Volume and shape changes of mandibular condyles in growing patients treated with fixed Class II appliances using CBCT

• Author / Creator

  Al Riyami, Ibtisam AS

• Objective: Evaluate the changes in the mandibular condyle volume and shape in growing Class II malocclusion patients, following the use of fixed functional Class II appliances (Herbst and Crossbow) compared to a control group that did not have any inter-arch Class II appliances. A validated semi-automatic condylar segmentation technique of the pre-and posttreatment 3DCBCT images were used to help understand which appliance might cause more changes.Methods: Fifty-one growing adolescent patients were randomly allocated to one of the three groups (Herbst appliance, Crossbow appliance, and Control group). A total of 102 CBCT images were taken pre-and post-treatment (average interval was 11.7 months). The pre-andposttreatment CBCT images were segmented using a newly developed and validated semiautomatic condylar segmentation technique. The mandibular condyle volume was assessed using Avizo software. The quantitative assessment of the condyle shape was done using Visualization Toolkit software, and the quantitative assessment of the mean distance differences of the condyle surfaces was done using the Iterative Closest Point technique.Results: A statistically significant increase in condylar volume was observed in all three groups (Herbst, Crossbow, and Control) and no significant differences in the magnitude of condylarvolumes between the Herbst and Crossbow groups were found. There were no statisticallysignificant changes in the mean distance differences of the shape of the condyle in all three groups.The three groups (Herbst, Crossbow, and Control) expressed different patterns of shape changes with no clear pattern associated with the treatment groups (Herbst and Crossbow).Conclusion: The use of fixed Class II functional appliances (Herbst and Crossbow) in Class IIgrowing patients is not associated with any statistically significant changes in mean condyle volume and shape. All three groups in this study showed similar increases in condylar volumeand no clear patterns of condylar shape changes, suggesting that any changes seen in the condyle volume and shape might be part of overall normal condylar growth.

• Subjects / Keywords

  • herbst
  • crossbow
  • class II appliance
  • semiautomatic segmentation

• Graduation date

  Fall 2021

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-hmm9-e058

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.