scholarly journals Surface and mechanical properties of adhesives with calcium phosphates challenged to different storage media

2020 ◽  
Vol 19 ◽  
pp. e200181
Author(s):  
Marcelo Matias Mederos Gómez ◽  
Isadora Martini Garcia ◽  
Vicente Castelo Branco Leitune ◽  
Fabrício Mezzomo Collares
Keyword(s):  
Lactic Acid ◽  
Calcium Phosphates ◽  
Octacalcium Phosphate ◽  
Sem Analysis ◽  
Distilled Water ◽  
Hydroxyethyl Methacrylate ◽  
Adhesive Resin ◽  
Storage Media ◽  
Water Ph ◽  
Initiator System

Aim: To evaluate the behavior of experimental dental adhesiveswith hydroxyapatite (HAp), alpha-tricalcium phosphate (α-TCP)or octacalcium phosphate (OCP) after storing them in threedifferent media: dry storage, distilled water, or lactic acid.Methods: An experimental adhesive resin was formulated withbisphenol A glycol dimethacrylate, 2-hydroxyethyl methacrylate,and photoiniciator/co-initiator system. HAp (GHAp), α-TCP(Gα-TCP), or OCP (GOCP) were added to the adhesive resin at 2wt.%, and one group remained without calcium phosphates tobe used as a control (GCtrl). The adhesives were evaluated forsurface roughness, scanning electron microscopy (SEM), andultimate tensile strength (UTS) after storing in distilled water(pH=5.8), lactic acid (pH=4) or dry medium. Results: The initialsurface roughness was not different among groups (p>0.05).GHAp showed increased values after immersion in water(p<0.05) or lactic acid (p<0.05). SEM analysis showed a surfacevariation of the filled adhesives, mainly for Gα-TCP and GHAp. GHApshowed the highest UTS in dry medium (p<0.05), and its valuedecreased after lactic acid storage (p<0.05). Conclusions:The findings of this study showed that HAp, OCP, and α-TCPaffected the physical behavior of the experimental adhesiveresins in different ways. HAp was the calcium phosphatethat most adversely affected the surface roughness and themechanical property of the material, mainly when exposed toan acid medium.

Physical Properties of Nanohybrid and Microhybrid Resin Composites Subjected to an Acidic Environment: A Laboratory Study

2020 ◽  
Vol 45 (3) ◽  
pp. E105-E113
Author(s):  
M Ferooz ◽  
R Bagheri ◽  
D Jafarpour ◽  
MF Burrow
Keyword(s):  
Lactic Acid ◽  
Color Change ◽  
Pearson Correlation ◽  
Color Stability ◽  
Time Interval ◽  
Distilled Water ◽  
Resin Composites ◽  
Acidic Environment ◽  
Hardness Tester ◽  
Storage Media

SUMMARY Background: This study investigated the hardness and color stability of five resin composites subjected to different polishing methods following immersion in distilled water or lactic acid for up to three months. Methods and Materials: Three nanohybrid, Paradigm (3M ESPE), Estelite Sigma Quick (Tokuyama), Ice (SDI), and two microhybrid, Filtek P60 and Filtek Z250, composites were examined. Disc-shaped specimens (10×1.5 mm) were prepared and immersed in distilled water for 24 hours then polished using either silicon carbide paper, the Shofu polishing system or were left unpolished (control). The CIE values and microhardness were determined using a spectrophotometer and digital Vickers hardness tester, respectively (n=10) after one, 45, and 90 days of storage in distilled water or lactic acid. Data were analyzed using analysis of variance, Tukey test, and Pearson correlation coefficient. Results: Ice exhibited the greatest color change, yet Paradigm and Filtek P60 demonstrated the least. Overall, discoloration of tested materials was multifactorial and the effect of storage media depended on the material, polishing method and time interval. The greatest hardness was obtained for Paradigm and the lowest for Estelite. Hardness was found to be significantly higher in lactic acid after 45 days (p=0.014) and even higher after 90 days (p&lt;0.001) compared with distilled water. Conclusions: An acidic environment did not adversely affect color stability or microhardness of the resin composites. There was a significantly mild reverse correlation between hardness and color change in both storage media.

SEM Evaluation of Fluoride Pretreatment Effects on Acid-Etching of Caries-Like Enamel Lesions In Vitro

1981 ◽  
Vol 39 ◽  
pp. 474-475
Author(s):  
M. John Hicks
Keyword(s):  
Dental Enamel ◽  
Preventive Measure ◽  
Acid Etching ◽  
Distilled Water ◽  
Adhesive Resin ◽  
Fluoride Treatment ◽  
Treatment Groups ◽  
Pretreatment Effects ◽  
Preparation Techniques

Acid-etching of enamel surfaces has been performed routinely to bond adhesive resin materials to sound dental enamel as a caries-preventive measure. The effect of fluoride pretreatment on acid-etching of enamel has been reported to produce inconsistent and unsatisfactory etching patterns. The failure to obtain an adequate etch has been postulated to be due to fluoride precipitation products deposited on the enamel surface. The purpose of this study was to evaluate the effects of fluoride pretreatment on acid-etching of carieslike lesions of human dental enamel.Caries-like lesions of enamel were created in vitro on human molar and premolar teeth. The teeth were divided into two fluoride treatment groups. The specimens were exposed for 4 minutes to either a 2% Sodium Fluoride (NaF) solution or a 10% Stannous Fluoride (SnF2) solution. The specimens were then washed in deionized-distilled water. Each tooth was sectioned into four test regions. This was carried out to compare the effects of various time exposures (0 to 2 minutes) and differing concentrations (10 to 60% w/w) of phosphoric acid (H3PO4) on etching of caries-like lesions. Standard preparation techniques for SEM were performed on the specimens.

scholarly journals Synthesis and Characterization of Polyphosphazenes Modified with Hydroxyethyl Methacrylate and Lactic Acid

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Evelyn Carolina Martínez Ceballos ◽  
Ricardo Vera Graziano ◽  
Gonzalo Martínez Barrera ◽  
Oscar Olea Mejía
Keyword(s):  
Lactic Acid ◽  
Ring Opening ◽  
Room Temperature ◽  
Block Structure ◽  
Ring Opening Polymerization ◽  
Synthesis And Characterization ◽  
Poly Lactic Acid ◽  
Hydroxyethyl Methacrylate ◽  
H Nmr

Poly(dichlorophosphazene) was prepared by melt ring-opening polymerization of the hexachlorocyclotriphosphazene. Poly[bis(2-hydroxyethyl-methacrylate)-phosphazene] and poly[(2-hydroxyethyl-methacrylate)-graft-poly(lactic-acid)-phosphazene] were obtained by nucleophilic condensation reactions at different concentrations of the substituents. The properties of the synthesized copolymers were assessed by FTIR,1H-NMR and31P-NMR, thermal analysis (DSC-TGA), and electron microscopy (SEM). The copolymers have a block structure and show twoTg's below room temperature. They are stable up to a temperature of 100°C. The type of the substituents attached to the PZ backbone determines the morphology of the polymers.

scholarly journals Preparations of Poly(lactic acid) Dispersions in Water for Coating Applications

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2767
Author(s):  
Giada Belletti ◽  
Sara Buoso ◽  
Lucia Ricci ◽  
Alejandro Guillem-Ortiz ◽  
Alejandro Aragón-Gutiérrez ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Gel Permeation Chromatography ◽  
Sem Analysis ◽  
Water Phase ◽  
Poly Lactic Acid ◽  
Water Emulsion ◽  
Preparation Conditions ◽  
Ft Ir ◽  
Homogenization Methods ◽  
Oil In Water Emulsion

A green, effective methodology for the preparation of water-based dispersions of poly(lactic acid) (PLA) for coating purposes is herein presented. The procedure consists of two steps: in the first one, an oil-in-water emulsion is obtained by mixing a solution of PLA in ethyl acetate with a water phase containing surfactant and stabilizer. Different homogenization methods as well as oil/water phase ratio, surfactant and stabilizer combinations were screened. In the second step, the quantitative evaporation of the organic provides water dispersions of PLA that are stable, at least, over several weeks at room temperature or at 4 °C. Particle size was in the 200–500 nm range, depending on the preparation conditions, as confirmed by scanning electron microscope (SEM) analysis. PLA was found not to suffer significant molecular weight degradation by gel permeation chromatography (GPC) analysis. Furthermore, two selected formulations with glass transition temperature (Tg) of 51 °C and 34 °C were tested for the preparation of PLA films by drying in PTFE capsules. In both cases, continuous films that are homogeneous by Fourier-transform infrared spectroscopy (FT-IR) and SEM observation were obtained only when drying was performed above 60 °C. The formulation with lower Tg results in films which are more flexible and transparent.

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 Impact Toughness and Ductility Enhancement of Biodegradable Poly(lactic acid)/Poly(ε-caprolactone) Blends via Addition of Glycidyl Methacrylate

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Wei Kit Chee ◽  
Nor Azowa Ibrahim ◽  
Norhazlin Zainuddin ◽  
Mohd Faizal Abd Rahman ◽  
Buong Woei Chieng
Keyword(s):  
Lactic Acid ◽  
Impact Strength ◽  
Glycidyl Methacrylate ◽  
Interfacial Adhesion ◽  
Tensile Modulus ◽  
Sem Analysis ◽  
Poly Lactic Acid ◽  
Biodegradable Poly ◽  
Interfacial Compatibility ◽  
The Impact

Poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends were prepared via melt blending technique. Glycidyl methacrylate (GMA) was added as reactive compatibilizer to improve the interfacial adhesion between immiscible phases of PLA and PCL matrices. Tensile test revealed that optimum in elongation at break of approximately 327% achieved when GMA loading was up to 3wt%. Slight drop in tensile strength and tensile modulus at optimum ratio suggested that the blends were tuned to be deformable. Flexural studies showed slight drop in flexural strength and modulus when GMA wt% increases as a result of improved flexibility by finer dispersion of PCL in PLA matrix. Besides, incorporation of GMA in the blends remarkably improved the impact strength. Highest impact strength was achieved (160% compared to pure PLA/PCL blend) when GMA loading was up to 3 wt%. SEM analysis revealed improved interfacial adhesion between PLA/PCL blends in the presence of GMA. Finer dispersion and smooth surface of the specimens were noted as GMA loading increases, indicating that addition of GMA eventually improved the interfacial compatibility of the nonmiscible blend.

A Comparative Study of Bioceramics In Vitro and In Vivo

2005 ◽  
Vol 284-286 ◽  
pp. 11-14 ◽  
Author(s):  
Yang Leng ◽  
Ren Long Xin ◽  
Ji Yong Chen
Keyword(s):  
Calcium Phosphates ◽  
Glass Ceramics ◽  
Octacalcium Phosphate ◽  
Rabbit Muscle ◽  
In Vivo Experiments ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Dental Applications

Bioactive calcium phosphate (Ca-P) formation in bioceramics surfaces in simulated body fluid (SBF) and in rabbit muscle sites was investigated. The examined bioceamics included most commonly used bioglass®, A-W glass-ceramics and calcium phosphates in orthopedic and dental applications. The Ca-P cyrstal structures were examined with single crystal diffraction patterns in transmission electron microscopy, which reduced possibility of misidentifying Ca-P phases. The experimental results show that capability of Ca-P formation considerably varied among bioceramics, particularly in vivo. Octacalcium phosphate (OCP) was revealed on the all types of bioceramics in vitro and in vivo experiments. This work leads us to rethink how to evaluate bioactivity of bioceramics and other orthopedic materials which exhibit capability of osteoconduction by forming direct bonding with bone.

scholarly journals Investigation on compatibility of PLA/PBAT blends modified by epoxy-terminated branched polymers through chemical micro-crosslinking

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 39-54 ◽  
Author(s):  
Bo Wang ◽  
Yujuan Jin ◽  
Kai’er Kang ◽  
Nan Yang ◽  
Yunxuan Weng ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Glass Transition ◽  
Sem Analysis ◽  
Branched Polymers ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Butylene Terephthalate ◽  
The Difference ◽  
Physical And Chemical ◽  
The Impact

AbstractIn this study, a type of epoxy-terminated branched polymer (ETBP) was used as an interface compati- bilizer to modify the poly lactic acid (PLA)/poly(butylene adipate-co-butylene terephthalate) (PBAT) (70/30) blends. Upon addition of ETBP, the difference in glass transition temperature between PLA and PBAT became smaller. By adding 3.0 phr of ETBP, the elongation at break of the PLA/PBAT blends was found increased from 45.8% to 272.0%; the impact strength increased from 26.2 kJ·m−2 to 45.3 kJ·m−2. In SEM analysis, it was observed that the size of the dispersed PBAT particle decreased with the increasing of ETBP content. These results indicated that the compatibility between PLA and PBAT can be effectively enhanced by using ETBP as the modifier. The modification mechanism was discussed in detail. It proposes that both physical and chemical micro-crosslinking were formed, the latter of which was confirmed by gel content analysis.

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