Force decay and elongation of orthodontic elastomeric chains exposed to different beverages common in the diet: An in vitro study

Background. Elastomeric chains promote controlled movements and are widely used in orthodontics. Objectives. The aim of the study was to evaluate the force decay and elongation of orthodontic chains exposed to low-pH saliva (pH = 4) and different beverages common in the diet. Material and methods. Force decay and elongation were determined in vitro at 6 time intervals over 21 days for 2 commercial elastomeric chains - Ormco (group A) and Borgatta (group B). The samples were immersed in artificial saliva (AS) at pH 4, Coca-Cola (R), coffee, or beer for 15 min every day, or in AS (the control group). For the remaining time, the chains were placed into AS at 37 degrees C. In addition, microscopic qualitative changes were recorded by means of scanning electron microscopy (SEM). Results. The group B chains showed higher force decay and elongation at the end of the follow-up as compared to the group A chains. Exposure to beer had a greater impact on the force decay and elongation of the chains as compared to other liquids, but it was not statistically significant. The group A chains showed a more irregular surface than the group B chains, in particular, those exposed to coffee. Conclusions. Elastomeric chains suffer force decay and elongation as a function of time, mainly in the first 24 h. At the end of the follow-up, the group A chains exhibited less force decay in comparison with the group B chains. The qualitative observations showed that the chains in group A had a more irregular surface than the chains in group B.