Effects of Er:YAG Laser Irradiation and Topical Fluoride Application on Inhibition of Enamel Demineralization

Objective:The aim of this study was to evaluate the effect of the Er:YAG laser and acidulated phosphate fluoride application on enamel solubility around orthodontic brackets via atomic absorption spectrometry.Materials and Methods:Twenty freshly extracted upper premolar teeth were divided into 2 halves. Each half was covered with a nail varnish, excluding 1 mm (width) of space around each side of the bracket base. Orthodontic brackets were bonded in the center of the isolated area. Four groups were generated. The first group was the control group, and no treatment was performed. In group II (F), only fluoride was applied. Groups III and IV were laser and fluoride combination groups. In Group III (LF), fluoride was applied to the laser-irradiated surface, whereas laser irradiation was performed on the fluoridated enamel surface in Group IV (FL group). Afterwards, samples were demineralized in an acidic solution for 96 hours, and calcium assessment was performed using atomic absorption spectrometry. Comparisons of the calcium ion release values of the groups were performed with Kruskal-Wallis and Tukey honestly significant difference post hoc tests. The statistical significance level was set at p < 0.05.Results:The least amount of calcium release was observed in the LF group (median, 112.7 ppm), while the parameter of the control group was the highest (median, 217.9 ppm). The differences between the control and F groups, control and LF groups, and LF and FL groups were statistically significant. No difference was recorded between the control and FL groups.Conclusion:Laser treatment followed by topical application of acidulated phosphate fluoride gel resulted in the lowest calcium dissolution from the enamel surface

Detection and quantification of a toxic salt substitute (LiCl) by using laser induced breakdown spectroscopy (LISS)

The use of Li salts in foods has been prohibited due to their negative effects on central nervous system; however, they might still be used especially in meat products as Na substitutes. Lithium can be toxic and even lethal at higher concentrations and it is not approved in foods. The present study focuses on Li analysis in meatballs by using laser induced breakdown spectroscopy (LIBS). Meatball samples were analyzed using LIBS and flame atomic absorption spectroscopy. Calibration curves were obtained by utilizing Li emission lines at 610 nm and 670 nm for univariate calibration. The results showed that Li calibration curve at 670 nm provided successful determination of Li with 0.965 of R-2 and 4.64 ppm of limit of detection (LOD) value. While Li Calibration curve obtained using emission line at 610 nm generated R-2 of 0.991 and LOD of 22.6 ppm, calibration curve obtained at 670 nm below 1300 ppm generated R-2 of 0.965 and LOD of 4.64 ppm

The Effect of Boron-Containing Nano-Hydroxyapatite on Bone Cells

Metabolic diseases or injuries damage bone structure and self-renewal capacity. Trace elements and hydroxyapatite crystals are important in the development of biomaterials to support the renewal of bone extracellular matrix. In this study, it was assumed that the boron-loaded nanometer-sized hydroxyapatite composite supports the construction of extracellular matrix by controlled boron release in order to prevent its toxic effect. In this context, boron release from nanometer-sized hydroxyapatite was calculated by ICP-MS as in large proportion within 1 h and continuing release was provided at a constant low dose. The effect of the boron-containing nanometer-sized hydroxyapatite composite on the proliferation of SaOS-2 osteoblasts and human bone marrow-derived mesenchymal stem cells was evaluated by WST-1 and compared with the effects of nano-hydroxyapatite and boric acid. Boron increased proliferation of mesenchymal stem cells at high doses and exhibited different effects on osteoblastic cell proliferation. Boron-containing nano-hydroxyapatite composites increased osteogenic differentiation of mesenchymal stem cells by increasing alkaline phosphatase activity, when compared to nano-hydroxyapatite composite and boric acid. The molecular mechanism of effective dose of boron-containing hydroxyapatite has been assessed by transcriptomic analysis and shown to affect genes involved in Wnt, TGF-beta, and response to stress signaling pathways when compared to nano-hydroxyapatite composite and boric acid. Finally, a safe osteoconductive dose range of boron-containing nano-hydroxyapatite composites for local repair of bone injuries and the molecular effect profile in the effective dose should be determined by further studies to validation of the regenerative therapeutic effect window