The longevity of space maintainers: a retrospective study.

METHODS: This retrospective study investigated the longevity of 301 space maintainers fitted in 141 patients aged 3.4-22.1 years in the Department of Pediatric Dentistry at Leeds Dental Institute between 1991 and 1995. RESULTS: Failure occurred in 190 space maintainers (63%), of which 36% were due to cement loss, 24% breakage, 10% design problems, and 9% were lost. Using the life table method, the median survival time (MST) for space maintainers was found to be 7 months. Band and loop (B&L) appliances had the highest MST of 13 months, while the lower lingual holding arch (LLHA) had the lowest of 4 months. Unilateral space maintainers survived longer than bilateral space maintainers (MST of 13 months vs. 5 months). Left B&Ls had a MST of 16 months, compared to only 4 months for right B&Ls, Gender, age, arch in which the appliance was placed, the operator planning it, fixed vs. removable, and adequacy of pretreatment assessment did not have a significant effect on survival time.