Comparison of the effects of different maintenance methods after orthodontic treatment

Objective To compare the effects of different retainers and maintenance methods on orthodontic patients after treatment. Methods A total of 60 patients undergoing non-extraction fixed orthodontic treatment from January 2019 to September 2019 were enrolled. They were randomly divided into four groups: group A using a Hawley retainer, group B using a vacuum formed retainer, group C using a fixed lingual retainer combined with a Hawley retainer at night, and group D using a fixed lingual retainer combined with a vacuum formed retainer at night. Each patient underwent intraoral scanning to print a 3-D model after orthodontic treatment and maintenance for one year. Their peer assessment rating (PAR) indexes before and after maintenance were measured on the model to evaluate the effects of maintenance. Results There was no significant difference in PAR index among the four groups after wearing retainer for one year (P>0.05). Patients in group A showed a higher total score of PAR index after maintenance for one year than those before maintenance (P<0.05). Patients in group C presented remarkable increases in disprepancy and total PAR score after maintenance for one year than those before maintenance (P<0.05). There were no statistical differences in other indicators. Conclusions For non-extraction orthodontic patients, vacuum formed retainer is recommended to maintain orthodontic treatment effect.