Background The aim of this study was to investigate the three-dimensional morphological characteristics of impacted maxillary central incisors to guide early orthodontic intervention strategies. Methods Cone-beam CT images of 102 patients with unilateral impacted maxillary central incisors were obtained and reconstructed into three-dimensional models. These models were imported into Mimics software for volume and surface area measurements. Root development was compared with that of the contralateral erupted maxillary incisors. The data were analyzed using independent t-tests, Chi-square tests, and multifactorial rank analysis. Results Quantitative analysis revealed significant developmental deviations in impacted incisors. Both inverted and labial impaction groups demonstrated substantially smaller crown dimensions compared to controls, with volume reductions of 14.4% (419.81 ± 87.87 mm3vs 486.53 ± 88.28 mm3) and 7.2% (455.13 ± 75.12 mm3 vs 512.96 ± 77.99 mm3), respectively (p < 0.01). Surface area measurements paralleled this pattern, showing 11.8% (433.27 ± 64.22mm2 vs 490.19 ± 63.7 mm2) and 14.4% (439.05 ± 73.11 mm2 vs 486.98 ± 66.37 mm2) deficits in inverted and labial groups (both p < 0.01). Root development exhibited significant retardation with median maturation stages delayed by one developmental phase in impacted groups (stage 8 vs control's stage 9, p < 0.01). Morphological abnormalities showed impaction-type specificity: inverted impactions presented the highest root bending prevalence (72.1%), predominantly in central (58.1%) and apical regions (9.8%). Labial impactions demonstrated lower root bending prevalence (15.4%) with uniform spatial distribution, while palatal cases showed coronal predilection (30%) (all inter-group comparisons p < 0.01). Conclusion Inverted impacted central incisors have a higher incidence of dilacerated roots and poorer root development, indicating the need for early orthodontic intervention strategies of impacted central incisors. Trial registration The trial was retrospectively registered and the trial protocol was approved by the ethics committee of the Hefei Stomatological Hospital (Approval number: 2024LW011).

Unlocking early solutions: 3D insights into managing impacted maxillary central incisors

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2025年6月17日

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Wei Chen,
Wei Zhang

摘要

Background

The aim of this study was to investigate the three-dimensional morphological characteristics of impacted maxillary central incisors to guide early orthodontic intervention strategies.

Methods

Cone-beam CT images of 102 patients with unilateral impacted maxillary central incisors were obtained and reconstructed into three-dimensional models. These models were imported into Mimics software for volume and surface area measurements. Root development was compared with that of the contralateral erupted maxillary incisors. The data were analyzed using independent t-tests, Chi-square tests, and multifactorial rank analysis.

Results

Quantitative analysis revealed significant developmental deviations in impacted incisors. Both inverted and labial impaction groups demonstrated substantially smaller crown dimensions compared to controls, with volume reductions of 14.4% (419.81 ± 87.87 mm³vs 486.53 ± 88.28 mm³) and 7.2% (455.13 ± 75.12 mm³ vs 512.96 ± 77.99 mm³), respectively (p < 0.01). Surface area measurements paralleled this pattern, showing 11.8% (433.27 ± 64.22mm² vs 490.19 ± 63.7 mm²) and 14.4% (439.05 ± 73.11 mm² vs 486.98 ± 66.37 mm²) deficits in inverted and labial groups (both p < 0.01). Root development exhibited significant retardation with median maturation stages delayed by one developmental phase in impacted groups (stage 8 vs control's stage 9, p < 0.01). Morphological abnormalities showed impaction-type specificity: inverted impactions presented the highest root bending prevalence (72.1%), predominantly in central (58.1%) and apical regions (9.8%). Labial impactions demonstrated lower root bending prevalence (15.4%) with uniform spatial distribution, while palatal cases showed coronal predilection (30%) (all inter-group comparisons p < 0.01).

Conclusion

Inverted impacted central incisors have a higher incidence of dilacerated roots and poorer root development, indicating the need for early orthodontic intervention strategies of impacted central incisors.

Trial registration The trial was retrospectively registered and the trial protocol was approved by the ethics committee of the Hefei Stomatological Hospital (Approval number: 2024LW011).