Stainless Steel Orthodontic Brackets Research Articles

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.

Microleakage beneath orthodontic brackets in high field magnetic resonance imaging (MRI) AT 1.5 & 3 Tesla.

The aim of the present study was to evaluate the effects of 1.5 T and 3 T MRI on the adhesion between the orthodontic brackets and the teeth by evaluating the microleakage between the enamel, adhesive and brackets interfaces. 58 extracted human premolars which were received a standard bracket bonding procedure were randomly divided into three groups; control group (n = 20; no MRI), 1.5 T MRI group (n = 19; 20 min MRI exposure of 1.5 T) and 3 T MRI group (n = 19; 20 min MRI exposure of 3 T). The teeth were kept in distiled water for 2 weeks, and thereafter subjected to 500 thermal cycles. Then, specimens were sealed with nail varnish, stained with 0.5% basic fuchsin for 24 h, sectioned and photographed under a stereomicroscope. Microleakage was scored with regard to the adhesive-enamel and bracket-adhesive interfaces at the occlusal and gingival levels. Statistical analysis was accomplished by Kruskal-Wallis and Bonferroni-Dunn tests. All of the groups exhibited statistically similar microleakage scores in the adhesive-enamel interface along occlusal margins (p>0.05, p = 0.331). The mean microleakage scores along gingival margins in the 3 T MRI group was significantly higher compared to the control group both in the adhesive-enamel and bracket-adhesive interfaces (p<0.05, p = 0.019 and p = 0.020 respectively). The microleakage scores along the gingival margins were also significantly higher than the occlusal margins in the 3 T MRI group (p<0.05, p = 0.029). 3 T MRI may weaken the adhesion between the enamel and the stainless steel orthodontic brackets.

A Systematic Review on Nano Coated Orthodontic Brackets and its Antibacterial Effects

Introduction: Oral cavity is a natural habitat of bacteria which proliferates when an orthodontic appliance is placed which leads to enamel demineralisation or white spot lesions. In order to reduce the bacterial proliferation, the surface coating of brackets using nano particles came into existence. Aim: The aim of this systematic review is to assess the different surface modifications using nano coating materials and evaluate the antibacterial properties of these nano coated orthodontic brackets. Materials and Methods: A systematic review was conducted in September 2021, analysing the microbial adhesion and antibacterial properties of orthodontic brackets after application of nano-coating against uncoated brackets was conducted from the available electronic database during January 2000 to June 2021, which included PubMed, Embase, Google Scholar. Because of the less number of in-vivo studies, in-vitro studies were also included. An analysis on the microbial adhesion and antibacterial effects of various orthodontic brackets was done. The results were tabulated after performing risk of bias assessment for each study. Results: Based on the inclusion and exclusion criteria, 13 studies were included in the study. Risk of bias was medium for majority of the selected studies. As per the previous literature, bacterial adherence of Streptococcus mutans, Streptococcus sobrinus, Aggregatibacter actinomycetemcomitans, Lactobacillus acidophilus, Actinomyces viscous and Candida albicans was reported lower in groups of brackets coated with silver nano particles than that in the groups of brackets without the addition of silver nano particles. The corrosion level on the silver or silver platinum (Ag-Pt)-coated specimens was lower than that on the non coated specimens. Conclusion: The stainless-steel orthodontic brackets coated with various nano coating materials like silver, silver-platinum, titanium, Zinc Oxide (ZnO) and Copper Oxide (CuO) exhibited adequate antibacterial effect. This shows that in orthodontic patients, especially the one susceptible to caries, the amount of plaque accumulation is significantly reduced when nano-coated orthodontic brackets are used. They reduce the microbial colony count and prevent enamel demineralisation and white spot lesions. Further clinical trials must be carried out on a large scale to confirm the results.

In-vitro Comparative Assessment of Antibacterial and Anti-adherent Effect of Two Types of Surface Modificants on Stainless Steel Orthodontic Brackets Against Streptococcus mutans

Objective: Comparative evaluation of antibacterial and anti-adherent properties of surface-modified stainless steel (SS) orthodontic brackets against Streptococcus mutans ( S. mutans). Materials and Methods: The study was conducted on 120 SS orthodontic McLaughlin, Bennett, Trevisi (MBT) 0.022″ slot by Leone, Italy. Orthodontic brackets that constituted the sample size were divided into 6 groups, consisting of 20 samples each in two control (non-surface coated) and four experimental groups. The experimental group’s surface coatings were photocatalytic zinc oxide (ZnO) and photocatalytic titanium oxide (TiO2), which were carried out by radiofrequency (RF) magnetron sputtering method for surface modification. Brackets were subjected to microbiological tests against S. mutans. For anti-adherence, weight change, pre- and postexposure, was evaluated to gauge the adherence of bacteria and colony-forming units/milliliter (CFU/mL) count measuring the survival rate of bacterial cells for antibacterial activity. Results: The TiO2-coated group showed statistically significant anti-adherence ( P-value &lt; .05) against S. mutans than control and ZnO groups. The CFU count of TiO2 group was lower than control as well as ZnO group. Conclusion: TiO2 is superior to ZnO and should be continued to be considered for surface modification of orthodontic brackets against White Spot Lesions (WSLs) and gingivitis.

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

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

Assessment of Microleakage under Stainless Steel Orthodontic Brackets Bonded with Various Adhesive Systems: An In Vitro Study

The aim of this study was to evaluate the extent of microleakage beneath stainless steel orthodontic brackets bonded with different adhesive systems. Freshly extracted 60 human premolar teeth from mandibular arch were included in this study. After sterilizing all teeth, they were stored in thymol solution of 1% for further preparation. Acrylic blocks were used to mount the teeth in a way their roots were totally implanted up to the cement enamel junction in acrylic with crown being visible. A 0.022 slot, stainless steel preadjusted edgewise premolar brackets were taken. Sixty premolars were categorized randomly into three groups (20 premolars in each group) as follows: group I: flowable composite, group II: Fuji Ortho LC, group III: Transbond XT. Later, all the samples were subjected to thermocycling and tested immediately and 24 hours after water storage. The samples were submerged for 24 hours in methylene blue solution (2%) at room temperature. A ×20 magnification stereomicroscope was used to examine all samples. The lowest microleakage (1.34 ± 0.20) was shown by Transbond XT restored teeth, followed by flowable composite group (1.79 ± 0.32) and Fuji Ortho LC group (2.98 ± 0.13). An analysis of variance showed statistically significant differences among various adhesive systems. A statistically significant difference (p <0.05) among groups I and II, and groups II and III adhesive materials was seen. This study demonstrated microleakage in all the examined adhesive groups but the lowest microleakage was found with Transbond XT group followed next by Filtek Z350 XT group and Fuji Ortho LC group. Due to microleakage, the bacteria and fluids present intraorally penetrate through the gaps along the enamel-adhesive boundary. This penetration results in significant esthetic and clinical complications. Such problems related to microleakage can be addressed with the use of an appropriate adhesive agent.

Effect of Curing Time on Bond Failurerct Based on Two Light Cure Units used in Bonding Orthodontic Brackets

In routine orthodontic practice, we usually aim at having a reduced chair side time while bonding as well as an appropriate bond strength for the brackets till the treatment completion. This is dependent on several factors which affect the quality of bond obtained between the bracket and the tooth structure. One such is the depth of cure by using different curing lamps. This study aimed at comparing the rate of bracket bond failure of brackets when bonded using light cure units with different curing time (3S and 20S). This was a randomized control trial performed as a split mouth study among patients who came for orthodontic correction of malocclusion. Among them, 24 patients were selected and split mouth study was performed. For this dental arch of each patient was split among two groups (Group A and Group B). MBT Stainless steel orthodontic brackets were bonded in both the dental arches. Group A was cured with 3 second light cure unit in I and III quadrant and 20 second light cure unit in I and III quadrant and vice versa for group B. The number of bond failures at the end of 4 weeks and 8 weeks were assessed. Bond failures among both the groups were summarized. Independent t test was used to assess the statistical difference between the groups. Overall it was evident that the bond failure was greater clinically in the group cured with 20 second curing light especially in the mandibular arch and the posterior teeth

Comparative evaluation of Stainless-steel wires and brackets coated with nanoparticles of Chitosan or Zinc oxide upon friction: An in vitro study

The present study was performed to affirm surface characterization, as well as to compare the effect of coating of stainless-steel (SS) orthodontic brackets and wires by nanoparticles Chitosan (CTS) or Zinc oxide (ZnO) during friction. Seventy SS brackets for the upper right central incisors with a 0.022-inch system and seventy 0.019×0.025-inch SS rectangular wires, with and without ZnO and CTS nanoparticle coating, were used. Coating was analysed by SEM. A universal testing machine was used to calculate the friction between the wires and brackets. Statistical analysis was performed using one-way ANOVA and Tukey's tests. Significant differences were detected between coated and uncoated wires and brackets for friction with either ZnO or CTS nanoparticles. The mean values of the wires and brackets coated with ZnO and CTS nanoparticles were 0.64±0.24N and 0.85±0.23N, respectively, while they were 1.79±0.61N for the uncoated group. In addition, there was a significant decrease of about 64% and 53% found after coating with ZnO and CTS nanoparticles, respectively. The results of CTS nanoparticle coating were consistent with those of ZnO nanoparticles. Friction force decreased significantly after coating of CTS or ZnO nanoparticles. These nanoparticles provide an opportunity to reduce friction during tooth movement, resulting in better anchorage control, reduced treatment time and risk ofroot resorption.

The Effect of Peri-Bracket Excess Adhesive on Shear Bond Strength and Enamel–Adhesive Interface Morphology With Confocal Laser Scanning Microscopy: An In Vitro Comparative Study

Aim: To evaluate the effect of leaving excess adhesive around orthodontic brackets on the shear bond strength and on the enamel–adhesive interface characteristics. Materials and Methods: One hundred forty four human premolars were randomly divided into two groups according to the test performed. For the shear bond strength, 120 teeth were bonded with stainless steel orthodontic brackets using Transbond XT light cure adhesive composites. After positioning the bracket and before light curing, excess adhesive was removed according to the test group: group 1, all excess adhesive was removed (0 mm excess); group 2, 1 mm excess adhesive was left; group 3, 2 mm excess adhesive was left; shear bond strength was measured immediately and after three months of natural aging using a universal testing machine; and adhesive remnant index scores were also evaluated. For the enamel–adhesive interface characteristics, 24 teeth were bonded with stainless steel orthodontic brackets using Transbond XT light cure adhesive composites mixed with Rhodamine B fluorescent dye, excess adhesive was removed in the same manner according to the test groups, and teeth were evaluated using confocal laser scanning microscopy. Results: Time did not significantly affect the bond strength results ( P = .888) but the amount of excess adhesive significantly affected the results ( P &lt; .05). Interaction terms were not significant ( P = .337). In both immediate and aged conditions, group 1 (0 mm excess) presented the highest bond strength results (MPa; P &lt; .05). No significant difference was found in adhesive remnant index scores or enamel–adhesive interface characteristics. Conclusion: Excess adhesive around orthodontic bracket does not increase shear bond strength.

A Comparative Study on the Effect of Different Methods of Recycling Orthodontic Brackets on Shear Bond Strength.

Aim The aim of this study was to evaluate and compare the effect of different methods of recycling stainless steel orthodontic brackets on shear bond strength. Methods One hundred twenty human premolars extracted for orthodontic purpose were randomly divided into four groups. Standard MBT (0.022″) brackets were bonded on the buccal surface of all samples with light cured adhesive primers using an LED curing unit for 10 seconds. Group I was assigned as control, and the brackets of Group II, Group III, and Group IV were subjected to recycling by flaming, flaming with sandblasting, and flaming with ultrasonic cleaning, respectively. The recycled brackets were rebonded, and final debonding of all brackets was performed using a universal testing machine at a crosshead speed of 0.5 mm/min and shear bond strength was determined. Data were analyzed with descriptive statistics, ANOVA, and post hoc tests. The adhesive remnant index was evaluated using a stereomicroscope at 10X magnification. Results The highest shear bond strength was obtained with Group I (10.35 ± 0.46 MPa), followed by Group III (9.36 ± 0.55 MPa) and Group IV (5.97 ± 0.66 MPa), and the least value was obtained with Group II (4.30 ± 0.55 Mpa). Significant differences among the groups were detected by analysis of variance. Tukey's post hoc multiple comparison test showed that the shear bond strength of each group was significantly different from one another (p < 0.001). Conclusions Shear bond strength of new brackets was significantly higher than that of the recycled brackets. Among recycled brackets, flaming with sandblasting provided adequate shear bond strength, flaming with ultrasonic cleaning provided a borderline value for clinical use, and flaming alone led to a significantly lower value.

Evaluation of three methods of surface treatment for bonding orthodontic metal brackets to resin composite in vitro

Objective: The aim of this study is to compare shear bond strength of orthodontic stainless steel brackets to resin composite surfaces In vitro using three different methods of surface treatment. Materials and methods: 60 composite resin discs, 6 mm in diameter and 2 mm in height, were prepared and aged by immersion in water for 4 weeks. After ageing, the specimens were randomly assigned to one of the following groups: (1) Control with no surface treatment, (2) 99 per cent Acetone, (3) methyl methacrylate monomer, (4) Diamond bur. The metal brackets were bonded to composite surfaces by means of an orthodontic adhesive. All specimens were stored in water for 1 week. Shear Bond Strength values were tested using a universal testing machine at a crosshead speed of 1 mm/minute, the brackets bases and corresponding RC discs were examined under stereomicroscope at 10X magnification for adhesive remnant evaluation. Shear bond strength values were analyzed using 1-way analysis of variance (ANOVA)), Adhesive remnant index scores were analysed using Chi-square test using Monte Carlo correction. Significance of the obtained results was judged at the 5% level (P ≤ 0.05). Results: The results of 1-way ANOVA for SBS means showed no statistical significant difference among the 4 groups (P = 0.564). The result of Chi-square test for ARI scores between the four groups showed a statistically significant difference (MCp = 0.039). Chi square comparisons of ARI scores showed statistically significant difference only between group 1 (control) with groups 3 (P1= 0.003) and group 4 (P1= 0.046)

The orthodontic bonding properties of human enamel after cryopreservation.

The aim was to investigate the effect of cryopreservation on the enamel bonding properties of orthodontic brackets. Sixty-six human premolars were randomly allocated to a control group or a cryopreserved group. Conventional stainless-steel orthodontic brackets were bonded with a light cure adhesive on the buccal side of the premolars. The shear bond strength (SBS) was determined at a crosshead speed of 1 mm/min. The SBS and adhesive remnant index (ARI) were evaluated respectively by an independent samples t test and Fisher's exact test (α≤0.05). The mean failure load was lower in the cryopreserved group. However, this difference in SBS was not significant (p=0.443). In both groups, the ARI mostly indicated a failure at the enamel-adhesive interface. The mean ARI scores for both groups were not significantly different (p=0.099). Within the limitations of this macro bond strength testing, it can be concluded that cryopreservation does not significantly affect the bonding properties of enamel.

Shear Bond Strengths of 3 Commonly Used Orthodontic Adhesives

Background: The purpose of this study was to compare the Shear Bond Strengths (SBS) of three types of orthodontic adhesives and to compare the Adhesive Remnant Index (ARI) after debonding. Materials and Methods: One hundred and seventy-four upper central incisors were extracted and randomly divided to 6 groups (n=29) based on the type of adhesive and two-time intervals post bonding (30 minutes (T1) and 24 hours (T2)): 1) Transbond XT™ 2) BracePaste®, 3) GoTo™. Stainless steel orthodontic brackets were bonded to the teeth. Debonding was completed by an instron machine and shear bond strength recorded together with the ARI following examination under stereo optical microscope with magnification of 10x. Normal distribution was tested using histograms, box plots, the Shapiro-Wilks test and the Kolmogorov-Smirnov’s test. The linear correlation between shear bond strength and ARI score was measured using Pearson’s correlation coefficient by individual test groups and for pooled data. To examine significance of ARI score by group multiple chi-square testing was used. All the analyses were carried out using SPSS version 25.0 and Stata version 15.0. Results: The bond strength of Transbond XT™ was the highest and the strengths at T1 and T2 were not statistically different. The statistical significance was set at 5%. The bond strength of GoTo™ adhesive significantly increased from T1 (200.49N ± 49.77) to T2 (234.89N ± 39.83). BracePaste® showed a statistically significant reduction of its bond strength after 24 hours; 165.07 ± 22.56, down from 187.40N ± 36.90 at T1. This was also significantly less than for the former two adhesives. Water ageing of 24 hrs had a positive impact on Transbond™ and GoTo™ but a negative one on BracePaste®. Transbond XT™ showed the highest score of 3 for ARI at T1 70% and T2 46% followed by GoTo 52% and 35% and BracePaste® 48% and 33%. Conclusion: Transbond XT™ and GoTo™ adhesives showed superior SBS at T1 and showed statistically higher SBS at T2 than for BracePaste®

A comparitive evaluation of the shear bond strength of Er:YAG laser ablation on enamel at 3 different power outputs with that of onventional acid etching technique - An invitro study

The aim of this study is to determine whether bonding of stainless steel orthodontic brackets to tooth enamel prepared by laser etching would result in a similar bonding capability as those prepared by acid etching using 37 % phosphoric acid; and also to compare the shear bond strength.Eighty four samples were prepared for the study. The 4 groups were Group 1- The enamel was etched with 37 % phosphoric acid, Group 2- Er: YAG laser etching was done at 1W power output, Group 3- Er: YAG laser etching was done at 2W power output and Group 4- Er:YAG laser etching was done at 3W power output. All groups have 20 teeth for shear bond strength testing and one tooth for SEM evaluation. Shear bond strength testing was performed on all teeth using Instron universal testing machine.Analysis of the variance indicated a significant difference (P &amp;#60; 0.005) among the groups. Maximum shear bond strength was shown by laser etching at 2 W to the tooth surface for 15 seconds in compared to conventional acid etching. In this study the highest shear bond strength was found in the 2-W laser etched group (16.09±0.42) MPa, followed by the 1-W laser etched group (12.62± 0.35) MPa, 3-W laser etched group( 12.01±0.31) MPa and acid etched group.(6.42±0.32)MPa.The results showed that at that laser etching at 2 W to the tooth surface for 15 seconds had statistically significant higher shear bond strength in comparison to conventional 37% phosphoric acid technique. The use of increasing the laser power output more than 2 W did not significantly increase the bond strength. The shear bond strength of all the three Laser etched groups was clinically acceptable. Enamel etching with Er: YAG Laser (2W for 15 seconds) produced maximum bond strength than acid etching and could be a viable alternative method.

Evaluation of the Shear Bond Strength and Antibacterial Activity of Orthodontic Adhesive Containing Silver Nanoparticle, an In-Vitro Study.

This study evaluated the effect of incorporating silver nanoparticles (AgNPs) into conventional orthodontic adhesive on its antibacterial activity and the shear bond strength (SBS) to stainless steel orthodontic brackets. Thirty-four extracted premolars were randomly allocated into two groups (n = 17). Orthodontic adhesive (Transbond XT, 3M Unitek) was blended with AgNPs (50 nm, 0.3% w/w) to form a nano-adhesive. In order to bond stainless steel twin brackets (0.022-inch, American Orthodontics), Transbond XT (n = 17) and nano-adhesive (n = 17) were used in each group, respectively, after acid etching (37% phosphoric acid, 30 s) and rinsing with water (15 s). SBS and the adhesive remnant index (ARI) scores were recorded. Antibacterial activity against Streptococcus mutans in both groups after 24 h and 30 days was assessed (Disc agar diffusion test) and the inhibition zone diameter around each specimen was measured and recorded. Adding AgNPs significantly (p = 0.009) reduced the mean (SD) SBS in the nano-adhesive group [10.51(7.15) MPa] compared to Transbond XT [17.72(10.55) MPa]. The ARI scores on the Transbond XT and nano-adhesive showed no statistically significant difference (p = 0.322). Nano-adhesive with AgNPs showed significant antibacterial activity against Streptococcus mutans at 24 h and 30 days (p < 0.001). In both groups, no significant decline in the zones of inhibition was detected after 30 days (p = 0.907). The findings suggest that SBS decreased after incorporation of AgNPs [0.3% (w/w)], but was still above the recommended SBS of 5.9–7.8 MPa. The nano-adhesive showed significant antibacterial activity which did not change much after 30 days.

Improvement of binding friction between stainless steel orthodontic wire and bracket by performing Rh-PTFE composite plating on the wire

ABSTRACT Purpose: During orthodontic treatment, it is important to ensure that the least frictional force is applied to the teeth to ensure optimal tooth movement. We applied electrolytic rhodium-polytetrafluoroethylene (Rh-PTFE) composite plating to stainless steel (SS) orthodontic wires with the aim of suppressing friction and corrosion in the wire and facilitating the longevity of treatment. Materials and methods: SS orthodontic wires were plated with a polytetrafluoroethylene (PTFE) particle suspended solution. The surface colour was changed to black with Rh-PTFE plating, and a homogeneous distribution of PTFE particles was observed in the plated layer using scanning electron microscopy (SEM). Results: The friction of Rh-PTFE plated wire with the SS bracket decreased to ½ to 1/3rd of the original force by increasing the PTFE content in the plated layer, despite the increase in surface roughness with plating. Corrosion suppression was also observed when Rh-PTFE plating was applied to a nickel wire. Conclusion: Ensuring smooth movement between the wire and bracket decreases the risk of metal dissolution, which can be effectively be achieved with Rh-PTFE plating. This finding will significantly assist orthodontists in choosing plated wires to ensure a more effective course of treatment for their patients in the future.