The Longevity of Band and Loop and Pontic–Crown Fixed Space Maintainers in Children Aged 4 to 7 Years: A Randomized Controlled Trial

The best way to prevent malocclusion and reduce the length of the arch in cases of early loss of primary teeth is placement of space maintainer. The aim of the present study was to compare the longevity of band and loop space maintainer with that of pontic–crown space maintainer. In this randomized control trial, 40 children aged 4 to 7 years, admitted to Isfahan School of Dentistry, were studied using convenient sampling method. They were randomly assigned into intervention and control groups. In the control group, the stainless steel crown (SSC) was fitted to the second primary molar tooth (E), and after laboratory stages, band and loop were cemented on the SSC. In the intervention group, a suitable SSC was fitted to the second primary molar tooth, and the molding was performed with alginate. After the laboratory procedure, the crown–pontic complex was cemented on the tooth. Both groups were followed-up every 6 months and the longevity of both space maintainers was examined for 18 months. Data were analyzed by Chi-square test, Kaplan–Meier survival analysis, and rank logarithm test. Within 18 months, four cases of decementation were seen in the band and loop group: two cases in the first 6 months (P = 0.487), one case in the second 6 months (P = 0.474), and one case in the third 6 months (P = 0.472); no loss due to decementation was observed in the crown–pontic group. There was only one treatment failure due to loss of solder that happened in the crown–pontic group during the second 6 months (P = 1). Four failures in the band and loop group and one failure in the crown–pontic group showed no significant difference between two groups in terms of frequency of failure (P = 0.152, Kaplan–Meier survival analysis). Pontic–crown space maintainer is a suitable alternative for band and loop space maintainer in treating the early loss of primary molars.