Abstract
The three-dimensional changes of the dental arch form and occlusion were investigated during the treatment of children with the anterior crossbite in the primary dentition period. Four kinds of the appliances, the chin cup, the activator, the lingual arch and the maxillary protracting bow appliance, were used for the occlusal guidance at the Pediatric Dental Clinic of Kyusyu University Dental Hospital. To compare the treatmemt effects of these four appliances, the arch forms of the mandibular dentition, the horizontally projected areas surrounded by the maxillary and the mandibular dental arches, as well as the horizontal relationship of occlusion, were three-dimensionally analyzed using the plaster models before and after the occlusal guidance.
The results were as follows:
1) The treatment of the anterior crossbite during the primary dentition period caused obvious changes in the forms of the mandibular dental arches in all groups.
2) The horizontally projected areas of the maxillary dental arches increased after treatment in the chin cup, the activator and the lingual arch groups, and decreased in the maxillary protracting bow appliance group. In cotrast, those of the mandibular dental arches decreased in all groups.
3) The lingual arch group showed the largest positional change of the anterior part of the maxillary and the mandibular dental arches. The maxillary protracting bow appliance group also showed the largest positional change of the posterior part of both dental arches.
