Abstract
The objective of this study was to explain importance of early treatment for functional lateral crossbite in primary dentition, and to explain results with treatment using Quad Helix.
We examined the teeth, dental arch forms and occlusion using upper and lower plaster models, The results were as follows;
1. Compared with the lower arch forms, the upper arch forms were narrower and the lower arch forms shifted with premature contact of the primary canine.
2. Because the midline of the upper arch expanded laterally matched those of the lower arch and occlusion was correct on both sides, the shift of the lower arch forms was improved.
3. Occlusal management from primary dentition is important for the normal growth of the dentition and jaw.
