Introduction: The assessment of forces and moments generated by fully customized lingual appliances and their effectiveness in tooth movement were compared with conventional labial bracket systems, applied to a specific malocclusion model.
Methods: Two fully customized lingual appliances (Incognito [3M Unitek, Monrovia, Calif] and WiN [DW Lingual Systems, Bad Essen, Germany]) and 2 labial bracket systems (Discovery classic and Discovery smart [Dentaurum, Ispringen, Germany]) were examined with nickel-titanium wires of different cross-sections (0.012, 0.014, 0.016, and 0.016 × 0.022-in) and 3 tooth types (canine, lateral incisor, and second premolar). Simulated movement was performed with a wire replacement as soon as forces or moments were no longer effective.
Results: Lingual and labial appliances showed statistically significant differences in initial forces and moments when tested with the same cross-section wires. Statistically significant differences between the 2 lingual bracket systems were also registered. Both lingual appliances rotated the premolar less than the conventional labial appliances.
Conclusions: In areas of smaller lingual interbracket distance and higher lingual slot misalignment, the tested lingual multibracket appliances showed higher forces than the labial appliances. The force difference was particularly prominent with vertically oriented lingual slots and rectangular wires. The tested lingual appliances presented difficulties in rotating the premolar.
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