Heat curing of UTMA-based hybrid resin: effects on the degree of conversion and cytotoxicity

Abstract

This study was designed to determine the effects of the heat curing time on a urethane tetramethacrylate (UTMA)-based hybrid resin and specifically on the degree of conversion (DC) and cytotoxicity. The materials used in this study were Estenia, a new-generation hybrid resin, and an experimental fiber reinforcement, Br-100. The DC values of the hybrid resin samples were measured using a Fourier transform infrared (FTIR) spectrophotometer after 180 s of light curing followed by heat curing (0, 15, 30, and 60 min). A method comparing intensities of C=C and N-H vibrations of the sample was used to calculate the final DC values. FTIR spectra were measured both inside and on the surface of the sample. The calculated DC values increased by increasing the heat curing times. After light curing only and after 15-min heat curing, the DC values inside the samples were smaller than the corresponding DC values at the surfaces of the samples. After 60 min of heat curing, the samples achieved homogeneous polymerization (DC% = 65). The cytotoxicity of the material was studied from the glass fiber-reinforced hybrid resin samples, which were first light cured and then heat cured (15, 30, and 60 min). Cytotoxicity was tested using both direct contact and extract methods. For the extract tests, the test specimens were incubated in a cell culture media at 37 degrees , 54 degrees , or 72 degrees C for 24 h. The heat curing times used had no effect on cytotoxicity. The incubation temperature, however, did have a significant effect. The extract obtained from 72 degrees C incubation showed a cytotoxic effect whereas the others did not. The direct contact test did not show cytotoxicity.

Effects of mechanical properties of adhesive resin cements on stress distribution in fiber-reinforced composite adhesive fixed partial dentures

“…Leveraging the advances in adhesive bonding technology, the conservative approach of minimally invasive dentistry allows the esthetics and function of anterior teeth to be restored with adhesive fixed partial dentures. Fueled by increasing interest in metal-free esthetic dentistry, glass fiber-reinforced composite (FRC) has been used in myriad dental applications [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] . Of particular interest to this paper are the adhesive fixed partial dentures (AFPDs), which have been favorably reported because of their good clinical performance [18][19][20][21] .…”

Measuring the effects of water immersion conditions on the durability of fiber-reinforced hybrid composite resin using static and dynamic tests

“…Säilynoja et al 22) suggested that temperature changes reduce flexural strength due to internal stress generated within the material. Both materials used in this study were composite materials containing matrix resin, glass-based filler, and glass fibers, which have different coefficients of thermal expansion.…”

“…The bonding property at the reinforcement/matrix interface is a critical factor affecting the mechanical properties of composite materials. In particular, the addition of filler particles to a bonding agent and substantially active silane-coupling treatment enhance interfacial bonding between the fibers and the hybrid resin matrix, improving the flexural strength of FRC [21][22][23][24] . In clinical practice, patients receiving prosthetics made of such materials have numerous concerns, including safety, durability, breakage, the effect of brushing on the shiny appearance, and whether to expect marginal leakage.…”

Three-dimensional finite element analysis of posterior fiber-reinforced composite fixed partial denture Part 2: influence of fiber reinforcement on mesial and distal connectors

“…As with any prosthetic devices, the materials used for fabricating FPDs play a pivotal role in determining the success rate and longevity of these dental restorations. In the case of FRC FPDs, numerous studies were carried out to examine the FRC material from different perspectives: mechanical properties [7][8][9][10] , material development in terms of flexural strength 11) , biocompatibility 12) , fatigue analysis 13,14) , structural analysis in terms of stress distribution 15,16) , and optimal design of FRC framework to obtain the maximum reinforcement effect for FPD 17,18) . Despite the much that is already known about the material properties of FRC framework and particulate-filled composite veneer through the numerous laboratory and clinical studies, much remains to be known about the mechanical behavior of FRC FPDs with respect to displacement and stress magnitude and distribution pattern which were induced during functional loading.…”