Influência da densidade de energia nas propriedades físicas e na resistência de união de dois sistemas restauradores

Author(s)

Anderson Catelan

• Document type: Doctoral Thesis
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2012-11-10

Examining board members

Flavio Henrique Baggio Aguiar; Paulo Henrique dos Santos; Débora Alves Nunes Leite Lima; Giselle Maria Marchi; Faiana Mantovani Gomes França

• Advisor: Flavio Henrique Baggio Aguiar

Abstract

The purpose of this study was to evaluate the influence of different energy densities on the physical properties and bond strength of methacrylate-[Clearfil SE Bond (Kuraray) + Filtek Z250 (3M ESPE)] and silorane-based [FiltekP90 system (3M ESPE)] restorative systems, light-cured with a second generation LED according to experimental groups. Specimens were carried out for the degree of conversion (DC) test; the absorption spectra were obtained by FT-IR and FTRamanspectroscopy for the adhesives (n = 10) and composites (n = 5), respectively. The Knoop hardness (KH) was evaluated at the top and bottom of the composites (n = 10). After 24 h of immersion in absolute ethanol, re-reading of KHwas performed to obtain the percentage reduction of the hardness. The water sorption (WS) and solubility (S) tests of the adhesives (n = 5) and composites (n =5) were performed according to ISO 4049:2009, except for specimens' dimension and light-curing protocol. For the bond strength (n = 7) and nanoindentation (n = 3) tests, Class II cavities were performed on the proximal of human molars, which were restored with the restorative systems evaluated. The micro tensile test was carried out in an universal testing machine under cross-head speed of 0.5 mm/min.In the nanoindentation technique were measured the nanohardness (NH) and reduced elasticity modulus (Er) of the dentin, hybrid layer, adhesive, and composite. The data obtained were subjected to statistical analysis (alpha = 0.05).For the adhesives the highest energy density improved only the DC (p < 0.05); the "primer" of the P90 exhibited greater DC, WS, and S compared to "bond" of the Clearfil and P90 (p < 0.05). The methacrylate composite showed higher DC, KH, P, and WS (p < 0.05) than silorane. There was no difference in the S of the composites (p > 0.05). Generally the top surface showed greater of DC and KHthan base (p < 0.05). The methacrylate-based restorative system, as well as increased energy density showed higher bond strength (p < 0.05), with no difference between 24 h and 6 months (p > 0.05). The NH and Ervalues methacrylate-based materials were greater than silorane (p < 0.05). The higher energy density did not improve the NH and Er materials (p > 0.05). The aging decreased the most nanomechanical properties of the components of the tooth restoration interface (p < 0.05), except the NH and Er of the composite and Erof the adhesive (p > 0.05). Thus, it can be concluded that the physical properties and bond strength were material-dependent; the highest energy density improved the bond strength, but not influenced, in general, physical and nanomechanicalproperties; and the aging reduced the most nanoproperties of the components of the tooth-restoration interface, but did not affect the bond strength of restorations (AU)

• FAPESP's process: 10/05666-9 - Influence of energy density on the physical properties and bond strength of two restorative systems
• Grantee: Anderson Catelan
• Support Opportunities: Scholarships in Brazil - Doctorate