Evaluation standard move molar, canine, incisors and labial changes in cases of premolar extraction in patients Class I of angle with lip protrusion

• Grant number: 15/10099-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2015
• End date: July 31, 2018
• Field of knowledge: Health Sciences - Dentistry - Orthodontics
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Luiz Gonzaga Gandini Júnior
• Grantee: Patricia Pigatto Schneider
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

The closing of the spaces, by extracting four first premolars in cases of lip protrusion may be performed in two different ways: by retracting the anterior teeth in "one-stage" or "two-stage". Orthodontists have used mechanical retracting in two stages in the case for believing that this type of retraction when it is used, the incorporation of the canines on the anchorage unit reduces the tendency of the posterior teeth migrate to the extraction space. Despite the relevance of the subject have been found in the literature only two studies effectively compared to the two forms of retraction, as regards the loss of anchorage of the posterior teeth, and amount of retraction of the anterior teeth. Nothing was found regarding the changes that occur in the facial profile associated with the two techniques. Front clinical relevance of this approach, since only two papers are to have little scientific certainty about some subject, the purpose of this study is to compare the anchorage loss and the anterior retraction, in relation the movement of molars, canines and incisors and the labial changes between the two forms of retraction of anterior teeth. The sample will consist of standardized lateral teleradiography and oblique 45 °, right and left, and model studies obtained after orthodontic treatment, which involved the extraction of the first four premolars, 48 patients with malocclusion Class I of Angle malocclusion, with lip protrusion and age is between 18-34 years. Half of the group received orthodontic treatment closing spaces in "one-stage" (Group 1) and the other half in "two-stage"(Group 2). Cephalograms of cephalometric radiographs will be traced and scanned in DFPlus software (Dentofacial Planner Software version 2.0, Toronto, Ontario, Canada). The superimposition of tracings obtained in the times t0 and t7, will evaluate the lateral teleradiography, changes the upper and lower lip in relation to the anterior retraction in both groups (Groups 1 and 2). In the oblique teleradiography, the times t1, t2, t3, t4, t5 and t6, the horizontal and vertical dislocation of the molars and canines, from a system of coordinates, a view to obtain the standard monthly movement of these teeth during the closing spaces for the group retracted in two stages (Group 2). Dental points will be established in the study models, collected in the times t0 and t7, and scanned the R700 3D Scanner, as well as measures of dental positions will be obtained from Ortho-Analyser software with the objective of determine the anchorage loss characteristics, anterior retraction and tooth movement of molars, canines and incisors in relation to the two forms of space closure (Groups 1 and 2). (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

SCHNEIDER, PATRICIA PIGATO; KIM, KI BEOM; MONINI, ANDRE DA COSTA; DOS SANTOS-PINTO, ARY; GANDINI JUNIOR, LUIZ GONZAGA. Which one closes extraction spaces faster: en masse retraction or two-step retraction? A randomized prospective clinical trial. ANGLE ORTHODONTIST, v. 89, n. 6, p. 855-861, NOV 2019. (15/10099-0)