A prospective clinical evaluation of mandibular lingual retainer survival

Bonded retainers are considered reliable, independent of patient co-operation, and highly efficient. However, most studies regarding the survival of retainers are retrospective. The aims of this investigation were to prospectively evaluate the failure rate of bonded lingual retainers, the influence of direct or indirect bonding procedures on survival, and to determine the distribution of failures over a 6 month period. Mandibular lingual retainers were bonded in 66 patients. Thirty-two retainers were bonded using a direct method and 34 by an indirect method. There were 23 females and 9 males (mean age 15.96 ± 3.21 years) in the direct group and 29 females and 5 males (mean age 19.44 ± 6.79 years) in the indirect group. A 0.016 × 0.022 inch Bond-a-Braid retainer wire (eight-braided, flattened, stainless steel dead soft wire) was used with Transbond LR. Following bonding, the patients were observed monthly. A chi-square test was used to analyse the influence of the direct and indirect procedures on survival rate.Twenty-five retainers failed. The failure rate was 46.9 per cent with the direct method and 29.4 per cent with the indirect method. The difference between the methods was not statistically significant. The total failure rate was 37.9 per cent. The highest failure rate was seen in the first month. Seven patients had repeated failures. The failure rate was higher in the right quadrant. The total survival rate was 62.1 per cent.