Optimizing the design of preactivated titanium T-loop springs with Loop software.
A TMA (Ormco Corp, Glendora, Calif) T-loop spring (TTLS), preactivated with a gable bend distal to the loop, holds promise for producing controlled tipping of the canines and translation of the posterior segment. However, there is currently no consensus as to where the preactivated gable bend or the loop should be placed, what the height of the loop should be, or how the interbracket distance changes the moments produced. Using the Loop software program (dHal, Athens, Greece), we systematically modified a .017 x .025-in TTLS (10 x 6 mm) that was preactivated with a 45 degrees gable bend distal to the loop, and simulated the effects. As the gable bend was moved posteriorly, the moment increased at the posterior bracket more than it decreased at the anterior bracket. As the loop was brought closer to the anterior bracket, the posterior moment decreased at the same rate that it increased anteriorly. As the loop was increased in size, the moments increased both posteriorly and anteriorly. As the interbracket distance increased, the posterior moment decreased, and the anterior moment remained constant. We concluded that the size of the loop should be slightly increased, to 10 x 7 mm, and it should be placed 2 mm from the anterior bracket, with a preactivation bend of 45 degrees , 4 to 5 mm from the posterior bracket (after 4 mm of activation).
Martins
Renato Parsekian
RP
FAEPO/UNESP and FAMOSP/GESTOS, Araraquara, São Paulo, Brazil. dr_renatopmartins@hotmail.com
Buschang
Peter H
PH
Martins
Lidia Parsekian
LP
Gandini
Luiz Gonzaga
LG
D001696:Biomechanical Phenomena; D003198:Computer Simulation; D003764:Dental Materials / Q000737:chemistry; D006801:Humans; D008954:Models, Biological; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D018583:Pliability; D012984:Software; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D014087:Tooth Movement Techniques / Q000295:instrumentation
D003764:Dental Materials; D014025:Titanium