quarta-feira, 26 de maio de 2010
The History and Development of Self-Ligating
Self-ligating brackets do not require an elastic or wire ligature, but have an
inbuilt mechanism that can be opened and closed to secure the archwire. In
the overwhelming majority of designs, this mechanism is a metal face to the
bracket slot that is opened and closed with an instrument or fingertip.
Brackets of this type have existed for a surprisingly long time in orthodontics—
the Russell Lock edgewise attachment being described by Stolzenberg
in 1935. Many designs have been patented, although only a minority have
become commercially available. In addition, there are lingual self-ligation
brackets, and in general terms, the same challenges and potential differences
apply on the lingual surface. Specific comparison of some types of
lingual self-ligating brackets can be found in the article by Silvia Geron in
this issue. New designs have continued to appear, the Time bracket (Adenta
GmbH, Gliching, Germany) becoming available in 1994, the Damon SL
bracket (“A” Company, San Diégo, CA) in 1996,5,6 and the TwinLock bracket
(Ormco Corp., Orange, CA) in 1998, being three designs from that decade.
Since the turn of the century, the pace of development has greatly accelerated
with the launch of at least 13 new brackets and rapidly increasing sales
for such brackets. This article aims to outline the history and development
of this type of bracket and to put the current situation in context. The
generic advantages claimed for these brackets will be described. In addition,
the problems encountered with various bracket types will be discussed to
provide a summary of why, despite these claimed advantages, self-ligation
has for so long and until so recently been a small part of orthodontics.
(Semin Orthod 2008;14:5-18.) © 2008 Elsevier Inc. All rights reserved.