Polymerization shrinkage and shrinkage stress development in ultra-rapid photo-polymerized bulk fill resin composites (original) (raw)
Related papers
Polymerization Shrinkage Stress Kinetics and Related Properties of Bulk-fill Resin Composites
Operative Dentistry, 2014
SUMMARY The present study assessed the polymerization shrinkage stress kinetics of five low-shrinkage light-cured bulk-fill resin composites: Surefil SDR flow (SF, Dentsply), Tetric EvoCeram Bulkfil (TE, Ivoclar Vivadent), Venus Bulk Fill (VB, Heraeus Kulzer), x-tra fil (XF, Voco), and experimental bulk fill (FB, 3M ESPE). Filtek Z250 (FZ, 3M ESPE) was used as a control. Real-time shrinkage stress of investigated composites was measured using a tensometer; maximum shrinkage stress, stress rate (Rmax), and time to reach maximum stress rate (tmax) were recorded. Flexural strength and modulus were measured using a standard procedure, and curing efficiency of 4-mm long specimens was determined using bottom/top percentage Knoop microhardness. Data were analyzed using one-way analysis of variance and Bonferroni multiple range tests at a significance level of α=0.05. Results of shrinkage stress, Rmax, and tmax of all bulk-fill materials were significantly lower (p<0.05) than those of th...
Linear polymerization shrinkage of Bulk Fill resins
Revista da Faculdade de Odontologia - UPF
Objective: the objective of the present study was to analyze the polymerization shrinkage gap of different composite resins. Methods: four commercial brands (n=5) were tested: Z350 (3M/ESPE); Filtek Bulk Fill (3M/ESPE); Surefill (Dentsply); Xtra Base (Voco). Increments of composite resins were inserted into a circular metal matrix of 7 mm internal diameter and 4 mm high and pressed by two glass plates supported on polyester strips. After photoactivation with a Optilight Plus device (Gnatus), with light intensity of 1000 ± 10mW/cm2, the test samples were polished and 24h later, taken to the scanning electron microscope for analysis of the polymerization shrinkage gap, measured at 4 points in the sample (3, 6, 9, and 12 o’clock). The data were analyzed by analysis of variance (Anova one-way). Results: the highest mean of polymerization shrinkage gap was observed for Filtek Z350 (3M/ESPE), while the lowest mean of gap was found for Xtra Base (Voco) brand, with significant differences b...
Brazilian Journal of Oral Sciences, 2004
The aim of this study was to evaluate the effect of different photoactivation methods and base materials on the stress generated by the polymerization shrinkage of composites. The evaluated groups for the base material were: (G1) 1 coat of adhesive; (G2) 3 coats of adhesive, and (G3) flowable composite as a liner. The groups were divided in agreement with the photoactivation method: Continuous light (CL); Stepped Light (SL); Intermittent Light (IL); LED and Xenon Plasma Arc (XP). The generated stress was measured in a universal testing machine 5 minutes after the end of the photoactivation. The results were submitted to ANOVA and the averages values compared by Tukey test (5%). Inside of G1 group the mean values varied between 1.62 MPa (XP) to 2.22 MPa (CL), in which the XP method presented statistically inferior values to the other appraised methods. The values inside of G2 and G3 varied from 1.64 MPa (LED) to 2.15 MPa (CL) and 1.24 MPa (IL) to 1.92 MPa (SL), respectively, and the ...
Polymerization shrinkage stress of composites photoactivated by different light sources
Brazilian Dental Journal, 2009
The purpose of this study was to compare the polymerization shrinkage stress of composite resins (microfilled, microhybrid and hybrid) photoactivated by quartz-tungsten halogen light (QTH) and light-emitting diode (LED). Glass rods (5.0 mm x 5.0 cm) were fabricated and had one of the surfaces air-abraded with aluminum oxide and coated with a layer of an adhesive system, which was photoactivated with the QTH unit. The glass rods were vertically assembled, in pairs, to a universal testing machine and the composites were applied to the lower rod. The upper rod was placed closer, at 2 mm, and an extensometer was attached to the rods. The 20 composites were polymerized by either QTH (n=10) or LED (n=10) curing units. Polymerization was carried out using 2 devices positioned in opposite sides, which were simultaneously activated for 40 s. Shrinkage stress was analyzed twice: shortly after polymerization (t40s) and 10 min later (t10min). Data were analyzed statistically by 2-way ANOVA and Tukey's test (a=5%). The shrinkage stress for all composites was higher at t10min than at t40s, regardless of the activation source. Microfilled composite resins showed lower shrinkage stress values compared to the other composite resins. For the hybrid and microhybrid composite resins, the light source had no influence on the shrinkage stress, except for microfilled composite at t10min. It may be concluded that the composition of composite resins is the factor with the strongest influence on shrinkage stress.
Journal of Dentistry of Tehran University of Medical Sciences, 2019
Objectives: The polymerization shrinkage of methacrylate-based composites is among the most important causes of failure of composite restorations. The manufacturers claim that bulk-fill composites have a lower polymerization shrinkage than conventional composites. This study aimed to assess the polymerization shrinkage of five bulk-fill composites in comparison with a conventional composite. Materials and Methods: In this in-vitro experimental study, composite discs (n=30) were fabricated using everX Posterior (EXP), Filtek Bulk-Fill Posterior (FBP), SonicFill 2 (SF2), Tetric N-Ceram Bulk-Fill (TNB), X-tra fil (XF), and Filtek Z250 conventional composite at the center of a metal ring bonded to a microscope slide and were covered with a coverslip. This assembly was transferred to a linear variable differential transformer (LVDT). Light-curing (1200 mW/cm2) was performed from underneath the slide for 30 seconds. The deflecting disc method and LVDT were used to assess the dimensional c...