British Journal of Orthodontics, Vol 21, 359-365, Copyright © 1994 by British Orthodontic Society

ARTICLES

A study to compare the effects of simulated torquing forces on pre- adjusted orthodontic brackets

MM McKnight, SP Jones and EH Davies
Department of Orthodontics, Institute of Dental Surgery, Eastman Dental Hospital, London, U.K.

The transmission of torquing forces between three types of preadjusted bracket was investigated. 0.022-inch Roth prescription 'A'-Company (stainless steel), Silkon (reinforced polycarbonate), and Allure III (polycrystalline ceramic) brackets were used. A selection of stainless steel archwires were chosen, 0.018 x 0.025, 0.019 x 0.025, and 0.021 x 0.025 inch. The brackets were torqued with respect to the archwire and force v. angular deflection was recorded on an Instron machine. The dimension of angular change was in part dependent on the ability of the bracket to elastically or plastically deform. There were no significant differences between bracket types with the 0.018 x 0.025-inch archwire. 'A'-Company brackets demonstrated a significantly lower resistance to loading compared to Silkon brackets in the 0.019 x 0.025-inch group. The greatest amount of distortion was seen in Silkon brackets with an 0.021 x 0.025-inch archwire. Allure III brackets demonstrated the greatest resistance to loading in all groups. As no apparent distortion under loading is seen in Allure III brackets, it is assumed that the load is largely transmitted to the tooth. Full thickness stainless steel rectangular wires should be avoided with these brackets, in order to prevent overloading.

This article has been cited by other articles:

				A. Hamdan and P. Rock The effect of different combinations of tip and torque on archwire/bracket friction Eur J Orthod, July 24, 2008; (2008) cjn017v1. [Abstract] [Full Text] [PDF]