In vitro study of force decay of latex and non-latex orthodontic elastics.
The aim of this study was to evaluate the force decay of two brands of orthodontic elastics, both offering latex and non-latex products. Samples were subjected to continuous stretching, measuring force at 5 seconds, 8 hours, and 24 hours in both dry and wet conditions. Five hundred samples were used, GAC® and Lancer® 0.25 inch and 4 oz, divided into testing sample sizes of n = 25 per group. For the dry test, elastics were kept stretched to three times their internal diameter for 5 seconds (initial force), 8 hours, and 24 hours; for the wet test, they were stretched for 8 and 24 hours. Both brands showed initial forces significantly greater than those specified by the manufacturers (P < 0.05). Comparing wet/dry conditions, there was a greater force loss in the wet medium than the dry. As for elastic composition (latex or non-latex), the only significant difference found was between Lancer elastics with and without latex in dry conditions, force loss being greater for latex-free elastics. Comparing brands, there was greater force loss with GAC than with Lancer. Comparing elastic force at the eight-hour mark and the twenty-four hour mark to the initial force (only in wet conditions), GAC latex and non-latex and Lancer latex elastics showed significantly less force at eight and twenty four hours than initially. On the other hand, Lancer non-latex was the only type of elastics that did not show a significant decrease in its initial elastic characteristics at eight hours in wet conditions. Nevertheless, Lancer non-latex did show significantly less force in wet conditions at twenty four-hours than the forces observed initially and at eight-hours.
Orthodontic Teaching Unit, Dental Clinic, University of Murcia, Murcia, Spain.
Noelia
N
López
Ascensión
A
Vicente
Luis A
LA
Bravo
José L
JL
Calvo Guirado
Manuel
M
Canteras
D003764:Dental Materials / Q000737:chemistry*; D004548:Elasticity; D006801:Humans; D007840:Latex / Q000737:chemistry*; D008422:Materials Testing; D009967:Orthodontic Appliances; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
D003764:Dental Materials; D007840:Latex; D014867:Water