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Introduction: Orthodontic elastics are frequently used in orthodontic treatment but there is little research into how to modify their prescription to improve their performance. The aim of this study was to evaluate potential wear modifications to a standard Class II intermaxillary elastic prescription on force levels and force degradation over time. Methods: For this in vitro study, Ormco (OR) and American Orthodontic (AO) latex elastics had five modifications made to a standard 1/4”/4.5oz control elastic (Group 1). These included an increase of force level by one unit to 6 or 6.5oz (Group 2); a decrease in lumen size to 3/16” (Group 3); a doubling of the control elastic (Group 4); a 720° twist added between the two ends (Group 5); and an increase in initial stretch length by one tooth (Group 6). Elastics were tested on an elastic stretching apparatus with parameters imitating the use of intermaxillary elastics for the treatment of Class II malocclusions. Intraoral conditions were simulated with a distilled water bath maintained at 37°C and cyclic stretching of 1 stretch/min to mimic oral functioning. Force was assessed at time points 1, 5, 30, 60, 180, 360 and 720 minutes. A Two-way Mixed ANOVA was used to identify statistically significant differences between groups and time points (p |
