Comparison of Tooth Anchored Expander and Damon System Appliances on Skeletal and Dental Anterior Relationships Assessed With CBCT Images

Objectives: To determine skeletal and dental anterior maxillary and mandibular differences between two maxillary expansion treatments (Hyrax and Damon system) using CBCT images.
Methods: 28 patients were randomly allocated into one of two groups. One group received orthodontic treatment with only the Damon system while the second group received orthodontic treatment with a Hyrax appliance and braces. CBCTs were taken pre- and post-treatment. The reconstructed images were examined using the software AVIZO®. Thirty-five landmarks were chosen and located for both patient groups and for both time points. Ten images were analyzed three times to determine the reliability and measurement error of each landmark using ICC prior to the data collection. Once data was collected, it was organized according to the method of the treatment, and the data analysis from the two groups were compared in terms of the changes in skeletal and dental structures using ANOVA and descriptive statistics.
Results: ICC values were excellent for all landmarks in all axis presenting measurements errors less than 1mm having the highest measurement error of 0.98 mm in the x-axis for 26 Pulp Chamber with the standard deviation of 0.68. The majority of landmarks showed statistically insignificant differences (>0.05) between the two patient groups except for three landmarks, 26 pulp chamber on x-axis (0.016), Right Foramen Ovale on Y-axis (0.043), and Right Foramen Ovale on Z-axis (0.020). However, the changes of these three values were clinically insignificant. Overall, the largest changes appeared in the X-axis was +2.69mm for 26 Pulp Chamber (Hyrax), in the Y-axis was +4.50mm for 33 Root Apex (Hyrax), and in the Z-axis was -8.99mm for 13 Pulp Chamber (Damon system).
Conclusions: The study concludes that Tooth Anchored Expander and Damon system appliances offer a similar treatment result in the anterior skeletal and dental structures.