The remineralization properties of two newly developed orthodontic primers.

Development of a graphene oxide/hydroxyapatite-containing orthodontic primer: An in-vitro study

Evaluation of a newly developed calcium fluoride nanoparticles-containing orthodontic primer: An in-vitro study

Background: Demineralization and white spot lesions are the most common complications in fixed orthodontic treatment. It is useful to enhance the remineralization properties of the orthodontic primer by the addition of remineralizing agents. Fluoride and calcium are regarded as the main component of enamel fluorohydroxyapatite crystals. This pilot study compared three mixing methods of calcium fluoride nanoparticles (nCaF2) with conventional orthodontic primer (Transbond XTTM) to develop a primer with enamel remineralization properties. Materials and methods: The nanoparticles were added to Transbond XTTM primer to form 20% (w/w) of the final solution. Three dark plastic bottles were prepared and stored until mixing. The first sample was mixed by a Vortex machine, the second was mixed with an electric agitator, and the third one was mixed with a customized plastic spatula adapted to a dental engine and a straight handpiece. Cured blocks of the developed primer were prepared and were examined for homogeneity, cracks, and agglomeration of the nanoparticles within the primer using Field Emission Scanning Electron Microscopy (FESM). Results: The third Sample showed a continuous distribution of nanoparticles with no apparent cracks or agglomeration of nanoparticles. In contrast, a higher agglomeration was seen in the first sample than in the other two. Conclusion: Mixing of nCaF2 with Transbond XTTM orthodontic primer was best achieved by the customized plastic spatula adapted to a dental engine compared to Vortex and electric agitator machines.

Investigation on biophysical properties of Hydroxyapatite/Graphene oxide (HAp/GO) based binary nanocomposite for biomedical applications

Purpose:This study aimed to develop a novel orthodontic primer that incorporated graphite fluoride (GF) and Bioactive glass (BAG) and to investigate its cell viability, bonding strength, and enamel damage, as well as its antibacterial and remineralization properties.Materials and Methods:Nine groups were prepared by adding different concentrations of GF (1, 2, and 4 wt.%) and BAG (1, 3, and 5 wt.%) to Transbond™ XT orthodontic primer. The prepared primers were compared to the control primer in terms of cell viability, shear bond strength (SBS), adhesive remnant index (ARI), enamel damage index (EDI), and antibacterial test. Then, the groups with better antibacterial properties (GFBAG 1-1, GFBAG 4-1, GFBAG 4-3, GFBAG 4-5) were evaluated for the remineralization properties.Results:All the prepared orthodontic primers with different concentrations of GF/BAG revealed acceptable cell viability levels, with comparable SBS and ARI values to the control primer (p>0.05). Simultaneously, the EDI was reduced, while the antibacterial properties were significantly enhanced when compared to the control group (p<0.05). The result of remineralization properties revealed that the selected groups had significantly higher remineralization ability than the control group; this was most pronounced in the GFBAG 4-3 group.Conclusions:All the prepared GF/BAG orthodontic primers are biologically safe with adequate SBS, ARI, and EDI values for clinical application with enhanced antibacterial properties. The GFBAG 4-3 experimental primer reveals the best antibacterial and remineralization properties which require further in-vitro and in-vivo investigations as a preventive measure of white spot lesions.

Three-dimensional hierarchical flower-like graphene oxide-hydroxyapatite (GO-HAp) nanocomposites were synthesized by a simple biomimetic method in a modified simulated body fluid (mSBF). The obtained GO-HAp nanocomposites were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and N2 adsorption-desorption analysis. The formation mechanism was proposed and the prepared GO-HAp was applied as an adsorbent to remove strontium from large volumes of aqueous solutions. A maximum adsorption capacity of 702.18 mg g(-1) was achieved on GO-HAp, almost two fold higher than that of bare HAp and nine fold higher than that of GO. The effects of pH, adsorbent content, contact time and Sr(2+) initial concentrations on Sr(2+) removal from solution by GO-HAp were systematically investigated, and the results indicated that the removal of Sr(2+) by GO-HAp was weakly dependent on solution pH. The results herein reveal that the GO-HAp nanocomposites had exceptional potential as a suitable material for preconcentration and solidification of radiostrontium from large volumes of aqueous solutions in nuclear waste management and radiostrontium pollution cleanup.

Novel bioactive root canal sealer with antibiofilm and remineralization properties

The preparation of graphene with high quality serves as a prerequisite for its usage. Traditional methods of graphene production, represented by liquid-phase exfoliation and chemical vapor depositi...

Porous nitrogen-doped graphene prepared through pyrolysis of ammonium acetate as an efficient ORR nanocatalyst

Electrophoretic deposition of graphene oxide reinforced hydroxyapatite on the tantalum substrate for bone implant applications: In vitro corrosion and bio-tribological behavior

Microbial biofilm accumulation around orthodontic brackets and composite is a common complication of fixed orth-odontic treatment. This study assessed the antibacterial effects of orthodontic primer containing chitosan nanoparticles (CNPs) against the multispecies biofilm of cariogenic bacteria in а rat model. Transbond XT orthodontic primer containing 0%, 1%, 5%, and 10% CNPs was experimentally prepared. The Wistar rats were randomly divided into four groups (n=7) of control (0% CNPs), 1%, 5% and 10% CNPs. The oral cavities of the rats were infected with cariogenic bacteria. After anesthetizing the rats, 1 drop (10 µL) of primer with different concentrations of CNPs was applied to their central incisor and light-cured for 20 seconds. Transbond XT orthodontic adhesive (2 × 2 mm) was applied on the primer. Another drop (10 µL) of primer was applied and light-cured for 40 seconds. The number of Streptococcus mutans, Streptococcus sanguinis, and Lactobacillus acidophilus colonies in the saliva of rats was quantified at 24 hours, 4 days and 7 days. Adding 1% (p=0.005), 5% (p<0.001) and 10% (p<0.001) of CNPs to orthodontic primer significantly reduced the S. mutans colony count at 24 hours compared with the control group. At 24 hours, the mean S. sanguinis colony counts in the 5% (p=0.04) and 10% (p=0.02) CNP groups were significantly lower than that in the control group. Also, at 4 and 7 days, the mean colony counts in the 5% and 10% CNP groups were significantly lower than that in the control group (p<0.05). At 24 hours and 4 days, the mean L. acidophilus colony count in the 10% CNP group was significantly lower than that in the control group (p<0.05). At 7 days, rats with failed adhesive showed a significantly higher count of all three bacteria compared with rats with adhesive (p<0.05). The addition of 5% CNPs to orthodontic primer significantly decreased the colony count of cariogenic bacteria in rats.

Improving reinforcement properties of CNTs in aluminium matrix composites: a case of surface modification through AlN nano-particle grafting

Water is essential to keep us to survive, but improper and careless treatment of the wastewater from industrialization may cause the release of heavy metals, such as Lead (Pb), Cadmium (Cd) and Copper (Cu) to water supply. These heavy metals may disrupt the supply chains and human health if the food and water were overdosed with heavy metals. Hence, detection of trace heavy metals in water is important for human health. The electroanalysis method was used with newly developed graphene-based working electrodes for the detection of trace heavy metals in aqueous solutions in this research due to their inexpensiveness, portability and sensitivity. In this project, two methods were used in the fabrication of the graphene-based electrodes. The first was an electrochemical method, with which drop-cast graphene oxide (GO) was electrochemically reduced to reduced graphene oxide (RGO). The electrochemical method was selected because it is simple and economic. In order to enhance the sensitivity of the electrodes, the electrochemically reduced RGO (ERGO) electrodes were decorated with tin nanoparticles (SnNPs). The second method was thermal reduction, where the drop-cast GO was thermally reduced to RGO at a high temperature. The thermal reduction method was chosen because it could potentially achieve large scale production. In addition, the thermally reduced RGO was further decorated with platinum (Pt) NPs to improve its sensitivity and selectivity towards the analytes (Cd2+, Pb2+ and Cu2+) in electroanalysis. In the characterization of the fabricated electrodes, several instruments, such as x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy (EDS) were been used. XPS was employed to investigate the reduction percentage of RGO by studying the carbon to oxygen (C/O) ratio. Raman spectroscopy was used to determine the graphitic structure of RGO by studying the D/G intensity ratio (ID/IG). FE-SEM was used to study the surface microstructure of the RGO based electrodes, while EDS was used to verify the elemental composition of metal NPs decorated RGO. In order to study the electrochemical behaviour of the electrodes, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed. The surface reversibility of the RGO based electrodes could be identified through CV, while the electron-transfer resistance (Ret) at the interface between electrodes and electrolytes could be determined through EIS. After that, several parameters, such as pH of buffer solution, pre-concentration potential and pre-concentration time, were systematically investigated to optimize the working conditions of the RGO-based electrodes during electroanalysis. Furthermore, the reproducibility, repeatability and storage stability of the prepared electrodes were also analyzed. After that, square wave anodic stripping voltammetry (SWASV) was performed to detect the analytes in aqueous solutions. Calibrations of the RGO-based electrodes were carried out to investigate the performance of the electrodes in electroanalysis, in terms of sensitivity, stability and selectivity. In addition, the limit of detection (LOD) of the analytes obtained from the electrodes was determined. Finally, real sample application was performed to justify the feasibility of the prepared RGO-based electrodes.

Introduction: Dicalcium phosphate dihydrate (DCPD) is a member of the family of calcium phosphates (CP), which has many uses in bone cement. Recently, graphene and its derivatives have been studied to increase the biological and mechanical properties of CP structures and their results have been satisfactory. Objective: In this study, the main objective is to investigate the physical properties of GO/DCPD powders, which has been synthesized via a simple precipitation method. Material and Methods: Calcium nitrate tetrahydrate and diammonium hydrogen phosphate were used as a precursor for DCPD synthesis. DCPD was precipitated in the presence of graphene oxide. The powders obtained after washing and drying were evaluated. The analysis performed in the sample includes inductively coupled plasma (ICP), Raman Spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, Energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy, Field Emission Scanning Electron Microscope (FE-SEM), and high-resolution TEM. Result: Raman Spectroscopy and XRD results showed that dicalcium phosphate dehydrate formed the hybrid powders along with graphene oxide. DCPD crystallite size was estimated at 138 nm. Microscopic images confirmed the preferred directional growth of DCPD particles. FTIR and XPS results confirmed the emerging bands. ICP and EDS results confirmed the presence of trace elements in the synthesized powders. Conclusion: According to the above, these powders will have a lot of potential for modifying the properties of bone cement.

To evaluate the efficacy of a new orthodontic primer (Ambar APS Ortho; FGM Dental Products, Joinville, SC, Brazil) on shear bond strength (SBS) and degree conversion (DC) of metallic brackets bonding. 240 sound maxillary premolars were randomized into 24 experimental groups based on: (1) Orthodontic primer (Ambar APS Ortho, Orthoprimer and Transbond XT); (2) Light-curing time (3-seconds and 10-seconds); (3) Light-curing unit (Valo Cordless and Quazar); and (4) Storage condition (immediate time [IT] and after thermocycling [TC]). After each storage time, specimens were subjected to SBS testing at a crosshead speed of 1 mm/min until failure, and values were recorded in MPa. For DC (%) analysis, adhesive discs were prepared and evaluated using micro-Raman spectroscopy at IT only. SBS and DC data were analyzed using four and four-way ANOVA, respectively and Tukey's post hoc test (α = 0.05). Ambar APS Ortho showed significantly higher SBS values across both light-curing units compared to all other groups (p = 0.0001). For DC, Orthoprimer showed the lowest values, while Ambar APS Ortho achieved the highest. Across all primers, a 10s light-curing exposure resulted in significantly higher DC values compared to 3s (p < 0.0001). Ambar APS Ortho exhibited superior performance in both SBS and DC, for both 3s and 10s light-curing times as well as IT or AT, supporting its reliability for bonding metallic orthodontic brackets.