Analyzing the force and chemical degradation of orthodontic chains

Introduction: Tooth movement is one of the most important intermediate targets in orthodontics. Using polyurethane based elastomeric appliances is one of the most frequently used methods to move teeth. The biggest limitation in these materials, is the occurrence of force degradation which gradually weakens their efficacy. Today we can find types of chains introduced to the market which claim to retain their efficacy and force. The aim of this study is to analyze the mechanical properties and chemical changes related to these chains in an extension period of 28 days. Methods: 4 types of elastomeric chains from the two manufacturers, American Orthodontic and Ortho technology were analysed in this study. Two of these chains were introduced as force retaining chains. The force depreciation was analysed in each chain at time intervals of 1, 7, 14 and 28 days. The chemical changes of the chains were analysed using FTIR at 0 and 28 days. The acquired data regarding mechanical properties were analysed using one way and two-way ANOVA (repeated measure) and Post hoc tests and SPSS version 22 software. Results : The obtained results reported a statistically significant reduction in exertion of force in all groups at the end of the study compared to the start. Both of the American Orthodontic brand chains had a statistically significant lower degradation rate of force compared to the Ortho technology brand chains. FTIR chemical analysis also showed that the American Orthodontic brand chains were more stable in the 0 to 28-day interval. Conclusion : The manufacturers’ claims regarding the force retention of chains is doubtable, but the both of the American Orthodontic brand chains showed a higher force retention ability compared to the Ortho technology brand chains. Furthermore, considering the chemical analysis the degradation in elastomeric chains is more likely related to changes in the hydrogen bond structures.