Bulk-fill Restorative Materials Research Articles

The impact of artificial aging using chewing simulator on micro-shear bond strength and micro-leakage of alkasite and bioactive resin based composites: an in-vitro comparative study

Objective The current study was conducted to assess and compare the impact of artificial aging using chewing simulator on the novel bulk fill restorative materials (Cention N) and Bioactive Resin Based Composites (ACTIVA) regarding, micro-shear bond strength and micro-leakage. Tetric N ceram bulk fill composite was used as control. Patients and methods For micro-shear bond strength testing, thirty recently extracted molars were collected, then their occlusal surfaces were cut horizontally using low-speed diamond saw under coolant exposing flat dentin surfaces. Tetric N-Bond adhesive was applied to the dentin surface, then Tygon tubes (three for each tooth) with height 1 mm and internal diameter 1 mm were placed on the flat surfaces, followed by light curing, then the restorative material (10 specimens for each material) was condensed inside the tubes. Half of the specimens is subjected to artificial aging (thermal and dynamic loading using Chewing Simulator). The specimens were mounted in blocks of stones, then placed horizontally in the universal testing machine. The load was applied using a knife-edge chisel till debonding of the composite cylinders from dentin surface. Fifteen extracted human molars were utilized for the purpose of evaluating micro-leakage. A total of thirty class II cavities were meticulously constructed on the mesial and distal surfaces of the teeth. The evaluation of micro-leakage was conducted using a dye penetration test, employing a scoring system ranging from 0 to 4. Results The nonaged specimens of the tested materials did not show significant differences regarding micro-shear bond strength, and micro-leakage. Aging had no significant effect on all of the tested properties in the three tested materials. Conclusion Short-term thermomechaical aging used in this study did not deteriorate micro-shear bond strength and micro-leakage of the tested materials. Alkasite (Cention N) and ACTIVA Bioactive Resin Based Composites are promising materials with physico-mechanical properties comparable to conventional bulk-fill composites. However, further in vitro and in vivo studies are needed to assess the properties of these recently introduced materials.

Two-year evaluation of a nano-hybrid and a bulk-fill resin composite: a randomized, double-blind split-mouth clinical study

ObjectivesThe aim of this study was to compare the 2-year clinical performance of a bulk-fill composite resin and a nano-hybrid-filled composite resin in 6-12-year-old children in a split-mouth design.Materials and methodsThis randomized, split-mouth, and double-blind study was conducted on 89 patients aged 6–12 years with caries on bilateral mandibular first molars. In a split-mouth design, restorations of mandibular permanent molars were completed with nano-hybrid organically modified ceramic (ORMOCER)-based bulk-fill composite resin Admira Fusion x-tra (Voco GmbH, Cuxhaven, Germany) and nano-hybrid composite Grandio (Voco, Cuxhaven, Germany). Futurabond U single dose (Voco, Cuxhaven, Germany) was used with selective enamel etching. The clinical success of the restorations was evaluated using USPHS and FDI criteria at 6, 12, and 24-month follow-up controls.ResultsIn the 2-year follow-up, all restorations were clinically acceptable. Grandio was significantly worse than Admira Fusion x-tra in terms of surface luster and superficial change (p < 0.05). Surface staining and color match scores increased in Admira Fusion x-tra compared with Grandio significantly (p < 0.05).ConclusionsAlthough both materials showed acceptable clinical performance over 2 years, a significant difference was observed between the surface luster, surface staining, marginal adaptation, and staining of the nano-hybrid composite placed with the incremental technique and the bulk-fill ORMOCER-based composite resin.Clinical relevanceAs an alternative to nano-hybrid composite resins, using bulk-fill restorative materials, which can be indicated in the proper case, may contribute to shortening treatment procedures and increasing patient and physician comfort, leading to clinical success.

Marginal Leakage Evaluation of Bioactive Bulkfill Restorative Materials in Class II Cavities: An In Vitro Comparative Study

Marginal Leakage Evaluation of Bioactive Bulkfill Restorative Materials in Class II Cavities: An In Vitro Comparative Study

Evaluation of color stability of bulk-fill restorative materials with different properties

Aims: The present study aims to evaluate the color stability of bulk-fill restorative materials with different properties over different time periods when immersed in a coffee solution.&#x0D; Methods: According to the selected restorative materials, the study groups were formed as follows: CNT/light (Alkasite, Cention N, Ivoclar Vivadent, light cure mode), CNT/self (Alkasite, Cention N, self cure mode) EQF (Glass hybrid restorative, Equia Forte HT, GC Corporation), AU (Single-shade bulk fill, Aura Bulk Fill, SDI), Z550 (Filtek Z550, 3M) (control group). A total of 50 samples (n=10) were prepared using standard molds (2mmx10mm). After finishing and polishing procedures, all samples were kept in distilled water at 37°C for 24 hours. The first color measurement (L*a*b ) was performed with Vita Easy Shade V (VITA Zahnfabrik). Samples were added to the coffee solution. Color was measured at times simulating 7 days, 1 month, 6 months and 1 year of clinical service. Color changes (ΔE1, ΔE2, ΔE3 and ΔE4) were calculated according to the CIE L*a*b system. Normality of the data was examined by D'Agostino &amp; Pearson omnibus normality test. One-way ANOVA analysis and Tukey test were performed. Statistical significance level was set at p 0.05 and statistical analysis software (GraphPad Prism 6.0, GraphPad Software, USA) was used for the analysis.&#x0D; Results: According to ΔE1 results; clinically unacceptable color change (ΔE&gt;3.3) values were observed in CNT/light and CNT/self groups. The color change values of EQF, Z550 and AU groups were statistically similar (p&gt;0.05). According to ΔE2 results; an unacceptable color change (ΔE&gt;3.3) was observed in all groups except EQF. According to ΔE3 results; an unacceptable color change (ΔE&gt;3.3) was observed in all groups. According to ΔE4 results; an unacceptable color change (ΔE&gt;3.3) was observed in all groups. The color change values of EQF, Z550 and AU groups were statistically similar (p&gt;0.05). CNT/light group showed the highest color change in all time periods, followed by CNT/self group.&#x0D; Conclusion: The color stability of single-shade bulk fill material and glass hybrid restorative materials is similar to the control group. The color stability of alkasite material needs to be improved.

The Depth of Cure, Sorption and Solubility of Dual-Cured Bulk-Fill Restorative Materials.

This study aimed to examine depth of cure (DoC), mass change, water sorption and solubility of dual-cured bulk-fill restorative materials (Surfil One and Activa) in comparison with a light-cured bulk-fill composite (Filtek One Bulk-Fill) and a resin-modified glass ionomer (Fuji II LC). Twenty specimens were prepared of each material using stainless steel molds designed with a slot (8 × 4 × 2 mm) and irradiated for either 20 or 40 s. The Vickers hardness (VHN) was measured at every 0.5 mm to assess the DoC after 24 h of storage at 37 °C. The depth of cure was reported as the depth corresponding to 80% of the maximum Vickers hardness. Disc-shaped specimens were prepared of each material (n = 5) to investigate mass change, sorption and solubility after 4 months of water storage. The data were analyzed using a two-way and one-way analysis of variance (ANOVA) followed by the Tukey post hoc test (p ≤ 0.05). Fuji II LC had the greatest DoC while Activa had the lowest. The two different irradiation times did not demonstrate a significant difference in DoC for all dual-cured materials (p > 0.05). Fuji II LC had the highest sorption while Filtek One showed the lowest. Surefil One and Fuji II LC had a negative solubility. This study concluded that dual-cured materials showed different depth of cure values despite having the same setting reaction. Both materials exhibited a high water sorption, which might jeopardize their dimensional stability and effect their clinical performance.

Caries affected disinfection using Phycocyanin activated by PDT, Holy Basil, and Ti-sapphire laser on adhesive bond strength, microleakage, and bond failure

AIMTo investigate the effect of different cavity disinfectants, Phycocyanin (PC), Ocimum Sanctum (OS), and Ti Sapphire Laser, on the bond integrity and microleakage of resin restorations. Material and method60 human mandibular molars were extracted and prepared based on ICDAS scores of 4 and 5. To obtain the CAD surface, a visual examination was supported by tactile sensation and a dye for caries detection. Samples were randomly allocated into 4 groups based on cavity disinfectants applied (n = 15). Group 1: Specimens disinfected with CHX, Group 2: Specimens disinfected with Ti sapphire laser, Group 3: Specimens disinfected with Phycocyanin activated by Photodynamic therapy, and Group 4: Specimens disinfected with OS. Following the disinfection of the CAD surfaces, composite bulk-fill restorative material was bonded to each specimen and all samples were subjected to thermocycling. Ten samples from each group underwent SBS testing performed on a universal testing machine. Five samples were subjected to a microleakage analysis. ResultThe maximum microleakage scores were displayed by Group 3: PC (0.521 nm) treated specimens. Whereas, and minimum microleakage was exhibited by Group 4: OS (0.471 nm). Group 4: OS (23.06±0.21 MPa) treated group displayed the maximum bond scores of resin adhesive to the CAD surface. However, Group 3: PC (21.67±0.24 MPa) treated specimens exhibited the lowest bond scores. Failure mode analysis revealed that among all the investigated groups the predominant type of failure was cohesive failure i.e., Group 1 (80%), Group 2 (80%), Group 3 (70%), and Group 4 (90%). ConclusionOcimum Sanctum, Phycocyanin activated by Photodynamic therapy, and Ti-sapphire laser for disinfection of caries-affected dentin have shown promise in terms of improved bond strength and reduced microleakage

Thickness-Dependent Light Transmittance and Temperature Rise in Dual-Cure Bioactive and Light-Cure Bulk-Fill Composite Resins.

This study aimed to assess the light transmittance (T) and temperature increase through different increments of dual-cure bioactive bulk-fill restorative material (ACTIVA), light-cure bulk-fill, and conventional composite resin materials. Cylindrical specimens with a diameter of 8 mm and heights of 1, 2, 3, and 4 mm of ACTIVA, Tetric-N-Ceram bulk-fill (TBF), Filtek One bulk-fill (FBF), and Filtek Z250 (FZ) (n = 6 per group, 96 in total) were light-cured with a visible blue low-intensity light-emitting diode (LED) (650-800 mW/cm2 irradiance). T, and the temperature increase, were measured using an optical power meter and a digital thermometer during curing. The T mean values ranged between 0.012 and 0.239 (76.02 to 98.81% light attenuation), while the temperature rise mean values ranged between 9.02 and 20.80 °C. The parameters, including material type (partial eta squared (ηp2) = 0.284, p < 0.0001), thickness (ηp2 = 0.284, p < 0.0001), and their interaction (ηp2 = 0.185, p = 0.047), significantly affected the T values, whereas only the material type (ηp2 = 0.352, p = 0.047) affected the temperature rise values. The T and temperature rise mean values were highest in ACTIVA increments of 1-mm increments, in particular, showing the highest T mean values, followed by similar increments of TBF. A significantly higher T was found in 1-mm increments compared to thicker increments for all materials (p < 0.0001), and a significant positive correlation existed between T and temperature rise values (r = 0.348, p = 0.001). These findings show that the bioactive material ACTIVA and TBF allow for better T than the other materials, with ACTIVA recording a higher temperature rise. However, the large light attenuation observed for all materials, irrespective of thickness, suggests that curing in more than one location with a low-intensity LED is necessary to optimize the curing process. Furthermore, incremental filling of bulk-fill materials using a low intensity LED could be beneficial.

Surface hardness and flexural strength of dual-cured bulk-fill restorative materials after solvent storage

BackgroundThis study aimed to evaluate the surface hardness (VHN) and biaxial flexural strength (BFS) of dual-cured bulk-fill restorative materials after solvent storage.MethodsTwo dual-cured bulk-fill composites (Surefil One® and Activa™ Bioactive), a light-cured bulk-fill composite (Filtek One Bulk-Fill) and a resin-modified glass ionomer (Fuji II LC) were investigated. Surefil One and Activa were used in the dual-cure mode, all materials were handled according to manufacturer’s instructions. For VHN determination, 12 specimens were prepared from each material and measured after 1 h (baseline), 1 d, 7 d and 30 d of storage in either water or 75% ethanol–water. For BFS test, 120 specimens were prepared (n = 30/material) and stored in water for either 1, 7 or 30 d before testing. Repeated measures MANOVA, two-way and one-way ANOVA followed by the Tukey post hoc test (p ≤ 0.05) were used to analyze the data.ResultsFiltek One had the highest VHN, while Activa had the lowest. All materials exhibited a significant increase in VHN after 1d of storage in water, except for Surefil One. After 30 d of storage, VHN increased significantly in water except for Activa, while ethanol storage caused a significant time-dependent reduction in all tested materials (p ≤ 0.05). Filtek One showed the highest BFS values (p ≤ 0.05). All the materials, except for Fuji II LC, exhibited no significant differences between 1 and 30 d BFS measurements (p > 0.05).ConclusionsDual-cured materials had significantly lower VHN and BFS compared to the light-cured bulk-fill material. The low results of Activa VHN and Surefil One BFS, indicate that these materials should not be recommended in posterior stress-bearing areas.

Clinical Evaluation of Class II Restorations Made with Bulk-fill Restorative Materials

Clinical Evaluation of Class II Restorations Made with Bulk-fill Restorative Materials

Micro-shear bond strength of different calcium silicate materials to bulk-fill composite.

This study aimed to compare the micro-shear bond strength (µSBS) performances of two resin-based calcium silicate-based cement (CSC) (TheraCal PT and TheraCal LC), Biodentine, and two modified-MTA CSC materials (NeoMTA 2 and BioMTA+) to bulk-fill restorative material. Fifty 3D printed cylindrical resin blocks with a central hole were used (2 mm in depth and 4 mm in diameter). CSCs were placed in the holes (per each group n = 10) and incubated for 24 h. Cylindrical polyethylene molds (2 mm in height and diameter) were used to place the bulk-fill restorative materials on the CSCs and polymerize for 20 s. Then, all specimens were incubated for 24 h at 37 °C at a humidity of 100%. Specimen's µSBSs were determined with a universal testing machine. Data were analyzed with one-way ANOVA (Welch) and Tamhane test. Statistically higher µSBS was found for TheraCal PT (29.91 ± 6.13 MPa) (p < 0.05) respect to all the other materials tested. TheraCal LC (20.23 ± 6.32 MPa) (p > 0.05) reported higher µSBS than NeoMTA 2 (11.49 ± 5.78 MPa) and BioMTA+ (6.45 ± 1.89 MPa) (p < 0.05). There was no statistical difference among TheraCal LC, NeoMTA 2 and Biodentine (15.23 ± 7.37 MPa) and between NeoMTA 2 and BioMTA+ (p > 0.05). Choosing TheraCal PT as the pulp capping material may increase the adhesion and µSBS to the bulk-fill composite superstructure and sealing ability.

Adhesive bond of Bioactive and bulk fill resin to disinfected caries affected dentin (lactobacillus specie) with laser and photodynamic therapy

AimsTo evaluate the antimicrobial effectiveness of cavity disinfectants chlorhexidine gluconate (CHX), Er, Cr, YSGG laser (ECL), and curcumin photosensitizer (CP) against Lactobacillus and shear bond strength (SBS) of Bioactive (BA) and bulk fill composite (BFC) restorative material bonded to carious affected dentin (CAD). Materials and MethodsSixty human mandibular molars scored 4 and 5 on the International Caries Detection and Assessment System (ICDAS) were included. After inoculating the specimens with lactobacillus specie all the samples were arbitrarily divided into three groups based on the disinfection regime used (n=20). Groups 1 and 2: CAD disinfection using ECL, Groups 3 and 4: CAD disinfection using CP, and Groups 5 and 6: CAD disinfection using CHX. After cavity sterilization, the survival rate was estimated and each group was further divided into two sub-groups based on the restorative material used. Groups 1, 3, and 5 (n = 10) were restored using BFC restorative material, and groups 2, 4, and 6 (n = 10) were restored using a conventional bulk-fill resin material. A universal testing machine (UTM) was used to determine the SBS and debonded surfaces were examined under a stereomicroscope to determine the modes of failure. Kruskal-Walis, ANOVA, and Post Hoc Tukey were applied to investigate the survival rate and bond strength values. ResultsECL group displayed the highest survival rate (0.73±0.13) of Lactobacillus. The least survival rate (0.17±0.09) was demonstrated by CP activated by PDT. Group 1 (ECL+ BA) treated specimens exhibited the maximum value of SBS (18.31 ± 0.22 MPa). However, group 3 (CP + BA) revealed the minimum values of bond strength (14.05 ± 1.02 MPa). The intergroup comparison revealed that group 1, group 2 (ECL+BFC) (18.11 ± 0.14 MPa), group 5 (CHX+ BA) (18.14 ± 0.36 MPa), and group 6 (CHX+BFC) (18.18 ± 0.35 MPa) displayed comparable outcomes of bond integrity (p>0.05). ConclusionCaries-affected dentin disinfected with Er, Cr: YSGG, and chlorhexidine improve bond scores of bioactive and conventional bulk-fill restorative material.

Water Sorption, Solubility and Color Stability of Different Bulk-Fill Restorative Materials

Objectives: The aim of this study was to evaluate the color stability, water sorption and solubility of recent bulk-fill restorative materials. Materials and Methods: Seventy disc shaped specimens (height:1mm, diameter:15mm) were prepared with a micro-hybrid composite resin (Z250; Filtek Z250, 3M ESPE), two resin-based bulk-fill (Filtek One Bulk Fill, 3M ESPE and EBF; Estelite Bulk-Fill Flow, Tokuyama Dental), glass ionomer-based restorative (Equia FF; Equia Forte Fil, GC Dental), self-cure and light-cure alkasite (CN; Cention N, Ivoclar Vivadent) and indirect composite resin (Gradia P; Gradia Plus, GC Dental) (n=10). Baseline color measurements were performed and mass of the samples (m1) were noted. Color measurements were repeated after 24 h and 28 days immersion of the specimens in water. After the 28-days immersion, mass was noted as m2. Specimens were kept in desiccators and final mass (m3) were recorded. The color change (ΔE00) water absorption (WSP) and water solubility (WSL) of the specimens were calculated. Results: After 28-days immersion, Gradia P showed significantly lower water sorption than EBF and Equia FF groups (p&amp;lt;0.05). Light-cured and self-cured CN groups showed similar sorption with resin composite groups (p&amp;gt;0.05). The lowest solubility was observed in Z250and Gradia P. The lowest (ΔE00) was observed in self-cured CN group (p&amp;lt;0.05) and Gradia P showed the highest ΔE00. Conclusions: Light-cured and self-cured CN groups demonstrated similar sorption to the conventional composite resin and indirect composite resin. Self-cured CN demonstrated higher water solubility than composite resins. Restorative materials showed moderately unacceptable color change after 28-day immersion in distilled water.

Effects of Different Beverages on Color Stability of Bulk-Fill Restorative Materials

Purpose: The aim of the study is to evaluate the color stability of a conventional composite resin and bulk-fill composite resins.&#x0D; Material Methods: A total of 120 samples of 10 mm diameter and 2 mm thickness were prepared from three bulk-fill (Beautifil Bulk-Fill, Filtek One Bulk-Fill, Tetric N-Ceram Bulk-Fill) and one conventional composite (Z250) and light cured. Initial color measurements were made with a spectrophotometer. Samples for each composite were randomly divided into 3 groups (black, kombucha and matcha tea) (n = 10). The samples were kept in the solutions for 12 days, and the color measurement was repeated. The values of ΔL, Δa, Δb and ΔE00 were calculated. SEM images were taken from a randomly selected sample from each group. Two-way analysis of variance (ANOVA) with Bonferroni correction was used to evaluate the color parameters.&#x0D; Results: Beautifil composite showed the greatest change in all values of E00, ΔL, Δa, and Δb., Filtek One and Tetric N-Ceram had the highest ΔE00 values values after Beautifil, respectively, and there was no difference between Z250 and Tetric N-Ceram. The lowest ΔL value belonged to Z250 composite, there was no difference between Tetric N-Ceram and Filtek One. Tetric N-Ceram had the highest Δa value after Beautifil and, there was no difference between the Z250 and Filtek One. Filtek One had the highest Δb value after Beautifil, there was no difference between the Tetric N-Ceram and Z250. &#x0D; Conclusion: Beverages can negatively affect the surface properties of bulk-fill composite resins in terms of color stability.

The Effect of Two Different Light-Curing Units and Curing Times on Bulk-Fill Restorative Materials.

This study aimed to evaluate the effect of two different light-curing units and curing times on the surface microhardness (SMH), compressive strength (CS), and volumetric shrinkage (VS) of four restorative materials (FiltekTM Z250, FiltekTM Bulk Fill Posterior, Beautifil® Bulk Restorative, ACTIVATM BioACTIVE). For all tests, each material was divided into two groups depending on the curing unit (Woodpecker LED-E and CarboLED), and each curing unit group was further divided into two subgroups according to curing time (10 s and 20 s). SMH was evaluated using a Vickers hardness tester, CS was tested using a universal testing machine, and VS was measured using video imaging. In all the restorative materials cured with Woodpecker LED-E, the 20 s subgroup demonstrated significantly higher SMH values than the 10 s subgroup. In both light-curing time subgroups, the CarboLED group showed significantly higher CS values than the Woodpecker LED-E group for all restorative materials except FiltekTM Bulk Fill Posterior cured for 20 s. ACTIVATM BioACTIVE showed significantly greater volumetric change than the other restorative materials. A higher curing light intensity and longer curing time had a positive effect on the SMH and CS of the restorative materials tested in this study. On the other hand, curing unit and time did not show a significant effect on the VS values of restorative materials.

Marginal Adaptation and Depth of Cure of Flowable versus Packable Bulk-fill Restorative Materials: An In Vitro StudyMarginal Adaptation and Depth of Cure of Flowable versus Packable Bulk-fill Restorative Materials: An In Vitro Study

Aim: To investigate the marginal adaptation and depth of cure of a flowable bulk-fill giomer (BEAUTIFIL Flow Plus X [BFP]), a flowable bulk-fill resin composite (PALFIQUE BULK FLOW [PBF]) bulk-fill resin composite, a packable bulk-fill giomer (BEAUTIFL-Bulk Restorative [BBR]), and two packable bulk-fill resin composites (X-tra fil [XF]) and (Filtek™ One Bulk Fill Restorative [FOB]).&#x0D; Materials and Methods: Twenty-five standardized class II cavities were prepared in the occlusomesial surfaces of maxillary premolars. A self-etching dental adhesive was used. All restorative materials were applied, and light cured according to their manufacturer's instructions. The teeth were subjected to 2500 thermal cycles between 5° C and 55° C. Epoxy resin replicas were obtained to examine the marginal by calculating the percentage of the continuous margin over the total margin length. using SEM at 200× magnification. For assessing the depth of cure, fifty specimens with 4 mm height were prepared. Vickers microhardness testing was used to assess the depth of cure was calculating the bottom-to-top ratio of each specimen. If this ratio reaches 0.80 or more, an adequate depth of cure is achieved.&#x0D; Results: Regarding marginal adaptation, there was no significant difference between different groups before (p=0.398) and after (p=0.644) thermocycling. Within all groups, there was a significant decrease in marginal adaptation after thermocycling (p&lt;0.001). Regarding the depth of cure, all restorative materials achieved the required 0.8 bottom-to-top ratio. There was a significant difference between different groups (p&lt;0.001). The highest value was found in BFP group (0.97±0.02), while the lowest value was found in BBR group (0.81±0.11).&#x0D; Conclusions: The marginal adaptation and depth of cure of bulk-fill giomer restorative materials are acceptable. Therefore, their use in restoration of 4-mm deep class II cavities is appealing.

AFM and SEM/EDS characterization of surfaces of fluorine-releasing bulk-fill restorative materials aged in common liquids

This study investigated the surface roughness (SR), surface microhardness (SH), and chemical composition of recently developed fluoride-releasing restorative materials aged in common liquids. A total of 276 disc-shaped samples with a diameter of 8 mm and a height of 2 mm were prepared by using four restorative materials: alkasite, Activa, Equia Forte, and Zirconomer. Atomic force microscopy (AFM) and the Vickers microhardness test were used to measure SR and SH, respectively. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM/EDS) was used for elemental analysis of the materials. The prepared samples were divided into 3 subgroups and immersed in coffee, cola, and saliva for 1 week at 37°C and 100% humidity. Cola and coffee significantly increased the SR of all materials except Zirconomer immersed in coffee (P < 0.05). The microhardness of alkasite and Activa significantly decreased in all liquids (P < 0.05) The percentage of fluorine (F) in the materials significantly changed after immersion for some liquids (P < 0.05). Aging differentially affected the surface characteristics and elemental mass ratios of the studied materials.

Polymerization shrinkage stress, internal adaptation, and dentin bond strength of bulk-fill restorative materials

To evaluate polymerization shrinkage stress (PSS), internal gap formation (IGF), and dentin bond strength (DBS) of one conventional resin composite and five bulk-fill restorative materials. One conventional resin composite (Filtek Supreme Ultra/SU) and five bulk-fill restorative materials: two regular paste-consistency composites (Tetric EvoCeram Bulk Fill/TE and Opus Bulk Fill/OP), one low-viscosity dual-cure composite (Fill-Up!/FI), one bioactive material (Activa BioActive Restorative/AC), and one high-viscosity glass ionomer (Equia Forte Fil/EQ) were tested. PSS was determined with a tensiometer attached to a universal testing machine (n = 5). For IGF, Class I cavities prepared in the occlusal surface of extracted third molars (n = 5) were filled up, cross-sectioned, and analyzed in scanning electron microscopy. The DBS was evaluated with microtensile bond strength test measured after 24 h or one-year storage. Data were statistically analyzed by one and two-way ANOVA and Tukey post-hoc test (α = 0.05). FI, SU, and OP presented higher PPS values and EQ showed the lowest ones. IGF was lower for OP and AC. SU showed the greatest DBS values and OP and FI the lowest after one-year storage. No correlation between PSS and IGF was found. Little difference in DBS among the restorative materials was detected, and its stability was material dependent.

Effect of Curing Modes on Depth-of-Cure in Bulk-Fill Composite

LED unit has different curing modes with variable intensities that influence polymerization of composite restorative material. Bulk-Fill composites claim more depth of cure compared to conventional composites. However, they have conflicting reports on their success. Hence, the purpose of this study is to explore the curing mode that could result in maximum depth cure in Bulk Fill restorative material. Thirty-three cylindrical composite specimens with dimension of 8mm length and 4mm diameter were made in preformed Teflon mold/frame by polymerization with LED using one of the three modes: Group1 constant mode; Group 2 pulse and Group 3 ramped mode. Once polymerized, each specimen was extruded from the mould and using the ISO 4049 scrapping method, uncured resin was removed. Specimen lengths were measured with a Vernier calliper. Each specimen was measured thrice and the mean was taken for the depth-of-cure. The data was subjected to ANOVA and Tukey's post hoc analysis. The pulse, constant and ramped modes resulted in depth of cure of SDR BulkFill composite of 2.88 ± 0.27mm, 2.92 ± 0.29mm and 3.18 ± 0.26mm, respectively. The difference in depth of cure between pulse and ramped curing mode was statistically significant on post-hoc analysis ( p -value=0.04). Maximum depth of cure of SDR BulkFill composite was achieved by ramped cure mode of LED unit followed by Constant and Pulse modes.

Assessing Fracture Resistance of Restored Premolars with Novel Composite Materials: An In Vitro Study.

During restorative treatment, premolars restored with resin filling materials using the conventional incremental-fill technique take longer restoration time and undermine the integrity of the tooth. The aim of this study was to assess fracture resistance of premolars restored by various types of novel bulk-fill composite resin materials. Forty-eight (n = 48) freshly extracted sound maxillary first premolars were used in this in vitro study. The teeth were divided into six groups, each having 8 specimens. Group A (positive control) was allocated for the intact teeth. For specimens in Groups B to F, a large cavity (Class-II MOD) was prepared with a standardized dimension of cavity (3 mm depth on the pulpal floor, 4 mm at the gingival seat, and 3 mm cavity width). Group B represented prepared teeth without any restoration. Group C, Group D, Group E, and Group F were restored with Tetric EvoCeram® incremental-fill (conventional), Beautifil bulk-fill, Filtek posterior bulk-fill, and SonicFill 2 bulk-fill restorative materials, respectively. All samples were finished and polished with an enhanced finishing kit and stored in distilled water for a month before the fracture resistance testing. All the samples were exposed to the axial loading (the speed of crosshead was 1 mm/min) in a computer-controlled universal testing machine (LARYEE, China) via a steel bar (6 mm in diameter) and the maximum applied force in Newton was recorded as the fracture resistance. One-way analysis of variance (SPSS 21) was used to compare the fracture resistance within the groups, and Tukey's post hoc test was used to determine the difference between the groups. The lowest value of fracture resistance was recorded for Group B, and the highest value was recorded for Group A followed by the values of Group D, Group C, Group F, and Group E. One-way ANOVA revealed a statistically significant difference between the groups (P < 0.05). Nonsignificant difference was found between the premolars restored by bulk-fill and conventional composites. Among the bulk-fill restored specimens, Beautifil restorative demonstrated significantly higher fracture resistance in comparison with the other two bulk-fill restored specimen groups (SonicFill 2 and Filtek). Bulk-fill composite such as Beautifil could be an alternative option to conventional incremental-fill composite for premolar restoration.

Invitro Effect of Bulkfill and Incremental Application Techniques with Different Composite Filling Materials on Marginal Microleakage

Abstract &#x0D; Objective: To assess the in vitro effect of bulkfill and incremental application techniques on the microleakage of class II dental cavities filled with three different bulkfill composite materials at occlusal and cervical margins.&#x0D; Methods: Standardized class II cavities were prepared on 120 human premolar teeth extracted for orthodontic treatment, which were randomly divided into two main groups of 60 teeth, corresponding to the two application techniques. Each group wasthen sub-dividedrandomly into three sub-groups based on the type of bulkfill restorative materials as follows: Tetric®N-Ceram BulkFill, Filtek™BulkFill flowable restorative material and X-trafil®BulkFill. All cavities were prepared and etched, and the corresponding self-etch bond adhesive systems were applied. A stereomicroscope was used to assess microleakage after thermocycling and immersion of the specimens in 0.1% methylene blue for 24 hours. Mann-Whitney U test was then used to analyze data.&#x0D; Results: No statistically significant difference was found in the marginal microleakage between the incremental and bulkfill techniques using the three types of composite materials at both occlusal and cervical margins. The X-trafil®BulkFill showed the lowest score of microleakage with both application techniques compared to other bulkfill composite materials.&#x0D; Conclusion: Both incremental and bulkfill application techniques using Tetric®N-Ceram BulkFill, Filtek™BulkFill flowable restorative material and X-trafil®BulkFill composite materials have a comparable effect on the marginal microleakage at occlusal and cervical margins of human teeth extracted from dental clinics in Sana’a city. Further studies are recommended to assess the clinical success of bulkfill composite materials using SEM or confocal microscope.&#x0D;