EFFECTS OF 2x4 APPLIANCE AND NiTi OPEN SPRING ON MIXED DENTITION

Abstract

Background/Objectives: The mixed dentition period is the best time to guide the occlusion and intercept a malocclusion. Among the preventive orthodontic procedures, space recovery is considered extremely important for the biogenesis of the occlusion to follow its normal course. Several orthodontic appliances indicated for space recovery in mixed dentition are mentioned in the literature and among them, mechanics with a fixed 2x4 partial appliance.This study aimed to evaluate changes in the dimensions of the upper arch after using a 2x4 fixed partial appliance with expanded CuNiTi wires and open NiTi springs. Material and Methods: Twenty-four children (±9 years) were assessed who had no space for the eruption of permanent teeth in the upper arch, treated with a 2x4 fixed partial appliance. Lateral teleradiography imaging, panoramic radiography and cast models were used before and after the treatment. The results were compared to a control group of 24 children who did not receive treatment and had their documents assessed for growth-related changes. The following changes were evaluated: dimension of arch perimeter, arch depth, intermolar distance, and inclination and displacement of permanent upper molars and incisors. Student’s t-test was used to assess the differences between pre- and post-treatment times, with significance level of 5%. Results: Increases were observed in arch perimeter (p=0) and arch depth (p=0) due to a distal movement of the crown (p=0) and the root of molars (p=0.004), and maintenance of the spatial position of the incisors, without protrusion (p=0.37) or vestibular movement (p=0.13). Limitations: the limitation of the present study was not to randomize the sample and not to use a control group identical to the group that received treatment. Conclusion: 2x4 fixed partial appliance was effective for the recovery of mixed dentition space, increasing the arch perimeter and depth through a distal movement of the upper molar and maintenance of incisor position.