Force decay of elastomeric ligature

Abstract

This study was carried out to evaluate the effect of stretching, time, media, and water sorption on the force decay value for a three companies (OrthoMatrix, Dentaurum, Leone). Eighty elastic ligatures were randomly collected from each company and divided into fourmain groups. Test group one was kept in dry media, test group two was submerged inartificial saliva, test group three was stretched in a dry media over a stainless steel rod with dimensions simulate the maxillary central twin bracket, and the test group four was similar to the previous but submerged in artificial saliva. All of these groups were kept in covered glass containers at a temperature of 37C°. The percentage of force decay and the moisture sorption were recorded for the sample at eight time intervals (zero time, 3 hrs, 24 hrs, 72 hrs, 168 hrs, 336 hrs, 504 hrs, and 672 hrs). The results showed the followings: The moisture and stretching had a pronounced effect on force decay, The greatest force decay occurred within the first 24hrs, and The decay pattern was similar for all ligatures tested.