Degradação química e citotoxicidade in vitro de cimentos resinosos fotopolimerizáveis

• Autor(a) principal: Laxe, Laísa Araujo Cortines
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14039
• topic: Resin cements; Cytotoxicity; Spectroscopy Fourier Transform Infrared; Methylmethacrylate; Cimentos de resina; Espectroscopia infravermelho transformada de Fourier; Metilmetacrilato; Citotoxicidade; CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA

The aim of this study was to evaluate the degradation of different light-activated resin cements after aging in artificial saliva and lactic acid solutions, and the in vitro cytotoxicity of salivary extracts obtained from the resin cements degradation on mouse fibroblast (Balb/c 3T3). The resin cements Variolink II, AllCem Veneer and RelyX Veneer were tested. For microstructure characterization, TGA, degree of conversion (DC) and granulometric distribution of filler particles were employed. The DC was calculated from baseline FTIR spectra obtained from uncured and cured samples of each resin cement. These samples were development on teflon mold (0.5 mm x 5.0 mm) and photoactivated by a LED (Elipar S10; 3M ESPE). After baseline FTIR spectra obtaining, 5 samples of each cement were immersed in 10 ml of artificial saliva (pH = 7.0) and the others 5 samples were immersed in 10 ml of lactic acid solution (pH = 4.0), individually, for 18 days, at 37°C. Then, the samples were submitted to new FTIR analyzes, at the same anterior conditions, and their new spectra were compared with the baselines by qualitative FTIR method. The cell viability of 3T3 fibroblast was evaluated of MTT test. The cells were exposed to salivary extracts for 24 h and 72 h. Control cells were exposed to pure artificial saliva solution. The data were submitted to ANOVA and Tukey s test. The results revealed significant higher mass percentage of filler particles for Variolink II (65.86%±0.17; p<0.05) when compared with RelyX Veneer (62.29%±0.30) and AllCem Veneer (62.15%±37.84); trimodal granulometric distribution for Variolink II (0.2 3.3 µm) and RelyX Veneer (0.6 29.0 µm), and monomodal distribution for AllCem Veneer (1.0 4.1 µm); significant higher baseline DC for AllCem Veneer (71.23%; p<0,05), while RelyX Veneer (66.00%±6.84) and Variolink II (62.24%±2.45) were not different from each other (p=0.1306). The lactic acid solution contributed to higher changes of the inorganic matrix for Variolink II cement. However, this cement revealed more polymeric degradation after aging in artificial saliva when compared with lactic acid solution. RelyX Veneer had chemical degradation in both solutions. AllCem Veneer not showed any chemical degradation after aging in both solutions. Within 24 h of exposure, the chemical wastes of the AllCem Veneer cement guaranteed the higher cell viability to 3T3 fibroblasts (90.0±6.30) and there was no difference with the control group (80.3±8.70). The chemical wastes of the Variolink II cement guaranteed the smaller cell viability at the same time (7.43±0.17). After 72 h of exposure, all salivary extracts, except for control group, caused important cytotoxic effects to 3T3 fibroblasts. Then, the resin cements evaluated in this study can suffer chemical degradation under conditions that simulate the oral environment. There was a direct relationship between chemical degradation and in vitro cytotoxicity.