Flowable Resin Research Articles

Fluorescence and color adjustment potentials of paste-type and flowable resin composites in cervical restorations.

Comparatively assess the fluorescence and color adjustment potentials of paste-type and flowable resin composites performed in cervical restorations. Five paste-type resin composites and 5 highly-filled flowable composites were investigated (n=5 for each). Class V cavities on 50 extracted A2 shade human central incisors were restored. Cross-polarization (CP) and fluorescence illumination (FI) images were recorded for each restoration. L*a*b* values were analyzed using the Photoshop software and color adjustment (ΔECP) and fluorescence adjustment (ΔEFI) levels were quantitatively assessed. Kruskal Wallis Test, Independent Samples t Test, One Way Anova-Welch test, and Pearson Correlation were used for the statistical analyses. The deemed significance was set at p<.050. Paste-type composites presented significantly lower ΔEFI and ΔECP values than the flowable composites (p=.006 and p<.001 respectively). ΔEFI and ΔECP values were positively correlated (r=0.584; p<.001). Paste-type Gaenial A'chord presented the lowest ΔEFI value [7.67 (5.35 - 10.99)b], while Estelite Asteria presented significantly the highest [19.94 (17.08 - 22.17)c]. Charisma Diamond One Flow presented the highest ΔECP value [3.25 (3.13 - 3.39)a] and Gaenial A'chord presented the lowest [0.79 (0.48 - 0.87)e] which was the only imperceptible score (<0.8). The only clinically acceptable color adjustment was found for Geanial Universal Injectable [1.06 (0.73 - 1.62)e] among the flowable composites. ΔEFI and b* values were positively correlated (r=0.493; p<.001). Color adjustment level and fluorescence adjustment level were considered coherent for particular composite brands. At the same time, both were better for the paste-type composites than the flowable composites on A2 base shade class V restorations. Fluorescence adjustment potential as well as the color adjustment potential varied among different composite brands regarding paste-type and flowable composites. Understanding both the color and fluorescence adjustment potentials of paste-type and flowable resin-based composite materials is clinically vital to achieve the high-end esthetics.

Effect of CAD-CAM block thickness and translucency on the polymerization of luting materials

AimThis in-vitro study aimed to evaluate the degree of conversion (DC) of dual-cured luting cement (Bifix QM, VOCO) and flowable composite (Grandio Flow, VOCO) under lithium disilicate glass-ceramic (IPS e.max CAD, Ivoclar Vivadent) and hybrid ceramic (Grandio Blocs, VOCO; Cerasmart, GC) CAD-CAM blocks with different thicknesses.Materials and methodsContrast ratio (CR), translucency (TPab, TP00), and opalescence (OP) parameters of 30 disc-shaped CAD-CAM blocks (n = 5) prepared with two different thicknesses (1.5 and 2 mm) and 8 mm diameters were calculated using a spectrophotometer (VITA Easyshade V, Zahnfabrik). A total of 36 Bifix QM and Grandio Flow samples were prepared at 100 μm thickness using a specific setup by polymerizing from the top of the blocks. Following immersion in distilled water at 37 °C for 24 h, luting materials were examined by Fourier Transform Infrared Spectroscopy for DC calculation. Data were analyzed using One-way ANOVA, Kruskal Wallis, Mann Whitney U, and Independent Samples t-tests (p < 0.05).ResultsIt was observed that, as the block thickness increased TPab, TP00, and OP decreased, while CR increased. There was no significant difference between the DC of Bifix QM and Grandio Flow when 1.5 mm blocks were used in all groups (p > 0.05). DC of Grandio Flow was significantly higher than Bifix QM under 2 mm-IPS e.max CAD (p = 0.011).ConclusionThe translucency of the CAD-CAM blocks varies depending on their thickness. However, there was no significant difference in the DC of the luting materials depending on the block thickness. Further studies are needed on the use of flowable resin composites as luting material.

Color Stability of Bulk-Fill Flowable Resin Composites After Artificial Aging.

This study aimed to evaluate the color stability of bulk-fill flowable resin composites with 2 difference shades at baseline and after artificial aging. Disk-shaped specimens (Ø10 × 4 mm) were fabricated from three bulk-fill flowable resin resin composites (Filtek Bulk-Fill Flow, Venus Bulk-Fill Flow, and Estelite Bulk-Fill Flow). The specimens in each bulk-fill resin composite group were divided into two subgroups (n = 10 per subgroup) with two different shades, A1 (N = 30) and A3 (N = 30), and were polymerized with light curing (800 mW/cm2/Valo LED Unit, Ultradent) and polished. The color difference between bulk-fill resin composites was evaluated at baseline and after artificial aging using a spectrophotometer (CM-700d, Konica Minolta, Tokyo, Japan) under D65 illumination. Color coordinates were measured with CIEDE2000, and color differences (∆E00) and relative translucency parameter (RTP) values were calculated. Subsequently, the comparison of color changes (∆E00) before and after thermocycling was performed using the t-test for paired samples. The bulk-fill flow resin composites evaluated in the present study were capable of mimicking important optical properties such as light transmission. All the resin composites provided acceptable color stability at baseline and after thermocycling when the color A1 was used. On the other hand, whenever the shade A3 was used, the Venus Bulk-Fill Flow demonstrated the best optical properties. There was no statistically significant difference when comparing baseline and after thermocycling in bulk-fill flowable resin composites (p > 0.05). After thermocycling, A1 bulk-fill flowable resin composites provided acceptable color stability, and all A3 bulk-fill flowable resin composites provided visible color change, except for the Venus Bulk-Fill Flow (∆E00 = 2.35). Estelite Bulk-Fill Flow displayed the best color stability (∆E00 = 2.22) between all the combinations evaluated.

Immediate and delayed shear bond strength evaluation between root canal sealers and restorative materials: an experimental study

BackgroundSeveral calcium silicate-based sealers have recently emerged in endodontics. This study aimed to compare the immediate and delayed shear bond strength between the bioceramic and calcium hydroxide-based sealers and different resin-based restorative materials.MethodsOne hundred and twenty specimens with a 3-mm depth and a 3-mm diameter were prepared. They were evenly divided into two groups, the bioceramic sealer and calcium hydroxide-based sealer groups. Each primary group was subdivided into two subgroups based on the restorative material used; i.e., the flowable resin composite and resin-modified glass ionomer subgroups. Moreover, each subgroup was further divided into the restoration process’s timing: either immediately post-sealing or delayed after setting the sealers for seven days. The mode of failure was assessed by stereomicroscopic examination.ResultsThe highest shear bond strength was found when the bioceramic sealer was used and restored with the flowable resin composite. The strengths were 8.45 (1.17) and 6.67 (1.60) megapascals (MPa) in the immediate and delayed restoration groups, respectively. In contrast, the lowest strength, 2.91 (1.22) MPa, was recorded when calcium hydroxide-based sealer was employed and restored after allowing the sealer to set completely with resin-modified glass ionomer. Notably, there were no cohesive fractures within the tested restorative materials. All observed fractures occurred within the sealer materials, at the interface of the sealer and restorative material, or in combination. Moreover, the most common failure was a mixed failure.ConclusionsWhen flowable resin composite was used immediately before complete setting, bioceramic sealers showed a higher bond strength than calcium hydroxide-based sealers.

Clinical study of pit and fissure sealant combined with light-cured flowable resin in prevention of dental caries in children.

Clinical study of pit and fissure sealant combined with light-cured flowable resin in prevention of dental caries in children.

Is use of flowable resin composite an option for occluso-proximal restorations in primary teeth? A fracture strength analysis.

Use of flowable resin composites for ocluso-proximal restorations in primary molars could improve cervical adaptation, and reduce the failure risk. To investigate the fracture strength of occluso-proximal restorations in primary teeth using different flowable resin composites (as an intermediate layer or entire cavity) and a conventional resin composite (incremental technique). Two standardized occluso-proximal cavities were prepared on mesial and distal surfaces of 50 sound primary molars. The teeth were randomly assigned into five groups (n = 10): 2 mm Filtek Bulk Fill Flow + Z350 XT; 4 mm Filtek Bulk Fill Flow; 2 mm Z350 XT Flow + Z350 XT; 4 mm Z350 XT Flow; and Z350 XT inserted by incremental technique. All restored teeth were subjected to cariogenic challenge and then submitted to fracture strength test. The failure pattern of each specimen was categorized as reparable or irreparable/need for replacement based on the World Dental Federation (FDI) criteria. Fracture strength means were submitted to one-way ANOVA and Tukey's post hoc tests. Failure pattern was analyzed descriptively. There was no statistically significant difference on fracture strength among groups (p = .48). A similar distribution of reparable (35%-40%) and irreparable (60%-65%) failures was observed among groups. Based on a laboratorial setting, the use of different flowable resin composites (as an intermediate layer or entire cavity) may be an option to restore occluso-proximal cavities in primary molars.

Assessment of Surface Roughness, Color, and Bonding Efficacy: Self-Adhesive vs. Conventional Flowable Resin.

This in vitro study aimed to analyze the surface roughness (Ra) and color stability (ΔEab, ΔE00) following simulated mechanical brushing and to evaluate the microtensile (μTBS) of self-adhering resin flowable (SARF) to dentin. The selected materials were Constic, Yflow AS, and Tetric N flow (TNF/control). Thirty composite resin cylinders were fabricated for surface property evaluation. Ra and color were assessed both before and after simulated brushing. The thresholds of 50:50% perceptibility and acceptability of color differences in the evaluated resins were assessed. For μTBS analysis, fifteen molars were selected, sectioned to expose flat dentin surfaces, and restored according to the manufacturers' instructions for microtensile testing. There were statistically significant differences in Ra among the groups, with Constic exhibiting the highest Ra value (0.702 µm; p < 0.05), whereas Yflow AS presented the lowest Ra value (0.184 µm). No statistically significant difference in color was observed among the groups (p > 0.05). The 50:50% perceptibility and acceptability thresholds were set at 1.2 and 2.7 for ΔEab and 0.8 and 1.8 for ΔE 00. All the results fell within the acceptable limits. The mean μTBS values of Constic, Yflow AS, and TNF were 10.649 MPa, 8.170 MPa, and 33.669 MPa, respectively. This study revealed increased Ra and comparable color stability among all the tested composite resins after abrasion. However, the SARF exhibited lower μTBS compared to conventional using an adhesive system.

Flexural Properties, Wear Resistance, and Microstructural Analysis of Highly Filled Flowable Resin Composites.

This study aimed to evaluate the flexural properties and two-body wear resistance of nine highly filled flowable resin composites relative to those of viscous and conventional low-filled flowable composites. In addition, scanning electron microscopy (SEM) analysis of the microstructures was performed. For each resin composite group (n=12), 12 specimen bars (25 mm × 2 mm × 2 mm) were fabricated using a silicon mold for performing flexural strength (FS), flexural modulus (E), flexural toughness (FT), Weibull modulus (m) tests, and SEM microstructural analysis. For each group, ten bars were tested using a three-point flexural test on a universal testing machine, while the other two were embedded in acrylic resin before being observed by SEM for structural analysis. During the two-body wear test with a chewing simulator, 8 specimens (12 groups, n=8) of each resin composite group were manufactured in a specific mold and subjected to 120,000 cycles of wear against a steatite ball, and the depth loss was measured. Three one-way ANOVA tests followed by Tukey's post hoc tests were conducted to compare the flexural and wear properties among the different groups. The majority of highly filled composites tested in this study exhibited similar flexural strengths (between 105.68 MPa and 135.49 MPa) and superior wear resistance to those of viscous composites. The flexural moduli (between 5.12 GPa and 9.62 GPa) of these composites were in between those of the viscous and low-filled composites tested in this study. The highly filled flowable composites tested in this study exhibited different in vitro properties but were often superior to those of viscous resin composite suggesting their possible use for posterior restorations.

Surface roughness of different types of resin composites after artificial aging procedures: an in vitro study

BackgroundThe temperature changes, chemical agents, and brushing activity that resin composite restorations are exposed to in the oral environment can cause changes in surface roughness. In this study, the aim was to investigate in vitro the clinical one-year surface roughness changes of different types of composites (flowable or conventional) from the same companies by subjecting them to immersion in solutions, brushing, and thermal cycling procedures to simulate intraoral conditions.MethodsFour different resin composite brands were included in the study using both their conventional (Charisma Smart, 3M Filtek Ultimate Universal, Omnichroma, Beautifil II) and flowable resin composites (Charisma Flow, 3M Filtek Ultimate Flowable, Omnichroma Flow, Beautifil Flow Plus F00), giving 4 groups with 2 types of resin composite in each. 40 samples were prepared for each group/resin type, for a total of 320 samples. After initial surface roughness measurements by a mechanical profilometer, the samples were divided into 4 subgroups (n = 10) and immersed in solutions (distilled water, tea, coffee, or wine) for 12 days. The samples were then subjected to 10,000 cycles of brushing simulation and 10,000 cycles of thermal aging. Surface roughness measurements were repeated after the procedures. For statistical analysis, the 3-way analysis of variance and the Tukey test were used (p < 0.05).ResultsIt was concluded that composite groups and types had an effect on surface roughness at time t0 (p < 0.001). At time t1, the highest surface roughness value was obtained in the Beautifil-conventional interaction. When the surface roughness values between time t0 and t1 were compared, an increase was observed in the Beautifil II and Beautifil Flow Plus F00, while a decrease was observed in the other composite groups.ConclusionComposite groups, types, and solutions had an effect on the surface roughness of resin composites. After aging procedures, it was concluded that the Beautifil group could not maintain the surface structure as it exceeded the threshold value of 0.2 μm for bacterial adhesion.

Fracture Resistance in Fibre-Reinforced Resin Composite Restorations in Deciduous and Permanent Molars: An Ex Vivo Study

AimThe aim of this study was to compare the fracture resistance levels of restored deciduous teeth and permanent molars restored with different materials, including ultra-polyethylene fibre tape (Ribbond-Ultra), fibre-reinforced resin composite EverX posterior, fibre-reinforced flowable resin composite EverX Flow and bulk-fill flow restorative material (Tetric N-flow) in the posterior region. MethodsWe tested sixty-four caries-free human mandibular molars (32 deciduous molars and 32 permanent molars). Deep and wide Class I cavities were prepared in each tooth. The teeth were embedded in poly(methyl methacrylate) resin up to the cementoenamel junction, leaving the crown completely exposed. Oral temperature fluctuations were then simulated using two thousand thermocycling cycles, each lasting 30 seconds in the hot phase (approximately 35 °C). The loading rate for our force-fracture tests was set at 0.5 mm/min. Direct restorations were made using a spherical tip and applying the force perpendicular to the sample surface. Visual inspection of the fractured specimens, in combination with adhesive scanning electron microscopy (SEM) and finite element analysis (FEA), provided detailed insights into the failure modes and stress distribution at the restoration–tooth interface. ResultsTeeth restored with fibre-reinforced composite (EverX Posterior) had the highest fracture resistance, followed by fibre-reinforced flowable resin composite (EverX Flow). Teeth restored with the ultra- polyethylene fibre tape (Ribbond-Ultra), followed by the flowable bulk-fill composite (Tetric N-flow) had the lowest resistance. Statistical analysis revealed significant differences between the groups, except for EverX Posterior and EverX Flow. A predictive algorithm was also proposed for the likelihood of restoration failure. ConclusionModern fibre-reinforced resin composites, such as EverX Posterior, effectively reinforce teeth against fractures, with success in both restored deciduous and permanent molars. Meanwhile, the use of polyethylene fibre tapes is less effective, and they involve a time-consuming application.

PGE2 binding to EP2 promotes ureteral stone expulsion by relaxing ureter via the cAMP-PKA pathway

BackgroundThis study investigated the relaxation effect of PGE2 on the ureter and its role in promoting calculi expulsion following calculi development.MethodsBy using immunofluorescence and Western blot, we were able to locate EP receptors in the ureter. In vitro experiments assessed the impact of PGE2, receptor antagonists, and agonists on ureteral relaxation rate. We constructed a model of ureteral calculi with flowable resin and collected ureteral tissue from postoperative side of the ureter after obstruction surgery. Western blot analysis was used to determine the protein expression levels of EP receptors and the PGE2 terminal synthase mPGES-1. Additionally, PGE2 was added to smooth muscle cells to observe downstream cAMP and PKA changes.ResultsThe expression of EP2 and EP4 proteins in ureteral smooth muscle was verified by Western blot analysis. According to immunofluorescence, EP2 was primarily found on the cell membrane, while EP4 was found in the nucleus. In vitro, PGE2 induced concentration-dependent ureteral relaxation. Maximum diastolic rate was 70.94 ± 4.57% at a concentration of 30µM. EP2 antagonists hindered this effect, while EP4 antagonists did not. Obstructed ureters exhibited elevated mPGES-1 and EP2 protein expression (P < 0.01). Smooth muscle cells treated with PGE2 displayed increased cAMP and phosphorylated PKA.ConclusionsPGE2 binding to EP2 induces ureteral relaxation through the cAMP-PKA pathway. This will provide a new theoretical basis for the development of new therapeutic approaches for the use of PGE2 in the treatment of ureteral stones.

Salivary levels of eluents during Invisalign™ treatment with attachments: an in vivo investigation

BackgroundThe aim of the present study was to investigate qualitatively and quantitatively the elution of substances from polyester-urethane (Invisalign™) aligners and resin composite attachments (Tetric EvoFlow) in vivo.MethodsPatients (n = 11) treated with the aligners and attachments (16 per patient, without other composite restorations) for an average of 20 months, who were planned for attachment removed were enrolled in the study. Patients were instructed to rinse with 50 mL of distilled water upon entry and the rinsing solution was collected (before removal). Then, the attachments were removed with low-speed tungsten carbide burs for adhesive residue removal, a thorough water rinsing was performed immediately after the grinding process to discard grinding particle residues, and subsequently, after a second water-rinsing the solution was collected for analysis (after removal). The rinsing solutions were analyzed for targeted (LC-MS/MS: Bis-GMA, DCDMA, UDMA, BPA) and untargeted (LC-HRMS: screening of leached species and their degradation products) compounds.ResultsTargeted analysis revealed a significant reduction in BPA after attachment removal (4 times lower). Bis-GMA, DCDMA, UDMA were below the detection limit before removal but were all detectable after removal with Bis-GMA and UDMA at quantifiable levels. Untargeted analysis reviled the presence of mono-methacrylate transformation products of Bis-GMA (Bis-GMA-M1) and UDMA (UDMA-M1), UDMA without methacrylate moieties (UDMA-M2), and 4-(dimethylamino) benzoic acid (DMAB), the degradation product of the photo-initiator ethyl-4-(dimethylamino) benzoate (EDMAB), all after attachment removal. Several amino acids and endogenous metabolites were also found both before and after removal.ConclusionsElevated levels of BPA were traced instantaneously in patients treated with Invisalign™ and flowable resin composite attachments for the testing period. BPA was reduced after attachment removal, but residual monomers and resin degradation products were found after removal. Alternative resin formulations and attachment materials may be utilized to reduce eluents.

Three dimensionally printed template with an interproximal isolation design guide consecutive closure of multiple diastema with injectable resin composite.

This article describes a novel 3D-printed template armed with interproximal matrices to isolate interproximal contact areas and guide injectable resin composite for consecutive closure of multiple diastema. Among several treatment options proposed for diastema closure, direct resin composite is noninvasive and easy to repair. The "composite injection technique" has been introduced to improve time efficiency and reduce technique sensitivity for clinicians. However, in the case of multiple diastema, the overflow of excess resin materials onto the adjacent teeth during injection poses challenges for recontouring the interproximal anatomy. A 3D-printed template with special-designed gaps at interproximal areas was designed and fabricated based on a virtual diagnostic wax-up. Flowable resin composite was then consecutively injected through the template to close diastemata at multiple adjacent teeth. This technique using a 3D-printed template with interproximal isolation design contributed to an efficient and accurate operation for multiple anterior diastema closure. Efficient and accurate freehand buildups of composite restoration for multiple diastema are challenging in operative dentistry. The described noninvasive full digital workflow provides a predictable method to accurately recontour the multiple target restorations and reduce the chair-side time and technical sensitivity.

Influence of etching mode on bonding performance of self-adhesive flowable resin composites to bovine teeth.

This study aimed to evaluate the bonding performance of self-adhesive flowable resin composites (SARs) to bovine teeth. Three SARs, one experimental, and two commercially available products, were used. The study parameters were shear bond strength (SBS), microleakage, and scanning electron microscopy (SEM) evaluation of bonding interfaces. The SBS of the materials was 14.1-15.1 MPa to enamel, 22.2-23.2 MPa to etched enamel, and 7.4-10.7 MPa to dentin. Specimens with pre-etching showed lower microleakage scores than those without pre-etching. SEM images of the interfaces of the materials showed excellent adaptation regardless of the substrate or etching mode. The study results indicate that enamel pre-etching can improve the bonding performance of SARs.

Evaluation of dental pulp stem cells response to flowable nano-hybrid dental composites: A comparative analysis.

Flowable resin composites (FRC) are tooth-colored restorative materials that contain a lower filler particle content, and lower viscosity than their bulk counterparts, making them useful for specific clinical applications. Yet, their chemical makeup may impact the cellular population of the tooth pulp. This in-vitro study assessed the cytocompatibility and odontogenic differentiation capacity of dental pulp stem cells (DPSCs) in response to two recent FRC material extracts. Extracts of the FRC Aura easyflow (AEF) and Polofil NHT Flow (PNF) were applied to DPSCs isolated from extracted human teeth. Cell viability of DPSCs was assessed using MTT assay on days 1, 3 and 7. Cell migration was assessed using the wound healing assay. DPSCs' capacity for osteo/odontogenic differentiation was assessed by measuring the degree of mineralization by Alizarin Red S staining, alkaline phosphatase enzyme (ALP) activity, and monitoring the expression of osteoprotegerin (OPG), RUNX Family Transcription Factor 2 (RUNX2), and the odontogenic marker dentin sialophosphoprotein (DSPP) by RT-PCR. Monomer release from the FRC was also assessed by High-performance liquid chromatography analysis (HPLC). DPSCs exposed to PNF extracts showed significantly higher cell viability, faster wound closure, and superior odontogenic differentiation. This was apparent through Alizarin Red staining of calcified nodules, elevated alkaline phosphatase activity, and increased expression of osteo/odontogenic markers. Moreover, HPLC analysis revealed a higher release of TEDGMA, UDMA, and BISGMA from AEF. PNF showed better cytocompatibility and enhancement of odontogenic differentiation than AEF.

Effect of preparation design and endodontic access on fracture resistance of zirconia overlays in mandibular molars: An in vitro study.

To evaluate the fracture resistance of zirconia overlays, considering various preparation designs and the presence of endodontic access. Ninety translucent zirconia (5Y-PSZ) overlay restorations were divided into six groups (n = 15/group) based on different preparation designs, with and without endodontic access: chamfer margin 4mm above the gingival level without (group 1) and with endodontic access (group 2); margin 2mm above the gingival level without (group 3) and with endodontic access (group 4); overlay with no chamfer margin without (group 5) and with endodontic access (group 6). Restorations were bonded to mandibular first molar resin dies, and the groups with endodontic access were sealed with flowable resin composite. All restorations underwent 100,000 cycles of thermal cycling between 5°C and 55°C, followed by loading until fracture. Maximum load and fracture resistance were recorded. ANOVA with Tukey post-hoc tests were used for statistical comparison (α < 0.05). Fracture resistance significantly varied among overlay designs with and without endodontic access (p < 0.001), except for the no-margin overlays (groups 5 and 6). Overlays with a 2mm margin above the gingival margin with endodontic access (group 4) exhibited significantly higher fracture resistance compared to both the 4-mm supragingival (group 2) and no-margin (group 6) designs, even when compared to their respective intact groups (groups 1 and 5). There were no significant differences between the no-margin and 4-mm supragingival overlays. The more extensive zirconia overlay for mandibular molars is the first choice since the 2mm margin above the gingival level design withstood considerable loads even after undergoing endodontic access. A no-margin overlay is preferred over the 4-mm supragingival design as it preserves more tooth structure and there was no outcome difference, irrespective of endodontic access. Caution is warranted in interpreting these findings due to the in vitro nature of the study.

The chemical and optical stability evaluation of injectable restorative materials under wet challenge

ObjectivesTo investigate and compare the chemical and optical stability of four restorative composite materials: two injectable resins, one flowable resin and one compomer. MethodsTwo injectable nano-filled composite resins: G-aenial Universal (GU) and Beautifil Injectable XSL (BI), a flowable composite resin: Filtek Supreme Flowable (FS) and a compomer: Dyract Flow (DF), in A2 shade were tested and compared. Water sorption and solubility were conducted according to ISO4049:2019 standard; ICP-OES and F-ion selective electrode were used to test the elemental release; Degree of conversion (DC) was obtained by using FTIR; water contact angle was obtained by static sessile drop method, and a spectrophotometer was used for optical properties (ΔE⁎, ΔL⁎ and TP). SPSS 28.0 was used for statistical analysis and the significant level was pre-set as α = 0.05. ResultsGU performed the best in water sorption and solubility, FS had the lowest elemental release, the best colour stability, and the highest DCIM and DC24-h. DF, the compomer had the lowest, and GU and BI, the injectable composites had the largest water contact angle, respectively. Correlations were found between water sorption and water solubility. ConclusionsThe four composite restorative materials showed different chemical and optical behaviours. Overall, composite resins performed better than compomer, while additional laboratory and in vivo tests are necessary to obtain a more comprehensive comparison between injectable and flowable composite resins. Wsp and Wsl are influenced by many common factors, and the values are highly positively related. Clinical SignificanceA comprehensive understanding of materials is crucial before selecting materials for clinical practice. Composite resins rather than compomers are recommended because of their exceptional properties, which make them eligible for a wide range of clinical applications and an elongated lifespan.

Bulk-Fill Ormocer versus Methacrylate-Based Resin Composite Restorative Systems: The Effect of Flowable Lining on Two-Year Clinical Performance in Class II Cavities

Abstract Objective The aim of this study was to assess and compare the impact of bulk-fill flowable resin composite liners (BFFL) on the 2-year clinical performance of bulk-fill ormocer (BORC) in comparison to methacrylate-based resin composites (BMRC) in Class II cavities. Materials and Methods Thirty participants, each aged between 18 and 30 years, were included in the study, each presenting four class II cavities. A total of 120 restorations were placed, with participants randomly assigned to one of four restorative systems through a blind drawing: Admira Fusion X-Tra (AFX) alone, AFX after lining with Admira Fusion Xtra-Base (AFB), X-Tra Fill (XF) for complete cavity filling, and XF after lining with Xtra-Base (XB). The universal adhesive system (Futura U bond Voco, Germany) was consistently applied for all restoration techniques using selective enamel etching. A single operator, following the manufacturer's instructions for each material, performed all restorations, and finishing/polishing occurred immediately after placement. Clinical evaluation, based on World Dental Federation (FDI) criteria, was conducted by two blinded examiners at baseline (7 days) and at 6, 12, and 24 months postoperatively. Results The chi-squared test was used to compare the four applied restorative systems within each follow-up period, while the marginal homogeneity test was employed to assess changes over time. No statistically significant differences were observed among the four restorative systems at any evaluation period. Conclusions After 2 years, the clinical performance of BFFL or complete bulk-fill technique remained similar, regardless of the material composition.

Biaxial flexural strength of hydrothermally aged resin-based materials

PurposeThe strength of temporary restorations plays a vital role in full-mouth reconstruction, and it can be impacted by the aging process. The aim of this in vitro study was to evaluate the biaxial flexural strength and fractographic features of different resin-based materials submitted to thermal aging. Material and methodsOne hundred and ninety-two resin disc-shaped specimens (6.5 mm in diameter and 0.5 mm in thickness) were fabricated and divided into six experimental groups according to the resin-based materials (Filtek Bulk-Fill flowable resin; J-Temp temporary resin; and Fuji Lining glass ionomer cement) and aging process (before and after thermal cycling). Biaxial flexural strength test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min before and after thermal cycling (5 °C and 55 °C, 5760 cycles, 30 s). The mechanical properties were assessed using Weibull parameters (characteristic strength and Weibull modulus) (n = 30). Fractured specimens were examined under a polarized light stereomicroscope to identify crack origin and propagation direction. The surface microstructure of the resin-based materials was assessed by scanning electron microscopy (n = 2). The Weibull modulus (m), characteristic strength, and reliability properties were calculated, and a contour plot was used to detect differences among groups (95% confidence interval). ResultsThe Weibull modulus (m), characteristic strength, and reliability of the resin-based compounds were influenced by material type and thermal aging (p < 0.05). Weibull modulus (m) revealed no differences when comparing the materials and aging process (p > 0.05), except for the preceding aging period where Filtek Bulk-Fill exhibited higher values compared to J-Temp (p < 0.05). Filtek Bulk-Fill demonstrated superior characteristic strength and reliability compared to J-Temp and Fuji Lining before and after thermal cycling (p < 0.05). Fractography of the resin-based materials showed fractures originating from surface defects exposed to tensile side and their propagation toward the compressive side. Generally, no differences in surface microstructure were observed on micrographs before and after thermal aging for Filtek Bulk-Fill and Fuji Lining. However, the aging process developed flaws in J-Temp. ConclusionResin-based material composition resulted in different flexural strength performance, impacting the Weibull modulus (m), characteristic strength, and reliability of the resin-based restorations.

The effect of octenidine dihydrochloride on the antibacterial activity of a formulated resin composite: an in vitro study

BackgroundIt has been noticed that failure of composite resin restorations can be attributed to either of the two following causes: fracture or secondary caries. For that reason, it is mandatory to formulate a restorative material with antibacterial effect. An octenidine dihydrochloride (OCT) has been assessed as an alternative to antimicrobial material, such as chlorhexidine due to their higher microbicidal effect and less cytotoxicity.ObjectiveCurrent study aimed to add different concentrations of octenidine dihydrochloride into experimental flowable resin composite and evaluate its antibacterial activity over different periods of time to provide the manufacturers with more precise information.MethodsA flowable resin composite material mix was formulated. Octenidine dihydrochloride antibacterial material was then added separately to the formulated mix at 1% wt. and 1.5% wt. concentration, respectively. Antibacterial activity was assessed against Streptococcus mutans using agar diffusion test and compared to a commercial resin composite.ResultsIt showed that by increasing the percentage of incorporated octenidine dihydrochloride (1% and 1.5%), respectively, the antibacterial efficacy against the Streptococcus mutans increased. Results of this study also showed the time had a significant decrease in the antibacterial effect.ConclusionsIt can be concluded that by the incorporation of octenidine dihydrochloride (1% and 1.5%), respectively, the antibacterial efficacy against the Streptococcus mutans increased. Time had a significant decrease in the antibacterial effect of OCT.