scholarly journals Anti-demineralizing protective effects on enamel identified in experimental and commercial restorative materials with functional fillers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matej Par ◽  
Andrea Gubler ◽  
Thomas Attin ◽  
Zrinka Tarle ◽  
Tobias T. Tauböck
Keyword(s):  
Lactic Acid ◽  
Acid Solution ◽  
Protective Effect ◽  
Bioactive Glass ◽  
Scanning Electron Micrographs ◽  
Lactic Acid Solution ◽  
Acid Addition ◽  
Restorative Materials ◽  
Functional Fillers ◽  
Scanning Electron

AbstractThe aim of this study was to investigate whether experimental and commercial dental restorative materials with functional fillers can exert a protective anti-demineralizing effect on enamel that is not immediately adjacent to the restoration. Four experimental resin composites with bioactive glass and three commercial restorative materials were investigated. Enamel blocks were incubated in a lactic acid solution (pH = 4.0) at a standardized distance (5 mm) from cured specimens of restorative materials. The lactic acid solution was replenished every 4 days up to a total of 32 days. Surfaces of enamel blocks were periodically evaluated by Knoop microhardness measurements and scanning electron microscopy. The protective effect of restorative materials against acid was identified as enamel microhardness remaining unchanged for a certain number of 4-day acid addition cycles. Additionally, the pH of the immersion medium was measured. While enamel microhardness in the control group was maintained for 1 acid addition cycle (4 days), restorative materials postponed enamel softening for 2–5 cycles (8–20 days). The materials capable of exerting a stronger alkalizing effect provided longer-lasting enamel protection. The protective and alkalizing effects of experimental composites improved with higher amounts of bioactive glass and were better for conventional bioactive glass 45S5 compared to a fluoride-containing bioactive glass. Scanning electron micrographs evidenced the protective effect of restorative materials by showing a delayed appearance of an etching pattern on the enamel surface. A remotely-acting anti-demineralizing protective effect on enamel was identified in experimental composites functionalized with two types of bioactive glass, as well as in three commercial ion-releasing restorative materials.

scholarly journals A study on highly concentrated lactic acid and the synthesis of lactide from its solution

2021 ◽  
pp. 174751982110210
Author(s):  
Xiaolong Xu ◽  
Lijuan Liu
Keyword(s):  
Lactic Acid ◽  
Acid Solution ◽  
Concentration Distribution ◽  
Raw Material ◽  
High Concentration ◽  
Composition Distribution ◽  
Lactic Acid Solution ◽  
H Nmr ◽  
Back Titration ◽  
Condensed Water

Lactic acid is an important platform compound used as raw material for the production of lactide and polylactic acid. However, its concentration and composition distribution are not as simple as those of common compounds. In this work, the mass concentration distribution of highly concentrated lactic acid is determined by back titration. The components of highly concentrated lactic acid, crude lactide, and polymer after the reaction are analyzed by HPLC. Different concentrations of lactic acid solution were prepared for the synthesis of lactide and its content in the product was determined by 1H NMR analysis. We found that lactide is more easily produced from high-concentration lactic acid solution with which the condensed water is easier to release. Hence, the removal of condensed water is crucial to the formation of lactide, although it is not directly formed by esterification of two molecules of lactic acid.

Storage of polyacid-modified resin composites (“compomers”) in lactic acid solution

1999 ◽  
Vol 15 (6) ◽  
pp. 413-416 ◽  
Author(s):  
J.W. Nicholson ◽  
B.J. Millar ◽  
B. Czarnecka ◽  
H. Limanowska-Shaw
Keyword(s):  
Lactic Acid ◽  
Acid Solution ◽  
Resin Composites ◽  
Lactic Acid Solution ◽  
Modified Resin

scholarly journals THE EFFECT OF LACTIC ACID AND ARTIFICIAL SALIVA SOLUTION IMMERSION TO THE RELEASE OF CALCIUM IONS ON BIOACTIVE RESIN

2021 ◽  
Vol 6 (2) ◽  
pp. 190
Author(s):  
Dewi Puspitasari ◽  
Nurah Tajjalia ◽  
Diana Wibowo ◽  
Agung Satria Wardhana
Keyword(s):  
Lactic Acid ◽  
Acid Solution ◽  
Calcium Ions ◽  
Calcium Ion ◽  
Artificial Saliva ◽  
Distilled Water ◽  
Acid Condition ◽  
Ion Release ◽  
Lactic Acid Solution ◽  
Solution Increase

Background: Bioactive resin can release calcium ions when contact with solution media, even in acid condition. In the oral cavity, pH may change into acid condition due to the metabolic results of Streptococcus mutans. The bacteria metabolize carbohydrates into organic acids, one of which is lactic acid. Purpose: Analyze the effect of lactic acid solution and artificial saliva on the number of the release of calcium ions of bioactive resin. Methods: Forty-two specimens (diameter 15 mm x thickness 1 mm; n= 7/group fabricated with Activa™ Bioactive Restorative (Pulpdent). The specimens that meet the criteria were divided into 6 groups. The specimen was immersed for 1 and 7 days in the incubator at 37oC. The number of calcium ion release is measured using titration method. Results: Two Way Anova test and Post Hoc Bonferonni test showed there were significant differences among all group for lactic acid 1 day (4.040 ± 0.360) µg, artificial saliva 1 day (0.640 ± 0.338) µg, distilled water 1 day (1.040 ± 0.504) µg, lactic acid 7 days (5.400 ± 0.312), artificial saliva 7 days (1.640 ± 0.215) µg, distilled water 7 days (3.520± 0.356 µg). Conclusion: There was an influence of lactic acid and artificial saliva on the number of calcium ion releases of bioactive resin. Immersion of bioactive resin in the lactic acid solution increase the calcium ion releases and artificial saliva decrease the calcium ion release compared to distilled water. Keywords: artificial saliva, bioactive resin, calcium ion release, lactic acid

scholarly journals PREPARATION OF LACTIC ACIDOLIGOMER

2019 ◽  
Vol 62 (6) ◽  
pp. 23-28
Author(s):  
Valentina N. Glotova ◽  
Tatyana V. Ushakova ◽  
Viktor T. Novikov
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Acid Solution ◽  
Aromatic Hydrocarbons ◽  
Azeotropic Distillation ◽  
Linear Structure ◽  
Gel Permeation Chromatography ◽  
Reaction Mass ◽  
Lactic Acid Solution ◽  
Simultaneous Process

The process of obtaining of lactic acid oligomer as by-product for synthesis of biodegradable polylactide was investigated. Synthesis of oligomer was carried out by azeotropic distillation of water. Aromatic hydrocarbons such as toluene, chlorobenzene, bromobenzene and o-dichlorobenzene were used. They form heteroazeotropes. This allowed to control the volume of distilled water. The time of obtaining of oligomer of lactic acid in presence aromatic hydrocarbons and without them was compare in the article. The reaction of obtaining of oligomer was carried out in a rotary vacuum evaporator and in laboratory distillation installation in presence of catalyst (ZnO in the amount of 1.5% by weight) for reaction assessment. It was shown that the using of azeotropic distillation of water from reaction mass allow to reduce the time of oligomer synthesis compared to standard distillation of water from the lactic acid solution. It implements by reducing of viscosity of reaction mass that improves heat and mass transfer in the reactor. These factors contribute to increase rate of distillation of solution water and water which release in the process of polycondensation of lactic acid. The oligomer yield also increases. The actual control of concentrating of the aqueous solution of lactic acid and the oligomer obtaining reaction carried out according to the rate of distillation of the water from the reactor. Also the control was carried out by changing the molecular weight of the oligomer. The molecular weight of the oligomers obtained was determined by gel permeation chromatography. It reached 1600 g/mol. Lactic acid oligomer of a linear structure was obtained under these conditions. IR spectra of the oligomer of lactic acid indicate the simultaneous process of concentration of the lactic acid solution and polycondensation of lactic acid.

scholarly journals Efficacy of Lactic Acid and Modified Atmosphere Packaging against Campylobacter jejuni on Chicken during Refrigerated Storage

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 109 ◽  
Author(s):  
Elena Gonzalez-Fandos ◽  
Naiara Maya ◽  
Alba Martínez-Laorden ◽  
Iratxe Perez-Arnedo
Keyword(s):  
Lactic Acid ◽  
Acid Solution ◽  
Campylobacter Jejuni ◽  
Modified Atmosphere Packaging ◽  
Modified Atmosphere ◽  
Distilled Water ◽  
Water Control ◽  
Lactic Acid Solution ◽  
Modified Atmospheres ◽  
Chicken Legs

The present study was conducted to evaluate the combined effect of lactic acid washing and modified atmospheres packaging on the counts of Campylobacter jejuni on chicken legs stored at 4 °C. In experiment 1, inoculated chicken legs were washed with either 1% or 2% lactic acid solution for 5 min or distilled water (control). The treatment with 2% lactic acid reduced C. jejuni counts 1.42 log units after treatment (day 0). In experiment 2, inoculated samples were packaged under different conditions: air, 100%N2, vacuum, 20%CO2/80%N2, or 40%CO2/60%N2. C. jejuni counts were higher in samples packaged under vacuum or atmospheres containing CO2 than in air. In experiment 3, inoculated chicken legs were washed with a 2% lactic acid solution for 5 min or distilled water (control). Samples were packaged under different conditions: air, vacuum, 20%CO2/80%N2, or 40%CO2/60%N2. C. jejuni counts were lower in samples treated with lactic acid than in samples non-treated. However, C. jejuni counts were higher in chicken legs treated with lactic acid and packaged in modified atmospheres than in those treated and packaged in air. Immersion of chicken legs in a solution containing 2% lactic acid can reduce C. jejuni counts on fresh chicken packaged in modified atmosphere.

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