Sagittal, rotational and transverse changes with three intraoral distalization force systems: Jones jig, distal jet and first class

Abstract

Background: To compare the maxillary dentoalveolar changes of patients treated with three distalization force systems: Jones Jig, Distal Jet and First Class appliances, using digitized models. Material and Methods: The retrospective sample comprised 118 digitized models of 59 patients with Class II malocclusion divided into three groups: Group 1 consisted of 22 patients treated with the Jones Jig appliance; Group 2 consisted of 20 patients treated with the Distal Jet, and Group 3 comprised 17 patients treated with the First Class appliance. Pretreatment and post-distalization plaster models of all patients were digitized and evaluated with OrthoAnalyzerTM software. The pretreatment and post-distalization variables regarding sagittal, rotational and transverse changes were compared by the One-way Analysis of Variance (ANOVA) and Kruskal-Wallis tests, depending on normality. Results: All appliances presented similar amounts of distalization. The Distal Jet appliance promoted significantly smaller mesial displacement of premolars and greater expansion of posterior teeth. The First Class presented the smallest rotation of the maxillary molars and treatment time. Conclusions: The distalizers were effective in correcting Class II molar relationship, however, a palatal force seems to provide fewer undesirable effects. Additionally, the degree of rotation and expansion was associated with the side of force application.