Stainless Steel Orthodontic Brackets Research Articles

Evaluation of cytotoxicity of copper oxide and zinc oxide hybrid nanocoated orthodontic brackets

Using a combination of two nanoparticles for coating stainless orthodontic brackets might alter their potential cytotoxicity. The study investigated the cytotoxicity of brackets nanocoated with copper oxide, zinc oxide and a combination of both the particles. Stainless steel orthodontic brackets (Ormco Mini -Diamond series 0.22” slot, MBT prescription) (ORMCO CORP Glendora, California, USA) (n= 31 in each group) were coated with nanoparticles of copper oxide, zinc oxide and a combination of copper oxide –zinc oxide using a spray pyrolysis method. The brackets was assessed for cytotoxicity in mouse fibroblast (L929) using MTT assay with a standard control and a group of uncoated brackets for comparison. The optical density and percentage of cell viability of the 5 groups were compared with ANOVA and Post hoc Tuckey HSD. P value ≤ 0.05 was considered as statistically significant. The three groups of coated brackets and the uncoated brackets exhibited significantly lesser percentage of cell viability than the control group. The percentage of cell viability in all the four groups was greater than 70% Zinc oxide and copper oxide nanocoated brackets exhibited lesser cell viability than the combination group and the uncoated brackets.Brackets coated with combination of copper oxide and zinc oxide nanoparticles exhibited lesser cytotoxicity than the brackets coated with copper oxide or zinc oxide nanoparticles.

Evaluation of Antibacterial Effect of Hybrid Nano-coating of Stainless Steel Orthodontic Brackets on Streptococcus Mutans – An In vitro Study

ABSTRACT Nano-coating of orthodontic brackets with a combination or hybrid of metals and metal oxides may reduce the streptococcus mutans count and incidence of enamel decalcification seen around brackets in patients undergoing fixed orthodontic treatment. In total, 255 orthodontic brackets (3M Unitek, Monrovia, California, USA) were divided into one control group (group I) of 60 and three experimental groups of 65 each (groups II, III, and IV). The experimental group brackets were coated with a combination of silver-zinc oxide, copper oxide -zinc oxide, and silver-copper oxide nanoparticles using physical vapour deposition method. The two nanoparticles used for each group were mixed in the ratio of 1:1 by weight for providing a uniform hybrid coating. Sixty brackets from each group were used for microbiological evaluation of antibacterial activity against Streptococcus mutans in blood agar medium, and the remaining five brackets from each experimental group were used for SEM analysis to check the uniformity of the coating. Nano-coated brackets demonstrated better antibacterial properties than uncoated brackets. Copper oxide–zinc oxide nanoparticles coated brackets demonstrated better antibacterial properties than the silver–zinc oxide and silver– copper oxide coated brackets.

PROPOLIS EXTRACT AS ANTI-CORROSIVE AGENT INHIBITS METAL IONIC RELEASE FROM ORTHODONTIC BRACKETS

Background: A combination of nickel (Ni), chromium (Cr), and iron (Fe) can be found in the stainless steel orthodontic bracket. Ion release takes place as a result of the chemical interaction between metals and the oral environment, which leads to the potential of hypersensitivity during fixed orthodontic treatment. Propolis contains phytochemicals that have the ability to reduce corrosion, making it a potential treatment option. Purpose: to determine the release of Ni, Cr, and Fe in metal brackets in an 8.2% propolis solutionMethod: Four sets of six brackets were made from 24 brackets. Artificial saliva, sodium fluoride, sterilized distilled water (aquabidest), and 8.2% propolis were applied to these brackets. After incubating at 37°C for seven days, ICP EOS measured the metal ions Ni, Cr, and Fe. The analysis revealed significant differences (p<0.05) in ionic release of Ni, Cr, and Fe among groups exposed to sterilized distilled water (aquabidest) and an 8.2% propolis solution. Additionally, the Mann-Whitney test showed substantial Ni ion release differences (p<0.05) between 8.2% propolis solution and sterilized distilled water. The 8.2% propolis solution and sodium fluoride solution released Cr ions differently. Fe ion levels differed between propolis solution 8.2%, sodium fluoride solution, sterilized distilled water, and fake saliva. Conclusion: Propolis affects metal bracket ionic release of Ni, Cr, and Fe. Keywords : Cr and Fe, ions of Ni, propolis solution, Stainless steel bracket

Correction to: Evaluating the efficiency of Er,Cr:YSGG laser for recycling of debonded stainless steel orthodontic brackets: an in vitro study

Correction to: Evaluating the efficiency of Er,Cr:YSGG laser for recycling of debonded stainless steel orthodontic brackets: an in vitro study

Application of an Antibacterial Coating Layer via Amine-Terminated Hyperbranched Zirconium–Polysiloxane for Stainless Steel Orthodontic Brackets

The massive growth of various microorganisms on the orthodontic bracket can form plaques and cause diseases. A novel amine-terminated hyperbranched zirconium–polysiloxane (HPZP) antimicrobial coating was developed for an orthodontic stainless steel tank (SST). After synthesizing HPZP and HPZP-Ag coatings, their structures were characterized by nuclear magnetic resonance spectroscopy, scanning electron microscopy, thickness measurement, contact angle detection, mechanical stability testing, and corrosion testing. The cell toxicity of the two coatings to human gingival fibroblasts (hGFs) and human oral keratinocytes (hOKs) was detected by cell counting kit eight assays, and SST, HPZP@SST, and HPZP-Ag@SST were cocultured with Staphylococcus aureus, Escherichia coli, and Streptococcus mutans for 24 hr to detect the antibacterial properties of the coatings, respectively. The results show that the coatings are about 10 μm, and the water contact angle of HPZP coating is significantly higher than that of HPZP-Ag coating (P<0.01). Both coatings can be uniformly and densely distributed on SST and have good mechanical stability and corrosion resistance. The cell counting test showed that HPZP coating and HPZP-Ag coating were less toxic to cells compared with SST, and the toxicity of HPZP-Ag coating was greater than that of HPZP coating, with the cell survival rate greater than 80% after 72 hr cocultured with hGFs and hOKs. The antibacterial test showed that the number of bacteria on the surface of different materials was ranked from small to large: HPZP@SST < HPZP-Ag@SST < SST and 800 μg/mL HPZP@SST showed a better bactericidal ability than 400 μg/mL after cocultured with S. aureus, E. coli, and S. mutans, respectively (all P<0.05). The results showed that HPZP coating had a better effect than HPZP-Ag coating, with effective antibacterial and biocompatible properties, which had the potential to be applied in orthodontic process management.

A Quantitative Evaluation of the Effectiveness of the Metal Artifact Reduction Algorithm in Cone Beam Computed Tomographic Images with Stainless Steel Orthodontic Brackets and Arch Wires: An Ex Vivo Study.

The presence of high-density and high-atomic number materials results in the generation of artifacts in cone beam computed tomographic (CBCT) images. To minimize artifacts in CBCT images, the metal artifact reduction (MAR) tool was developed. This study aims to quantitatively evaluate the effectiveness of the MAR algorithm in CBCT images of teeth with stainless steel orthodontic brackets with or without arch wires in buccal and lingual positions obtained using the Galileos Sirona CBCT scanner. In this in vitro study, 20 stainless steel brackets were attached to the maxillary dentition from the right second premolar to the left second premolar teeth of a human skull. In the first group, 10 brackets were bonded to the buccal surface, and in the second group, 10 brackets were bonded to the palatal surface of these teeth. CBCT scans were obtained for each group with or without orthodontic stainless steel wires using a Galileos Sirona CBCT scanner with exposure parameters of 85 kVp and 21 mAs. CBCT images were obtained two times with and two times without MAR activation. The DICOM format of the CBCT images was imported to ImageJ software (version 1.54), and the contrast-to-noise ratio (CNR) was calculated and compared for each bracket in 15 and 20 mm distances and 20, 40, and 90 degrees on each side. Statistical analysis was performed using the t test (α = 0.05). CNR values of different distances and different teeth were not significantly different between the two MAR modes (p > 0.05). MAR activation had a significant impact in increasing CNR and reducing artifacts only when brackets were in palatal (p = 0.03). In the other bracket and wire positions, the effect of the MAR algorithm on CNR was not significant (p > 0.05). In conclusion, MAR activation significantly increased CNR, but only when the brackets were in a palatal position. In the other bracket and wire positions, the effect of the MAR algorithm is not significant.

Laser surface textures enhance the friction and wear behaviour of orthodontic brackets

AbstractMinimising the friction force of the archwire‐bracket sliding contact is crucial for achieving a high‐quality orthodontic treatment. Micro‐dimples and micro‐grooves textures were successfully produced on the two slot surfaces of the stainless steel orthodontic brackets with the laser surface texturing technology. The effect of surface texture on reducing the friction and wear behaviour of the stainless steel archwire‐bracket sliding contact combinations in artificial saliva environment was investigated. Friction coefficients of less than 0.15 and mild wear were obtained by using the three rows micro‐grooves textured bracket with a width of 60 μm and a spacing of 150 μm. The friction and wear performance was further enhanced with the addition of orthodontic wax materials. It was strongly argued that the synergetic effects of the fabricated micro‐grooves texture and the added orthodontic wax materials leading to the outstanding friction and wear behaviour of the archwire‐bracket sliding contacts.

A comparison of the shear bond strength of metal orthodontic brackets that have been treated with various light-emitting diode intensities and curing times: In-vitro research

The study aims to test the effects of LED light at three different power settings (500mW/cm2, 1000mW/cm2& 1500m W/cm2) and three different exposure times (5sec, 10sec & 20sec) adhesive composites for use with stainless steel orthodontic brackets, and their shear bond strengths. Current In-vitro work used 120 teeth, mostly premolars, separated into 10 equal groups of 12. After the crowns of the teeth were exposed by mounting them vertically into self-heal acrylics, the buccal-enamel exterior was prepared for bonding (PEA) 0.022”x 0.028” stainless steel premolar bracket using a thin layer of light cure adhesive primer and paste (Transbond-XT-3M Unitek Monrovia, Calif). Brackets in Group 1 comprising the Control group treated by usual halogen light source for forty sec, in remaining 9 groups (Experimental group) three commercially available LED curing light units i.e., Woodpecker, Guilin, Guangxi, China; Stealth Soft Equinox, Denmark, Holland; Radii plus, SDI, Australia, having three different light intensity 500mW/cm2, 1000mW/cm2, 1500mW/cm2 respectively were used to bond the brackets at three contact time (5/10/20 sec). The universal testing equipment was used to determine the shear bond strength of each specimen. The uppermost average SBS was found in the group cured with LED of intensity 1500 mW/cm2 for 20 sec (20.08 + 4.82 MPa) which was statistically significant compared the to control group (12.72 + 2.42 MPa). The lowest mean SBS values were obtained for groups cured with LED of intensity 500 mW/cm2 even at different curing times of 5, 10 and 20 sec i.e., 5.46 + 1.99 MPa, 8.77 + 2.38 Mpa and 11.24 + 2.59 MPa, respectively. Increasing the intensity of the LED light curing unit provides a clinically acceptable SBS even after reducing the curing times, thereby reducing the chairside time for bonding of orthodontic brackets.The study aims to test the effects of LED light at three different power settings (500mW/cm2, 1000mW/cm2& 1500m W/cm2) and three different exposure times (5sec, 10sec & 20sec) adhesive composites for use with stainless steel orthodontic brackets, and their shear bond strengths. Current In-vitro work used 120 teeth, mostly premolars, separated into 10 equal groups of 12. After the crowns of the teeth were exposed by mounting them vertically into self-heal acrylics, the buccal-enamel exterior was prepared for bonding (PEA) 0.022”x 0.028” stainless steel premolar bracket using a thin layer of light cure adhesive primer and paste (Transbond-XT-3M Unitek Monrovia, Calif). Brackets in Group 1 comprising the Control group treated by usual halogen light source for forty sec, in remaining 9 groups (Experimental group) three commercially available LED curing light units i.e., Woodpecker, Guilin, Guangxi, China; Stealth Soft Equinox, Denmark, Holland; Radii plus, SDI, Australia, having three different light intensity 500mW/cm2, 1000mW/cm2, 1500mW/cm2 respectively were used to bond the brackets at three contact time (5/10/20 sec). The universal testing equipment was used to determine the shear bond strength of each specimen. The uppermost average SBS was found in the group cured with LED of intensity 1500 mW/cm2 for 20 sec (20.08 + 4.82 MPa) which was statistically significant compared the to control group (12.72 + 2.42 MPa). The lowest mean SBS values were obtained for groups cured with LED of intensity 500 mW/cm2 even at different curing times of 5, 10 and 20 sec i.e., 5.46 + 1.99 MPa, 8.77 + 2.38 Mpa and 11.24 + 2.59 MPa, respectively. Increasing the intensity of the LED light curing unit provides a clinically acceptable SBS even after reducing the curing times, thereby reducing the chairside time for bonding of orthodontic brackets.

Evaluation of surface-modified orthodontic brackets with silver nanoparticles and its influence on bacterial inhibition – An in vitro study

: Compared to other fixed orthodontic appliances, orthodontic brackets have a substantial impact on enamel demineralization. This demineralization is a result of organic acid production by various microorganisms, primarily from Streptococcus mutans and Lactobacillus acidophilus. Preventing white spot lesions and caries during orthodontic treatment presents a considerable challenge for clinicians. Silver exhibits broad-spectrum antimicrobial activity against various microorganisms, including Gram-positive and Gram-negative bacteria, certain viruses, fungi, protozoa, and antibiotic-resistant strains. As such, the purpose of this research is to investigate the antibacterial properties of orthodontic brackets coated with silver nanoparticles against Streptococcus mutans and Lactobacillus acidophilus. The study involved 80 stainless steel orthodontic brackets, which were divided into four groups, each containing 20 brackets. In each group, there were uncoated brackets serving as the control group, and the experimental group consisted of brackets coated with silver dioxide. Coating was done by physical vapor deposition with the help of RF Magnetron sputtering unit. Surface morphology and material composition was analyzed by SEM and EDS unit. Afterward, the brackets underwent microbiological tests to evaluate their antibacterial efficacy against Streptococcus mutans and Lactobacillus acidophilus.The study found that silver nanoparticle-coated stainless-steel brackets exhibited effective antibacterial properties against both Streptococcus mutans and Lactobacillus acidophilus when compared to the uncoated brackets. Silver nano particle coated SS brackets showed increased anti-bacterial effect towards S. mutans than L acidophilus.Using silver nanoparticles to coat orthodontic brackets represents an innovative and effective approach to prevent the formation of white spot lesions in patients receiving fixed orthodontic treatment. The antimicrobial properties of silver nanoparticles can combat bacteria like Streptococcus mutans and Lactobacillus acidophilus, responsible for enamel demineralization and the occurrence of white spot lesions. This advancement in bracket technology has the potential to significantly reduce the risk of enamel damage and improve overall oral health outcomes for orthodontic patients.

Evaluation of the Shear Bond Strength of Chitosan Nanoparticles-Containing Orthodontic Primer: An In Vitro Study.

The present study was intended to investigate the effect of different concentrations of chitosan nanoparticles mixed with an orthodontic primer on the shear bond strength and bond failure of stainless steel brackets bonded to dental enamel. Four concentrations of chitosan nanoparticles (0%, 1%, 5%, and 10%) were prepared and mixed with Transbond™ XT primer. Forty-eight extracted maxillary first premolars were bonded under a standardized procedure with stainless steel orthodontic brackets utilizing those different concentrations (12 teeth per each group). After the bonding procedure, the specimens were stored in deionized water (37°C for 24 hr) and then thermocycling 5,000 times before shear bond testing, which was performed using a universal testing device. Bond failure sites were examined under a stereomicroscope. Scanning electron microscopy and X-ray diffraction were also performed to verify and evaluate the phase of the nanopowder. The data were statistically analyzed using one-way analysis of variance) and Kruskal-Wallis H tests, and the findings revealed statistically nonsignificant group differences regarding the shear bond strength and adhesive remnant index (p > 0.05). Primers containing varying concentrations of chitosan nanoparticles demonstrated acceptable shear bonding strength and adhesive remnant index.

Shear bond strength of orthodontic brackets to specimens fabricated from temporary restorative materials by 3D-printing, CAD/CAM technology, and the conventional technique after surface treatment by sandblasting and laser

This study assessed the shear bond strength (SBS) of stainless steel (SS) orthodontic brackets to specimens fabricated from polymethyl methacrylate (PMMA) temporary restorative material by 3D-printing, computer-aided design/computer-aided manufacturing (CAD/CAM) technology, and the conventional technique, after surface treatment by sandblasting and laser. In this in vitro study, 60 disc-shaped specimens with 8mm diameter and 1mm height were fabricated from PMMA temporary restorative material by 3D-printing, CAD/CAM, and the conventional technique. In each group (n=20), half of the specimens were sandblasted while the other half underwent Er,Cr:YSGG laser irradiation. Brackets were bonded to the specimens and underwent thermocycling followed by SBS testing. Data were analysed by one-way ANOVA, independent t-test, and LSD test (alpha=0.05). A significant difference existed among the three fabrication methods in SBS in both laser (P<0.001) and sandblasting (P<0.001) surface treatment groups. In laser group, the mean SBS of CAD/CAM (P=0.000) and conventional (P=0.000) groups was significantly lower than that of 3D-printing group. In sandblasting group, the SBS of CAD/CAM group was significantly lower than 3D-printing (P=0.000) and conventional (P=0.000) groups. The mean SBS of laser-treated specimens was significantly higher than sandblasted specimens in 3D-printing group (P=0.000), and significantly lower than sandblasted specimens in the conventional group (P=0.000). A significantly higher SBS was obtained by laser treatment compared with sandblasting irrespective of the fabrication method (P=0.000). The highest SBS of SS orthodontic brackets to temporary restorative material was recorded for 3D-printed specimens treated by Er,Cr:YSGG laser irradiation.

The effect of soaking stainless steel orthodontics bracket with robusta coffee (coffea canephora) on the release of fe ions

Introduction: Robusta coffee (Coffea canephora) is one of the most produced and popular types of coffee in Indonesia. Robusta coffee is included as an acidic beverage because it has an average pH of 5.6 which can increase corrosion. Stainless steel orthodontic bracket is a type of orthodontic bracket that has more resistance to corrosion, however, exposure to stainless steel orthodontic bracket by robusta coffee (Coffea canephora) which has an average pH of 5.6 can increase the corrosion process so that more Fe ions are released. Objective: To determine the effect of soaking stainless steel orthodontic bracket with robusta coffee (Coffea canephora) on increasing the release of Fe ions Methods: Laboratory experiment with post test only control group design. The experiment was divided into two groups, namely the control and treatment groups. In the control group there were 16 stainless steel orthodontic brackets which were soaked in 20 ml of artificial saliva in an incubator at 370C for 24 hours. In the treatment group there were 16 stainless steel orthodontic brackets soaked in 10 ml of artificial saliva and 10 ml of robusta coffee (Coffea canephora) in an incubator at 370C for 24 hours. After that, a test was carried out using AAS tool to see the release of Fe ions contained in the test solution. Results: Robusta coffee (Coffea canephora) increases the release of Fe ions in stainless steel orthodontic brackets. In the treatment group that were soaked in robusta coffee, there was an average of 7.96 ppm of Fe ions released, while in the control group only 4.07 ppm of Fe ions were released. Conclusion: Robusta coffee (Coffea canephora) has been shown to increase the release of Fe ions on stainless steel orthodontic brackets

THE EFFECT OF GREEN BETEL LEAF EXTRACT IMMERSION ON NICKEL ION RELEASE IN STAINLESS STEEL ORTHODONTIC BRACKET

The orthodontic bracket is an essential component in fixed orthodontic appliances. One of the materials commonly used in orthodontic brackets is stainless steel. Stainless steel orthodontic brackets have good deformation and corrosion resistance. Still, corrosion resistance is compromised by certain conditions in the oral cavity, such as salivary pH due to food and beverage consumption and toothpaste and mouthwash. One of the herbal plants that are widely used for dental and oral health is green betel leaf. Green betel leaves have an acidic pH that may cause corrosion. Corrosion has a detrimental effect on the brackets because it causes a continuous loss of nickel ions. The purpose is to determine the number of nickel ions released from stainless steel orthodontic brackets due to immersion in the green betel leaf extract. This type of research is a laboratory experimental research design with a post-test control group design. The test was carried out on 27 samples divided into three groups. Brackets were immersed in 25% green betel leaf extract, artificial saliva, and a mixture of 25% green betel leaf extract and artificial saliva for 48 hours and measured using an Atomic Absorption Spectrophotome (AAS). The results showed the most significant release of nickel ions occurred in the 25% green betel leaf extract group with a value of 16.37 mg/Kg, and the minor release of nickel ions occurred in the artificial saliva control group with a weight of 1.95 mg/Kg. The conclusion is that green betel leaf extract influences the release of nickel ions in stainless steel orthodontic brackets.

Comparison of residual monomer amounts released from indirect bonding adhesives.

To quantify the amount of residual monomer released from orthodontic adhesives used in the indirect bonding technique and compare it to a direct bonding composite resin. Five hundred stainless steel orthodontic brackets were bonded on bovine incisors using five groups of bonding resins: Transbond XT (TXT), Transbond Supreme LV (SLV), Sondhi Rapid-Set (SRS), Transbond IDB (IDB), and Custom I.Q. (CIQ). Liquid samples were gathered on the first, seventh, 21st, and 35th days. Residual monomer release was measured from the liquid samples with a liquid chromatography device. In addition, the amount and shape of the adhesive between the tooth surface and the bracket base was evaluated using obtained electron microscopy images. The data were analyzed using analysis of variance, and a Tukey post-hoc test was applied. Hydroxyethylmethacrylate and bisphenol A-glycidyl methacrylate monomers were released by all study groups. Urethane-dimethacrylate was released from the TXT, SLV, IDB, and CIQ groups. Triethylene glycol dimethacrylate was released from TXT, SLV, IDB, and SRS groups. The amount of total monomer release was higher in chemically cured adhesives than in light-cured adhesives. Among the chemically cured adhesives, premix adhesives had the highest amount of total monomer release. The light-cured adhesives had less thickness. Light-curing adhesives have significantly less monomer release than chemically polymerized adhesives.

PowerScope 2 functional appliance: A 3D finite element simulation of its action on the mandible.

of study: This study evaluated the action of the PowerScope 2 appliance for correcting Class II malocclusion and the stresses and displacement of the mandible during loading using three-dimensional finite element analysis (FEA). The sites of the mandibular skeletal and/or dental corrections were also distinguished. Using the AutoCAD (2010) Program, a 3D model of the human mandible with teeth was created based on a CT image of a 20-yr-old patient. Orthodontic stainless-steel brackets with Standard Edgewise (0.022 in) slots bonded to five mandibular teeth and inserted into a bounded tube on the first molar were simulated. A rectangular archwire (0.019×0.025 in) ligated the brackets. The created models were uploaded to the Autodesk Inventor Professional Computer Program (FE) version (2020). The FEA presented the three-dimensional results qualitatively and quantitatively as von Mises stress and displacement. The colour ruler on the upper left side demonstrates the stress and displacement distribution pattern of the mandible, with the minimum value in blue and the maximum value in red. Mandibular movement was achieved three-dimensionally. There was obvious sagittal forward mandibular movement, and high stress was observed at the chin prominence (the pogonion). In the transverse plane, the mandible was highly bent buccally, especially at the gonial angle and antegonial notch. In the vertical plane, the highest ranges of mandibular movements were seen in the chin, the anterior part of the mandibular body, and the associated dentoalveolar region. The results of this FEA, PowerScope 2 functional appliance proved to be effective as a Class II malocclusion corrector. Its mode of action on the mandible was achieved in three planes of space, and its orthodontic effects were gained dentally and skeletally. An bbvious sagittal forward mandibular movement was observed, particularly at the chin prominence. Apparent buccal bending, especially at the gonial angle and antegonial notch, was observed. Vertically, the chin and anterior part of the mandible, with the associated dentoalveolar structures, were clearly stressed under the action of this appliance.

Comparison of shear bond strength of rebonded stainless steel brackets with three different enamel surface conditioning methods.

During the orthodontic bonding process, the need for repositioning or rebonding of orthodontic brackets on the enamel surface occurs frequently. The aim of this study is to compare the shear bond strength (SBS) in rebonding orthodontic stainless steel brackets with three different methods of enamel surface conditioning methods. In this in vitro study, 80 human premolars that were extracted for orthodontic purposes were randomly divided into four groups and underwent orthodontic bonding procedure (N = 20). Except for the control group, three other groups underwent debonding and rebonding process in which after removing the remaining adhesive with tungsten-carbide bur, enamel surface conditioned by three different methods including re-etching with phosphoric acid, sandblasting + acid etching, and Erbium-doped Yttrium-Aluminum-Garnet laser. Then, the SBS of the bracket to the enamel surface was compared between different groups. Scanning Electron microscopy images were also obtained from a number of samples. Statistical analysis was performed by Kruskal-Wallis and Mann-Whitney tests. The highest SBS was observed in the primary bond (control group) with an average of 29,440 MPa. There was a significant difference between the studied groups (P < 0.001) and only the group that was re-etched with phosphoric acid had no significant difference with the control group (P = 0.708) ∝ =0.05. Rebonding of brackets using phosphoric acid for reconditioning of the enamel surface creates bond strength comparable to the primary bond. Other groups had significantly lower SBS than the control group.

Effects of Two Fluoride Mouthwashes on Surface Topography and Frictional Resistance of Orthodontic Wires.

Objectives: This study compared the effects of fluoride mouthwashes on surface topography of orthodontic wires, and static and kinetic frictional forces between the stainless steel (SS) orthodontic brackets and SS and nickel-titanium (NiTi) archwires. Materials and Methods: This in vitro, study evaluated 240 standard SS maxillary central incisor brackets and 0.018, and 0.025×0.019 inch NiTi and SS archwires. The wire-bracket sets (different combinations of wire diameters and types) were exposed to artificial saliva (control), 0.05% sodium fluoride (NaF) for 1 minute daily, or 0.2% NaF for 1 minute, weekly (37°C) for 3 months. The wires were pulled in bracket slots by 5 mm in a universal testing machine (10 mm/minute). The static and kinetic forces were measured. The surface topography of wires was inspected under a scanning electron microscope (SEM; x500). Data were analyzed by SPSS 25. Results: The mean static and kinetic frictional forces of 0.025×0.019 inch NiTi wire in 0.05% NaF group were significantly greater than SS wire (P=0.000). The mean kinetic frictional force in 0.05% NaF was significantly greater than 0.2% NaF and artificial saliva for all wires (P=0.001). The mean static and kinetic forces in 0.2% NaF were significantly greater than in artificial saliva (P=0.025). In all groups, larger wires showed higher mean frictional forces (P=0.000). SEM results revealed higher wire surface roughness in 0.05% NaF followed by 0.2% NaF group. Conclusion: Weekly use of 0.2% NaF mouthwash is recommended during sliding mechanics to minimize frictional forces between the SS and NiTi wires and SS brackets.

Comparison of shear bond strength of orthodontic stainless-steel brackets on temporary crowns fabricated by three different methods: An in vitro study

Different methods are available for making temporary restorations. The purpose of this study was to determine and compare the shear bond strength of orthodontic brackets on temporary crowns made by three different methods. In this experimental study, disc form samples (N=54) were made in dimensions 8×1mm, according to the manufacturer's instructions. In this study, we had three groups (N=18) based on manufacturing methods (3D printing, conventional, and CAD/CAM). Following surface preparation of the samples, the brackets were bonded in the centre of the discs. Before the shear bond strength test, the samples were subjected to the thermocycling process. The shear bond strength of brackets was measured by Universal Testing Machine. Data were analysed by one-way ANOVA and LSD post hoc test. The findings indicated that the mean shear bond strength of orthodontic stainless-steel brackets on temporary crowns varied between CAD/CAM and 3D printing methods (P<0.001) and also between CAD/CAM and conventional methods (P<0.001). The mean shear bond strength of orthodontic stainless steel brackets on temporary crowns was not different between 3D printing and conventional methods (P=0.7). The shear bond strength of orthodontic stainless-steel brackets bonded to temporary crowns fabricated by conventional and 3D printing methods was similar, and the shear bond strength in the samples fabricated by CAD/CAM method was lower than other specimens.

In vitro study of the antibacterial effect of plasma surface treatment using Argon gas on orthodontic stainless steel brackets against Streptococcus mutans and Lactobacillus acidophilus

Orthodontic treatment improves dental aesthetics. However, the prolonged duration of treatment and patient's oral hygiene results in more significant biofilm buildup and boosting concentrations of acidogenic bacteria, resulting in enamel demineralization. Plasma treatment technology has developed an interest in enhancing appliances' surface properties. The present study aimed to investigate cytotoxicity and antibacterial activity represented by anti-adhesion and anti-biofilm formation of Argon plasma treatment on orthodontic brackets against Streptococcus mutans and Lactobacillus acidophilus and evaluation the effect of change in plasma exposure duration on these properties in vitro. The study included three groups, group 1: untreated stainless steel brackets, group 2: brackets treated for 15 min, and group 3: brackets treated for 30 min. S.mutans and L.acidophilus were isolated from patients undergoing fixed orthodontic treatment. Microbiological tests included adhesion assay using plate counting method and biofilm formation assay using ELISA plate reader. S. mutans&amp; L. acidophilus were cultivated in three groups, and their adherence and biofilm formation were measured and compared. The biocompatibility of treated stainless steel brackets was evaluated by MTT assay. Results showed that groups 2 &amp; 3 had better anti-adhesion and anti-biofilm activity when compared with group 1, with a significant difference between group 1 &amp;group 3, in which group 3 recorded the lowest biofilm formation and the highest anti- anti-A adhesion activity. MTT showed that groups 2 and 3 exhibited more than 80% cell viability after 24, 48, and 72 hours. Plasma surface treatment of metal brackets possesses antibacterial activity against S.mutans and L.acidophilus; alteration exposure time impacts the development of these properties. Keywords. Plasma treatment, Argon gas, orthodontic brackets, biofilm, antimicrobial.

Evaluation of Shear Bond Strength of a Primer Incorporated Orthodontic Composite Resin: An In-Vitro Study.

IntroductionNewer adhesive systems are available eliminating the separate priming step during the bonding procedure thereby reducing the chances of introduction of error during bonding. The purpose of this study was to compare the shear bond strength of a primer-incorporated adhesive with that of a self-etching primer system and conventional bonding system.Materials and methodSixty-six extracted human premolars were cleaned, mounted, and randomly divided into three groups. In group A (control), 22 teeth were bonded with stainless steel orthodontic brackets using the conventional bonding system; in group B, 22 teeth were bonded using a self-etching primer system (Transbond Plus SEP, 3M Unitek, Monrovia, CA) and in group C, 22 teeth were bonded using the new primer-incorporated adhesive system (GC Ortho Connect, GC Orthodontics, Breckerfeld, Germany). After bonding, the teeth were stored in artificial saliva at 37ºC for 24 hours and debonded with a universal testing machine. The adhesive remnant index (ARI) was also evaluated. Statistical analysis was done using one-way ANOVA to compare the shear bond strength values among the three groups and Kruskal Wallis test was used for comparison of ARI scores.ResultsThe SBS values in group A (11.60 ± 2.95 MPa), group B (9.44 ± 4.46 MPa) and group C (12.68 ± 6.25 MPa) were found to be comparable with no statistically significant difference. The ARI scores were also similar among the tested groups with the predominant site of bond failure being the bracket-adhesive interface indicating a safe bond-failure site.ConclusionGC Ortho Connect was found have clinically acceptable shear bond strength values that are comparable with that of self-etching primer and conventional bonding system. Therefore, it can be used effectively for saving the clinician’s chairside time by reduction in the number of steps during bonding without compromising on the bond strength.