| 3797 Friction of elastic, PTFE-coated, and uncoated ligatures during simulated mastication | ||
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J.T. PHILIPOSE, L. GETTLEMAN, and B.E. JOHNSON, University of Louisville, KY, USA Purpose: Movement along orthodontic archwires is impeded if they bind in the bracket, but chewing affects motion between components. This preliminary study measured the friction between 3 types of ligature when mastication was simulated by tapping the tooth.
Methods: Friction was measured by drawing a rubber-mounted tooth and mounted bracket along a 0.016" x 0.022" stainless steel archwire at 2 cm/min under a water film (JDR 80:Abstr. No. 2020, 2001). Mastication was simulated by applying 5.9 taps/sec with a McShirley Elecro-Mallet to the tooth. An Alastic elastic ligated the archwire, which was drawn 15 times through the bracket. A 0.008" SS ligature wire, and then a 0.008" (0.012" finished diameter) PTFE-coated SS wire were then carefully torqued around a spacer and released 1/8 turn to control tension on the archwire, which was drawn again 3 times through the bracket for each of 45 ligatures. Mean friction was recorded in grams-force, converted to mN. ANOVA and Tukey HSD tests were performed on data.
Results: Friction with and without mastication (ąSD) for the Alastic ligature was 806 (66.0) and 850 (58.0) mN, for the SS ligature was 500 (40.7) and 590 (38.8) mN, and for PTFE-coated SS ligature was 376 (36.9) and 448 (38.9) mN, respectively. Significant differences (p£0.001) were found between all variables except Alastic ligatures with and without mastication. Variation was low due to the repeated measures of only 1 archwire sample for the 45 ligatures tested 6 times.
Conclusions: Under the conditions of this study, the elastic ligature displayed nearly twice the friction of either wire ligature. All 3 ligatures displayed reduced friction during simulated mastication. The PTFE-coated SS ligature was significantly easier to slide than uncoated SS. Simulated mastication reduced friction by 15% for both SS and PTFE-coated ligatures, but only 5% for the elastic ligature.
Supported by UofL School of Dentistry. | ||
| Seq #340 - Methods of Orthodontic Treatment 11:00 AM-12:15 PM, Saturday, 9 March 2002 San Diego Convention Center Exhibit Hall C | ||
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