Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Jan 3;14(1):225.
doi: 10.3390/jcm14010225.

Second Versus First Molar Extractions in Class II Division 1 Malocclusion Treatment: A Retrospective Longitudinal Outcome Study into Maxillary Canine, Premolar, and Molar Movement

Akkelien H A Oostenbrink  1 , Ewald M Bronkhorst  2 , Johan W Booij  3 , Arjan J A Dieters  4 , Yijin Ren  1 , Anne Marie Kuijpers-Jagtman  1   5   6 , Robin Bruggink  7   8
Affiliations

Second Versus First Molar Extractions in Class II Division 1 Malocclusion Treatment: A Retrospective Longitudinal Outcome Study into Maxillary Canine, Premolar, and Molar Movement

Akkelien H A Oostenbrink et al. J Clin Med. .

Abstract

Background/objectives: This retrospective longitudinal outcome study comparing orthodontic extraction modalities, including extraction of maxillary first or second molars, aimed to compare the three-dimensional tooth movement of maxillary canines (C), premolars (P1, P2), and molars (M1, M2) in Class II division 1 malocclusion treatment with fixed appliances. Methods: A sample of 98 patients (mean age 13.20 ± 1.46 years) was selected for the M1 group, and 64 patients (mean age 13.20 ± 1.36 years) were chosen for the M2 group. Tooth movement was analyzed three-dimensionally on pre-treatment (T0) and post-treatment (T1) digital dental casts. Regression analyses compared the tooth movements (in mm) between the M1 and M2 groups. Results: The mean treatment duration for the M1 group was 2.51 ± 0.55 year, while, for the M2 group, it was 1.53 ± 0.37 year. The data showed limited distal movements of the C, P1, and P2 of approximately 2 mm in the M1 group and 1 mm in the M2 group during orthodontic treatment, but the M1 group exhibited significantly more distal movements than the M2 group (mean difference 1.11 to 1.24 mm). Vertical movements of the C, P1, and P2 in both groups were also minor (0.16 to 1.26 mm). The differences between groups did not exceed 0.2 mm and were not significant. Both treatment modalities resulted in a significant degree of anchorage loss with a distinct mesialization (8.40 ± 1.66 mm) of M2 in the M1 group and limited distalization (0.83 ± 0.98 mm) of M1 in the M2 group. Conclusions: The findings highlight the importance of thorough case evaluation when choosing between extraction modalities in Class II treatment. If a large distal movement of canines and premolars is required, additional anchorage mechanics should be considered.

Keywords: 3-D imaging; longitudinal studies; malocclusion Angle Class II; maxillary first molar extraction; maxillary second molar extraction; orthodontics; treatment outcome.

PubMed Disclaimer

Conflict of interest statement

The author A.M.K.-J. is a member of the Section Board of JCM Section Stomatology. Author R.B. is a developer for 3DMedX®, a commercially available software package.

Figures

Figure 1
Figure 1
Loaded T0 model with its segmented teeth visualized. Each tooth is numbered according to the Féderation Dentaire International (FDI) teeth numbering.
Figure 2
Figure 2
Teeth with their roots still attached (tooth 11–17) in comparison with teeth with their roots cut off (tooth 21–27). Each tooth is numbered according to the Féderation Dentaire International (FDI) teeth numbering.
Figure 3
Figure 3
The T1 model is superimposed over the T0 model by using an ICP algorithm with the palate as the reference area.
Figure 4
Figure 4
The superimposition of the teeth (pink) on their T0 location (blue) (left picture) towards the T1 maxillary model (right picture).
Figure 5
Figure 5
The six degrees of freedom for describing the movement of each tooth.
Figure 6
Figure 6
Box plot of the amount of movement (mm) in three dimensions of the maxillary C, P1, P2, and M2 in the M1 extraction group and of the maxillary C, P1, P2, and M1 in the M2 extraction group. e = Euclidean distance; x, y, z = Movement on the x-, y-, z-axis, respectively.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Proffit W.R., Fields H.W., Jr., Larson B. Contemporary Orthodontics. 6th ed. Elsevier; Philadelphia, PA, USA: 2018. pp. 140–202.
    1. Thiruvenkatachari B., Harrison J.E., Worthington H.V., O’Brien K. Early Orthodontic Treatment for Class II Malocclusion Reduces the Chance of Incisal Trauma: Results of a Cochrane Systematic Review. Am. J. Orthod. Dentofac. Orthop. 2015;148:47–59. doi: 10.1016/j.ajodo.2015.01.030. - DOI - PubMed
    1. Evrard A., Tepedino M., Cattaneo P.M., Cornelis M.A. Which factors influence orthodontists in their decision to extract? A questionnaire survey. J. Clin. Exp. Dent. 2019;11:e432–e438. doi: 10.4317/jced.55709. - DOI - PMC - PubMed
    1. Alsaggaf D.H., Afify A.R., Zawawi K.H., Alsulaimani F.F. Factors influencing the orthodontic treatment plan in Class II malocclusion. Am. J. Orthod. Dentofac. Orthop. 2022;161:829–837.e1. doi: 10.1016/j.ajodo.2021.01.034. - DOI - PubMed
    1. Trevisi H., Trevisi Zanelato R. State-of-the-Art Orthodontics, Self-Ligation Appliances, Miniscrews and Second Molar Extractions. Elsevier; Philadelphia, PA, USA: 2018. pp. 156–223.