Evaluation of the effects of different lingual retainer materials on post-treatment stability

Abstract Objective To evaluate the effects of different lingual retainers on mandibular anterior tooth stability one-year follow-up period. Materials and methods A total of 140 patients who had undergone non-extraction orthodontic treatment were included in the investigation. For lower incisor retention, Group 1 received a bonded 0.0175-inch seven-strand stainless steel wire (Ortho Technology, Tampa, FL, USA), Group 2 received a 0.022 × 0.016-inch eight-strand dead-soft wire (Bond-A-Braid, Reliance Orthodontic Products, IL, USA), Group 3 received a 0.038 × 0.016-inch prefabricated stainless steel wire (Ortho FlexTech®, Reliance Orthodontic Products, Itasca, IL, USA), and Group 4 received a fibre-reinforced composite wire (StickTech, Turku, Finland). Tooth stability was assessed using Little’s Irregularity Index, intercanine width, and arch length measurements taken at five different time points. Results After one year, changes in Little’s Irregularity Index were statistically greater in Groups 2 and 4 than in Groups 1 and 3. Reductions in intercanine width were also significantly greater in Groups 2 and 4. No significant differences in arch length changes were found between the groups. Wire breakages were statistically more frequent in Group 4, and bonding failures were higher in Group 2. Using a 0.0175-inch seven-strand stainless steel wire or a 0.038 × 0.016-inch prefabricated stainless steel wire for lingual retainers is recommended. Conclusion Stainless steel retainers are recommended for 1-year stability due to their durability and lower failure rate, whereas fibre-reinforced composite retainers may be less reliable.