A comparison between the band-and-loop space maintainer with a loop-design fibre-reinforced composite space maintainer

Abstract

The band-and-loop space maintainer (BLSM) is a non-invasive device commonly used to maintain space after the early loss of a single deciduous tooth until the permanent tooth erupts. Unfortunately, however, these devices are difficult to fabricate, require laboratory work and are expensive. Clinically, they tend to fracture, bend or debond under occlusal forces and they are not considered aesthetic. These obvious limitations and challenges warrant the investigation of new materials and device designs for the treatment of premature single tooth loss. The fibre-reinforced composite space maintainer (FRCSM) has many advantages and has been suggested as an alternative to the BLSM. This study considers the clinical failure rates and reasons for failure for a loop-design FRCSMs, as placement techniques have not yet been standardised. The aim of the study was to comparatively investigate the in vivo failure rates (as well as the reasons for failures) of the loop-design FRCSM and the metal BLSM over a 6 month period. The data collected could be useful in the development of more successful FRCSMs. A total of 20 space maintainers were placed – 10 BLSMs and 10 loop-design FRCSMs. For each BLSM placement, an orthodontic band was fitted around the anchor tooth and an alginate impression was taken. This impression, with the band in position, was sent to the dental laboratory for fabrication of the device. At a second appointment, the BLSM was fitted and cemented with glass ionomer cement. For each FRCSM placement, a unidirectional glass fibre bundle was positioned in a continuous loop design extending from the buccal to the lingual surface of the anchor tooth. The fibre bundle was secured in position with a flowable composite, light-cured, and subsequently finished and polished. Monthly follow-up appointments were scheduled over a six-month period and parents/ patients were instructed to report immediately for an emergency appointment if any problem or failure occurred between these arranged appointments. This ensured that the timing of (and reasons for) the failures of both types of device were accurately recorded. With respect to the BLSM, the main reason for device failure was bending of the wire and subsequent impingement on the soft tissue. With respect to the FRCSM, the main reasons for device failure were debonding at the enamel-composite interface and fibre loop fracture. Within the six month follow-up period, both space maintainer types exhibited a 50% failure rate, but 30% of the failed FRCSMs could be repaired chairside whilst the failed BLSMs had to be refabricated in the laboratory. Although the results of this study do not show a significant statistical difference between the failure rates of the two space maintainer types tested (p=0.53), the FRCSM performed well clinically in that it was more easily repairable and remained clinically effective even in cases where the device broke. From the data gathered during this study, it is recommended that further research be done on the effectiveness of the loop-design FRCSM when it is bonded to permanent teeth, and on whether this device would prove more successful if mechanical retention were enhanced when bonding the device to deciduous tooth enamel. Whilst this study has generated valuable new clinical information, the FRCSM cannot yet be confidently recommended as a reliable alternative to the BLSM. Further research on this topic (based on a larger sample size and with a longer follow-up period) is necessary.