IADR Abstract Archives
Skeletal and Dental Changes in Orthodontic Treatments Involving Expansion With Hyrax or Damon System
Objectives: Compare skeletal and dental changes in orthodontic treatments involving expansion with Hyrax or Damon System using cone-beam computed tomography (CBCT).
Methods: CBCTs from 49 patients diagnosed with maxillary deficiency and treated with maxillary expansion were taken from the University of Alberta Graduate Orthodontic Program database. These patients were randomly assigned to one of two groups, Hyrax group or Damon System. Each patient had two CBCTs, one at initial of treatment and the second at the end of all the orthodontic treatment (19-27 months apart). CBCTs were analyzed using the software platform AVIZO. Forty landmarks were located in the CBCTs and their coordinates were used to analyze linear and angular changes. Ten additional images were analyzed three times to determine the reliability and measurement error of each landmark (ICC). Descriptive statistics, ANOVA and paired t-test were used.
Results: ICC values were excellent (>0.992) for all landmarks in all axis having the highest measurement error of 1.38 mm in the y-axis for the left infraorbital foramen landmark. Paired sample test and ANOVA show that there were statistical significant differences between the two techniques to expand the maxilla. The Hyrax group showed a difference of 6mm between the distance right and left U6 pulp chamber, between the right and left U6 mesial buccal root and alveolar bone around the root while Damon system had a difference of 2mm for all three values. Damon system presented greater lower intermolar reduction.
Conclusions: The Hyrax technique demonstrated higher expansion values in the maxilla. Both treatment techniques showed significant difference in terms of dental distance and angulation changes in terms of expansion in the posterior sections. Hyrax presented changes in upper intermolar width while Damon system gained correction with lingualization of lower molars.
Methods: CBCTs from 49 patients diagnosed with maxillary deficiency and treated with maxillary expansion were taken from the University of Alberta Graduate Orthodontic Program database. These patients were randomly assigned to one of two groups, Hyrax group or Damon System. Each patient had two CBCTs, one at initial of treatment and the second at the end of all the orthodontic treatment (19-27 months apart). CBCTs were analyzed using the software platform AVIZO. Forty landmarks were located in the CBCTs and their coordinates were used to analyze linear and angular changes. Ten additional images were analyzed three times to determine the reliability and measurement error of each landmark (ICC). Descriptive statistics, ANOVA and paired t-test were used.
Results: ICC values were excellent (>0.992) for all landmarks in all axis having the highest measurement error of 1.38 mm in the y-axis for the left infraorbital foramen landmark. Paired sample test and ANOVA show that there were statistical significant differences between the two techniques to expand the maxilla. The Hyrax group showed a difference of 6mm between the distance right and left U6 pulp chamber, between the right and left U6 mesial buccal root and alveolar bone around the root while Damon system had a difference of 2mm for all three values. Damon system presented greater lower intermolar reduction.
Conclusions: The Hyrax technique demonstrated higher expansion values in the maxilla. Both treatment techniques showed significant difference in terms of dental distance and angulation changes in terms of expansion in the posterior sections. Hyrax presented changes in upper intermolar width while Damon system gained correction with lingualization of lower molars.