Force-extension characteristics of orthodontic elastics.

The force-extension characteristics for a wide range of elastics were determined. It was found that (1) selection of elastics were determined. It was found that (1) selection of elastics based on 3 x lumen size will probably result in more force being generated than was previously reported, (2) there is very little difference seen in force-extension characteristics when the two manufacturers' elastics are compared, and (3) for experimental purposes, elastic testing can be done in the dry state for force-extension characteristic studies. This investigation has shown that stretching an orthodontic elastic to twice its original lumen diameter produces a force which better represents the manufacturer's expected value. Keeping these principles in mind, a more effective tooth-moving force can be realized, enabling the clinician to properly select orthodontic elastics for intra- and intermaxillary biomechanical procedures.