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
Comparative Study
. 2011 Sep;40(6):351-7.
doi: 10.1259/dmfr/13993523.

Comparison of two methods for quantitative assessment of mandibular asymmetry using cone beam computed tomography image volumes

Abeer AlHadidi  1 , L H S Cevidanes, A Mol, J Ludlow, M Styner
Affiliations
Comparative Study

Comparison of two methods for quantitative assessment of mandibular asymmetry using cone beam computed tomography image volumes

Abeer AlHadidi et al. Dentomaxillofac Radiol. 2011 Sep.

Abstract

Objectives: The aim of this study was to compare two methods of measuring mandibular asymmetry. The first method uses mirroring of the mandible in the midsagittal plane; the second uses mirroring of the mandible and registration on the cranial base.

Methods: Surface models were constructed from cone beam CT (CBCT) scans of 50 patients with asymmetry. For the first approach, a midsagittal plane was defined for each patient as the plane passing through nasion, anterior nasal spine and basion. Mirrors for both halves of the mandible were created. The second approach consisted of mirroring the image volume by flipping the left and right sides and then registering the mirrored image onto the cranial base using a mutual information maximization method. Surface distances between hemimandibles and mirrors were calculated for nine regions.

Results: There was no statistically significant difference between the mean surface distance measurements obtained with the two approaches and when comparing both halves in most areas.

Conclusion: Both mirroring techniques provided similar quantification of mandibular asymmetry in this cohort.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Assessment of asymmetry following two different mirroring methods
Figure 2
Figure 2
A box plot demonstrating the mean of the absolute difference in surface distance measurements (mm) using both mirroring methods on each region of interest on the left side (* indicates statistical significance)
Figure 3
Figure 3
A box plot demonstrating the mean of the absolute difference in surface distance measurements (mm) using both mirroring methods on each region of interest on the right side (* indicates statistical significance)
Figure 4
Figure 4
A box plot showing the mean of the absolute difference in surface distance measurements (mm) of the left and right sides of the mandible using mirroring on the midsagittal plan (* indicates statistical significance)
Figure 5
Figure 5
A box plot showing the mean of the absolute difference in surface distance measurements (mm) of the left and right sides of the mandible using using arbitrary mirroring followed by registration on cranial base
Figure 6
Figure 6
Examples of patients with challenging asymmetries for quantification. Asymmetric cranial base (a) and cleft palate (b) would interfere with both mirroring protocols. Severe cant (c) and rotation (d) is hard to deal with using iterative closest point algorithm
See this image and copyright information in PMC

References

    1. Severt TR, Proffit WR. The prevalence of facial asymmetry in the dentofacial deformities population at the University of North Carolina. Int J Adult Orthodon Orthognath Surg 1997;12:171–176 - PubMed
    1. Proffit WR, Fields HW, Jr, Moray LJ. Prevalence of malocclusion and orthodontic treatment need in the United States: Estimates from the NHANES III survey. Int J Adult Orthodon Orthognath Surg 1998;13:97–106 - PubMed
    1. Cevidanes LH, Bailey LJ, Tucker GR, Jr, Styner MA, Mol A, Phillips CL, et al. Superimposition of 3D cone-beam CT models of orthognathic surgery patients. Dentomaxillofac Radiol 2005;34:369–375 - PMC - PubMed
    1. Cevidanes LH, Bailey LJ, Tucker SF, Styner MA, Mol A, Phillips CL, et al. Three-dimensional cone-beam computed tomography for assessment of mandibular changes after orthognathic surgery. Am J Orthod Dentofacial Orthop 2007;131:44–50 - PMC - PubMed
    1. Cevidanes LH, Franco AA, Gerig G, Proffit WR, Slice DE, Enlow DH, et al. Comparison of relative mandibular growth vectors with high-resolution 3-dimensional imaging. Am J Orthod Dentofacial Orthop 2005;128:27–34 - PubMed

Publication types

MeSH terms