Effect of plasma deposited SiO2 film on the coefficient of friction between aesthetic brackets of polycrystalline alumina and orthodontic arches of nickel-titanium

• Grant number: 18/04050-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2018
• End date: December 31, 2018
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Lucas Hian da Silva
• Grantee: Natália Ferraz Piller
• Host Institution: Pró-Reitoria de Pós-Graduação, Pesquisa e Extensão. Universidade Cidade de São Paulo (UNICID). São Paulo , SP, Brazil

Abstract

The objective of this study will be to evaluate qualitatively and quantitatively the effect of a silica film deposited by Physical Vapor Deposition (PVD) on the slot of a self-ligating bracket made by polycrystalline alumina in the frictional coefficient with orthodontic arches of nickel-titanium . The deposition process will be carried out by vaporizing a solid in atoms or molecules in the form of vapor in an environment composed of low pressure gas (PVD-plasma). In order to perform this evaluation, the friction coefficients of brackets with and without deposition of silica film will be compared. Twenty self-ligating polycrystalline alumina brackets will be used, Roth 0.022 inch prescription, with indication for upper central incisor. The brackets will be divided into 2 experimental groups (n=10) according to the treatment they will receive in their slots: AlumiSilica and Alumi. Both groups will be composed of new and unused brackets, the AlumiSilica group will receive the deposition of the silica film in the brackets slots, while the control group (called Alumi) will not be treated. Prior to the mechanical test, all brackets will be cleaned by ultrasonic bath in isopropyl alcohol for 10 minutes. The bracket/wire assemblies will be submitted to the mechanical test of wire pulling in the bracket slot using a load cell of 50 kgf at a speed of 0.5 mm/min in a universal test machine. The results corresponding to the friction force will be recorded and used to calculate the frictional coefficient. The obtained data will be submitted to statistical analysis ANOVA one factor and Tukey test (± = 0.05). The surfaces of the specimens, after the mechanical test, will be analyzed by means of scanning electron microscopy and digital optical profilometry to analyze the topographic profile.