506 - Changes in Usage of Space Maintainers Over a 20-year Period

Purpose:
The purpose of this retrospective study was two-fold: 1) to demonstrate proportional changes in usage of bilateral and unilateral space maintainers over a 20-year period and 2) to describe the specific types of space maintainers used during two different time periods. We hypothesize that the introduction of the prefabricated unilateral space maintainer changed usage of space maintainers.

Methods:
Data were collected from two sources: the Orthodontics Appliance Book, used prior to 2012, and axiUm electronic patient records used after 2011. Two groups were created for comparison purposes: 2001 - 2005 (Group 1) and 2016 - 2020 (Group 2).

Results:
Group 1 included 297 appliances - 94 (43%) unilateral and 203 (68%) bilateral. Group 2 included 497 appliances - 471 (95%) unilateral and 26 (5%) bilateral. A significant difference in the proportions of unilateral and bilateral appliances was found between Group 1 and Group 2 using Chi-Squared Test. The distribution of type of appliances ordered in Group 2 was: prefabricated band and loop = 393 (79%), lab fabricated band and loop = 78 (16%) lower lingual holding arch = 15 (3%), Nance or TPA appliance = 11 (2%). A significant difference in the distribution of Space Maintainers used between Group 1 and Group 2 was demonstrated using the Chi-Squared Test for Contingency (p < 0.05).

Conclusions:
Over a 20 year period, usage of space maintainers changed from predominantly bilateral to predominantly unilateral. A shift in treatment philosophy at the UCLA Pediatric Dentistry Clinic, likely due to the introduction of the prefabricated band and loop, is thought to have led to the increased use of unilateral appliances.