Force decay evaluation of thermoplastic and thermoset elastomeric chains:A mechanical design comparison

Abstract

TS chains decayed less than TP chains, and chain loop retraction was beneficial only when using OrTP chains. Contrary to the interchangeable use of TP and TS chains in the published literature and in clinical practice, this study demonstrates that they perform differently under stress and that a clear distinction should be made between the two.

Force decay and dimensional changes of thermoplastic and novel thermoset elastomeric ligatures

“…Some companies make elastomeric chains in both TP and TS materials, and a recent study by Masoud et al 6 compared the two in vitro. They showed that TS elastomeric chains decayed less than did TP elastomeric chains.…”

“…The second type is synthetic elastomers, which are used in elastomeric chains, elastomeric ligatures, and elastic threads and are usually referred to as "alastiks." 1,3,6 Synthetic elastomers are made mainly from polyurethanes 8,12 and can either be thermoplastic (TP) or thermoset (TS). 6 TP materials can be made plastic and are moldable at high temperatures, while TS materials are irreversibly cured during the process of manufacturing, are not remoldable, and will burn at high temperatures.…”

“…1,3,6 Synthetic elastomers are made mainly from polyurethanes 8,12 and can either be thermoplastic (TP) or thermoset (TS). 6 TP materials can be made plastic and are moldable at high temperatures, while TS materials are irreversibly cured during the process of manufacturing, are not remoldable, and will burn at high temperatures. TP materials have weak dipole or Van der Waal bonds between their polymers, while TS materials have stronger covalent chemical bonds.…”

“…TP materials have weak dipole or Van der Waal bonds between their polymers, while TS materials have stronger covalent chemical bonds. 6 Both TP and TS elastomers can be manufactured by either injection molding or die cut stamping. The specimens used in this study were all die cut stamped.…”

“…Disadvantages include microbial accumulation, lack of complete seating of the wire in the slot, friction, and rapid force decay which drives orthodontists to replace them at 4-week intervals. [1][2][3][4][5][6][7][8] Factors that accelerate force decay include a basic pH, 9 heat, 10 and moisture. 11 Two types of elastomers are used in orthodontics.…”