Author, year Country Study design Number of patients (n) With drawals - dropouts Results Comments Intervention Fixed retainer Control No retainer Artun, [14] Norway CT n=108 Group 1: n= 31 Group 2: n=18 Group 3: n=14 (Group 4: n=20) Group 5: n= 25   ? a No caries No caries Dental caries on lingual surfaces Group 1 =    Mandibular cuspid retainer .032 spiral wire. Group 2 =    Mandibular cuspid retainer .032 plain wire. Group 3 =    Maxillary .0195 flexible spiral wire. Group 4 =    Maxillary retainer plate Group 5 =    No retainer. Cuspid retainer = bonded only to cuspids. 3-3- retainer = bonded to each tooth.

a Withdrawals and drop-outs not explicitly stated. CT = non-randomised, controlled study. ns = not significant

Table 11: Fixed orthodontic retainer versus no retainer - Dental caries (alphabetically, according to study design).