328 - Spontaneous Space Closure After Extraction of First Permanent Molars

Abstract:

Purpose: This study aimed to determine the success rate of spontaneous space closure after extraction of the first permanent molar (FPM). Additionally, we attempted to establish the ideal developmental stage of the second permanent molar (SPM) to allow the most favorable outcome.

Methods: Panoramic radiographs taken before and after extraction were used to analyze spontaneous space closure. A total of 2,579 charts of patients under the age of 12 years who underwent FPM extraction between 2010 and 2019 were reviewed.

Results: A total of 302 charts met the inclusion and exclusion criteria for analysis. The overall success rate of spontaneous space closure by the SPM was 52%. There was a statistically significant difference between arches with an 81% success rate in the maxillary and a 38% success rate in the mandibular arch (p < 0.001). The success rate was also associated with earlier stages of SPM development. The highest success rate was observed at crown (no bifurcation) formation (94%), whereas the late root formation (6.7%) exhibited the lowest success rate.

Conclusion: Early extraction of the FPM before age of 9 and the stage of SPM development before early root formation have strong potential to result successful spontaneous space closure. Extraction of FPMs in the maxillary arch yields higher success rates of spontaneous space closure than the mandibular arch. The maxillary arch may have potentially positive outcomes, regardless of a patient’s chronological age or SPM developmental stage.