تغييرات ابعاد قوسهاي دنداني بدنبال تعريض گام با دستگاه Acrylic Bonded Palatal EXPander

Evaluation of dental arch changes after rapid palatal expansion by bonded palatal expander. 10 patients (5 boys & 5 girls) with uni or bilateral crossbite in mixed-dentition period were selected and records including , both arches casts , maxillary occlusal radiography , infra & extra - oral photographies obtained. Rapid palatal expansion applied by acrylic bonded palatal appliance during 14 days (about 7mm expansion was done). After a period of three months retention , appliance replaced by removable one and the same above records obtained . The average changes of arch width in the first permanent molar & deciduous first molar and canine area of both arches were measured . Paired t-test was used for analysis. The minimum changes in both arches was in deciduous canine area (3.7 mm expansion in maxilla & 0.5 mm in mandible) . The maximum changes in maxilla was 6.77 mm in deciduous first molar area , in mandible was 0.86 mm in permanent molar area. In spite of spontaneous expansion in lower dental arch following maxillary expansion (correlation coefficient 0.82) we must expand lower arch independently in clinical use , because the amount of spontaneous expansion isnʹt significant clinically.