Artículo
Simple and Low-Cost Thermal Treatments on Direct Resin Composites for Indirect Use
Fecha
2019Registro en:
0103-6440
Autor
Grazioli, Guillermo
Francia, Alejandro
Cuevas Suárez, Carlos Enrique
Henrique Zanchi, Cesar
Ratto De Moraes, Rafael
Institución
Resumen
The aim of this study was to evaluate the influence of three low-cost additional thermal
treatments, available in the dental office, on the mechanical, chemical and optical
properties of a light-cured resin composite indicated for direct restorations but used as
indirect restorative. The direct resin composite TPH3 (Dentsply) was light-polymerized using
a light-emitting diode curing unit and submitted to three experimental additional thermal
treatments: dry heat at 170 °C for 5 min, autoclave at 121 °C for 6 min, or microwave
oven at 450 W for 3 min. The resin composite without any thermal treatment was used
as negative control group. An indirect resin composite (Vita CM LC, Vita Zahnfabrik) was
tested as a reference. Flexural strength, elastic modulus, microhardness, degree of C=C
conversion, roughness before and after simulated toothbrush abrasion, translucency
parameter and color difference (ΔE00) were evaluated. Data were analyzed at α=0.05. The
indirect resin composite presented lower C=C conversion and mechanical performance.
The flexural strength was significantly higher in the dry oven group compared with
the control. The roughness was not different among groups before or after brushing,
but the thermal treatments caused an increase in C=C conversion, microhardness, and
elastic modulus without affecting the translucency parameter or showing visible color
alteration (ΔE00<1.8). These results suggest that the use of additional thermal methods of
polymerization represents an economical and simple alternative to enhance the mechanical
and chemical properties of direct resin composites when used as indirect restoratives.