Bis-acryl resins are used for temporary dental restorations and have shown advantages over other materials. The aim of this work was to evaluate the in vitro cytotoxicity of two bis-acryl composite resins (Protemp 4 and Luxatemp Star), obtained at 1, 7 and 40 days after mixing the resin components, using a standardized assay employing human primary cells closely related to oral tissues. Human gingival fibroblast cell cultures were exposed for 24 h to either bis-acryl composite resins, polystyrene beads (negative control) and latex (positive control) extracts obtained after incubation by the different periods, at 37 °C under 5% CO2. Cell viability was evaluated using a multiparametric procedure involving sequential assessment (using the same cells) of mitochondrial activity (XTT assay), membrane integrity (neutral red test) and total cell density (crystal violet dye exclusion test). The cells exposed to the resin extracts showed cell viability indexes exceeding 75% after 24 h. Even when cells were exposed to extracts prepared with longer conditioning times, the bis-acryl composite resins showed no significant cytotoxic effects (p>0.05), compared to the control group or in relation to the first 24 h of contact with the products. There were no differences among the results obtained for the bis-acryl composite resins evaluated 24 h, 7 days and 40 days after mixing. It may be concluded that the bis-acryl resins Protemp 4 and Luxatemp Star were cytocompatible with human gingival fibroblasts, suggesting that both materials are suitable for use in contact with human tissues.
There are various soft materials on the market for relining prostheses; however, the effects of these materials on tissues need to be clarified to avoid problems for patients.
Objective: To compare the bond strength of three-step and self-etch adhesive systems with and without prior acid etching on bonding of fiberglass posts in root canals. Material and Methods: Experiments were conducted on roots of five upper molars without curvature and sectioned in a cervical-apical direction. With the aid of a highspeed turbine and diamond tips, cylindrical cavities 7 mm in depth and 1.4 mm in diameter were made in the dentine. The roots of the same tooth were used, where the retainers were cemented, thus generating three groups: Group A: Adper Scotchbond Multipurpose Plus (SBMP) + Rely X ARC; Group B: Single Bond Universal (SBU-1) + Rely X ARC, with acid etching prior to adhesive insertion; Group C: Single Bond Universal (SBU-2) + Rely X ARC. The samples were stored in a bacteriological incubator at 37ºC with 100% humidity for 48h and were subsequently cross-sectioned to obtain 3 dentine discs 1mm in thickness. Forty-five specimens were subjected to the push-out test. Results: Through the analysis of variance and Tukey's test, it was found that SBMP showed, with statistical significance (p<0.05), highest bond strength when compared with the SBU-1 and SBU-2 systems. The observed difference in the discs was located in the cervical portion. Conclusion: The three-step adhesive system had higher bond strength with the substrate than the self-etching adhesive only in the disc in the cervical portion; further, statistically, the prior application of phosphoric acid in SBU-1 did not affect its bond strength significantly.
Composite resins are polymeric restorative materials that have acceptable mechanical properties, so they are used in anterior and posterior teeth. There is, however, polymerization shrinkage inherent in the polymeric materials. This contraction is responsible for the formation of cracks at the interface of the restoration. These gaps contribute to the staining of the composite resin and the appearance of cavities. In order to minimize the effects of polymerization shrinkage, variations in restorative technique has been introduced to fulfill this goal. The preheating resin composite is one of them.This study aimed to assess the formation of marginal gaps, using scan electron microscopy, in composite resin restorations created using one room-temperature composite resin and one preheated to 60°C. 20 recently-extracted human molars with circular cavities in the surface dentine of each proximal surface were used. The cavities were restored using Filtek Z350 (3M) composite resin affixed with Adper Scotchbond Multipurpose Adhesive (3M) and divided into two groups of 10 samples: group 1 – room-temperature composite resin restorations (n=10) and group 2 – composite resin restorations preheated to 60oC (n=10). The samples were kept in a bacteriological incubator for a period of seven days. After this, the restorations were polished and epoxy resin replicas were created using a casting with addition silicone for subsequent SEM analysis. The gaps were measured with the aid of UTHSCSA Image tool software and the results were submitted to Student “t” test statistical analysis, achieving the following results: the highest marginal gap figures were obtained with Filtek Z350 resin preheated to 60oC (t= -3.961 and p=0.000). Based on the methodology employed and the results achieved, it can be concluded that there was a greater formation of marginal gaps in the dentin-composite resin interface where Filtek Z350 resin preheated to 60°C was used for restorations, thus making it preferable to use room-temperature composite resin.Keywords:Composite resin. Marginal gaps. Electronic microscopy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.