In the previous study, the author reported that the DC-4978 thermosetting polyurethane was the most efficient material for orthodontic ringlets.
The purpose of this paper was to examine the clinical application of the newly produced ringlets made from DC-4978.
Four different forms of this new material were compared with the same kind of currently available commercial material.
Using these five samples, the following tests were carried out:
1) Basic examination for tensile strength, aging effect, and permanent elongation; 2) Clinical examination of the amount of tooth movement after four weeks, time course changes of tooth movement during the four weeks, and physical properties after clinical use.
The findings were as follows: 1) The DC-4978 series proved to be of better quality than the commercial material as an orthodontic ringlet from all the basic physical property tests, especially the aging effect; 2) Among the DC-4978 series, the amount of tooth movement after four weeks was dependent on the thickness of the ringlet; 3) The degree of tooth movement using these two different materials showed a great difference after two weeks of clinical use due to the residual stress.