Evaluation of Eruption Pattern of Second Permanent Molars Following Extraction of Compromised First Permanent Molars in Children and Its Predicting Factors: A Retrospective Radiographic Study.

OBJECTIVES

To evaluate eruption pattern, in terms of space closure and alignment of second permanent molars (SPM), following extractions of first permanent molars (FPM) and assess the effect of predicting factors including age at extraction, developmental stage of SPM, angulation of adjacent teeth and presence of third permanent molars (TPM) on the outcome.

MATERIALS AND

METHODS

This retrospective study included healthy children aged 6-12 years who had undergone extraction of one or more severely compromised FMPs and had complete pre- and post-extraction radiographic records until completion of the root formation of SPM and second premolar. Data on age, arch, extraction site, SPM developmental stage (Demirjian scale), angulation of adjacent teeth and presence of TPMs were collected from patients' records and pre-extraction panoramic radiographs. Space closure and angulation of SPM were evaluated via post-extraction radiographs. Descriptive statistics and logistic regression models were applied.

RESULTS

Sixty teeth, from 60 patients (mean age at extraction: 10.4 years; mean follow-up: 32 months) were evaluated. Overall complete space closure was achieved in 75%, more prominent in the maxilla than the mandible (80% vs. 73%). Significantly higher closure rates were recorded in patients < 10 years at extraction (p = 0.01) and when the SPM was at Demirjian developmental stages E-F (p = 0.04). Upright angulation of SPM was observed in 78% of the cases, significantly more frequently in the maxilla (100%) than in the mandible (67%) (p = 0.01). Regression analysis identified the SPM developmental stage and the TPM presence as significant predictors of space closure, while the dental arch was the only significant predictor of upright SPM alignment.

CONCLUSION

Spontaneous space closure and favourable alignment of the SPM occurred in most cases following extraction of compromised FPMs. The highest success rates were observed when extraction was performed between 8 and 10 years of age and when the SPM was at Demirjian developmental stages E-F, suggesting that these factors may represent the most reliable clinical indicators for optimal timing of extraction.