Discoloration and force degradation of orthodontic elastomeric ligatures

Abstract

OBJECTIVE: 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.

Thermoset and thermoplastic elastomeric chain comparative strength: An in vitro study

“…[4,9] The results of research conducted are consistent with research conducted by Mirhashemi et al where the decrease in strength after the first 24 h occurred at 20.7%-31.2% in elastomeric chains of thermoplastic materials and 9.3%-12.4% in elastomeric chains of thermoset materials. [5,8] The greatest decrease in strength that occurs after the first 24 h is also in accordance with the research conducted by Yagura et al, [10] where the greater the initial strength given to elastomeric chains, the greater the decrease in strength that occurs. Buchmann et al [3] and Mirhashemi et al [8] suggested that the decrease in strength up to the seventh day was caused by absorption of saliva and formation, which coincided with hydrogen adhesion between water molecules and elastomeric macromolecules.…”

“…Deformation mechanisms are related to chain slippage and molecular stretching. [5] Thermoplastic and thermoset chains are different manufacturer's materials of elastomeric chains. Thermoplastic is a plastic that is softened by heating and will harden when cooled.…”

The influence of elastomeric ligatures pigmentation on smile aesthetics during orthodontic treatment

“…2,[17][18][19] Orthodontics, a dental specialty that works directly with smile aesthetics, requires continuous updating of its material collection to keep up with the demands of the overall population. 4,5,[20][21][22][23][24] Therefore, testing the color change of elastomeric ligatures is required to guide orthodontists seeking to respect the decision of patients desiring an aesthetic smile even during orthodontic treatment. Therefore, several studies have been conducted 1, [6][7][8][9][10][11][12][13]15,16 with the aim of explaining which of the aesthetic elastomeric ligatures have the least effect on smile aesthetics.…”

“… 2 , 17 - 19 Orthodontics, a dental specialty that works directly with smile aesthetics, requires continuous updating of its material collection to keep up with the demands of the overall population. 4 , 5 , 20 - 24 …”

Evaluation of degradation of force of esthetic elastomeric chains

“…Elastomer chains can be classified as short, medium or long according to the distance between the links 5,6 . They have the advantages of being practical, hygienic, having elastic memory, being easy to place and comfortable for the patient to use, biocompatible and inexpensive [7][8][9] . However, they also have disadvantages because they are incapable of releasing constant levels of force for a long period of time and undergo changes in their physical properties when exposed to the oral environment, where they absorb saliva and become deformed due to breakdown of internal bonds.…”