Effect of preheating and light-curing unit on physicochemical properties of a bulk fill composite.
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ABSTRACT:
SUBMITTER: Theobaldo JD
PROVIDER: S-EPMC5477166 | biostudies-other | 2017
REPOSITORIES: biostudies-other
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Project description:ObjectivesCuring lights cannot be sterilized and should be covered with an infection control barrier. This study evaluated the effect of barriers when applied correctly and incorrectly on the radiant power (mW), irradiance (mW/cm2), emission spectrum (mW/nm), and beam profile from a multi-peak light-curing unit (LCU).MethodsFive plastic barriers (VALO Grand, Ultradent; TIDIShield, TIDI Products; Disposa-Shield, Dentsply Sirona; Cure Sleeve, Kerr; Stretch and Seal, Betty Crocker) and one latex-based barrier (Curelastic, Steri-Shield) were tested. The radiant power (mW) and emission spectrum (mW/nm) from one multi-peak LCU (VALO Grand, Ultradent) was measured using an integrating sphere. LCU tip internal diameter (mm) was measured, then the tip area and irradiance (mW/cm2) were calculated. The beam profiles were measured using a laser beam profiler.ResultsWhen applied correctly, the plastic barriers reduced the radiant power output by 5-8%, and the latex-based barrier by 16%. When the plastic seam or barrier opaque face was positioned over the LCU tip, the power output was reduced by 8-11%. When the plastic barriers were wrinkled, the power output was significantly reduced by 14-26%. The wrinkled latex-based barrier reduced by 28%, and further reduced the violet light. The beam profiles illustrated the importance of correctly barrier use without wrinkles over the tip.ConclusionsPlastic barriers applied correctly reduced the light output (mW) by 5-8%. The barriers applied incorrectly significantly reduced the light output by 14-26%. The latex-based barrier wrinkled also reduced the amount of violet light.Clinical relevanceInfection control curing light barriers should be used to prevent cross-infection between patients. However, they must be applied correctly to reduce their negative effects on the light output.
| S-EPMC7569381 | biostudies-literature
Project description:BackgroundDespite recent advances in restorative dentistry adhesive restorations may cause postoperative sensitivity which leads to restoration failure.AimThis study aimed to compare and evaluate the incremental and bulk fill resin Composite postoperative sensitivity in class II posterior restorations bonded with two adhesive systems (self-etch and etch-and-rinse).MethodsSixty patients were randomly selected, their age range from twenty-five to forty years old, divided into two groups according to the packing technique of resin composite material; incremental Tetric Evoceram and Tetric Evoceram bulk-fill resin composite. Thirty patients (n = 30) for incremental Tetric Evoceram resin composite restorations and according to the adhesive systems used they were equally divided (n = 15 teeth).Thirty patients (n = 30) for Tetric Evoceram bulk-fill resin composite restorations and according to the adhesive systems used (etch and rinse or self-etch), they were equally divided (n = 15 teeth). Post-operative pain assessed at 24 hours, 1 week and 1 month using the Visual Analog Scale Score (VAS). Each patient was instructed to put a mark on the VAS line at home to point out the intensity of pain at each assessment period. The problem of measuring the pain that pain tolerance of individuals may be different from the others. This may be due to different reasons, and it is not always because of a problem in the restoration.ResultsAfter 1 day, 1 week as well as 1 month, no statistically significant disagreement between the two resin composite types using self-etch adhesive strategy and total-etch adhesive strategy. Also, when the two adhesive systems were compared using Bulk Fill resin composite and incremental Nano resin composite no statistically significant disagreement between the two adhesive systems after 1 day, 1 week as well as 1 month.ConclusionThe post-operative hypersensitivity is related to many factors as the procedure of cavity preparation, adhesive approach, and type of resin composite used and placement technique of the resin composite.
| S-EPMC6765082 | biostudies-literature
Project description:OBJECTIVES:To assess the color stability and surface microhardness of Bulk-Fill composite materials available in the Saudi Arabia market. METHODS:Five composite materials (Filtek Z350, Filtek Bulk-Fill, Tetric N-Ceram Bulk-Fill, Sonic Fill 2, and SDR) were investigated. Samples (n = 20; 10 mm in diameter and 2 mm in thickness) were fabricated using a stainless-steel mold and were immersed in tea, coffee, berry juice, and distilled water (control). Baseline (T0) shades of specimens were recorded using a spectrophotometer and after 10 (T1), 30 (T2), 60 (T3), and 90 days (T4) of immersion. Measurements were obtained against a black background and CIE L*a*b* data was used to calculate ?E for each group. Vickers microhardness values were obtained at T0 and T4. Data was analyzed using mixed model repeated measure ANOVA at 0.05 significance level. RESULTS:Time, material, and solution effects have statistically significant effect on ?E. Tea was the most staining solution. Z350 was associated with the highest ?E values while SDR showed the lowest values. No other materials showed significant difference between each other. Solutions were statistically different from each other. All materials were different from each other regarding microhardness. CONCLUSION:Bulk-Fill materials showed more color stability but lower microhardness values compared to universal resin control.
| S-EPMC7040906 | biostudies-literature
Project description:The objective of this systematic review and meta-analysis was to determine the clinical effectiveness of bulk-fill and conventional resin in composite restorations. A bibliographic search was carried out until May 2020, in the biomedical databases Pubmed/MEDLINE, EMBASE, Scopus, CENTRAL and Web of Science. The study selection criteria were: randomized clinical trials, in English, with no time limit, with a follow-up greater than or equal to 6 months and that reported the clinical effects (absence of fractures, absence of discoloration or marginal staining, adequate adaptation marginal, absence of post-operative sensitivity, absence of secondary caries, adequate color stability and translucency, proper surface texture, proper anatomical form, adequate tooth integrity without wear, adequate restoration integrity, proper occlusion, absence of inflammation and adequate point of contact) of restorations made with conventional and bulk resins. The risk of bias of the study was analyzed using the Cochrane Manual of Systematic Reviews of Interventions. Sixteen articles were eligible and included in the study. The results indicated that there is no difference between restorations with conventional and bulk resins for the type of restoration, type of tooth restored and restoration technique used. However, further properly designed clinical studies are required in order to reach a better conclusion.
| S-EPMC7464794 | biostudies-literature
Project description:The aim of the study was to compare under in vitro conditions marginal sealing of 4 different bulk-fill materials composite restorations of class II.Comparative evaluation concerned 4 composites of a bulk-fill type: SonicFill, Tetric EvoCeram Bulk Fill, Filtek Bulk Fill, and SDR. The study used 30 third molars without caries. In each tooth 4 cavities of class II were prepared. The prepared tooth samples were placed in a 1% methylene blue solution for 24 h, and after that in each restoration the depth of dye penetration along the side walls was evaluated.The highest rating (score 0, no dye penetration) was achieved by 93.33% of the restorations made of the SDR material, 90% of restorations of SonicFill system, 86.66% of restorations of the composite Filtek Bulk Fill, and 73.33% of restorations of the Tetric EvoCeram Bulk Fill.The performed study showed that bulk-fill flowable or sonic-activated flowable composite restorations have better marginal sealing (lack of discoloration) in comparison with bulk-fill paste-like composite.
| S-EPMC4385685 | biostudies-other
Project description:A new category of commercial bulk fill composite resins (CRs) enables the placement of 4-mm-thick layers as an alternative to the traditional time-consuming incremental technique. The purpose of the present study was to compare the efficiency of the polymerization, adaptation and porosity of two high-viscosity 'sculptable' bulk fill CRs (Filtek™ Bulk Fill (3M™ ESPE, St. Paul, MN, USA) and Tetric EvoCeram® Bulk Fill (Ivoclar Vivadent AG, Schwan, Liechtenstein)) and two low-viscosity 'flowable' bulk fill CRs (SureFil® SDR™ flow (Dentsply Sirona, Charlotte, NC, USA) and Tetric EvoFlow® Bulk Fill (Ivoclar Vivadent AG, Schaan, Liechtenstein)). Cylindrical samples of the bulk fill CRs (4 mm height × 10 mm diameter) were analyzed by Fourier-transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Additionally, occlusal cavities were prepared in twelve extracted human molars and restored with the bulk fill CRs (n = 3 for each CR). The adaptation and porosity of the bulk fill CRs were evaluated by X-ray microcomputed tomography (µCT) with a 3D morphometric analysis, and the adaptation was also analyzed by scanning electron microscopy (SEM) on longitudinal vestibulo-oral sections of the restored teeth. The AFM analysis demonstrated that the surface roughness of the SureFil® SDR™ flow was higher than that of the Tetric EvoFlow® Bulk Fill and that the surface roughness of Filtek™ Bulk Fill was higher than that of Tetric EvoCeram® Bulk Fill. µCT and SEM confirmed that the flowable bulk fill CRs had excellent adaptation to the cavity walls. The 3D morphometric analysis showed the highest and lowest degrees of porosity in Filtek™ Bulk Fill and Tetric EvoFlow® Bulk Fill, respectively. In general, the flowable bulk fill CRs exhibited better adaptation, a higher efficiency of polymerization and lower porosity than the sculptable materials.
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Project description:We investigated the influence of anion type (salicylate, [(MOB)MIm][Sal], vs chloride, [(MOB)MIm][Cl]) of imidazolium-based ionic liquid (IL) and its content on the curing kinetics of bisphenol A diglicydyl ether (DGEBA of molecular weight M n = 340 g/mol). Further physicochemical properties (i.e., glass transition temperature, T g, and conductivity, σdc) of produced polymers were investigated. The polymerization of the studied systems was examined at various molar ratios (1:1, 10:1, and 20:1) at different reaction temperatures (T reaction = 353-383 K) by using differential scanning calorimetry (DSC). Interestingly, both DGEBA/IL compositions studied herein revealed significantly different reaction kinetics and yielded materials of completely distinct physical properties. Surprisingly, in contrast to [(MOB)MIm][Cl], for the low concentration of [(MOB)MIm][Sal] in the reaction mixture, an additional step in the kinetic curves, likely due to the combined enhanced initiation activity of anion (salicylate)-cation (imidazolium-based), was noted. To thoroughly analyze the kinetics of all studied systems, including the two-step kinetics of DGEBA/[(MOB)MIm][Sal], we applied a new approach that relies on the combination of the two phenomenological Avrami equations. Analysis of the determined constant rates revealed that the reaction occurring in the presence of the salicylate anion is characterized by higher activation energy with respect to those with the chloride. Moreover, DGEBA/[(MOB)MIm][Sal] cured materials have higher T g in comparison to DGEBA polymerized with [(MOB)MIm][Cl] independent of the IL concentration. This fact might indicate that, most likely, the products of hardening are highly cross-linked (high T g) or oligomeric linear polymers (low T g) in the former and latter cases, respectively. Such a change in the chemical structure of the polymer is also reflected in the dc conductivity measured at the glass transition temperature, which is much higher for DGEBA cured with [(MOB)MIm][Cl]. Herein, we have clearly demonstrated that the type of anion has a crucial impact on the polymerization mechanism, kinetics, and properties of produced materials.
| S-EPMC7467775 | biostudies-literature
Project description:A major challenge in the repair and regeneration of soft tissue damage occurring as a result of aging, injury, or disease is recapitulating the biomechanical properties of the native tissue. Ideally, a candidate biomaterial for soft tissue engineering applications should be biocompatible, nonlinearly elastic to match soft tissue mechanical behavior, biodegradable to enable tissue remodeling, and tailorable to achieve a range of nonlinear elastic mechanical properties to match specific soft tissues. In addition, for cardiac and other applications, the biomaterial should have shape memory characteristics to facilitate minimally invasive and/or catheter-based delivery. Poly(glycerol dodecanoate) (PGD) is a shape memory material that has nonlinear elastic properties at body temperature and elastic-plastic behavior at room temperature. In this study, we investigated the effects of curing conditions on the nonlinear elastic, shape memory, and biocompatibility properties of PGD. Increased curing and crosslinking resulted in an increase in both the initial stiffness and the nonlinear strain stiffening behavior of PGD. After shape fixation at 60% strain, 100% shape recovery was achieved within 1 min at body temperature for all conditions tested. Polymer curing had no adverse effects on the cellular biocompatibility or non-hemolytic characteristics of PGD, indicating the potential suitability of these formulations for blood-contacting device applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1618-1623, 2017.
| S-EPMC6662581 | biostudies-literature
Project description:Clinical studies are being conducted in less strict conditions in order to establish an adequate scientific basis for decision making. The aim of this pragmatic randomized clinical trial is to evaluate the effectiveness of single and multiple-surfaces restorations performed following the Atraumatic Restorative Treatment (ART) premises compared with Conventional Treatment (CT) using bulk fill composite restorations in primary and permanent teeth.A total of 1,214 5-to-13 year-old children with at least one single or multiple-surface dentin caries lesion in primary or permanent molars will be selected in public schools of Barueri-SP, Brazil. The participants will be randomly assigned into 2 groups: CT (caries removal with bur and restoration performed with Scotchbond™ Universal Adhesive system associated with Filtek Bulk Fill - 3 M/ESPE) and ART (Caries removal with hand instruments and restoration with high viscosity glass ionomer cement Ketac Molar Easy Mix - 3 M/ESPE). Ten untrained dentists will perform the treatment in in dental offices located at public schools. The restorations will be evaluated after 6, 12 and 24 months by an independent trained and calibrated examiner. The restoration and tooth survival, the cost-effectiveness analysis between the two groups and the operators' preferences regarding the techniques will be also evaluated. Kaplan-Meier survival analysis and log-rank test will be applied for the restoration and tooth survival. All the average event rates in the two groups will be modelled and compared with a Cox proportional hazard shared frailty model since there is an operator-cluster effect. The significance level for all analyses will be 5 %.Our hypothesis is that despite similar expected effectiveness between ART using high viscosity GIC and conventional treatment using bulk fill composite resin when treating single or multiple-surface in posterior primary and permanent teeth, ART will present superior cost-effectiveness. The results of this trial will support decision-making by clinicians and policy makers.NCT02568917 . Registered on May 10th 2015.
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Project description:The binding interactions of bovine serum albumin (BSA) with tetraphenylborate ions ([B(Ph)4]−) have been investigated by a set of experimental methods (isothermal titration calorimetry, steady-state fluorescence spectroscopy, differential scanning calorimetry and circular dichroism spectroscopy) and molecular dynamics-based computational approaches. Two sets of structurally distinctive binding sites in BSA were found under the experimental conditions (10 mM cacodylate buffer, pH 7, 298.15 K). The obtained results, supported by the competitive interactions experiments of SDS with [B(Ph)4]− for BSA, enabled us to find the potential binding sites in BSA. The first site is located in the subdomain I A of the protein and binds two [B(Ph)4]− ions (logK(ITC)1 = 7.09 ± 0.10; ΔG(ITC)1 = −9.67 ± 0.14 kcal mol−1; ΔH(ITC)1 = −3.14 ± 0.12 kcal mol−1; TΔS(ITC)1 = −6.53 kcal mol−1), whereas the second site is localized in the subdomain III A and binds five ions (logK(ITC)2 = 5.39 ± 0.06; ΔG(ITC)2 = −7.35 ± 0.09 kcal mol−1; ΔH(ITC)2 = 4.00 ± 0.14 kcal mol−1; TΔS(ITC)2 = 11.3 kcal mol−1). The formation of the {[B(Ph)4]−}–BSA complex results in an increase in the thermal stability of the alfa-helical content, correlating with the saturation of the particular BSA binding sites, thus hindering its thermal unfolding.
| S-EPMC8588492 | biostudies-literature