ABSTRACT
Background: Functional posterior crossbites are a common finding in children with deciduous teeth and must be treated as soon as they are diagnosed in order to avoid unwanted changes in normal growth and development patterns. Objective: This study objective was to evaluate the changes caused by Planas' direct tracks treatment on the arch dimensions of patients with functional posterior crossbite in first dentition. Materials and Methods: The sample consisted of 20 children, 4 to 6 years old, divided into two groups, paired up according to age and gender. Group test was composed of 10 patients with functional posterior crossbite treated with PDT. Group control consisted of 10 children with normal occlusion. The evaluation criteria were intercanine and intermolar distances and Carrea's analysis (arch perimeter). All data were collected by a pre-calibrated examiner on study casts obtained at baseline and after 4 months of treatment. The statistical analysis of the data was achieved using GraphPad InStat software, version 3.05 for Windows, with the level of significance set at 0.05. For the comparison between intercanine and intermolar distances, the Tukey-Kramer Multiple Comparisons test was used. When Carrea's analysis was considered, the Mann-Whitney test was used. Results: At the beginning of the study, all the evaluated criteria showed lower mean values in patients with posterior crossbites, and significant differences between test and control groups were noticed (P<0.05). After the end of follow-up period, these differences could not be verified (P>0.05). Conclusions: Within the limits of the present study, it is possible to conclude that the treatment with Planas' direct tracks was able to give back the normal dimensions of deciduous arch in patients with unilateral functional posterior crossbites, thus making it possible a better growth pattern.