Simple and Low-Cost Thermal Treatments on Direct Resin Composites for Indirect Use

Abstract

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.

Computer‐aided design and computer‐aided manufacturing indirect versus direct composite restorations: A randomized clinical trial

“…2 With this technique, the composite can be post-cured by additional light and heat exposure, which improves its physical and mechanical properties, as well its wear resistance. [15][16][17][18][19] Furthermore, as the material is cured outside the mouth, all shrinkage occurs before its placement into the preparation. The only shrinkage during the clinical procedure will be related to the polymerization of the thin layer of resin cement, resulting in little stress on the remaining tooth structure or bonded interface.…”

Resistencia flexural y estabilidad de color en resinas híbridas y cerómeros empleadas en restauraciones indirectas

“…(12) La estabilidad de color de las restauraciones varía en dependencia de su reacción de deterioro químico ante el ambiente oral; en ocasiones, los materiales utilizados cambian en este sentido como consecuencia de la ingesta de alimentos con agentes colorantes, hábitos tóxicos y por la absorción de agua. (13) Entre las limitaciones fundamentales del estudio que se presenta se puede señalar que: hubiera sido preferible utilizar grupos muestrales con un mayor número de ejemplares y que, además de realizar pruebas in vitro en condiciones de laboratorio, también se realizaran observaciones de la evolución del color en un grupo de pacientes con restauraciones empleando los materiales los odontológicos en cuestión. De igual manera, se recomienda para futuras investigaciones que se planifique la obtención de datos a mediano y largo plazo.…”

Restaurações indiretas e semi-diretas com resinas compostas em dentes posteriores

“…Após isso, realiza-se a polimerização extrabucal que pode ser feita tanto com a mesma unidade fotoativadora utilizada inicialmente quanto através de um "tratamento térmico" que pode ser realizado de diversas formas (Netto e Burger, 2009;Alharbi et al, 2014). Grazioli et al (2019) relata que esses tratamentos térmicos são realizados usando-se forno de esterilização convencional, autoclave, forno de cerâmica ou forno de micro-ondas.…”

“…As RC empregadas na confecção de restauração indiretas de laboratório são semelhantes às utilizadas na técnica direta convencional intrabucal em relação à composição, sendo ambas constituída de matriz orgânica, agente de união e partículas de carga (Baratieri et al, 2015;Grazioli et al, 2019). Entretanto, de acordo com Cardoso et al (2012) essas RC diferem significativamente no que concerne à matriz orgânica, sendo as RC indiretas formadas não apenas por monômeros bifuncionais (Bis-GMA, TEGDMA e UDMA) mas Research, Society and Development, v. 9, n. 12, e26991211242, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i12.11242 também por monômeros multifuncionais de quatro a seis sítios, os quais possibilitam a formação de maior quantidade de ligações cruzadas.…”