Pigment effect on the long term elasticity of elastomeric ligatures

Abstract

OBJECTIVE: To evaluate the response of elastomeric ligatures in several colors for a 4 mm traction over time. METHODS: Morelli® elastomeric ligatures, were submitted to traction forces using two rods of circular cross section, until a 4 mm distance was reached, matching the approximate diameter of an upper central incisor bracket of the same manufacturer. The ligatures were kept in artificial saliva immersion at 37 ºC. Forces levels were measured immediately (0 h), 2, 4, 6, 8, 10, 12, 24, 48, 72, 96 hours, 1, 2, 3, 4 weeks and results were submitted to two-way repeated-measures ANOVA statistical analysis. RESULTS: The gray samples showed the higher initial values of tensile strength. The lowest values were presented by purple, light pink, green, black and red groups. The greater tensile strength instability was presented by red, black, silver, green and gray groups. The greater tensile strength stability was presented by deep pink, dark blue, blue, purple and light pink groups. CONCLUSION: Elastomeric ligatures do not present stable behavior when suffering traction forces over time and different colors display different behaviors. Deep pink, dark blue, blue, purple and light pink groups, displayed the most stable forces, suggesting that they should be used during the treatment to obtain constant forces

Effect of sodium fluoride in chlorhexidine mouthwashes on force decay and permanent deformation of orthodontic elastomeric chain

“…The range was influenced by the rate and loading duration, and the preliminary force was controlled before immersion by the environmental conditions. 18 Since the study was done under static conditions in vitro, the performance of the elastomeric chain could not simulate the degradation seen in-vivo. Further study is needed controlling the pH and temperature of the sample while examining the effects of various sodium fluoride concentrations on force decay and permanent deformation.…”

Colored or Transparent Orthodontic Ligatures, Which One Has the Best Performance?

“…These dyes can give rise to different interactions and consequently different behaviors in the face of mechanical activation [32]. In a study that evaluated orthodontic elastics of 4 different colors, 2 trademarks and two stretching intensities, different initial strengths and strength loss percentages were observed.…”

Reliability of Digital Camera over Spectrophotometer in measuring the Optical Properties of Orthodontic Elastomeric Ligatures

“…23,29 The in vitro aging process of the polyurethane involves, initially, the degradation of the ether group, followed by the loss of the free urethane not linked to the ester group and the loss of the hydrogen linked to the urethane of the ester group and urea group which promotes structural degradation of the polymer's chain and accelerates the aging and weakening process of the material. 30 Thus, discoloration of elastomeric modules increases as immersion time increases. The values obtained with the digital camera showed a non significant difference with the values obtained from spectrophotometer as shown in Tables 3 to 5.…”