Comparation of three methods for measuring the Edge Bevel Radius of rectangular orthodontic wires: An in-vitro study.

Autores da FMUP

• Rui Manuel Lopes Nunes

  Autor

Participantes de fora da FMUP

• Neves JG
• Santamaria-Jr M
• Yagüe Ballester R
• Costa AR
• Vedovello SAS
• Vedovello Filho M

Unidades de investigação

• Medicina da Comunidade, Informação e Decisão em Saúde

• RISE-Health

  

  Investigador

  Fernando Carlos De Landér Schmitt

Abstract

OBJECTIVE: To establish a simplified method for measuring the edge bevel radius of 0.019×0.025-in steel rectangular orthodontic wires, achievable in the clinical environment, and to compare it with the photographic method. MATERIALS AND METHODS: Aided by the AutoCAD™ 2016 software, the theoretical mathematical relationship was determined between the edge rounding radius and cross-sectional dimensions (height, width, diagonals), through rectangle drawings that represent cross-sections. Two hundred segments (n=20) were obtained from the posterior portions of 100 archwires from 10 brands (Dentaurum™; American-Orthodontics™; GAC™; 3M-Unitek™; Abzil™; Morelli™; Orthometric™; Aditek™; A-Company™; Orthomundi™). The cross-sectional measures of each segment were obtained with a micrometer and a caliper, and the edge bevel radii of these segments were calculated with the use of a mathematical formula. For the "gold standard", the segments were included longitudinally in a phenolic resin cylinder, cross-sectioned, polished, and photographed in scanning electron microscope (SEM). The images were amplified 770× and the radii were measured with an acetate template. The micrometer and caliper measuring methods were subjected to Bland-Altman analysis and compared with the gold standard (SEM), considering ±10µm as the maximum acceptable difference between methods. RESULTS: In the micrometre measurement, 95% of the differences from the standard were within the limits of agreement (-7.21 and 5.56µm). For the caliper method, 95% of the differences were between -5.46 and 19.83µm, which exceeded the fixed limit ±10µm. CONCLUSION: The calculation method with micrometre measurements is equivalent to the photographic method, but there is no such equivalence for the caliper measurements.

Copyright © 2020 CEO. Published by Elsevier Masson SAS. All rights reserved.

Keywords

• Orthodontics; Rectangular archwires; Torque