Filtek Z250 Research Articles

Effect of Different pH Beverages on the Color Stability of Smart Monochromatic Composite

Omnichroma is a smart monochromatic material and is believed to attain the shade of the surrounding tooth structure in which it is placed. However, the color stability of this material is unknown. Therefore, this study was conducted to evaluate the effect of different pH beverages on the color stability of the Omnichroma composite and its comparison with micro-hybrid composite resin. Sixty extracted human maxillary premolars of different shades, viz. A2, A3, B2 and B3, were selected in equal numbers. A Class V cavity was prepared on the buccal and palatal sides of each tooth. After the cavity preparation, etching of the cavity was performed with 35% phosphoric acid followed by bonding. The prepared cavities were then filled with Omnichroma composite resin on the buccal side and Filtek Z250 composite on the palatal side. The baseline color measurements of all tooth samples were performed by a spectrophotometer. The teeth were then divided into three groups, the Pepsi group, coffee group and milk tea group. Five teeth from each shade, viz. A2, A3, B2 and B3, were immersed in 10-mL of Pepsi, coffee, and milk tea for 14 days. After the completion of the 14 days, the teeth were rinsed and kept in distilled water for 24 h. Finally, a spectrophotometer was used to calculate the color alteration value ΔE. Mean difference in ΔE values of the samples before and after immersion in different beverages was calculated and analysed by SPSS 25. One-way ANOVA test was applied to compare groups. Further stratification was performed using the Post-Hoc Tukeys test. Samples immersed in milk tea showed a statistically significant difference (p < 0.05) in A2, A3, and B2 shades of the OM-milk tea group in comparison with the FT-milk tea group. In summary, the immersion of teeth in beverages with a different pH and colorants showed an apparent alteration in the color of both the smart monochromatic and micro-hybrid composites. Hence, the type of resin composite material should be selected wisely depending on the patient’s drinking and social habits.

Effect of Incorporation of Bioactive Glass-Ceramic into Self-etch Adhesives.

This study evaluated the effect of incorporating different concentrations of biosilicate in an experimental self-etch adhesive (SE). Biosilicate microparticles (0, 2, 5, and 10 wt%) were incorporated into the primer, and degree of conversion (DC) and wettability were tested (one-way ANOVA, Tukey's test, p < 0.05). The two best concentrations were selected (2% and 5%) for µTBS evaluation. Sound human molars (n=20) were sectioned into quarters and randomly assigned to 4 experimental groups: 1. experimental SE + 0% biosilicate (Exp0%; negative control); 2. experimental SE + 2% biosilicate (Exp2%); 3. experimental SE + 5% biosilicate (Exp5%); 4. AdheSE (Ivoclar Vivadent, positive control). After adhesive application, Filtek Z350 (3M Oral Care) composite was built up incrementally to 5 mm. Each quarter tooth was sectioned into sticks (0.9 mm2) and stored in distilled water (37°C) for 24 h, 6 months, or 1 year. After storage, sticks were submitted to µTBS (0.75 mm/min). The Ca:P ratio was analyzed using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Data were analyzed using two-way ANOVA with Bonferroni's correction, with statistical siginificance set at p < 0.05. Fracture patterns were observed under a digital microscope and adhesive interfaces with transmission electron microscopy (TEM). Exp2% presented the highest DC (p < 0.05), Exp5% exhibited the lowest µTBS (p < 0.05), and adhesive failures were predominant in all groups. TEM suggested remineralized areas in Exp2% and to a lesser degree in Exp5%. Exp2% and Exp5% showed a higher Ca:P ratio after aging (p < 0.05). The incorporation of biosilicate microparticles can improve the properties of self-etch adhesives. It increased the DC of the experimental adhesive as well as mineral deposition. However, the adhesive properties are concentration dependent, as a higher concentration of microparticles can adversely affect the mechanical properties of an adhesive.

The Effect of Different Light Curing Units and Tip Distances on Translucency Parameters of Bulk fill Materials

ObjectivesTo evaluate the effect of light curing unit (LCU) types and distance from light curing unit tip on the translucency parameters (TP) of bulk fill composite materials. Materials and MethodsTwo bulk-fill resin composites and one nanohybrid composite were used in this study. The specimens were divided into groups based on the type of curing unit used, and further subdivided based on the distance of the curing source to the surface of the resin composite. Translucency was evaluated at 4 mm thickness (for the bulk-fill) and 2 mm thickness (for nanohybrid) after curing using two different light curing units at zero, 2 mm, and 4 mm distance. The results were analyzed using two-way ANOVA at the significance level of a p-value of < 0.05. ResultsAmong all the tested materials, Filtek Bulk Fill Posterior RBC showed the highest TP at 0 mm distance when cured with Blue phase G2 LED LCU and it was the least affected by the differences in distances. However, Filtek Z350 nanohybrid composite had no significant differences between the three distances when cured with Blue phase G2 LCU. ConclusionTranslucency values among the studied bulk-fill materials are affected by material composition, curing units and the distance of the tip of the light source to the restoration surface.

Development of Novel Antimicrobial Dental Composite Resin with Nano Cerium Oxide Fillers

Objectives To assess the antibacterial efficacy of experimental dental composite resin with cerium oxide nanoparticles as fillers. Methods The cerium oxide nanoparticles were prepared by the coprecipitation procedure. Synthesized 3wt% CeO2 nanoparticles were added to the composite resin as antibacterial filler. Experimental composite resin was manually prepared by adding ingredients. The resin matrix consisted of two mixed monomers, bisphenol A-glycidyl methacrylate and triethylene glycol dimethacrylate, diketone as the photo initiator, and N, N-dimethylaminoethyl methacrylate as a coinitiator. The antibacterial efficacy against Streptococcus mutans, Streptococcus mitis, Streptococcus aureus, and Lactobacillus spp. bacterial strains was tested using the microdilution method keeping commercially available 3M Filtek Z250 restorative composite as control. Results The experimental dental composite demonstrated 99.503% efficacy against Streptococcus mutans, 99.441% efficacy against Streptococcus mitis, 99.416% efficacy against Streptococcus aureus, and 99.233% efficacy against Lactobacillus spp. Conclusion Integrating cerium oxide nanoparticles as fillers into dental composite resin can be promising in terms of antibacterial activity, provided furthermore study has to be conducted to examine other properties. Clinical Significance. Previous studies attempted adding CeO2 nanoparticles into acrylic resins that showed improvement in mechanical properties, but literature is nil on the dental composite resin and cerium oxide nanoparticles. This study demonstrates the development of an experimental antibacterial dental composite resin that can resolve most of the problems related to secondary caries around dental composite restorations.

Effect of Fluoride-based Varnishes with Added Calcium and Phosphate on Microhardness of Esthetic Restorative Materials: An In Vitro Study.

Fluoride varnishes are being used to prevent caries in children. The high concentration of fluoride in varnishes apart from caries prevention may cause changes in surface properties of esthetic restorations. The study aims to evaluate and compare the effect of four commercially available fluoride varnishes with added calcium and phosphate on microhardness of three esthetic materials namely conventional GIC (Fuji II), high viscosity GIC (Fuji IX), and nanocomposite (Filtek Z350). A total of 28 pellets were made of each material and stored in distilled water at 37 °C for 48 hours. The microhardness of the pellets was tested which served as a baseline. These were then randomly divided into four subgroups. In one subgroup Profluorid varnish was applied, second subgroup MI varnish was applied, third subgroup Embrace varnish was applied, and in the fourth subgroup Enamel Pro varnish was applied as per protocol. Thereafter, all the pellets were subjected to microhardness testing (load = 100 g for 15 seconds). The fluoride varnishes increased the microhardness of conventional GIC (Fuji II) whereas in case of high viscosity GIC (Fuji IX) the application of varnishes reduced the microhardness. In case of nanocomposite restorative material (Filtek Z350) only Profluorid varnish increased its microhardness. Fluoride varnish and calcium-phosphate containing fluoride varnish effect on the microhardness of restorative material is material dependent. So, the choice of fluoride varnish with or without proprietary additives depends on the nature and composition of the restorative material. Shetty RS, Bhat SS, HK Sundeep, et al. Effect of Fluoride-based Varnishes with Added Calcium and Phosphate on Microhardness of Esthetic Restorative Materials: An In Vitro Study. Int J Clin Pediatr Dent 2022;15(2):187-193.

Effect of Different Cavity Dimensions and Curing Systems on Cuspal Deflection of some types of Composite Resin Restorations

The cuspal deflection of different composite resin restorations cured with different systems and restoring different cavity dimensions were investigated using a total 60 freshly extracted human maxillary premolars. These teeth were divided into three main equal groups, based upon the tested restorative materials. Group (I) used T-Econpm Plus, Group (A1) (II) used Filtek Z250 XT (A2), and Group (III) used Filtek P90 (A3). Each group was subdivided into two subgroups based upon the prepared cavity dimensions. Each subgroup was further subdivided into two groups whether cured with Halogen (C1), or LED (C2). MOD cavity with two different dimensions, each restorative material was packed according to the manufacturer's instructions and cured. Dye penetration technique was used and specimens were sectioned in mesiodistal direction and examined by stereomicroscope. Collected data was statistically analyzed. The result showed T-Econom plus had statistically significant higher microleakage value, while Filtek P90 had statistically significant lower microleakage value. There was no statistically significant difference between groups cured with Halogen and LED. It can be concluded that silorane based composite, LED curing system, and smaller cavity dimension could significantly decreased cuspal deflection.

Relationship Between Operator Experience And In Vitro Microleakage of Different Composite Materials in Class II Restorations

Objectives: To evaluate the influence of operator experience on microleakage in class II restorations performing by different restorative materials. Material and Method: 2 cavities of 4x4x3mm dimensions were carried out on the mesial and distal surfaces of 20 molar teeth by one operator. The teeth were randomly assigned to two groups according to the operator’s skill: student group and expert group. It was divided into subgroups as specialist bulk-fill composite: Group 1A, student bulk-fill composite: Group 2A, specialist micro-hybrid composite: Group 1B, student micro-hybrid composite: Group 2B, Prime bond nt, a total-etch adhesive system, is used in all restorations. Each operator restored the mesial cavities with the bulk technique using a bulk-fill composite (Tetric-N-Ceram-Bulk) and the distal cavities with the layering technique using a micro-hybrid composite (Filtek Z250, 3M ESPE). After 24 hour of water storage and thermocycling the marginal microleage was evaluted using dye penetration technique and data were analyzed. Results: When the restorative materials were evaluated without considering the applying operator, and when the scores of the operator who applied the restorations were evaluated without considering the restorative materials used, no statistically significant difference was found between them (p&amp;gt;0.05).When the occlusal and gingival leakage scores of Group 2A were evaluated, more gingival leakage was observed than occlusal (p&amp;lt;0.05). There was no statistically significant difference between the in-group occlusal and gingival leak scores of the other groups (p&amp;gt;0,05). Conclusion: There was no difference between the expert and the student in terms of microleakage values.

Effect of at-home bleaching gels with different thickeners on the physical properties of a composite resin without bisphenol A.

To investigate, in vitro, the influence of at-home bleaching with 16% carbamide peroxide (CP) gels containing different thickeners on the color, gloss, roughness, and microhardness of a composite resin with bisphenol A (BPA) and without bisphenol A (BPA-free). Cylindrical samples (7×2mm) of a composite resin with BPA (Filtek Z350 XT®; 3M/ESPE) and composite resin BPA-free (Vittra APS®; FGM) were subdivided into six subgroups (n=12), according to the bleaching gel used: no bleaching (control), commercial gel with 16% CP and carbopol, experimental gel with 16% CP and carbopol, experimental gel with 16% CP and natrosol, experimental gel with carbopol and experimental gel with natrosol. At the end of the experimental phase, the specimens were analyzed for color (ΔE*ab and ΔE00 ), surface roughness (Ra), gloss (GU), and surface microhardness (SMH). The data for all analyzes were submitted to Levene's test, Shapiro-Wilk's test and ANOVA. For ΔE*ab and ΔE00 no statistically significant differences were found between all groups evaluated. Bleaching with experimental 16% CP gel with carbopol resulted in the lowest GU values for both composite resins evaluated. 16% CP experimental gel with natrosol resulted in higher Ra for the BPA composite resin and the bleaching with natrosol resulted in higher Ra for BPA-free. About 16% CP experimental gel with carbopol and 16% CP experimental gel with natrosol resulted in the lowest final SMH for composite resin with BPA. For the BPA-free composite resin, no differences were found between the groups in SMH for the same resin, however they presented the lowest values compared with all others groups. The effects on physical properties are dependent on the composition of the composite resin and the thickener/bleaching gel used. The BPA-free composite resin showed less changes after exposure to bleaching agent, although its initial physical properties were worse compared to a bleached BPA. The hydrogen peroxide and thickener of the at-home bleaching gel does impact the properties of composites with BPA or BPA-free such as gloss, roughness and surface microhardness, extremely important factors for maintaining an aesthetically and physically satisfactory restoration. BPA-free composite resins have inferior properties after at-home bleaching with different thickeners.

Effect of the thicknesses of bulk-fill composites on bonding strength.

This work evaluated the effects of thickness on resin bonding strength. We set the two bulk-fill composites Filtek Bulk Fill Posterior (FBF) and Tetric N-Ceram Bulk Fill (TBF) as the experimental groups and the two conventional composites Filtek Z100 (Z100) and Spectrum TPH (ST) as the control groups. The translucency parameter (TP), color difference, Vickers hardness (HV), and microtensile bond strength (μTBS) of dentine and the resin composites were measured at different depths. In each group, TP and HV decreased with the increase in thickness. At the same depth, the TP of the bulk-fill composites was higher than that of the conventional composites. At the same depth, the HV of the four different resin composites followed the order of Z100>FBF>TBF>ST (except for the upper surface). Except for FBF at 3 and 4 mm, all of the other groups showed no visible color change at all the tested thicknesses. Although the μTBS values of the four different composites obtained through the bulk-fill technique were lower than those of composites obtained through the incremental fill technique, the μTBS of the bulk-fill composites obtained through the bulk-filling technique can reach 30 MPa. Bulk-fill composites applied in single 4 mm increments can meet the requirements of clinical application. However, the color stability of some bulk-fill composites cannot be maintained.

Effect of a fiber-reinforcing technique for direct composite restorations of structurally compromised teeth on marginal microleakage.

To evaluate if the marginal microleakage of extensive Class I composite resin restorations can be affected by applying ultra-high-molecular-weight polyethylene (UHMWPE) fibers with the wallpapering technique combined with different restorative materials and methods. A 120 human molars were selected and one extensive Class I cavity was prepared on the occlusal surface of each tooth. The specimens were divided into 12 groups (n=10) according to the type of restorative material (Filtek Z550, Beautifil II LS or Beautifil Bulk Restorative), the use or not of reinforcing fibers (ribbond) and the applied restorative technique (incremental or bulk). The specimens were subjected to thermocycling and then immersed into a 50 wt% silver nitrate solution following a dying protocol. Subsequently, the teeth were prepared for SEM observations to evaluate the extent of marginal microleakage. Three-way ANOVA revealed that the type of material, the use of ribbond fibers and the type of restorative technique significantly affected marginal microleakage (p < 0.001). Application of ribbond fibers decreased marginal microleakage to all tested restorative materials, regardless of the restorative technique, in a range of 31.2-81.4%. In the groups with no-use of ribbond fibers, among the materials there were no significant differences in microleakage when the teeth were restored with the incremental technique (p > 0.05). The use of UHMWPE fibers with wallpapering technique in Class I composite restorations may be an effective method to reduce marginal microleakage, regardless of the selected restorative technique or the material. Clinicians may be encouraged to utilize reinforcing fiber restorative techniques for direct restorations of structurally compromised teeth as a valid alternative to indirect restorations.

Evaluation of Microhardness of Two Bulk-fill Composite Resins Compared to a Conventional Composite Resin on surface and in Different Depths.

Statement of the Problem: One of the problems with light-cured composite resins is the limitation and inadequate depth of curing and polymerization, resulting in low surface microhardness and restoration failure.Purpose: The present study aimed to compare the surface microhardness of two different bulk-fill composite resins and one conventional composite resin using the Vickers microhardness test.Materials and Method: In the present in vitro study, 108 samples from two different bulk-fill composite resins (Tetric N Ceram and Xtrafil) and one conventional composite resin (Filtek Z250) were prepared in metallic molds (2×4×10 mm) (n=36 for each composite resin). Six samples from each composite resin (n=6) underwent a hardness measurement test at specific depths (0.1, 1, 2, 3, 4 and 5mm). The samples were then stored at 37ºC for 24 hours, followed by a microhardness test at the depths mentioned above.Results: In all the composite resin samples, microhardness decreased with an increase in depth. The highest microhardness was recorded in Filtek Z250, followed by Xtrafil, with no significant difference. The lowest microhardness was recorded in Tetric N Ceram bulk-fill. Both bulk-fill composite resins at all the depths exhibited depth-to-surface standard microhardness (>80%).Conclusion: According to the results, both evaluated bulk-fill composite resins exhibited favorable surface microhardness up to a depth of 5 mm.

Determination of Endocrine Disruptor Bisphenol-A Leakage from Different Matrices of Dental Resin-based Composite Materials

Background: Bisphenol A (BPA) derivatives monomers as resins are common components in dental restorative materials and materials used for orthodontic treatment. However, they are a source for BP-A leakage, which can affect adult and child health as an endocrine disruptor. Objective: This study aimed to investigate the level of BPA leakage from four selected weights (0.1, 0.2, 0.3, 0.4 mg) of five different resin combinations used in dental restorative materials. Method: The resin combinations were cured with light for 20 seconds, kept in 1 mL of acetonitrile, and sonicated for 30 minutes. Separation was achieved by using BEH C18 (1.7 μm, 2.1 x 100 mm) analytical column (Waters® Acquity UPLC) and a mobile phase composed of water and acetonitrile (68:32 v/v). Moreover, Waters® Xevo G2-SQToF coupled with Waters® Acquity UPLC system with binary Solvent Manager (I-Class) via electrospray ionization (ESI) interface was used to confirm peaks identities. Results: BPA was detected in all resin combinations and in all selected sample weights. However, BPA was below the limit of quantification (LOQ) in all selected weights of the Filtek Z350 XT Universal Restorative System. The results show that BPA is still released from selected dental resin combinations available in the market despite the general concern about its potential adverse effects. Conclusion: Nevertheless, the amounts of BPA were within the acceptable levels indicated by the U.S. Environmental Protection Agency and the U.S. Department of Health and Human Services National Toxicology Program and represent a very small contribution to the total BPA exposure. The use of alternative materials such as high-viscosity glass ionomers, inorganic biomaterials, and ceramic would be ideal and healthier for adults and children.

Effect of C-factor on Micro-tensile Bond Strength of Bulk fill V/S Micro-hybrid Composite in Class II Restorations - An In-Vitro Study.

High Configuration factor (C-factor) results into increased polymerization shrinkage causing stress at resin-dentin interface leading to failure of the restoration. The purpose of this study was to evaluate the effect of C-factor on micro-tensile bond strength (μTBS) of bulk fill composites in class-II cavities when restored in 4mm of bulk as compared to conventional composite. A total of 90 carious, crack free extracted human mandibular permanent molars were selected and randomly divided into 3 groups (n=30). On all samples, class II cavities (3.5X 3.5cm) were made by single operator and divided as Gp1 (2.5mm), Gp2 (4mm), and Gp3 (6mm) on the basis of depth of cavities. Sampling units of 30 in each group were further randomly subdivided into 3 subgroups (n=10 each subgroup), according to the type of composite resin systems to be used for restoration. Experimental Subgroup includes SubGp1 restored with SDR Surefil (Dentsply, caulk, USA) and SubGp2 restored with Sonic fill (kerr, orange, CA, USA), whereas SubGp3 restored with FILTEK Z250 served as control. After storage in water at 37◦C, the teeth were sectioned perpendicular to the restorative tooth interface as 1×1 mm non-trimmed rectangular micro-specimens for micro-tensile bond strength (μTBS) testing. Beams (n=30 max) from each SubGp were fixed to a metal jig and subjected to micro-tensile bond strength testing. The data collected for micro-tensile bond strength (expressed in Mpa) were statistically analysed using one way ANOVA and Tukey's post hoc test. In class II cavities with high C-factor, SDR Surefil showed better μTBS than SonicFill and micro-filled composite when filled in bulk of 4mm, as compared to micro-hybrid composite filled incrementally. There is no effect of high C-factor on μTBS of tooth restored with both SDR Surefil and Sonic Fill in class II cavities as compared to microhybrid composites.

Effect of Nd:YAG laser irradiation, used as a desensitizing strategy, on bond strength to simulated hypersensitive dentin.

To evaluate the effect of Nd:YAG laser irradiation as a prior desensitizing strategy on immediate and medium-term microtensile bond strength (µTBS) to simulated hypersensitive dentin. Flat mid-coronal dentin was obtained from third molars and submitted to a 600-grit SiC paper (1min; N: normal dentin) or subsequently challenged with citric acid (6%, 1min; H: simulated hypersensitive dentin). Afterwards, dentin was or was not (C: control; HC, NC - each n = 7) irradiated with Nd:YAG laser (L: laser; 1.0W/10Hz/100mJ/4 irradiations of 50-60s; HL, NL - each n = 7). A 2-step self-etch adhesive (Clearfil SE Bond) was applied and composite (Filtek Z350) buildups were constructed. After 24-h (distilled water/37°C) storage, specimens were sectioned into beams and tested (µTBS; 0.5mm/min) immediately or after 6-month aging. Three-way ANOVA and Tukey tests were applied (α = 0.05). Qualitative evaluation of the adhesive interface (n = 1 extra tooth per group) was performed by Confocal Laser Scanning Microscopy. Substrate condition (p < 0.001), laser irradiation (p < 0.001), and aging (p = 0.002) influenced the results. Furthermore, there was interaction between substrate and irradiation (p < 0.001). Laser irradiation favored µTBS exclusively to hypersensitive dentin immediately and after aging. µTBS to hypersensitive dentin was higher than that to the normal substrate only when it was laser-irradiated. In any case, immediate µTBS was always higher than that after aging. CLSM revealed longer and more numerous resin tags for simulated hypersensitive dentin, and shorter and fewer resin tags for laser-irradiated dentin. No differences were observed in the hybrid layer itself. Nd:YAG laser irradiation prior to restoration favored the µTBS of a self-etch adhesive and resin composite to hypersensitive dentin. Desensitizing strategies are usually tried before performing restorative treatments in hypersensitive dentin; therefore, they may influence behavior of the adhesive interface established. However, instead of causing concern, Nd:YAG laser irradiation revealed a favorable effect on the aforementioned interface.

The effect of contemporary finishing and polishing systems on the surface roughness of bulk fill resin composite and nanocomposites.

To evaluate the effects of various finishing and polishing (F/P) systems regarding the surface roughness (Ra ) value of two nanocomposites and a bulk fill resin composite. Three resin composites (Filtek Z550, Filtek Ultimate Body, Filtek Bulk Fill Posterior) were tested. Forty disk-shaped specimens of each material were cured under Mylar strip and then randomly divided into four subgroups according to the F/P method (n=10): Control, Sof-Lex Spiral Wheels, Astropol, and Clearfil Twist Dia. Ra values was measured and the surfaces were examined under scanning electron microscope. The data were analyzed by generalized linear models (p < 0.05). The Filtek Bulk Fill Posterior had the highest Ra value while Filtek Ultimate Body was the resin composite with the lowest roughness (p < 0.05). Considering the average Ra values after polishing, while the lowest Ra in all groups was obtained with the control group, the Clearfil Twist Dia showed similar Ra to the control group (p > 0.05). The samples polished with Sof-Lex Spiral Wheels had the highest Ra (p < 0.05). In addition to the resin composite type, the F/P technique greatly affected the Ra value of resin composite. The nanocomposites exhibited with the lowest Ra compared to the bulk fill resin composite after F/P. It was observed that the diamond containing-polishing system created smoother surfaces than the aluminum oxide containing- and silicon carbide containing-polishing systems. In terms of Ra , the nanocomposites exhibited better performance than the bulk fill resin composites. Nowadays, newly developed polishing systems containing diamonds can be successful at a comparable level to existing polishing systems. For this reason, these systems are preferable for polishing both nanocomposites and bulk fill resin composites.

Marginal microleakage and modified microtensile bond strength of Activa Bioactive, in comparison with conventional restorative materials.

This study aimed to assess the enamel and dentin marginal microleakage and dentin microtensile bond strength (μTBS) of ACTIVA BioACTIVE Restorative with and without a bonding agent compared with conventional restorative materials. For enamel and dentin microleakage, Class II boxes were prepared in the mesial (1 mm under the cementoenamel junction) and distal (1 mm above the cementoenamel junction) surfaces of 90 extracted human third molars. The teeth were randomly divided into five groups (n = 18): Group Z (G-Premio Bond + Filtek Z250 XT), Group X (G-Premio Bond + X-tra fil bulk-fill), Group AA (G-Premio Bond + Activa Bioactive restorative), Group A (Activa Bioactive restorative), and Group G (dentin conditioner + Fuji II LC Improve). The teeth were thermocycled, and their microleakage was quantified using the dye penetration test under a stereomicroscope. For dentin μTBS measurement, 12 specimens were fabricated in metal molds (1 × 1 × 12 mm³) for each group mentioned above, and a universal testing machine measured their μTBS. Data were analyzed using one-way analysis of variance (ANOVA), the Kruskal-Wallis test, and multiple comparisons tests. Significant differences were noted among the groups in marginal microleakage and μTBS (p < .001). The highest mean microleakage scores at the enamel and dentin margins were noted in Group A, which had significant differences with other groups (p < .001). The highest μTBS was found in Group X, with significant differences with Group G and Group A (p < .05). The lowest µTBS was noted in Group A, with significant differences with Groups X, Group AA, and Group Z (p < .001). Activa Bioactive without a bonding agent showed significantly lower µTBS to dentin, and higher microleakage at the enamel and dentin margins. Application of adhesive resin with Activa Bioactive provided a dentine bond strength and marginal seal comparable to other restorative materials.

Remineralization potential of P11-4 and fluoride on secondary carious primary enamel: A quantitative evaluation using microcomputed tomography.

The aim of this study was to assess the ability of self-assembling peptide (P11-4) diffusion, assembly, and remineralization to effect artificial secondary caries-like lesions in human primary teeth in vitro. Enamel-dentin blocks obtained from extracted human primary molars were embedded into epoxy resin blocks. Cavities (approximately 1 × 1 × 2 mm) were prepared on the surface using a high-speed diamond bur under constant water cooling and filled with composite restorative material (Filtek Z250; 3M ESPE). The samples were immersed in demineralizing solution (20 ml) for 96 h to produce secondary caries lesions and divided into two groups according to the testing materials: fluoride varnish (Duraphat; Colgate, UK) and P11-4 (Curodont Repair; Credentis, Switzerland). Except for the control areas, all samples were remineralized for 3-5min using the remineralizing agents, and then all the sections were placed in a pH-cycling system for 5 days at 35°C. The pH cycling procedure was followed by micro-CT analysis for the qualitative evaluation of surface changes. The Mann-Whitney U test was used to compare two independent groups. In the comparison of more than two dependent groups, Bonferroni smoothed pairwise analyses were used to determine the source of the Kruskal-Wallis H test difference. The results of the study revealed that the remineralization depths of the peptide group were higher than those of the fluoride group (p < .01). There was a statistically significant difference in remineralization effects between the fluoride and peptide groups. P11-4 can be considered as an effective remineralizing agent for secondary caries lesions.

Polymer characteristics and mechanical properties of bulk-fill, giomer, fiber-reinforced and low-shrinkage composites

Introduction/Objective. The objective was to determine the degree of conversion (DC), cross-link density, percentage of leachable monomers, flexural strength (FS), and hardness (HV) of nanohybrid, nanofilled bulk-fill, giomer, fiber-reinforced, and low-shrinkage composites. Methods. Standardized specimens (n = 5/group) of Tetric EvoCeram Bulk Fill, Filtek Bulk Fill, Beautifil, EverX posterior, Kalore, Filtek Z250 (microhybrid control), and Tetric EvoCeram (nanohybrid control) were subjected to micro-Raman spectroscopy, three-point bending, and HV. Cross-linking density and leachable monomers were ascertained based on the ratio of HV and DC before and after immersion in absolute ethanol. Results. DC was in the range 50.4?70.5%, the highest for Filtek Bulk and the lowest for Kalore. The highest %DC change was in Beautifil (10.3%) and the lowest in Filtek Bulk (1.4%) and Z250 (1.28%). FS ranged between 78.9 MPa (TEC) and 126.7 MPa (Filtek Bulk). HV ranged between 58.6 (Kalore) and 113.9 (Z250) and significantly decreased post-immersion (19?55%). HV48h inversely correlated to HV% loss (r = -0.761), whilst DC positively correlated with FS (r = 0.893). Conclusion. Filtek Bulk, EverX, and Z250 showed the highest DC. The lowest DC and mechanical properties were observed for Kalore. The greatest cross-link density was shown by Filtek Bulk. There were up to 10% of leachable monomers. DC and FS positively correlated.

Порівняльна оцінка міцностних характеристик композитів світлової полімеризації для реставрації зубів за методом трьохточкового згину

Purpose: to carry out a comparative analysis of the strength characteristics of composites of swiil polymerization for the restoration of teeth using the threepoint bending method. Results. It was determined that in terms of bending strength, dental composites were arranged in the following order: Tetric N-Ceram (164.44 MPa) &lt; Charisma Classic (141.19 MPa) &lt; Filtek Z250 (129.38 MPa) &lt; Latelux (60.75 MPa). According to the Tukey criterion, the bending strength of the Latelux composite is statistically significantly different from other materials (p &lt; 0.01). At the same time, between the fracture load of composites Tetric N-Ceram and Charisma Classic (p &gt; 0.2), Charisma Classic and Filtek Z250 (p &gt; 0.09), Tetric N-Ceram and Filtek Z250 (p &gt; 0.8) this difference is not significant. Conclusion. In terms of bending strength parameters and elastic modulus, the studied materials meet modern requirements for the strength of hybrid materials, and the Tetric N-Ceram composite has the best performance. Key words: polymer composites, strength, acoustic emission method.

Spectrophotometric evaluation of staining of different types of light-cure composite resins after exposure with different light-cure intensities: An in vitro study.

Relation between the adequate intensity output of curing lights on color stability of composite resin is well accepted. To investigate the effect of different light-curing intensities and its relation to color stability of different polymerized composite resin materials using the spectophotometric analysis. Comparative in vitro study done on composite resin discs. A total of 180 discs comprising sixty discs prepared from three different composite resins, namely microhybrid composite resin (Filtek Z100,3M ESPE), nanohybrid composite resin (Filtek Z250 XT, 3M ESPE), and nanofilled composite resin (Filtek Z350 XT,3M ESPE) using three different light curing intensities, viz., 325-425 mW/cm2, 750-850 mW/cm2, and 1000-1100 mW/cm2. Later these discs were stained with 2% methylene blue followed by re-absorption in absolute alcohol for supernatant solution preparation which is used for the spectrophotometric analysis. Spectrophotometric absorption values were analyzed using the one-way ANOVA test for intergroup analysis. Mean stain absorption was the highest with nanofilled composite resin (Filtek Z350 XT,3M ESPE) after exposure with light-curing intensity of 325-425 mW/cm2 and least with microhybrid composite resin (Filtek Z100, 3M ESPE) after exposure with light-curing intensity of 750-850 mW/cm2 and this difference found was highly significant statistically (P < 0.001). Microhybrid composite resin (Filtek Z100, 3M ESPE) cured with intensity of 750-850 mW/cm2 showed least stain absorption indication most color stability and esthetic function.