An Investigation of Fluoride Release from Orthodontic Elastomeric Ligatures Nuttachai Viriyakosol 1,a , Surachai Dechkunakorn 1,b , Niwat Anuwongnukroh 1,c , Peerapong Tua-ngam 2,d , Wassana Wichai 2,e 1 Department of Orthodontics, Faculty of Dentistry, Mahidol University, Thailand 2 Research office, Faculty of Dentistry, Mahidol University, Thailand a iamxpotter@hotmail.com, b surachai.dec@mahidol.ac.th, c niwat.anu@mahidol.ac.th (Corresponding Author), d peerapong.tua@mahidol.ac.th, e wassana.wic@mahidol.ac.th Key words: Elastomeric ligatures, Fluoride mouthrinse, Fluoride release, Decalcification, White spot lesion Abstract. The study aimed to investigate the amount of fluoride release from 3 brands of elastomeric ligatures in vitro, after exposure to daily fluoride mouthrinse. The study used 3 brands of elastomeric ligatures (Morelli, Brazil; Unitek, USA; Thai, Thailand). Two elastomeric ligatures from each brand were moistened by de-ionized water and then divided into control and test groups (n=5 per group). In both groups, elastomeric ligatures were placed in individual plastic bottle with 3 ml of de-ionized water. However, In the test group, They were exposed to fluoride mouthrinse (250 ppm fluoride/0.05%NaF) for 1 minute daily. All samples were stored at 37°C for 1, 3, 5, 7 days. After the end of each observation period, the amount of fluoride release in de-ionized water was measured by fluoride ion electrode. The data were analyzed by Kraskal-Wallis and Mann-Whitney U tests (p<0.05). Amount of fluoride release in test group was greater than in the control group in all 3 brands. Within 7 days of daily fluoride exposure, the fluoride released from elastomeric ligatures was continuously increased. Fluoride release from Morelli (0.067±0.013 ppm) and Unitek (0.067±0.012 ppm) were significantly higher than Thai (0.040±0.03 ppm). The fluoride level measured from Morelli and Unitek were not significantly different. The orthodontic elastomeric ligatures can absorb fluoride from mouthwash and release the detectable amount of fluoride within seven days. This fluoride might help prevention of enamel decalcification adjacent to the bracket during orthodontic treatment. Introduction Enamel decalcification, that manifested as a white spot lesions, adjacent to orthodontic brackets is a problem in orthodontic treatment with fixed appliance. This lesions can take only 1 month to develop [1-4]. Many fluoride-releasing materials, such as orthodontic adhesives and elastomeric ligatures, were used to aid in preventing demineralization and enhance remineralization of enamel during treatment. Fluoride-releasing adhesives include conventional glass ionomer cements (GICs), resin-modified glass ionomer cements (RMGICs) and poly-acid modified composite resins [5] . These adhesives have attracted considerable interest, because fluoride is deposited directly to the area around bracket. However, the highest amount of fluoride is released during the first few days with a rapid decline to much lower levels [6-9]. Systematic review showed weak evidence that GICs and RMGICs is more effective than composite resin in preventing white spot formation [10, 11]. Fluoride-impregnated elastomeric ligatures were developed to provide long-term low-dose fluoride release [12, 13]. The fluoride sources are replenished at each orthodontic visit by simply changing the elastomeric rings. Clinical studies have demonstrated favorable results with reduction of enamel decalcification [14, 15]. Nevertheless, studies published afterwards reported contradictory results [16-18]. In addition, fluoridated elastomers have been reported to poor Advanced Materials Research Vols. 1025-1026 (2014) pp 787-791 Submitted: 27.06.2014 Online available since 2014/Sep/12 at www.scientific.net Accepted: 11.07.2014 © (2014) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMR.1025-1026.787 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 202.28.179.5-13/10/14,04:54:55)