Bulk-fill Restorations Research Articles

Microtensile Bond Strength Evaluation of Composite Resin to Discolored Dentin After Amalgam Removal

BackgroundTo obtain prolonged clinical success with composite restorations, better bonding of resin to the tooth substrate is crucial.AimThe study was aimed to evaluate the microtensile bond strength (µTBS) of bulk-fill composite resin restorations when bonded to a cavity previously restored with amalgam, comparing with that of freshly prepared dentin.Materials and methodMesio-occlusal cavity preparations were done on 80 extracted human mandibular molars with a buccolingual width of 4 mm and a 1.5 mm axial depth by placing the gingival seat 0.5 mm coronal to the cementoenamel junction (CEJ) and were restored with fine-grain amalgam alloy. After thermocycling, the amalgam restorations were removed. Disto-occlusal cavities with similar dimensions of mesial cavities were prepared, and both the proximal surfaces were filled with bulk-fill composite using either etch-and-rinse or self-etch adhesives. Following thermomechanical cyclic loading, all the teeth were sectioned for µTBS testing. Bond strength data expressed in megapascals (MPa) were subjected to statistical analyses using analysis of variance (ANOVA) and Tukey’s multiple post-hoc tests.ResultsThe total-etch adhesive exhibited statistically higher bond strength values to both dentin substrates compared to self-etch adhesives (p<0.05). Failure mode analysis reported more of adhesive failures.ConclusionThe µTBS of bulk-fill composite resin restorations bonded to a cavity previously restored with amalgam was significantly lower than that of freshly prepared dentin. Total-etch adhesives bond strength was higher than self-etch adhesives to both the substrates tested.

Influence of Bulk-fill Restoration on Polymerization Shrinkage Stress and Marginal Gap Formation in Class V Restorations

Restoring Class V cavities with a regular bulk-fill composite presents a more favorable biomechanical behavior than restoring with a regular nano-filled composite.

Fracture resistance of extensive bulk-fill composite restorations after selective caries removal

This study evaluated the effect of selective carious tissue removal on the fracture strength and failure mode of composite restorations in molars presenting only the buccal cusps. Deep cavities were prepared on the occlusal surface, and the lingual cusps were removed. Carious lesions in the middle of the pulpal wall were artificially induced with acetic acid (pH = 4.5) for 35 days. The demineralized dentin was left intact or was completely removed prior to restoration with a bulk-fill composite (n = 10). Images of the specimens were obtained by optical coherence tomography (OCT) before and after the caries induction/removal. The mechanical resistance to fracture by axial compressive loading and the failure type and extension were determined. The pulpal wall/composite interface of the fractured specimens was analyzed by OCT. The data were analyzed for significance with t-tests (α = 0.05). The deepest cavities and a more frequent occurrence of pulpal exposure were observed more often for non-selective carious tissue removal. The protocol of carious tissue removal did not affect the fracture strength (p = 0.554). An increased occurrence of catastrophic failures involving the roots was observed for non-selective carious tissue removal. Some occurrences of restoration displacement or cracks throughout the resin-dentin were observed only for the selective carious tissue approach. Selective carious tissue removal is a feasible approach to extensively damaged teeth since it reduced the occurrence of pulpal exposure and root fractures, without compromising the fracture strength.

Comparative Evaluation of Depth of Cure of Bulk-fill Composite Resin and Alkasite Restorative Material by Vicker’s Hardness Test

Comparative Evaluation of Depth of Cure of Bulk-fill Composite Resin and Alkasite Restorative Material by Vicker’s Hardness Test

Effect of Composite Resin and Restorative Technique on Polymerization Shrinkage Stress, Cuspal Strain and Fracture Load of Weakened Premolars.

To compare shrinkage stress, cuspal strain and fracture load of weakened premolars restored with different conventional and bulk-fill composite resins and restorative techniques. Fifty premolars received a 4.0 x 3.5mm mesio-occlusal-distal (MOD) class II preparation. The lingual and buccal cups were internally weakened. Specimens were restored according to the following 5 groups: Filtek Z350 XT/10 increments; Filtek Z350 XT/8 increments (both 3M Oral Care); Filtek Bulk Fill Flowable Restorative + Filtek Z350 XT (both 3M Oral Care); SDR + Spectra Basic (Dentsply Sirona); and Tetric N-Ceram Bulk Fill (Ivoclar Vivadent). Cuspal strains were measured using strain gauges (n = 10). After restoration, specimens were submitted to thermal/mechanical cycles and fractured. Post-gel shrinkage of the composites was determined. Additionally, residual shrinkage strains and stresses were analyzed using three-dimensional finite element analysis (3D-FEA). The data were statistically analyzed using one-way ANOVA and Tukey's HSD (α = 0.05). One-way ANOVA revealed statistically significant differences among composite resins (p < 0.001) for the post-gel shrinkage. Filtek Z350 XT had the highest post-gel shrinkage and no difference was found between Spectra Basic and Tetric N-Ceram Bulk Fill (p = 0.110). The Filtek Z350 XT/10 increments, Filtek Z350 XT/8 increments and Filtek Bulk Fill Flowable Restorative/Filtek Z350 XT had statistically significantly higher cuspal deformation values when compared to the SDR/Spectra Basic and Tetric N-Ceram Bulk Fill techniques. 3D-FEA confirmed higher stress levels in the incrementally filled conventional restorations. Fracture loads were not statistically significantly different. The bulk-fill restoration techniques resulted in less cuspal strain and stress than the incremental technique with conventional composite resin. Fracture resistance was not affected by the restorative techniques.

Effect of Preheating and Fatiguing on Mechanical Properties of Bulk-fill and Conventional Composite Resin.

Bulk-fill composite resins may have comparable mechanical properties to conventional composite resin. Preheating does not reduce the mechanical properties of composite resins.

24-Month Clinical Evaluation of Different Bulk-Fill Restorative Resins in Class II Restorations.

The objective of this study was to evaluate the 24-month clinical performance of three different bulk-fill restorative resin materials in class II restorations. Forty patients with at least three approximal lesions in premolar and molar teeth participated in the study. A total of 120 class II cavities were restored using Tetric EvoCeram Bulk Fill (n=40), SureFil SDR flow + Ceram.X mono (n=40), and everX Posterior + G-aenial Posterior (n=40) with their respective adhesives according to the manufacturers' instructions. All restorations were placed by one operator. The restorations were evaluated at baseline and at six, 12, 18, and 24 months using modified US Public Health Service criteria by one examiner. The restoration groups for each category were compared using the Pearson chi-square test, while the Cochran Q-test was used to compare the changes across different time points within each restorative material (p<0.05). At the end of 24 months, 94 restorations were evaluated in 33 patients, with a recall rate of 82.5%. There were no statistically significant differences between the groups in terms of retention (p>0.05). At the 24-month recall, two restorations from the SureFil SDR flow + Ceram.X mono group and four from the everX Posterior + G-aenial Posterior group showed slight marginal discoloration and were rated as bravo. No marginal discoloration was observed in any of the Tetric EvoCeram Bulk Fill restorations. Six restorations from the Tetric EvoCeram Bulk Fill group, six from the SureFil SDR flow + Ceram.X mono group, and 12 from the everX Posterior + G-aenial Posterior group received bravo scores in terms of marginal adaptation. No difference was found among the three groups for any of the evaluation criteria tested (p>0.05). There were statistically significant differences between the baseline and 24-month recall in the everX Posterior + G-aenial Posterior group in terms of marginal discoloration (p<0.05). For marginal adaptation, a significant difference was observed between baseline and 24 months for all the restorative resins (p<0.05). All the restorative resins tested performed similarly and showed acceptable clinical performance during the 24-month evaluation.

Dynamic Viscoelastic Characterization of Bulk-fill Resin-based Composites and Their Conventional Counterparts.

This study compared the viscoelastic properties of restorative and flowable bulk-fill resin-based composites (RBCs) with their conventional counterparts and evaluated the impact of aqueous solutions on viscoelastic properties. The materials examined included three conventional RBCs (Filtek Z350, Tetric N Ceram, and Beautifil II), three restorative bulk-fill RBCs (Filtek Bulk-Fill Restorative, Tetric N Ceram Bulk-Fill, and Beautifil Bulk-Fill Restorative) in addition to three flowable bulk-fill RBCs (Filtek Bulk-Fill Flowable, Tetric N Flow Bulk-Fill, and Beautifil Bulk-Fill Flowable). Beam-shaped specimens (12×2×2 mm) were fabricated using customized stainless-steel molds, finished, and measured. The specimens were randomly divided into four groups and conditioned in air (control), artificial saliva, 0.02 N citric acid, and 50% ethanol-water solution for seven days at 37°C. They were then subjected to dynamic mechanical analysis (n = 10) in flexure mode at 37°C with a frequency of 0.1 to 10 Hz. Storage modulus, loss modulus, and loss tangent data were subjected to statistical analysis using one-way analysis of variance/Tukey post hoc test at a significance level of α = 0.05. Viscoelastic properties of the RBCs were found to be product and conditioning medium dependent. For most RBCs, exposure to aqueous solutions, particularly an ethanol-water solution, degraded viscoelastic properties. With the exception of Filtek Bulk-Fill Restorative, bulk-fill restorative and flowable RBCs generally had significantly lower storage and loss modulus than their conventional counterparts regardless of conditioning medium. Conventional RBCs are thus favored over their bulk-fill counterparts, particularly for high-stress-bearing areas.

Comparison of Flexural Properties of Bulk-fill Restorative/Flowable Composites and Their Conventional Counterparts.

The objectives of the study were to compare the flexural modulus and strength of restorative and flowable bulk-fill resin-based composites (RBCs) to their conventional counterparts and to determine the effects of conditioning environment on their flexural properties. The materials evaluated included three conventional RBCs (Filtek Z350, Tetric N Ceram, and Beautifil II), three restorative bulk-fill RBCs (Filtek Bulk-Fill Restorative, Tetric N Ceram Bulk-Fill, and Beautifil Bulk-fill Restorative), as well as three flowable bulk-fill RBCs (Filtek Bulk-Fill Flowable, Tetric N Flow Bulk-Fill, and Beautifil Bulk-Fill Flowable). Specimens were fabricated using customized stainless-steel molds, finished, measured, and randomly divided into four groups. The various RBCs were conditioned in the following mediums (n=10) for seven days at 37°C: air, artificial saliva (SAGF), 0.02 N citric acid, and 50% ethanol-water solution. After conditioning, the specimens were rinsed, blotted dry, measured, and subjected to flexural testing using a universal testing machine. Data were subjected to statistical analysis using analysis of variance and the Tukey test at a significance level of α = 0.05. Significant differences in flexural properties were observed between materials and conditioning mediums. Bulk-fill restorative RBCs exhibited higher flexural modulus than their bulk-fill flowable and conventional counterparts. With the exception of Filtek Bulk-Fill Flowable, bulk-fill flowable RBCs had significantly higher flexural strength than bulk-fill restorative and conventional RBCs. Flexural properties were highest when RBCs were conditioned in air and generally the lowest after exposure to ethanol.

Postoperative sensitivity after placement of bulk-fill posterior restoration

The purpose of this observational retrospective clinical study was to assess the post-operative sensitivity reported by patients following the placement of bulk-fill composite restorations. Patient records of the seventy-two subjects with previously untreated teeth requiring restorations due to caries lesions were used. Seventy-two restorations that were radiographically judged to be located in neither middle nor inner one-third of dentin were included in the study. Two resin composites had been used: Group 1- bulk-fill posterior resin composite (Filtek Bulk Fill Posterior Restorative); Group 2- conventional resin composite (Filtek Z250). The same resin adhesive system (Single Bond Universal Adhesive) had been used with both composites. Patients had been contacted on days 2, 7, 14 and 30 postoperatively and asked about any presence sensitivity, the stimuli that created the sensitivity, if any, the duration of any sensitivity, and the intensity of any sensitivity using a rating from none too severe. The chi-square test showed cavity deepness (p=0.003) significantly affected post-operative sensitivity, while no significances between the different resin composites (p=0.465), cavity sizes (p=0.702) were revealed at day 2, respectively. By day 2, 8.3% of restorations placed in the middle one-third, and 37.5% of restorations placed in the inner one-third of dentin were slightly sensitive. By day 14, there had been no sensitive tooth. Both composite types have potential post-operative sensitivity with limited duration following their placements. The use of bulk-fill posterior restorative for restoration of the deep carious lesion does not seem to affect postoperative sensitivity of composite restorations.

Temperature changes in the pulp chamber induced by polymerization of resin-based dental restoratives following simulated direct pulp capping

The objective of this study was to measure temperature changes in the pulp chamber induced by polymerization of resin-based dental restoratives following a simulated procedure of direct pulp capping. Class I cavities with a microperforation at the pulp horn were prepared in extracted human molar teeth. The complete procedure of direct pulp capping and cavity restoration was performed with the root part of extracted teeth fixed in a water bath at 37 ?C. Mineral trioxide aggregate, bioactive dentin substitute or calcium-hydroxide paste were used as pulp capping materials. Cavities were restored with a light-cured or chemically-cured resin-modified glass ionomer, universal adhesive and a bulk-fill composite, cured with a high-intensity LED unit. Pulp capping materials caused a slight temperature decrease. Lower temperature increase was recorded during light-curing of the glass ionomer liner after direct capping with mineral trioxide aggregate and calcium-hydroxide than that recorded for the bioactive dentin substitute. Adhesive light-curing increased temperature in all groups with higher mean temperatures in groups with chemically-cured as compared to those for the light-cured glass ionomer liner. Direct pulp capping with mineral trioxide aggregate or calcium-hydroxide followed by the light-cured resin-modified glass ionomer liner and a bonded bulk-fill composite restoration induced temperature changes below the potentially adverse threshold of 42.5?C.

Micro‐computed tomography evaluation of internal void formation of bulk‐fill resin composites in Class II restorations

The aim of this study was to quantify the internal void volume formation in bulk‐fill resin composites with using 3D micro‐computed tomography (μCT). Class II box cavities in 4‐mm depth were prepared and treated with Clearfil S3 Bond Plus (Kuraray Medical). Five resin composites were evaluated: one conventional paste‐like (Filtek Ultimate Universal Restorative‐as the control), one conventional flowable (Filtek Ultimate Flowable Restorative), two flowable bulk‐fill (Voco Extrabase, SDR), one paste‐like bulk‐fill (Filtek One BulkFill Restorative). Resin composites were light cured using a light‐emitting diode light‐curing unit (SDI Radii Plus, SDI Limited, Australia). Samples were evaluated by μCT, and data were imported into software The NRecon (ver. 1.6.10.4, SkyScan) and CTAn (ver. 1.16.1.0, SkyScan) for 3D reconstruction, from which the percentage of void volume was calculated. Data were analyzed using the Kruskal‐Wallis test and the Mann–Whitney U‐test at a significance level of 5%. All restorative tested materials showed different levels of voids. Filtek One BulkFill Restorative showed the least void formation, which was statistically less than that of the conventional flowable composite group (p &lt; 0.05). All other restorative materials showed similar void formation. POLYM. COMPOS., 40:2984–2992, 2019. © 2018 Society of Plastics Engineers

Evaluation of the Cuspal Deflection of Premolars Restored with Different Types of Bulk Fill Composite Restorations (A comparative in vitro study)

This in vitro study aimed to assess and compare premolars cuspal deflection that restored with different bulk fill resin materials types (SonicFillTM2, Beautifil Bulk Fill restorative, and FiltekTM Bulk Fill posterior restorative) to those incrementally restored group with conventional composite restorations (low shrinkage universal Tetric Evoceram). A total of 40 intact human maxillary first premolars were prepared into large MOD. Then teeth were randomly classified into four groups (n=10 for each group) according to restorative materials as following: Group A: Teeth were restored with Sonic FillTM2 composite, Group B: restored with Beautifil Bulk Fill restorative material, Group C: Teeth were restored with Filtek BulkTM Fill posterior restorative, and Group D: Teeth were restored with Universal Tetric Evo Ceram®. Digital microscope was used to measure intercuspal distance between two index reference points on the tips of the cusps before preparation, after preparation, and 15minutes after completion of restorations. The differences registered as cuspal deflection. All teeth were exposed to inward cuspal deflection after restoration and all groups that restored with bulk fill restoration reported lower cuspal deflection in compared to group D that restored with conventional composite in layering technique. Beautifil Bulk Fill restorative produced significantly greater cuspal deflection than other bulk fill groups. The study concluded that the use of new bulk fill restorative materials might reduce amount of cuspal deflection significantly. However, type of bulk fill restorative materials also influenced on amount of cuspal deflection so restoration with Sonic Fill™2 composite and Filtek Bulk™ Fill posterior reported lower cuspal deflection than Beautifil Bulk Fill restorative material.

Viscoelastic Properties of Contemporary Bulk-fill Restoratives: A Dynamic-mechanical Analysis.

This study investigated the viscoelastic properties of contemporary bulk-fill restoratives in distilled water and artificial saliva using dynamic mechanical analysis. The materials evaluated included a conventional composite (Filtek Z350), two bulk-fill composites (Filtek Bulk-fill and Tetric N Ceram), a bulk-fill giomer (Beautifil-Bulk Restorative), and two novel reinforced glass ionomer cements (Zirconomer [ZR] and Equia Forte [EQ]). The glass ionomer materials were also assessed with and without resin coating (Equia Forte Coat). Test specimens 12 × 2 × 2 mm of the various materials were fabricated using customized stainless-steel molds. After light polymerization/initial set, the specimens were removed from the molds, finished, measured, and conditioned in distilled water or artificial saliva at 37°C for seven days. The materials (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C and a frequency of 0.1 to 10 Hz. Storage modulus, loss modulus, and loss tangent data were subjected to normality testing and statistical analysis using one-way analysis of variance/Dunnett's test and t-test at a significance level of p < 0.05. Mean storage modulus ranged from 3.16 ± 0.25 to 8.98 ± 0.44 GPa, while mean loss modulus ranged from 0.24 ± 0.03 to 0.65 ± 0.12 GPa for distilled water and artificial saliva. Values for loss tangent ranged from 45.7 ± 7.33 to 134.2 ± 12.36 (10-3). Significant differences in storage/loss modulus and loss tangent were observed between the various bulk-fill restoratives and two conditioning mediums. Storage modulus was significantly improved when EQ and ZR was not coated with resin.

Clinical evaluation of bulk-fill composite resin and layered composite resin restoration in class I cavity of permanent molar teeth

The purpose of the present study was to compare the clinical performance of bulk-fill composite resin with that of layered composite resin restorations in occlusal class I cavity of permanent molar teeth. This study includes a total of 104 teeth having class I cavity of 3-4 mm depth in the occlusal surface. They were restored either with layered composite resin or bulk-fill composite resin of 52 teeth in each group. To observe the retention, marginal adaptation and color match, all restorations were assessed by using modified United States Public Health Services (USPHS) and Ryge’s criteria at baseline, 3, 6 and 12 months. The results of 12 months observation showed that retention of 38 layered composite and 48 bulk-fill composite resin restorations revealed alpha rating, which was statistically significant. The marginal adaptation of 37 layered composite resin and 47 bulk-fill composite resin restorations also demonstrated alpha rating and the differences between two groups were statistically significant. However, there were no significant differences between the layered composite resin and bulk-fill composite resin restorations in respect to color match. It can be concluded that bulk-fill composite resin showed better clinical outcome than that of layered composite resin in the restorations of occlusal class I cavity.

Comparative Effect of Self- or Dual-Curing on Polymerization Kinetics and Mechanical Properties in a Novel, Dental-Resin-Based Composite with Alkaline Filler. Running Title: Resin-Composites with Alkaline Fillers.

Dental bulk-fill restorations with resin-composites (RBC) are increasing in popularity, but doubts concerning insufficient curing in depth still disconcert clinicians. An alternative might be offered by modern dual-cured RBCs, which additionally provide bioactive properties. This study assessed the impact of additional light-curing on polymerization kinetics, the degree of conversion (DC) and mechanical properties of a novel, dual-cured RBC with alkaline fillers. Since the bioactivity of a material often implies a release of compounds, the mechanical stability in simulated clinical environments was also evaluated. Polymerization kinetics and DC were assessed at 2- and 4-mm specimen depths in real-time up to one hour (n = 6). Incident and transmitted irradiance and radiant exposure were recorded at 2- and 4-mm depths. Micro-mechanical profiles (n = 6) were assessed in 100-µm steps along 6-mm deep specimens at 24 h post-polymerization. Flexural strength and modulus (n = 10) were determined up to three months of immersion in neutral (6.8) and acidic (4) pH conditions. DC variation in time was best described by a sigmoidal function (R2 > 0.98), revealing a retarded (3.4 ± 0.4 min) initiation in C=C double bond conversion in self-cured versus dual-cured specimens. The setting reaction kinetic was identical at 2- and 4-mm depths for the self-cure mode. For the dual-cure mode, polymerization initiated at 2-mm depth instantly with light-irradiation, while being retarded (0.8 min) at 4-mm depth. The material behaves similarly, irrespective of curing mode or depth, later than 11 min after mixing. Flexural strength and modulus was comparable to regular RBCs and maintained up to three months in both neutral and acidic conditions. Additional light-curing initially accelerates the polymerization kinetic and might help shorten the restauration procedure by hardening the material on demand, however with no effect on the final properties.

Comparative Evaluation of Postoperative Sensitivity in Bulk Fill Restoratives: A Randomized Controlled Trial.

Aim:Comparative evaluation of postoperative sensitivity (POS) among three bulk fill restorative materials (Cention N, Equia Forte, Activa™ Bioactive restorative) in Class I posterior restorations.Materials and Methods:One hundred and forty-four patients having occlusal caries were arbitrarily selected and divided into three groups. Standardized Class I cavity was prepared and restored with Cention N, Equia forte, and Activa™ Bioactive restorative material. POS of restored tooth was assessed with a standardized cold test and air stimulus by air blow from the air syringe. Patient responses were assessed at an interval of 24 h, 1 week, and 1 month using a visual analog scale. Statistical analysis was performed using paired t-test, independent t-test, one-way ANOVA test, and Tukey's post hoc test using SPSS 11.0 program (SPSS Inc., Chicago, IL, USA) for windows.Results:The statistical analysis showed a significant difference in the clinical evaluation of POS at 24 h interval among three groups (Cention N, Activa™ Bioactive Restorative, Equia forte). However, following 1 week and 1 month, there is no significant difference in Group C (Activa™ Bioactive Restorative).Conclusion:POS was seen more in Cention N contrast to Equia forte and Activa™ bioactive restorative material.

Preliminary data on clinical performance of bulk-fill restorations in primary molars.

In pediatric clinic practice, bulk fill composite is gaining importance for shortened clinical time with a limited shrinkage. The present study evaluated the 1 year clinical performance of bulk fill composite and conventional composite material in occlusal caries of primary molars. The study was designed as randomized single blind clinical trial and a total of 160 restorations were placed in the cavities of the 80 patients. Each patient received two restorations: one with Filtek Z250 (3M ESPE, St Paul, MN 55144, USA); the other restored with Filtek Bulk-Fill Restorative (FBF) (3M ESPE, St Paul, MN, USA). All restorations were clinically evaluated after baseline, 6 months, and 1 year in terms of retention, color matching, marginal discoloration, marginal adaptation, secondary caries, surface texture, anatomic form, and postoperative sensitivity. Besides the descriptive statistical methods, the Friedman test and the Wilcoxon Signed Ranks were used. Bulk fill was found to be worse compared to control with regard to postoperative sensitivity at baseline without statistical significance (P > 0.05). All of the evaluated restorations were retained and were still in function after 1 year (P > 0.05). With respect to marginal discoloration and marginal integrity, there were no significant differences between bulk fill and composite restorations at all intervals (P > 0.05). Based on this short term data, restoration of Class I cavities with both bulk fill and conventional composite restorations can be performed successfully. Postoperative sensitivity can be an issue with the restorations completed with Bulk fill restorative.

Clinical performance of bulk-fill and incremental restorations in endodontically-treated molars

Clinical performance of bulk-fill and incremental restorations in endodontically-treated molars

Microtensile bond strength of bulk-fill restorative composites to dentin.

BackgroundTo facilitate the easier placement of direct resin composite in deeper cavities, bulk fill composites have been introduced. The Mechanical stability of fillings in stress bearing areas restored with bulk-fill resin composites is still open to question, since long term clinical studies are not available so far. Thus, the objective of the study was to evaluate and compare the microtensile bond strength of three bulk-fill restorative composites with a nanohybrid composite.Material and MethodsClass I cavities were prepared on sixty extracted mandibular molars. Teeth were divided into 4 groups (n= 15 each) and in group I, the prepared cavities were restored with nanohybrid (Filtek Z250 XT) restorative composite in an incremental manner. In group II, III and IV, the bulk-fill composites (Filtek, Tetric EvoCeram, X-tra fil bulk-fill restoratives) were placed as a 4 mm single increment and light cured. The restored teeth were subjected to thermocycling and bond strength testing was done using instron testing machine. The mode of failure was assessed by scanning electron microscope (SEM). The bond strength values obtained in megapascals (MPa) were subjected to statistical analysis, using SPSS/PC version 20 software.One-way ANOVA was used for groupwise comparison of the bond strength. Tukey’s Post Hoc test was used for pairwise comparisons among the groups.ResultsThe highest mean bond strength was achieved with Filtek bulk-fill restorative showing statistically significant difference with Tetric EvoCeram bulk-fill (p< 0.003) and X-tra fil bulk-fill (p<0.001) composites. Adhesive failures are mostly observed with X-tra fil bulk fill composites, whereas mixed failures are more common with other bulk fill composites.ConclusionsBulk-fill composites exhibited adequate bond strength to dentin and can be considered as restorative material of choice in posterior stress bearing areas. Key words:Bond strength, Bulk-fill restoratives, Configuration factor, Polymerization shrinkage.