Background: Retainers vary in their effectiveness in maintaining teeth in their treated positions and in their acceptability by patients.
Aims: To compare the effectiveness and acceptability of Essix and Begg retainers.
Methods: Two hundred and twenty-four patients were randomly assigned to receive either upper and lower Essix or upper and lower Begg retainers. Subject acceptability was evaluated with seven questions related to chewing and biting, fit, speech, appearance, oral hygiene, comfort and maintenance recorded on a 10-point visual analogue scale. The effectiveness of the retainers to maintain alignment was assessed on study models taken on the day after debonding (T1), after three months retention (T2) and six months retention (T3) with the Peer Assessment Rating (PAR) and Irregularity Index (II). In addition to the upper and lower retainers, all subjects had bonded lower lingual retainers placed at the end of active treatment.
Results: There were small, but statistically significant, deteriorations in the PAR scores in both groups at T2 and T3. The T2-T1 and T3-T1 differences between the groups were statistically significant (Begg > Essix), but the differences did not exceed 2 points. For the Irregularity Index, the T3-T1 difference was statistically significant (Begg > Essix), but clinically insignificant as the difference was only 0.25 points. Subjects preferred the Begg retainer for chewing and biting (p = 0.000), and liked the appearance (p = 0.000) and comfort (p = 0.05) of the Essix retainers. The subjects in both groups reported both retainers had an acceptable fit.
Conclusions: More subjects wearing Essix retainers considered their retainers were comfortable and had an acceptable appearance than subjects wearing Begg retainers, and more subjects with Begg retainers considered that their retainers were acceptable for biting and chewing than the subjects wearing Essix retainers. Both retainers allowed some relapse of teeth post-treatment, but the 6-month differences were small and may not be clinically significant.
