Three-dimensional evaluation of hybrid expander appliances: A pilot study.

OBJECTIVE: To evaluate transverse dimensional changes in dentoalveolar and skeletal structures caused by hybrid expander, using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: The CBCT records of nine patients (five boys and four girls) (mean age 13.61 +/- 0.72 years) treated with hybrid expander were examined. CBCT images were taken at pretreatment and after the expansion. ELSA (point equidistant to both foramina spinosa) was determined as a reference point to compare the distances in all three dimensions. Nineteen transversal dimensions and four angles were measured for both right and left sides. Wilcoxon signed rank test was used for statistical comparison at P < .05 levels. RESULTS: A V-shaped expansion of suture was successfully achieved in all patients without teeth support. The amount of opening was greater in anterior than posterior and in inferior than superior. An 8.75-mm screw expansion was achieved for all patients. Expansion effects reverberated to maxillary central incisor, canine, first premolar, and first molar at 70%, 75%, 92%, and 89%, respectively. The molar teeth tipped buccally (right 3.06 degrees and left 3.24 degrees ) as did premolars (right 2.88 degrees and left 3.02 degrees ). CONCLUSION: The hybrid expander, minimally invasive expansion appliance that protects teeth by including bone support, can be used easily for rapid maxillary expansion treatment.