO2-53.9%CaO-3.0%CaF2, mol.%) and 45S5(6.0%P2O5-45.0%SiO2-24.5%CaO-24.5%Na2O, mol.%) were synthesized by traditional melt method. (2) The above BGs were soaked in simulated body fluid (SBF) for 24 hours. Then X-ray diffraction (XRD) was used to analyze the formation of hydroxyapatite (HA) crystals. (3) Prepared 1 mm thick dentin slices were soaked in 17% ethylene diamine tetraacetic acid (EDTA) for 1 week to demineralize the dentin. Then the dentin slices treated by BG were soaked in SBF for 1 week. Field emission scanning electron micro-scopy (FE-SEM) was used to observe the surface morphology of the dentin slices. (4) Four cavities were prepared to 1 mm depth in each 2 mm thick dentin slice, then were treated with lactic acid for 2 weeks to form the artificial dentin caries. Wax, mineral trioxide aggregate (MTA), PSC and FBG were used to fill four cavities as blank control group, MTA group, PSC group and FBG group respectively. Then the spe-cimens were soaked in SBF for 4 weeks. The changes of depth and density of demineralized dentin were analyzed using Micro-CT before filling and after 2 and 4 weeks filling.
RESULTS: (1) PSC and FBG promoted mineral formation on the surfaces of the demineralized dentin. And the speed was faster and crystallinity was higher in PSC group than the FBG and 45S5 groups. (2) The increased mineral density of artificial dentin caries in PSC group were (185.98 ± 55.66) mg/cm3 and (213.64 ± 36.01) mg/cm3 2 and 4 weeks after filling respectively, which were significantly higher than the control group [(20.38 ± 7.55) mg/cm3, P=0.006; (36.46 ± 10.79) mg/cm3, P=0.001]. At meanwhile, PSC group was also higher than MTA group [(57.29 ± 10.09) mg/cm3; (111.02 ± 22.06) mg/cm3], and it had statistical difference (P=0.015; P=0.006). The depth of remineralized dentin in PSC group were (40.0 ± 16.9) μm and (54.5 ± 17.8) μm 2 and 4 weeks respectively, which were also statistically different from the control group (P =0.010;P=0.001). There were no statistical differences between the control group and MTA group. The above effects of FBG group were between PSC and MTA.
CONCLUSIONS: PSC has advantages in the speed, quality and depth of mineral deposition in the demineralized layer of artificial dentin caries. It would be expected to be an ideal material to promote the remineralization of dentin caries.
摘要：
目的：研究新型生物活性玻璃（BG）包括高磷组分的PSC和掺氟元素的FBG促进人工牙本质龋再矿化的作用。
方法：（1）本研究中使用的BG如下：PSC（10.8％P2O5-54.2％SiO2-35.0％CaO，mol.%)是以植酸为磷前驱体通过溶胶-凝胶法合成的。FBG(6.1%P2O5-37.0%SiO2-53.9%CaO-3.0%CaF2,mol.%)和45S5(6.0%P2O5-45.0%SiO2-24.5%CaO-24.5%Na2O，mol.%)采用传统熔融法合成。(2)将上述BG在模拟体液(SBF)中浸泡24小时。然后使用X射线衍射（XRD）分析羟基磷灰石（HA）晶体的形成。(3)将制备的1mm厚的牙本质切片在17%乙二胺四乙酸(EDTA)中浸泡1周以使牙本质脱矿质。然后将BG处理的牙本质切片在SBF中浸泡1周。使用场发射扫描电子显微镜（FE-SEM）观察牙本质切片的表面形态。（4）在每个2毫米厚的牙本质切片中制备1毫米深的四个空腔，然后用乳酸处理2周形成人工牙本质龋。蜡,矿物三氧化物骨料（MTA），用PSC和FBG填充四个腔作为空白对照组。MTA组,分别为PSC组和FBG组。然后将特殊的柠檬浸泡在SBF中4周。采用Micro-CT分析充填前、充填后2、4周脱矿牙本质的深度和密度变化。
结果：（1）PSC和FBG促进了脱矿质牙本质表面上的矿物质形成。PSC组比FBG和45S5组的速度更快，结晶度更高。（2）填充后2周和4周，PSC组人工牙本质龋的矿物质密度分别为（185.98±55.66）mg/cm3和（213.64±36.01）mg/cm3。显著高于对照组[(20.38±7.55)mg/cm3,P=0.006;(36.46±10.79)mg/cm3,P=0.001]。与此同时,PSC组也高于MTA组[(57.29±10.09)mg/cm3;(111.02±22.06)mg/cm3],差异有统计学意义(P=0.015;P=0.006)。PSC组牙本质再矿化深度2周和4周分别为(40.0±16.9)μm和(54.5±17.8)μm,与对照组也有统计学差异(P=0.010;P=0.001)。对照组与MTA组比较差异无统计学意义。FBG组的上述影响介于PSC和MTA之间。
结论：PSC在速度方面具有优势，人工牙本质龋脱矿质层中矿物沉积的质量和深度。它有望成为促进牙本质龋齿再矿化的理想材料。
方法：（1）本研究中使用的BG如下：PSC（10.8％P2O5-54.2％SiO2-35.0％CaO，mol.%)是以植酸为磷前驱体通过溶胶-凝胶法合成的。FBG(6.1%P2O5-37.0%SiO2-53.9%CaO-3.0%CaF2,mol.%)和45S5(6.0%P2O5-45.0%SiO2-24.5%CaO-24.5%Na2O，mol.%)采用传统熔融法合成。(2)将上述BG在模拟体液(SBF)中浸泡24小时。然后使用X射线衍射（XRD）分析羟基磷灰石（HA）晶体的形成。(3)将制备的1mm厚的牙本质切片在17%乙二胺四乙酸(EDTA)中浸泡1周以使牙本质脱矿质。然后将BG处理的牙本质切片在SBF中浸泡1周。使用场发射扫描电子显微镜（FE-SEM）观察牙本质切片的表面形态。（4）在每个2毫米厚的牙本质切片中制备1毫米深的四个空腔，然后用乳酸处理2周形成人工牙本质龋。蜡,矿物三氧化物骨料（MTA），用PSC和FBG填充四个腔作为空白对照组。MTA组,分别为PSC组和FBG组。然后将特殊的柠檬浸泡在SBF中4周。采用Micro-CT分析充填前、充填后2、4周脱矿牙本质的深度和密度变化。
结果：（1）PSC和FBG促进了脱矿质牙本质表面上的矿物质形成。PSC组比FBG和45S5组的速度更快，结晶度更高。（2）填充后2周和4周，PSC组人工牙本质龋的矿物质密度分别为（185.98±55.66）mg/cm3和（213.64±36.01）mg/cm3。显著高于对照组[(20.38±7.55)mg/cm3,P=0.006;(36.46±10.79)mg/cm3,P=0.001]。与此同时,PSC组也高于MTA组[(57.29±10.09)mg/cm3;(111.02±22.06)mg/cm3],差异有统计学意义(P=0.015;P=0.006)。PSC组牙本质再矿化深度2周和4周分别为(40.0±16.9)μm和(54.5±17.8)μm,与对照组也有统计学差异(P=0.010;P=0.001)。对照组与MTA组比较差异无统计学意义。FBG组的上述影响介于PSC和MTA之间。
结论：PSC在速度方面具有优势，人工牙本质龋脱矿质层中矿物沉积的质量和深度。它有望成为促进牙本质龋齿再矿化的理想材料。
