An evaluation of survival of space maintainers: a six-year follow-up study.

The aim of this study was to evaluate the median survival time of fixed and removable space maintainers related to age groups, gender, and their distribution in upper and lower dental arches. The adherence of patients to a periodic recall program and the success rate of different types of space maintainers related to different arches were also evaluated. This study included 663 patients aged between 4-15 years old that were treated between the years of 1997 and 2002. The patients were categorized into four main groups: lost to follow-up, failed, successful, and censored at the end of study. Three hundred forty-five space maintainers were considered lost to follow-up, 83 were considered failed, 206 successful, and 20 censored-at-end. The overall median survival time of the appliances was 6.51 months. Median survival time was 7.25 months in the 4-6 age group, 6.35 months in the 7-12 age group, and 7.0 months in the 13+ age groups. Median survival time was 5.76 months in girls and 7.11 months in boys. Median survival time of space maintainers was 7.17 months for maxilla and 6.69 months in the mandible. Median survival time was 5.25 months for space maintainers fabricated in both arches.