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J Dent Med-tums 2026, 39 - : 0-0 |
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Rostami A, Seyedmajidi S, Arash V, Ramyar A, Hedayati Goodarzi N, Ghasemi A et al . The effect of first premolar extractions on overall and anterior Bolton ratios in patients with bimaxillary dentoalveolar protrusion. J Dent Med-tums 2026; 39 : 7
URL: http://jdm.tums.ac.ir/article-1-6371-en.html
URL: http://jdm.tums.ac.ir/article-1-6371-en.html
Amirhosein Rostami1 
, Seyedali Seyedmajidi2 , Valiollah Arash3 , Abbas Ramyar4 , Nima Hedayati Goodarzi5 , Amirhosein Ghasemi5 , Reza Faraji *3
, Seyedali Seyedmajidi2 , Valiollah Arash3 , Abbas Ramyar4 , Nima Hedayati Goodarzi5 , Amirhosein Ghasemi5 , Reza Faraji *3
1- Student Research Committee, Babol University of Medical Sciences, Babol, Iran
2- Dental Materials Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
3- Oral Health Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
4- Faculty of Mechanical Engineering, Babol Noshirvani University of Technology, Babol, Iran; CEO, Tapeshtech Company, Health Technology Incubator Center, Babol University of Medical Sciences, Babol, Iran
5- Researcher, Babol Noshirvani University of Technology, Babol, Iran; Board Member, Tapeshtech Company, Health Technology Incubator Center, Babol University of Medical Sciences, Babol, Iran
2- Dental Materials Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
3- Oral Health Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
4- Faculty of Mechanical Engineering, Babol Noshirvani University of Technology, Babol, Iran; CEO, Tapeshtech Company, Health Technology Incubator Center, Babol University of Medical Sciences, Babol, Iran
5- Researcher, Babol Noshirvani University of Technology, Babol, Iran; Board Member, Tapeshtech Company, Health Technology Incubator Center, Babol University of Medical Sciences, Babol, Iran
Abstract: (147 Views)
Background and Aims: Bimaxillary dentoalveolar protrusion (BDP) is a common orthodontic anomaly characterized by protrusive dental arches and lip prominence. Extraction of the first premolars is a frequently employed treatment approach in these patients. However, the effect of this intervention on Bolton ratios-particularly the overall and anterior ratios-remains unclear. This study aimed to evaluate the impact of first premolar extractions on Bolton ratios in patients with BDP.
Materials and Methods: This experimental study was conducted on archived physical models of 34 Class I patients with BDP and functional lip incompetency (>4 mm) accompanied by lip protrusion, available at the Orthodontics Department of School of Dentistry, Babol, in 2024. All patients had a full complement of teeth from the first incisor to the first molar in each quadrant. After digitizing the models, mesiodistal tooth widths and the overall and anterior Bolton ratios were calculated. Digital simulation of first premolar extraction was performed, followed by reassessment of Bolton ratios. Pre- and post-treatment values were statistically compared using paired t-tests in SPSS (significance level set at 0.05).
Results: Among 34 studied casts, 67.6 % belonged to females. The mean overall Bolton ratio decreased significantly from 90.33 ± 2.23% to 87.72 ± 2.39%, and the anterior ratio declined from 78.19 ± 2.96% to 77.85 ± 3.03% (P<0.001). Additionally, 15 patients exhibited residual space post-treatment, primarily in the mandibular arch.
Conclusion: Based on the results of the present study, first premolar extraction significantly reduced both the overall and anterior Bolton ratios in patients with bimaxillary dentoalveolar protrusion. However, the likelihood of residual space—particularly in the lower arch-should be carefully considered during orthodontic treatment planning to ensure long-term stability and success.
Materials and Methods: This experimental study was conducted on archived physical models of 34 Class I patients with BDP and functional lip incompetency (>4 mm) accompanied by lip protrusion, available at the Orthodontics Department of School of Dentistry, Babol, in 2024. All patients had a full complement of teeth from the first incisor to the first molar in each quadrant. After digitizing the models, mesiodistal tooth widths and the overall and anterior Bolton ratios were calculated. Digital simulation of first premolar extraction was performed, followed by reassessment of Bolton ratios. Pre- and post-treatment values were statistically compared using paired t-tests in SPSS (significance level set at 0.05).
Results: Among 34 studied casts, 67.6 % belonged to females. The mean overall Bolton ratio decreased significantly from 90.33 ± 2.23% to 87.72 ± 2.39%, and the anterior ratio declined from 78.19 ± 2.96% to 77.85 ± 3.03% (P<0.001). Additionally, 15 patients exhibited residual space post-treatment, primarily in the mandibular arch.
Conclusion: Based on the results of the present study, first premolar extraction significantly reduced both the overall and anterior Bolton ratios in patients with bimaxillary dentoalveolar protrusion. However, the likelihood of residual space—particularly in the lower arch-should be carefully considered during orthodontic treatment planning to ensure long-term stability and success.
Article number: 7
Type of Study: Research |
Subject:
Orthodontics
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