Cephalometric evaluation of dentoskeletal and soft tissue changes in young individuals with class II malocclusion treated with Distal Jet distalizers

Author(s)

Rachelle Simões Reis Lopes

• Document type: Master's Dissertation
• Press: Bauru.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Bauru (FOB/SDB)
• Defense date: 2007-03-12

Examining board members

Jose Fernando Castanha Henriques; Guilherme dos Reis Pereira Janson; Ary dos Santos Pinto

• Advisor: Jose Fernando Castanha Henriques

Abstract

This study evaluated the dentoskeletal and soft tissue changes promoted by the intraoral distalizer Distal Jet, by analysis of lateral cephalograms. The sample was composed of 44 patients, divided into two groups, as follows. Group 1 (study group) was composed of 22 patients, being 5 males and 17 females, with Class II malocclusion, among which 72,72% exhibited ½ Class II, 18,18% ¼ Class II, and 9,09% ¾ Class II. The initial age ranged from 10,54 years to 14,77 years (mean 12,71 years). These patients were treated with the intraoral distalizer Distal Jet for a mean period of 1,20 years. Group 2 (control group) comprised 22 patients, being 13 males and 9 females, aged 11,03 to 14,63 years (mean 12,27 years) at the onset of follow-up, presenting with untreated Class II malocclusion, who were followed for a mean period of 1,18 years. The groups were rendered compatible as to age, period of treatment/observation, severity of malocclusion and initial cephalometric variables. The Student t test for independent samples was applied to compare the initial and final ages, period of treatment/observation, initial cephalometric variables and actual mean changes in the comparison between groups. The severity of malocclusion between groups was analyzed by the chi-square test. The initial and final changes for the study group were evaluated by the t test for dependent samples. The Distal Jet distalizer did not change the anteroposterior positioning of maxilla and mandible, yet promoted an increase in facial growth pattern due to a significant change in mandibular plane angle (FMA). The maxillary first molars exhibited significant distalization, yet did not present statistically significant distal inclination and extrusion. The maxillary second molars presented significant distal inclination, extrusion and distalization. The reciprocal effect of Distal Jet on the anchorage unit promoted significant buccal tipping and protrusion of maxillary incisors, as well as mesialization of the maxillary first premolars, leading to an increased overjet. There were no significant changes in the extrusion of maxillary first premolars and incisors, overbite and facial profile. (AU)