Non-latex Elastics Research Articles

In vitro study of structural and mechanical properties of latex and non-latex intermaxillary orthodontic elastics.

We evaluated bacterial endotoxin adhesion, superficial micromorphology and mechanical properties of latex and non-latex intermaxillary orthodontic elastics. To quantify the adhered bacterial endotoxin, elastics were divided into 5groups: experimental (n = 12) latex and non-latex elastics, previously contaminated by an endotoxin solution, negative control (n = 6) latex and non-latex elastics without contamination, and positive control (n = 6) stainless steel specimens (metallic replicas), contaminated by an endotoxin solution. In parallel, the structural micromorphology (n = 6) and surface roughness of latex and non-latex intermaxillary orthodontic elastics were assessed using confocal laser microscopy. Force degradation(g) and deformation of the internal diameter change (mm) were also evaluated. Structural micromorphology, surface roughness (µm), force degradation(g) and internal diameter (mm) change were evaluated at time 0and after 24and 72 h in adeformation test. Data were analyzed by the Shapiro-Wilk, Kruskal-Wallis, Dunn, ANOVA and Bonferroni tests (α = 5%). Endotoxin adhered similarly to both types of elastics withscores of 3 (> 1.0 EU/mL). The surface microstructure of both types of elastics showed irregularities and porosities at all times. Initially, the latex elastics had ahigher surface roughness (p < 0.001) than the non-latex ones. After 24 h loading, surface roughness of the latex elastics was significantly reduced (p < 0.001), while after 72 h, the values were similar for both types (p > 0.05). The non-latex elastics had significantly higher force generation values (p < 0.05) at 0, 24and 72 h compared with the latex elastics, although there was asignificant reduction (p < 0.001) in force over time for both elastics. Despite similar initial values, non-latex elastics had asignificantly larger internal diameter (p < 0.001) after the loading periods of 24and 72 h compared with the latex elastics. Both elastics showed high affinity with endotoxin and microstructural irregularities of their surface. The non-latex elastics generated higher force values but demonstrated greater deformation of the internal diameter after loading.

Dynamic force decay evaluation of latex and non-latex orthodontic elastics.

To evaluate the force decay over time of latex and non-latex orthodontic elastics subjected to either static or dynamic stretching under simulated intraoral conditions. Four types of elastics (1/4-inch 4.5 ounces and 1/4-inch 6.5 ounces, each latex and non-latex) were subjected to either static stretching to 3times internal diameter (ID) or dynamic stretching from 3 to 4.5times ID in artificial saliva at 37 °C for 24 h. Forces generated by the elastics were measured at 0, 1, 2, 4, 8, 12, and 24 h. Differences among elastic types, time points, and between stretching regimens were tested for statistical significance (P < 0.05). Both stretching regimens caused rapid force decay in all elastic types, which was significantly higher in the non-latex elastics than in the latex elastics. In contrast, there were no differences between elastic types made of the same material. With both stretching regimens, the force decay was significant only after the first hour for the latex elastics, whereas it remained significant up to 24 h for the non-latex elastics. All elastic types generated significantly lower forces after dynamic stretching than after static stretching with 70.2, 68.8, and 66.1% of the initial force remaining after 4, 8, and 24 h for latex elastics and 48.0, 40.8, and 29.5% for non-latex elastics. Latex elastics retained significantly more force over time than their non-latex equivalents. Because of the higher force decay in adynamic environment, it is important that non-latex elastics be changed more frequently.

Evaluation of latex and non-latex intermaxillary elastics strength degradation when submitted to the use of chlorhexidine

ABSTRACT Purpose: To assess the influence of 0.12% chlorhexidine solution (CHX) in the strength degradation of different intermaxillary latex and non-latex elastics. Materials and methods: Eighty ¼ inch elastics were separated into eight groups (n = 10) according to manufacturers (Morelli™ and American Orthodontics™), elastic’s type (latex and non-latex) and storage solution (artificial saliva and CHX). Each sample was extended to 19.2 mm, corresponding to 3x the size of their inner diameter, and initial force was verified on the universal testing machine. The elastics were then kept extended, immersed in artificial saliva and their strength was once again evaluated in the following period of time: 12 and 24 hours. Following the storage period, elastics of CHX groups were immersed for 1 min into PerioGard (0.12% chlorhexidine solution) before the strength evaluation. The data (gf) was submitted to a three-way repeated measure analysis of variance and Tukey’s test (α = 0.05). Results: Significant differences between elastics and time were observed (p < 0.000). Statistically significant reduction in strength was found in non-latex and latex elastics between the initial condition and after 12 h and 24 h (p < 0.05). The non-latex elastics showed statistically higher degradation values than the latex elastics, in the three analysis times (p < 0.05). No statistical difference was found between saliva and CHX, regardless of the time and elastic type (p > 0.05). Conclusions: Generally, the latex elastics showed less strength degradation compared to non-latex elastics. CHX did not affect strength degradation and time influenced strength degradation in the first 12 hours, keeping practically constant for up to 24 hours.

Mechanical Properties of Experimental Non-Latex Orthodontic Elastic Bands

. Elastics, a source of continuous orthodontic force, are divided into two types, latex and non-latex, which are made from natural rubber and synthetic rubber, respectively. The major advantage of natural latex elastics is its resiliency to intraoral tractive forces. However, as the incidence of allergic reactions to natural latex has become more widely recognized, non-latex orthodontic elastics have been developed as an alternative. The aim of this study is to investigate the in vitro mechanical properties of Thai non-latex orthodontic elastics as compared to commercially available products. 30 samples of each two Thai non-latex elastics (MTEC1, MTEC2) and two commercial elastics (AO, GAC) with a specified diameter of ¼ inches were used. Width, cross-sectional thickness (CT), and internal diameter (ID) of all samples were measured. Mechanical tests were then carried out to determine the initial extension force (F0), 24-hour residual force (F24), and percentage of force decay. The data were analyzed with one-way ANOVA and Tukey’s test (p &lt; 0.05). Statistically significant differences in elastic width among all four groups except between the Thai non-latex groups (MTEC1 and MTEC2) were found. AO elastics showed the greatest CT followed by GAC, MTEC2 and MTEC1. ID was significantly highest in GAC elastics and lowest in MTEC1 elastics. Although MTEC1 elastics had the lowest F0, the force still falls within the acceptable range for tooth movement (100-250g or 0.981–1.471N). MTEC2 elastics had the greatest F24 and also the lowest percentage of force decay followed by MTEC1, GAC, and AO elastics, which displayed the highest force decay, though no significant differences were found between the two commercial elastics. Thai non-latex elastics are suitable for orthodontic tooth movement due to its lower percentage of force decay after 24 hours.

Analysis in vitro of strength degradation comparing latex and non-latex elastics

Aim: This study was conducted in order to evaluate and compare the behavior of latex and non-latex elastics, as the loss of strength over time in vitro. Methods: The study evaluated 15 of each elastic material for the pre-selected times: 0, 1, 3, 12 and 24 hours. The rubber bands were transferred to the testing machine (EMIC DL-500 MF). The force values were recorded after stretching the elastic to a length of 25mm. Independent t-test was applied. Analysis of variance (ANOVA) was used to check the variation of the forces generated between those determined times. To identify between which times the difference was present, Tukey post-hoc test was accomplished. Results: As regards the initial forces (zero time), the values of force for non-latex elastic were slightly higher than the latex elastic. In subsequent times, the forces generated by the latex elastic showed higher values. Regarding the material degradation, at the end of 24 hours the highest percentage was observed for non-latex elastic. Conclusion: The latex elastic had a more stable behavior during the studied period compared with non-latex.

Force degradation trend of latex and nonlatex orthodontic elastics after 48 hours stretching.

BackgroundTwo types of orthodontic elastics exist based on their material, latex and nonlatex, each of which has different properties in clinical use. Some of the differences include their initial force and force degradation over time. This study was conducted to compare the force changes in both materials.AimTo evaluate the force degradation of latex and nonlatex elastics under moderate stretching over time.MethodsMedium-force orthodontic latex and nonlatex elastics from American Orthodontics (AO) and Ortho Technology (OT) of lumen size 1/4 inches and 3/16 inches (total sample 110 elastics) were submerged in artificial saliva (pH 6.7) and incubated for 48 hours. Then, the elastic force was measured at the following time intervals: initial, 1, 3, 6, 12, 24, and 48 hours. Orthodontic latex and nonlatex elastics from AO and OT were analyzed using Fourier-Transform Infrared Spectroscopy and energy-dispersive X-ray to know the chemical bond structure and elements.ResultsThere was a statistically significant difference between latex and nonlatex force degradation over a period of 0–24 hours (P<0.05), while no significant difference existed between 24–48 hours (P>0.05). Force degradation of latex elastics was higher than that of nonlatex elastics. Energy-dispersive X-ray results on nonlatex elastic bands from OT and AO showed higher C element in the latex elastic band from OT, while the latex elastic band from AO had higher Al element.ConclusionMedium-force latex and nonlatex elastics 1/4 inches and 3/16 inches in size both showed force degradation at 1, 3, 6, 12, and 24-hour intervals under 30 mm stretching when kept in artificial saliva (pH 6.7) and incubated at 37°C for 48 hours.

Force decay evaluation of latex and non-latex orthodontic intraoral elastics: in vivo study.

ABSTRACTObjective: This clinical study was conducted in order to evaluate force decay over time of latex and non-latex orthodontic intraoral elastics. Methods: Patients (n = 15) were evaluated using latex and non-latex elastics in the periods of : 0, 1, 3, 12 and 24 hours. The rubber bands were transferred to the testing machine (EMIC DL-500 MF), and force values were recorded after stretching the elastic to a length of 25mm. Paired t test was applied and analysis of variance (ANOVA) was used to evaluate the variation of force generated. LSD (Fisher’s least significant difference) post-hoc test was thus employed. Results: As regards the initial forces (zero time), the values of force for non-latex elastic were slightly higher than for the latex elastic. In the subsequent times, the forces generated by the latex elastic showed higher values. Regarding the material degradation, at the end of 24 hours the highest percentage was observed for non-latex elastic. Conclusions:The latex elastics had a more stable behavior during the studied period, compared with non-latex.

Influence of temperature and humidity on the long-term storage of latex and non-latex orthodontic elastics.

The objective of this study was to evaluate the influence of long-term storage on latex and non-latex orthodontic elastics. The sample consisted of 300 orthodontic elastics, 150 latex and 150 non-latex (American Orthodontics® *(AO) and Morelli®) of medium force and a standard size of 3/16'' divided into 20 groups, 10 for each manufacturer, with 15 specimens each. The groups (G1*-G10* and G1-G10) were made up based on the manufacturer, storage temperature (ambient and refrigerated), material, and ambient humidity (exposed and non-exposed). The elastics were stretched and their forces measured in five progressive increases of 100% of their inner diameter, starting at a level of 200% stretching, by the MESDAN LAB 3000® (MESDAN, Italy) testing machine. The tests were carried out at two different times: immediately in as-received state and again after 1 year. Data were analysed using SPSS 16.0 software, the Student's t-test, one-way analysis of variance (ANOVA) and the Tukey's post-test. There was a statistically significant difference between the average forces exerted by the latex elastics compared to the non-latex elastics for all distention levels evaluated, except for 300%; however, the different storage conditions of temperature and humidity did not interfere in the mechanical properties. Both the latex and non-latex elastics may be stored under any of the conditions tested in the present study, since there were no changes in the potential of the force exerted by the elastics in relation to their percentage stretch over a 1-year period.

Degradation and deformation of latex and non-latex orthodontic elastics

Abstract Background Intermaxillary elastics are widely used in corrective orthodontic treatment particularly for the interdigitation of buccal segments and the correction of the midline. However, latex has been known to cause allergy, which may restrict elastic use. As alternative materials, non-latex elastics are available. However, clinicians must be aware of their mechanical properties, especially those of deformation and force degradation that affect these materials over time. Objectives The aim of this study was to compare force degradation and deformation of3/16” non-latex and latex elastics supplied by several manufacturers. Materials and methods Special acrylic plates were fabricated to incorporate orthodontic brackets to which elastics were attached and stretched to a distance of approximately 20 mm. The internal diameter and force magnitude of each elastic was measured at time intervals of 0, 24, 72 and 504 hours. The samples were stored in artificial saliva at room temperature during the entire experimental period. Results Latex elastics showed smaller and more uniform deformation than the non-latex elastics. The non-latex elastics showed greater degradation at all time intervals (p &lt; 0.001). The Morelli brand delivered greater force than other brands for both the latex and non-latex elastics at all time intervals (p &lt; 0.05). The G&amp;H latex elastics showed greater force degradation in comparison with the other brands (p &lt; 0.05). The evaluation of the Dentaurum and Orthopli non-latex elastics showed greater degradation (p &lt; 0.05). Conclusions The non-latex elastics showed greater force degradation than the latex elastics. Of the latex elastics, G&amp;H showed greater force degradation, and for the non-latex elastics, those made by Dentaurum and Orthopli degraded most.

Latex and nonlatex orthodontic elastics: In vitro and in vivo evaluations of tissue compatibility and surface structure.

To test the null hypothesis that there is no difference between latex and nonlatex orthodontic elastics with respect to tissue compatibility and surface structure. Latex and nonlatex elastics were implanted in the subcutaneous connective tissue of 45 Wistar rats. In the control groups, no material was implanted (sham). After 24 hours, 3, 7, 14, and 21 days, the animals were euthanized; tissue samples were processed and analyzed by descriptive and semi-quantitative microscopic analysis and quantification of plasma extravasation. The surface structure of elastics was evaluated by scanning electron microscopy (SEM). The results were analyzed by analysis of variance (ANOVA), Tukey test and Kruskal-Wallis test at 5% significance level. Peri-implant plasma extravasation was significantly higher (P < .05) in the animals that received latex elastics compared with those with nonlatex elastics and those that were control animals. The microscopic analysis revealed a more intense inflammatory infiltrate in the initial periods without statistically significant difference (P > .05) between the experimental and control groups. The SEM analysis revealed that the latex elastics presented microspheres and porosities, while the nonlatex elastics exhibited crystals on their surface and absence of porosities. The null hypothesis was rejected since the latex elastics were more irritating to the connective tissue than the nonlatex elastics in the initial periods and presented a more porous surface.

Comparisons of the Mechanical Properties of 3 Commercial Brands of Non-Latex Orthodontic Elastics

Nonlatex orthodontic elastics have been developed as alternative products for latex allergic patients. However, to date, the studies on nonlatex elastics are limited and controversial. Therefore, further investigation of the mechanical properties of nonlatex elastics should be conducted.

Comparison of the Mechanical Properties of Thai Nonlatex with Commercial Latex Orthodontic Elastics for Orthodontic Application

Natural rubber latex products are used as orthodontic elastics but the increased incidence of latex allergies has led to the development of nonlatex orthodontic products. In Thailand, commercial nonlatex orthodontic elastics are not readily available and the cost of imported non latex products is relatively high. Thai non latex elasticshave been developedas alternative orthodontic products for latex-allergic patients and their costs are affordable.Objective: Tocomparethe mechanical properties of Thai nonlatex elastics with commercial natural latex orthodontic elastics for orthodontic application. Materials and Methods: Samples of imported latex orthodontic elastics [Ormco(USA), G&amp;H (USA), Creative Orthodontics (China), Tomy Elastics (Japan)]were selected to compare their dimensional characteristics and mechanical properties with Thai non latex elastics. The dimensional characteristics of the elastics (i.e., inner diameter, cross-sectional thickness and cross-sectional area) were determined and their mechanical properties [(i.e., initial extension force (F0), 24 h- residual force (F24), percentage of force loss, force exerted at 3x the specified inner diameter(F3xID) and breaking force] were tested next. The data were analyzed with One-way ANOVA and multiple comparison by Tukey’s test was used among groups (p&lt;0.05). Results:Significant differences of dimensional characteristics and mechanical properties were found among each brand of elastics. Thai non latex elastics had significantly different mechanical properties from natural latex elastics as reported in previous studies(p&lt;0.05). Thai non latex elastics had the lowest initial extension force (0.82N), 24-h residual force (0.56 N) and breaking force (19.63 N, 8.183 MPa) but the highest percentage of force loss after 24 h (32.62%).However, the percentage of force loss was higher than commercial non latexelastics as previously reported. Conclusion:Thai nonlatex elastics were not comparable to those of the latex elasticsregardingmechanical properties;however,these are acceptable for orthodontic application. Therefore, the clinical selection of elastics should be based on the patient’s medical history and the specific mechanical properties of the type of elastic. Thai nonlatex orthodontic elastics can be a valid alternativefor patients with latex allergy in Thailand and this study contributes to the continuous development of Thai nonlatex orthodontic elastics.

The effect of static and dynamic testing on orthodontic latex and non-latex elastics

The purpose of this study was to test the force decay properties of different kinds of orthodontic elastics after subjecting them to static and cyclic testing. Latex and non-latex elastics obtained from GAC, American Orthodontics and Ortho-Organizers were used in a sample size of 10 elastics per group. Static testing involved stretching the elastics three times the internal diameter, while in cyclic testing, the elastics were stretched up to 50 mm to simulate maximum mouth opening. Elastic forces generated were measured using the Instron testing machine and recorded in grams. Elastics on average lose 10% and 12% as a result of static test and 30% and 35% as result of cyclic test for latex and non-latex brands respectively, and most of the force loss occurs during the first half hour and after the first 10 cycles. This difference in force loss between latex and non-latex elastics could be due to the different structure and composition of the polymer involved. There are no significant differences between different groups of latex elastics in terms of force loss or even between the different groups of the non-latex elastics under static testing, however, under cycling testing differences between the groups were detected. Forces generated by the elastics are different from the manufacturers’ labeled forces.

Evaluation of the cytotoxicity of latex and non-latex orthodontic separating elastics

To test the hypothesis that a difference in cytotoxicity exists between latex and non-latex orthodontic separating elastics. Five intra-oral separating elastics from different manufactures (four latex and one non-latex) were divided into five groups of 15 elastics each: Group MA (non-latex elastics, Masel), Group MO (natural latex, Morelli), Group DE (natural latex, Dentaurum), Group TP (natural latex, TP Orthodontics) and Group UN (natural latex, Unitek). The cytotoxicity assay was performed using cell cultures (epithelial HEp-2 cells originating from human laryngeal carcinoma) that were submitted to the cell viability test with neutral red (dye-uptake) at 24, 48, 72 and 168 h. Analysis of variance (anova) with multiple comparisons and Tukey's test were employed (p < 0.05). The results showed no statistically significant differences between groups MA, DE, TP and UN in relation to Group CC (cell control) for experimental times of 24, 48 and 168 h (p > 0.05). Morelli, Dentaurum, TP Orthodontics and Unitek elastics induced a great amount of cell lyses at 72 h. One can demonstrate that the Masel elastic induced less cell lysis compared with other elastics, but all trademarks were found to be clinically biocompatible. Separating orthodontic elastics are used in the interdental subgingival region with the aim to separate the teeth for placement of orthodontic bands. However, latex has been known to cause allergy. As these materials are widely used in clinical orthodontics, care regarding the cytotoxicity of orthodontic elastics should be taken. Thus, clinically proven biocompatible materials should be acquired whenever possible.

In vitro neuronal cytotoxicity of latex and nonlatex orthodontic elastics

Although the toxicity of many dental materials has been thoroughly investigated, the toxicity of orthodontic elastic materials has not been extensively tested. We evaluated the neurotoxicity of 3 latex and 3 nonlatex orthodontic elastics in murine cerebral cortical cell cultures. Standard-sized pieces of each material from 3 manufacturers (American, Masel, and GAC) were placed on culture well inserts, allowing the material to be exposed to the culture bathing media without causing physical disruption of the cells. Cell death was quantified by assaying the release of the cytosolic enzyme lactate dehydrogenase. Exposure of cortical cultures to the nonlatex elastics did not cause significant neuronal death, but exposure to each of the latex elastics resulted in significant neuronal death. The neuronal death induced by each of the latex elastics was blocked by adding the metal chelator, EDTA (calcium disodium ethylenediaminetetraacetate). Because many latexes use zinc-containing compounds in the prevulcanization process, and the death induced had characteristics similar to zinc-induced neuronal death, it seems likely that the toxicity of latex elastics was mediated by zinc release. Because ingestion of zinc is not a health risk, the results suggest that, in spite of the finding that latex elastics have higher in vitro cytotoxicity than nonlatex elastics, the use of latex elastics in orthodontics is acceptable.

In vitro assessment of the mechanical properties of latex and non-latex orthodontic elastics

The increased incidence of latex allergies has led to the development of non-latex orthodontic products. The purpose of this study was to compare the mechanical properties of latex and non-latex orthodontic elastics. The elastics tested were from 2 manufacturers (GAC and Masel) and made of 2 materials (latex and non-latex). The properties tested included cross-sectional area, breaking force, peak load, peak stress, stiffness, modulus, hysteresis, and 24-hour load relaxation. The data were analyzed with 1-sample t tests, an analysis of variance, and the Fisher PLSD test. Between GAC and Masel, the GAC non-latex elastics had greater breaking forces than did the Masel non-latex elastics. The Masel latex elastics had greater breaking forces than did the Masel non-latex elastics. The GAC non-latex elastics showed more viscoelastic properties than both the GAC latex elastics and the Masel non-latex elastics; however, the Masel elastics were more viscoelastic than the GAC elastics. Forces generated by the elastics decreased over 24 hours to an average load approximating 75% of the manufacturers' values (GAC latex, Masel latex, and Masel non-latex elastics) and to 60% for the GAC non-latex elastics. The mechanical properties of the non-latex elastics were not comparable to those of the latex elastics. Therefore, the clinical choice of elastics should be based on the patient's medical history and the specific mechanical properties of the type of elastic. (Am J Orthod Dentofacial Orthop 2001;120:36-44)