Using PAR score to evaluate the clinical effects of thermoplastic retainer and Hawley retainer on patients with premolars extracted

Objective To find different clinical effects of thermoplastic retainer and Hawley retainer.Methods 40 children patients were chosen after orthodontic treatment with the first premolar extracted.20 patients wore thermoplastic retainer after their treatment(Team A),while 20 patients wore Hawley retainer(Team B).The models were collected on debonding day(T1) and one year after treatment(T2).The data were analysed with SPSS 13.0.Results There were no significant differences between the two groups,except for tooth alignment.Conclusions Thermoplastic retainer was superior to Hawley retainer on tooth alignment for patients with extracted first premolars extracted.