Aim: The aim of this prospective study was to radiographically assess root morphology changes in maxillary and mandibular premolars following Herbst appliance treatment.
Patients and methods: Twenty-five consecutive adolescents (19 boys and six girls, mean age 13.08 years) with Class II, Division 1 malocclusion were treated with the banded Herbst appliance for a mean period of 13.16 months. Periapical radiographs of the upper and lower premolars were obtained before appliance insertion and immediately after appliance removal using the parallel technique. All radiographs were scanned, digitized and analyzed using appropriately adjusted cephalometric software. The pre- and post-treatment length and area of the first and second maxillary and mandibular premolar roots were calculated. Statistical analysis included paired t-tests to evaluate pre- and posttreatment changes, and independent t-tests to compare the pre and post-treatment differences between the first and the second premolars, which served as controls. The level of significance was set at p <or= 0.05 for all tests.
Results: No statistically significant decrease in premolar root lengths or areas was noted following removal of the Herbst appliance. We observed a statistically-significant decrease in the root area of the first mandibular premolars compared to that of the second mandibular premolars.
Conclusions: Although we observed no statistically-significant root morphology changes in the first and second premolars following Herbst appliance treatment, the mandibular first premolars revealed significantly more root resorption than did the mandibular second premolars.