Correlation of incisor inclination and position of mini-implants in anterior retraction

• Grant number: 19/26923-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2020
• End date: December 31, 2020
• Field of knowledge: Health Sciences - Dentistry - Orthodontics
• Principal Investigator: Gladys Cristina Dominguez Morea
• Grantee: Victória Martins Nóbrega
• Host Institution: Faculdade de Odontologia (FO). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

One of the main complaints of patients with biprotrusion class I malocclusion is the positioning of the incisors, which, in these cases, present with a proinclination and reduction of the incisal angle, reflecting the projection of the lips, and convexity of the face resulting in a compromised face. aesthetic (Bills et al., 2005; Upadhyay et al., 2008). Goal the aim of the present study is to correlate the placement of mini-implants in the maxilla with the inclination of maxillary incisors at the end of retraction of the upper anterior teeth by sliding mechanics. Materials and methods. In the present study, 28 computed tomography (CT) (n = 14 pre-retraction CT and n = 14 post-retraction CT) will be used from a collection of patients treated at the MBT Clinic of the School of Dentistry of the University of São Paulo (CAAE: 13955419.8.0000.0075).CT scans will be evaluated in Dolphin Imaging 11.95 Premium software by two previously calibrated examiners (AL and SPF). Pre-retraction and post-retraction teleradiographs will be obtained from patients' CT scans. The cephalometric quantities of interest for the present study will be: angle 1.NA - angle formed by crossing the NA lines and the long axis of the incisor; 1-NA distance - distance between the buccal face of the incisor superior to the NA line; 6-NA distance - distance between the mesial surface of the upper 1st molar superior to the NA line; SN. Long incisor axis - angle formed between SN line and long incisor axis. Cephalometric measurements will be tabulated and descriptive statistics will be shown in tables. The linear correlation coefficient will be calculated between the variables mini-implant height and maxillary incisor inclination, and anteroposterior mini-implant positioning and maxillary incisor inclination. (AU)