Orthodontic Elastomeric Ligatures Research Articles

Synthesis and Characterization of a Sustained Nitric Oxide-Releasing Orthodontic Elastomeric Chain for Antimicrobial Action.

The acidic byproducts of bacteria in plaque around orthodontic brackets contribute to white spot lesion (WSL) formation. Nitric oxide (NO) has antibacterial properties, hindering biofilm formation and inhibiting the growth of oral microbes. Materials that mimic NO release could prevent oral bacteria-related pathologies. This study aims to integrate S-nitroso-acetylpenicillamine (SNAP), a promising NO donor, into orthodontic elastomeric ligatures, apply an additional polymer coating, and evaluate the NO-release kinetics and antimicrobial activity against Streptococus mutans. SNAP was added to clear elastomeric chains (8 loops, 23 mm long) at three concentrations (50, 75, 100 mg/mL, and a control). Chains were then coated, via electrospinning, with additional polymer (Elastollan®) to aid in extending the NO release. NO flux was measured daily for 30 days. Samples with 75 mg/mL SNAP + Elastollan® were tested against S. mutans for inhibition of biofilm formation on and around the chain. SNAP was successfully integrated into ligatures at each concentration. Only the 75 mg/mL SNAP chains maintained their elasticity. After polymer coating, samples exhibited a significant burst of NO on the first day, exceeding the machine's reading capacity, which gradually decreased over 29 days. Ligatures also inhibited S. mutans growth and biofilm formation. Future research will assess their mechanical properties and cytotoxicity. This study presents a novel strategy to address white spot lesion (WSL) formation and bacterial-related pathologies by utilizing nitric oxide-releasing materials. Manufactured chains with antimicrobial properties provide a promising solution for orthodontic challenges, showing significant potential for academic-industrial collaboration and commercial viability.

Antibacterial coating of orthodontic elastomeric ligatures with silver and bismuth nanofilms by magnetron sputtering:Afeasibility study.

Magnetron sputtering was evaluated to equip surfaces of orthodontic elastomeric ligatures with silver and bismuth nanofilms. Antibacterial properties were evaluated by the adhesion of Streptococcus mutans. Polyurethane-based elastomeric ligatures were coated with silver and bismuth nanofilms via direct current magnetron sputtering. Surface roughness (Ra ) and surface-free energy (SFE) were assessed. Coated specimens were incubated with S. mutans for 2 h. Adhering bacteria were visualized by Hoechst staining and quantified by an ATP-based luminescence assay. One-way analysis of variance with Tukey post hoc testing and Pearson correlation analysis were performed (p < .05) to relate bacterial adhesion to surface roughness and surface-free energy. Elastomeric ligatures were successfully coated with silver and bismuth nanofilms. Ra was significantly reduced by silver coating. Silver and bismuth coatings showed significantly higher SFE than controls. Adhesion of S. mutans was significantly decreased by silver coating. No correlation between bacterial adhesion and SFE was found. Correlation between bacterial adhesion and Ra was positive but not statistically significant. Magnetron sputtering proved to be a feasible method to equip orthodontic elastomeric ligatures with silver and bismuth nanofilms. Silver coatings of elastomeric ligatures may reduce white spots and carious lesions in orthodontic patients. Future research is required to stabilize coatings.

Nanotechnology in orthodontics: A detailed review

Nanotechnology is a technological revolution that has caught the scientific world's attention in recent decades. This is perhaps one of the most quickly moving fronts in recent times, with widespread applicability in a variety of fields, including health care. This article aims to summarize and describe the most recent and well-known nanotechnology innovations in dentistry, with a particular emphasis on orthodontics and the use of new nanomaterials in the fabrication of orthodontic elastomeric ligatures, orthodontic power chains, and orthodontic Mini screws.

Physico-mechanical and antimicrobial properties of an elastomeric ligature coated with reduced nanographene oxide-nano curcumin subjected to dual-modal photodynamic and photothermal inactivation against Streptococcus mutans biofilms

BackgroundWhite spot lesions (WSLs) are a common side effect of fixed orthodontic treatment. Streptococcus mutans is the primary causative agent of WSLs and dental caries on the teeth during treatment. According to the unique features of reduced graphene oxide-nano curcumin (rGO-nCur), this study aimed to investigate the mechanical properties and antimicrobial potency of rGO-nCur coated orthodontic elastomeric ligatures as a novel coating composite following dual-modal photodynamic inactivation (PDI) and photothermal inactivation (PTI) against S. mutans biofilms. MethodsAfter confirmation of rGO-nCur synthesis and coating elastomeric ligatures with different concentration levels of 1.25, 2.5, 5, 7.5, and 10 % of rGO-nCur, tensile strength, force decay, extension to tensile strength, and contact angle of the coated elastomeric ligatures were measured using universal testing machine and sessile drop method, respectively. To investigate the mechanism through which irradiated rGO-nCur can inhibit the formation of S. mutans biofilms, intracellular reactive oxygen species (ROS) generation, and increase in temperature of rGO-nCur solutions under the 450 and 980 nm laser irradiation, respectively, were measured. The anti-biofilm activity and inhibition of water-insoluble extracellular polysaccharide (EPS) production ability of irradiated rGO-nCur coated elastomeric ligatures using a 450 nm diode laser (195 J/cm2), a 980 nm diode laser (195 J/cm2), and a combination of both (78 J/cm2 of irradiation from each one) (i.e., PDI, PTI, and dual-modal PDI/PTI, respectively) were determined. Also, the expression of virulence genes involved in biofilm formation (comDE, gtfD, and smuT) was assessed by quantitative real-time polymerase chain reaction (RT-qPCR) following the mentioned treatment. One-way ANOVA test and Tukey post-hoc test at a p-value equal to/or less than 0.05 were used to analyze the obtained data. ResultsThe synthesis of GO nano-sheets in a layered structure with a thickness of 0.76 nm was confirmed by AFM analysis. FESEM showed that the exfoliated sheet of synthesized GO had several micrometers in lateral size. DLS revealed that the mean particle size and density index of synthesized nCur were 57.47 ± 2.14 nm and 10 % respectively. In DLS analysis, rGO-nCur showed more positive surface charge (24 mV) than the nano-sheets of GO. FESEM confirmed the coating of rGO-nCur on elastomeric ligatures. ANOVA revealed that tensile strength of 1.25, 2.5, and 5 % rGO-nCur coated elastomeric ligatures were not decreased statistically significantly (P > 0.05). Mean tensile strength and recorded force of 7.5 and 10 % rGO-nCur coated elastomeric ligatures decreased significantly after 14 days’ immersion in the artificial saliva (P < 0.05). On the 28th day of the study, the mean of the tensile strength of elastomeric ligatures coated with 10 % rGO-nCur (13.03 ± 0.10 N) was recorded as 55.90 % of the initial tensile strength (23.31 ± 0.41 N in uncoated elastomeric ligatures), while the mean tensile strength of elastomeric ligatures coated with 7.5 % rGO-nCur (16.01 ± 0.10 N) was measured as 68.94 % of the initial tensile strength (23.22 ± 0.09 N in uncoated elastomeric ligatures). When comparing the coated elastomeric ligatures at 7.5 % and 10 % to the original uncoated elastomeric ligatures at similar time intervals, statistically significant decreases in extension to tensile strength (0.42 to 0.71 mm or 3.02 to 5.05 %; all P < 0.05) were observed. The largest contact angle was measured in elastomeric ligatures coated by 10 % rGO-nCur followed by 7.5 and 5 % rGO-nCur (128 ± 2.19°, 117 ± 2.23°, and 99 ± 1.83°; respectively). The results revealed a rise of 6.4-fold in intracellular ROS and an 11.2 °C increase in the temperature of rGO-nCur solutions following the 450 nm and 980 nm laser irradiation, respectively. The 5 % rGO-nCur coated elastomeric ligature mediated dual-modal PDI/PTI showed the most inhibition of the biofilm formation of S. mutans by 83.62 % (P = 0.00). Significant reductions in water-insoluble EPS were detected in biofilm cultures of S. mutans on 1.25 % rGO-nCur coated elastomeric ligatures following irradiation with dual waves of the 450 nm and 980 nm diode lasers (i.e., dual-modal PDI/PTI; 96.17 %; P = 0.00). The expression levels of comDE, gtfD, and smuT virulence genes were significantly downregulated (7.52-, 13.92-, and 8.23-fold, respectively) in the biofilm cultures of S. mutans on 1.25 % rGO-nCur coated elastomeric ligatures following dual-modal PDI/PTI in comparison with biofilm cultures on non-coated elastomeric ligatures. Conclusion5 % rGO-nCur coated elastomeric ligatures following irradiation with dual waves of the 450 and 980 nm diode lasers (dual-modal PDI/PTI), without adverse effects on the physico-mechanical properties of elastomeric ligatures, can be used to inhibit the formation of S. mutans biofilms on the coated elastomeric ligatures around orthodontic brackets.

Antibacterial Effect of Experimental Orthodontic Elastomeric Ligature Coated with Zinc Oxide Particles

Objectives . This study aimed to evaluate antibacterial activity of elastomeric ligatures coated with Zinc oxide particles against Streptococcus mutans. Methods. ZnO particles grafted with (3-Aminopropyl) trimethoxysilane (APTMS) were prepared in situ. The ATR-FTIR spectrum was used to analyze the APTMS grafted on ZnO surfaces. Two concentrations of ZnO-APTMS, i.e., 5 and 10 wt%, were coated on orthodontic elastomeric ligatures by the dip coating method. Antibacterial property of the ZnO-APTMS coated elastomeric ligatures against S. mutans ATCC25175 were investigated by the agar diffusion test. The effect of ligature aging on antibacterial property was evaluated by the direct contact test, in which the growth of bacteria was determined by the turbidity after exposed to the samples that had been immersed in distilled water for 0, 3, 7, 14, 28 days. The drop plate test was also performed to determine the inhibitory and the bactericidal effects. Results. The analysis of ATR-FTIR spectrum confirmed that APTMS was successfully grafted on ZnO surfaces. The agar diffusion test could not demonstrate the antimicrobial effects of the ZnO-coated elastomeric ligatures. However, results from the direct contact and the drop plate tests showed the inhibitory effects on bacterial growth compared to the positive controls (p &lt; 0.05). The inhibitory effect of the ZnO-coated elastomeric ligatures was observed even after they had been immersed in distilled water for 28 days. Conclusions. The surface coating elastomeric ligatures with 5 and 10 wt% ZnO-APTMS exhibited antibacterial activity against cariogenic bacteria, S. mutans. The bacterial inhibitory effect was prolonged until 28-day.

A Novel Coating of Biosynthesized Silver Nanoparticles on Orthodontic Elastomeric Ligatures

Background: Fixed orthodontic appliances especially with orthodontic elastomeric ligatures can increase the risk for development of white spot lesions, which are often irreversible. Due to their huge surface area, silver nanoparticles are effective antimicrobials. Green synthesis employs the use of plant extracts such as Clove and Cardamom which possesses antimicrobial, antiinflammatory and antioxidant properties. Aim: This study aims to discover a novel approach to coat orthodontic elastomeric modules or ligatures with biosynthesized silver nanoparticles using clove and cardamom as plant extract. Materials and methods: Aqueous extract of cardamom and clove was prepared. Biosynthetic silver nanoparticles were synthesised by reacting silver nitrate ions with clove and cardamom extract (as bioreductant). Using a magnetic stirrer and a hot plate, silver nanoparticles (AgNPs) were synthesised directly on orthodontic elastomeric ligatures. Characterization of silver nanocoated elastomeric ligatures was done using Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). Results: At the end of third day formation of AgNPs were reported by color shifting from orange-red to dark brown. Reducing silver ions to AgNPs, as shown by UV-vis spectroscopy, generated a peak at 462 nm. SEM and EDX confirms the presence of elemental silver on silver nanocoated elastomeric ligatures. Conclusion: An innovative coating technique incorporating magnetic stirrer along with a hot plate allows for the efficient coating of biosynthesized silver nanoparticles on orthodontic elastic ligatures. The SEM and EDX results indicate the structural integrity of the Ag nanoparticles on the biosynthetically produced orthodontic elastic ligatures is enhanced.

An In - vivo study to evaluate the force decay of three different orthodontic elastomeric ligatures.

Abstract: Background: In vitro studies conducted under simulated oral environment under estimated the force decay of elastomeric ligatures. There are only few invivo studies that are reported evaluating the force decay of elastomeric ligatures. Aim &amp; Objectives: The aim of this in-vivo study was to evaluate the force decay of three different clear elastomeric ligature modules stretched over the lower incisor brackets intra orally over three different time periods at 24 hrs, 7 days and 21 days by comparing it with the force levels evaluated at as received conditions . Materials and methods: Ten patients undergoing fixed orthodontic treatment with Roth Prescription, 0.022" slot preadjusted edgewise stainless steel brackets with aligning and levelling completed and 0.019" x 0.025" SS arch wire placed passively in the lower arch were included in the study. The three types of elastomeric ligature modules formed the three study groups [Group I: Molded“O” (Ormco, USA),Group II: Alastik (3M Unitek, USA)&amp;Group III: Uni-stick (American orthodontics, USA)] Each group was assigned with a specific lower incisor in each patient and the respective modules were used in the teeth during the study period. The force levels required to stretch the modules to a predetermined length of 4.1mm were evaluated at 4 different time intervals at 0 hour (as received), 24, 7 days, and 21 days after intra-oral use using a universal testing machine (Instron model 1112, Instron Corp.). The mean force values and standard deviations for all the groups at each time period. The mean percentage of force decay between time periods for each study group was calculated. One way ANOVA followed by Post hoc Tukey HSD was performed for within the group and between group comparisons. Paired T test was done for pairwise comparisons. (P value≤ 0.05) Results: The mean force level recorded were high at the base line level with as received modules before inserting into the patients mouth for all the three study groups. The mean force level was 766.50 ± 3.659 gms, 650.50±2.759 gms and 594 .10 ± 4.630 gms for group I, II &amp; III respectively in the as received condition. The percentage of force decay was 32.94 % at 24 hrs and 69.85% at 7 days and 79.31% at 21 days for Group I. A force decay of 31.36%, 70.76% and 79.83% from the base line value was noted in group II at the same time intervals. In Group III The force decay rate at 24 hrs, 7 days and 21 days were 33.29%, 66.10% and 77.12% respectively. One way ANOVA for within group and between group comparison showed a significant difference between the force levels recorded at different time intervals within and between all the three study groups. Post Hoc Tukey HSD revealed a significant difference between the three groups at all the time intervals tested except at 7 days and 21 days where the force levels exerted by the group II and Group III samples were not significantly different. Paired sample T test for pairwise comparison of force exerted between different time intervals in all the three groups revealed a significant difference. Conclusion: Group I clear modules exhibited significantly high mean force and less force decay compared to other groups at all four time intervals tested. The elastomeric modules exhibited significant force decay after 24 hours, 7days and 21 days of intra-oral use except at 7 days and 21 days where the force levels exerted by the group II and Group III samples were not significantly different. The forces at the end of three weeks of intra oral use appeared to be insufficient for effective torquing effect and severe rotational corrections in all the three study groups and hence changing modules sfter three weeks may be beneficial in those cases

Disinfection of Orthodontic Elastomers and Its Effects on Tensile Strength.

This study aimed to investigate the effect of different disinfection protocols on the mechanical properties of orthodontic elastomeric ligatures (EL), an important issue to biosafety improvement and infection control, and to avoid cross-contamination. A total of 120 EL were randomly divided into 6 experimental groups (n = 20) according to the disinfection method employed: group 1, EL were not immersed in a disinfectant solution (control group); group 2, EL were immersed in 2% glutaraldehyde; group 3, EL were immersed in 70% alcohol solution; group 4, EL were cleaned in an ultrasound washing (UW) machine by immersion in 0.5% enzyme detergent solution; group 5, UW procedure was performed, followed by immersion in 2% glutaraldehyde; Group 6, UW procedure was performed, followed by immersion in 70% alcohol. After disinfection, EL were subjected to a tensile strength test where the maximum strength, maximum elongation, and work at failure were determined. Data were statistically evaluated using one-way ANOVA and Dunnett's t-test for multiple comparisons. Statistically significant different (P < .05) values were found between the disinfection methods, and 70% alcohol showed negative changes in all mechanical properties of orthodontic elastomers. By contrast, 2% glutaraldehyde did not show significant alteration in mechanical properties, whereas the UW procedure showed significant alteration in maximum strength and work at failure. Of the tested substances for disinfection, 2% glutaraldehyde was the only substance that did not cause significant changes in the mechanical properties of orthodontic elastics and is considered as an alternative for elastic disinfection before its use.

Importance of determining and establishing latex allergy in orthodontic patients

Introduction: The current study was commended with the aim of assessing the incidence of latex allergy in orthodontic patients. Materials and Methods: Silver-coloured orthodontic elastomeric ligatures (modular) from six different manufacturers were selected for the cytotoxicity study, being one of natural latex, two of latex-free and three containing polyurethane. The samples were divided into 6 groups of 15 elastics each. The cytotoxicity of these orthodontic elastics was determined through the dye-uptake technique, which is based on the neutral red absorption by living cells. Different periods of time were considered: 1, 2, 3, 7 and 28 days. Results: Among all the respondents to the survey, 7.5% showed positive change after wearing elastics. Most of the positive changes were seen in females Conclusion: Safe orthodontics practice is dependent upon recognising patients with allergy along with awareness of etiologic materials.

Influence of Coca-Cola on orthodontic materials. A systematic review.

This analysis was conducted to assess the impact of Coca-Cola on orthodontic materials compared to that of other fluids. Electronical searches were carried out in PubMed, Livivo, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov, supplemented by manual searches in the reference lists of the articles selected for full text evaluation. The risk of bias was assessed on the basis of a "risk of bias summary." A total of 216 bibliographic summaries of articles were obtained, eleven of which were relevant. Nine of these papers showed a low risk, while two publications from one in vivo study exhibited a high risk of bias. The continuing influence of Coca-Cola caused significant discoloration of elastomeric materials and resulted in significantly lower shear bond strength of the brackets and higher corrosion. With regard to orthodontic appliances, additional in situ and in vivo studies are desirable. Special attention should be paid to an appropriate number of samples or patients, as most investigations lacked a sufficient number of test subjects. In addition, investigations with long observation periods and documented beverage consumption should be preferred. The intake of cola-containing beverages during orthodontic therapy and the exposure duration of these beverages to orthodontic material should be reduced to a minimum, as this can impair the adhesive strength and lead to corrosion of orthodontic brackets. The interval between orthodontic appointments should be short to avoid discoloration of orthodontic elastomeric ligatures.

Application of Nanotechnology in Orthodontic Materials: A State-of-the-Art Review.

Nanotechnology refers to the science that manipulates matter at molecular and atomic levels, and studies matter at the nanoscale level to detect and exploit the useful properties that derive from these dimensions; materials with components less than 100 nm in at least one dimension are called nanomaterials. Nanotechnology is applied in many fields, such as medicine (nanomedicine) and dentistry (nano-dentistry). The purpose of these innovations and research in this field is to improve human life and health. This article aims to summarize and describe what the most recent and known innovations of nanotechnology in dentistry are, focusing on and paying particular attention to the branch that is orthodontics, and on the application of new nanomaterials in the realization, for example, of orthodontic elastomeric ligatures, orthodontic power chains, and orthodontic miniscrews. We also address a very important topic in orthodontics, which is how to reduce the friction force.

Chlorhexidine hexametaphosphate as a coating for elastomeric ligatures with sustained antimicrobial properties: A laboratory study

White spot lesions are a common side effect of orthodontic treatment. This laboratory study aimed to explore the suitability of chlorhexidine hexametaphosphate (CHX-HMP) as a coating for orthodontic elastomeric ligatures to provide sustained chlorhexidine (CHX) release. Dissolution kinetics of CHX-HMP were firstly explored using spectroscopy and a colorimetric phosphate assay. Elastomeric ligatures were categorized into 3 groups-acetone-conditioned, ethanol-conditioned, and as received-and were then immersed in 5mM CHX-HMP suspension or 5mM chlorhexidine digluconate solution and rinsed. CHX release was measured over 8weeks, and the effects of conditioning and immersion on elastomeric force and extension at rupture and surface topography were investigated. CHX-HMP exhibited a gradual equilibration that had not reached equilibrium within 8weeks, releasing soluble CHX and a mixture of polyphosphate and orthophosphate. CHX digluconate-treated ligatures showed no CHX release, whereas CHX-HMP-treated ligatures showed varying degrees of release. As received, CHX-HMP-treated ligatures showed a modest release of CHX up to 7days. Acetone conditioning did not enhance CHX-HMP uptake or subsequent CHX release and caused a deterioration in mechanical properties. Ethanol conditioning enhanced CHX-HMP uptake (6×) and led to a sustained CHX release over 8weeks without affecting mechanical properties. Within the inherent limitations of this in-vitro study, CHX-HMP led to a sustained release of CHX from orthodontic elastomeric ligatures after ethanol conditioning. Conditioned and coated elastomeric ligatures may ultimately find application in the prevention of white spot lesions in orthodontic patients.

Effect of color differences on elastomeric ligatures adhesion on streptococcus mutans in saliva liquid

Objective: Of this study was to determine the effect of color differences in elastomeric ligatures on the adhesion of streptococcus mutans in salivary fluidMaterial and Methods: Type of research used was laboratory experimental with cross sectional study, using elastomeric ligatures 10 pieces of orthodontic elastomeric ligatures dark clear fruits. The samples were then divided into 2 groups. Each group of samples was each immersed in 100 cc of artificial saliva pH 4 which had been given each cc of streptococcus mutans and cultured in the media to see the number of colonies attached to elastomeric ligatures. The results of calculating the number of colonies were then analyzed using the SPSS version 24 program and using the Independent t test with a significant value of 0.05.Results: The results showed that there are significant differences between the ligatures elastomeric orthodontic dark and elastomeric ligatures clear.Conclusion: Elastomeric ligatures darker color have more adhesion to streptococcus mutans when compared to adhesion streptococcus mutans to elastomeric ligatures clear.

Metals and Metalloids Release from Orthodontic Elastomeric and Stainless Steel Ligatures: In Vitro Risk Assessment of Human Exposure

Elastomeric ligatures are increasingly used as a part of esthetic orthodontic treatment, particularly in children. The aim of the present study was to experimentally test whether these appliances may contribute to exposure to toxic elements. In the present study, elastomeric ligatures (ELs) were incubated in artificial human saliva for 1 month (a typical period of their use) and the release of 21 metals (Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mg, Mo, Ni, Pb, Rb, Tl, Ti, Sb, Sr, Sn, Zn, U, V) and 2 metalloids (As and Ge) was studied using inductively coupled plasma–mass spectrometry. For comparison, stainless steel ligatures (SLs) were incubated for 1, 3, and 6 months (since sometimes their use is prolonged) under similar conditions. The determined metal levels were compared to the corresponding safety limits for human exposure. During 1 month, the ELs released Cd, Co, Cr, Mn, Ni, and Sn at total mean ± SD level of 0.31 ± 0.09, 0.98 ± 0.30, 3.96 ± 1.31, 14.7 ± 8.5, 13.8 ± 4.8, and 49.5 ± 27.7 μg, respectively. Other elements were always below the detection limits. In case of SL, the release of Co, Cr, Fe, Ni, Mn, and Sn was observed, and the determined values increased over the studied period. After 6 months, their total mean ± SD levels amounted to 28.6 ± 0.2, 21.7 ± 0.2, 623.5 ± 3.0, 1152.7 ± 1.8, 5.5 ± 0.3, and 22.6 ± 0.2 μg, respectively. The released metal levels from both ligature types were always below safety limits. The release of Ni from SL during 6 months would constitute 5.0 and 11.5% of tolerable intake in adults and children, respectively. The results of this in vitro study highlight that the use of ligatures in orthodontic treatment can be considered safe in terms of metal exposure although elastic ligatures replaced on a monthly basis appear to be advantageous in comparison to the prolonged use of stainless steel appliances.

Discoloration and force degradation of orthodontic elastomeric ligatures.

ABSTRACTOBJECTIVE: The aim of the present study was to evaluate color changes and force degradation of orthodontic elastomeric ligatures in different stretching patterns during a 8-weeks period. METHODS: Two elastomers with the minimum and two with the maximum color changing, and gray elastomers of two brands (American Orthodontics and Ortho Technology) were selected according to an opinion poll with clinicians and color changes after 4 weeks of intraoral use were evaluated. These elastomers were mounted on special jigs fabricated using a CAD-CAM technique, underwent different stretching patterns and the force was measured in 0, 24 hours, 2, 4 and 8 weeks. During in vivo part of the study, force levels of elastomers were measured after 4 weeks on a material testing machine. Data were analyzed with four-way ANOVA and Tukey post hoc tests.RESULTS: All the elastomers showed color changing but the degree of color stability was significantly different. The mean force degradation was higher in 1-mm stretch groups. After 8 weeks, the average residual force of elastomers was 1.45 ± 0.18 N and the maximum force decay was seen in the elastomers that exhibited the maximum initial force.CONCLUSION: There is significant relationship between the stretching pattern and the amount of residual force of elastomers. Elastomers with higher initial forces exhibited higher percentages of force loss after 8 weeks. It seems that there is a relationship between initial color and color changing of elastomers.

Cytotoxicity of three commercial orthodontic elastomeric ligature brands

This study aimed to evaluate cytotoxicity of three commercial brands of orthodontic elastomeric ligatures. Materials and Methods: The three commercial orthodontic elastomeric ligature brands were C-brand, T-brand and U-brand from different manufacturing countries. The cytotoxic assay was performed using cell cultures (L929) which were subjected to the cell viability test with methyl-tetrazolium (MTT). The L929 cell line was grown in 96-well tissue culture plates (1×10 5 cells/cm 3 ). Elastomeric ligatures (0.2 g) from each brand was placed in 1 ml of Minimum Essential Medium (MEM) at 37°C with 5% CO 2 at 100% humidity in an incubator for 24 hours. After incubation, the cell mitochondrial activity was evaluated by the MTT test for detecting viable cells from optical density according to ISO 10993-5: 2009 (E) test procedure. Cytotoxic effects were determined by the percentage of cell viability. Results: Microscopic investigation showed that all commercial elastomeric ligatures caused alterations in the fibroblast cell morphology from an elongated to a spherical form. The cell viability of C-brand, T-brand and U-brand were 51.10, 73.04 and 93.04%, respectively. Conclusion: T-brand and U-brand orthodontic elastomeric ligatures were non cytotoxic potential. U-brand had the greatest cell viability and C-brand had the lowest cell viability at 24 hours.

Analysis of the Influence of Food Colorings in Esthetic Orthodontic Elastomeric Ligatures

Proposition:The purpose of this study was to evaluate in vitro the color changes of esthetic orthodontic elastomeric ligatures of different shades when exposed to four food colorings commonly found in the diet of patients.Materials and Methods:The sample consisted of esthetic orthodontic elastomeric ligatures in the colors pearl, pearl blue, pearl white and colorless, which were immersed for 72 hours in five different solutions: distilled water (control group), coffee, tea, Coca-Cola ® and wine. The color changes of the esthetic orthodontic elastomeric ligatures were measured with the aid of a spectrophotometer, at T1 - as provided by the manufacturer; and T2 - after colorings process. Results: The results indicated that the esthetic orthodontic elastomeric ligatures of all initial hues are susceptible to pigmentation. Among the evaluated colors, all changed the finished look and the color of the samples tested. In ascending order, the color of the samples was as follows: distilled water, Coca-Cola®, black tea, wine and coffee. Conclusion:The substances that have a greater potential for pigmentation in esthetic orthodontic elastomeric ligatures were black tea, wine and coffee, respectively. All shades of esthetic orthodontic elastomeric ligatures are susceptible to color change.

Evaluation of Tensile and Friction Resistance of Various Orthodontic Elastomeric Ligatures

Evaluation of Tensile and Friction Resistance of Various Orthodontic Elastomeric Ligatures

Effect on Mechanical Properties of Orthodontic Elastomeric Ligatures on Immersion in Disinfecting Solutions - an in vitro Study

Effect on Mechanical Properties of Orthodontic Elastomeric Ligatures on Immersion in Disinfecting Solutions - an in vitro Study

Citotoxicity of nonlatex elastomeric ligatures of orthodontic use

The aim of this study is to evaluate cytotoxicity between polyurethane and non-latex orthodontic elastomeric ligatures. Seven elastomeric ligatures of black-coloured from different manufactures (3 non-latex, 3 polyurethane and 1 latex) were divided into 7 groups of 10 elastics each: Group UK (nonlatex, 3M Unitek), Group TP (nonlatex, TP Orthodontics), Group AO (nonlatex, American Orthodontics), Group O (Polyurethane, OrthoSource), Group M (Polyurethane, Morelli), Group TD (Polyurethane, Tecnident) and Group TC (latex - Control, TP Orthodontics). The cytotoxicity essay was performed using cell cultures (L-929 line cells, mouse fibroblast) that were submitted to the cell viability test with neutral red (dye-uptake) at 1, 2, 3, 7 and 28 days. Analysis of variance (ANOVA) with 1-way analysis followed by the Tukey post hoc test were employed (p .05). There was a statistically differences (p .05) between the groups O, M and TD at in all experimental times. It can be concluded that the nonlatex elastomeric ligatures of Unitek, TP Orthodontics, and American Orthodontics showed higher cell viability compared to others ligatures.