Evaluation of tensile strength of different configurations of orthodontic retraction loops for obtaining optimized forces.
The aim of this study was to analyze the mechanical behavior of different orthodontic retraction loops. Two designs of orthodontic loops for closing space were analyzed: teardrop-shaped (T) and circle-shaped loop (C), of two different heights (6 and 8 mm), and two types of orthodontic wires (stainless steel - 0.19' x 0.25'; TMA - titanium molybdenum alloy - 0.016' x 0.016'). The sample consisted of 80 loops, divided into 8 groups determined by the combination shape/height/type of wire, which were submitted to tensile testing at a speed of 2 mm/min., to measure the quantity of force generated when activated in the interval of 0.75 mm and 2.25 mm. The results were submitted to the ANOVA and Tukey statistical tests to compare the groups, and the Student's-t test to compare the means of two groups. Statistically higher values were observed for the size 6 mm, circle shape and stainless steel composition. The group "teardrop-8 mm-TMA" together with the group "circle-8 mm-TMA" presented the lowest mean value, differing statistically from all of the other groups. It was concluded that the alloy of the wire and the height of the loop would be more important than the loop design.
Pontifical, Catholic University of Rio Grande do Sul, Brazil.
Miceli Beck Guimaraes
MB
Blaya
Graziela Henriques
GH
Westphalen
Magali Beck
MB
Guimaraes
Luciana Mayumi
LM
Hirakata
D000497:Alloys / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D016382:Orthodontic Appliance Design; D009969:Orthodontic Wires; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
D000497:Alloys; D003722:Dental Alloys; C525450:titanium molybdenum alloy; D013193:Stainless Steel