The use of a neodymium - iron - boron magnet device for positioning a multi-stranded wire retainer in lingual retention — a pilot study in humans

SUMMARY The aim of this study was to evaluate the time requirement of a newly developed device made of neodymium – iron – boron (NdFeB) magnets for positioning a multi-stranded, canine-to-canine retainer during bonding compared with dental fl oss and a transfer tray. Forty-fi ve patients aged between 12 and 33 years (26 male, 19 female) previously treated with fi xed appliances were enrolled in the study. The patients were randomly allocated to three groups (15 per group). For each group a mandibular canine-to-canine retainer of 0.018 inch Dentafl ex multi-stranded wire (Dentaurum) was prefabricated for each patient on a cast. The bonding procedure was identical, except for the method of positioning the wire during adhesive fi xation: group A dental fl oss, group B a small prefabricated transfer tray of dental resin and group C the NdFeB magnet device. For each group, the time required for the complete bonding process was measured. Kruskal – Wallis and Wilcoxon – Mann – Whitney tests were used for group and pairwise comparisons, respectively. The three methods required statistically signifi cant different times ( P < 0.001). The Wilcoxon – Mann – Whitney test revealed that wire positioning with the magnet device was signifi cantly faster [4.98 minutes; standard deviation (SD) 0.68 minutes] than with dental fl oss (7.65 minutes, SD 1.14 minutes; P = 0.0001) or with transfer tray (5.75 minutes, SD 0.57 minutes; P = 0.001). The NdFeB magnet device is a timesaving appliance for positioning a multi-stranded, canine-to-canine retainer during bonding when compared with dental fl oss and an individually prefabricated transfer tray.