RESUMEN
AIM: The aim of this study was to determine the prognostic factors, such as the developmental stage of second permanent molar (SPM), the angulation of SPM, and presence/absence of the third molar associated with the spontaneous space closure after the mandibular first permanent molars (FPM) extraction. MATERIAL AND METHODS: A total of 177 mandibular SPMs were evaluated in this cross-sectional study. The prognostic factors determining successful space closure such as SPM developmental stage, SPM angulation, and presence/absence of the third molar were evaluated. RESULTS: The mean age of the patients at the time of extraction of SPM was 9.4 years and post-extraction assessment at the time of the study was 12.7 years. Of the total 177 mandibular SPMs, 36 SPMs (20.3%) were at Demirjian stage D, 63 (35.6%) at stage E, 60 (34%) at stage F, 18 (10.1%) at stage G. 18 SPMs (10.1%) had distal angulation, 23 SPMs (13.0%) had mesial angulation and 136 SPMs (76.9%) had upright angulation. At the time of radiographic assessment, 79.1% of the mandibular quadrants showed evidence of third molar formation. Of the 177 mandibular SPMs, 93 (52.5%) exhibited successful space closure in the mandibular arch. CONCLUSIONS: There is no statistical significance between the chronological age and the developmental stage of the mandibular SPM with regard to the successful spontaneous space closure at the time of the dental extraction of FPMs. The presence of the mandibular third molar may be a consideration for spontaneous space closure in the mandibular arch.