Bulk-fill Group Research Articles

New Perspectives in Overcoming Bulk-Fill Composite Polymerization Shrinkage: The Impact of Curing Mode and Layering.

The purpose of this study was to investigate the effect of different light curing modes on the polymerization shrinkage of a bulk-fill composite and to evaluate the impact of two layering techniques on the cuspal deflection. Nine different light curing modes were tested on bulk-fill composite samples in aluminum MOD cavities. Intensity, duration, and illumination distance were the factors that changed during the different curing modes. The digital image correlation method was used to visually represent the displacement of carbon particles on the materials' surface caused by shrinkage along both the horizontal and vertical axes. For simulating cuspal deflection, a separate protocol was used, with a bulk and horizontal layering technique. The results showed that the largest horizontal displacements were present in the soft start group (6.00 ± 0.82 µm) and in the X-tra power group (5.67 ± 1.21 µm). The smallest horizontal displacements were detected in normal curing modes (4.00 ± 1.58 µm; 4.00 ± 2.68 µm). The largest vertical displacements, at the bottom layer, were present in the normal curing mode group with a 20 s curing time (5.22 ± 1.56 µm), while the smallest vertical displacements were shown in the X-tra power group (2.89 ± 0.60 µm). The observed particle displacements showing the shrinkage of the composite were correlated with the curing mode. The bulk-fill group showed less cuspal deflection than the horizontal layering group did, but the difference was not statistically significant (p = 0.575). Within the limitations of this in vitro study, it can be concluded that lower intensities of curing lights (1200 mW/cm2) may perform better from the point of view of material shrinkage than high and extreme light intensities do. The pulse delay mode might be recommended in the case of bulk-fill materials. The number of layers did not significantly affect the cuspal deflection in the case of the studied composite.

Evaluation of Microvoid and Microleakage Potential of Bulk-Fill Resin Composites in MOD Restorations

Background: Polymerization shrinkage and microvoid formation has been a significant problem giving way to resin composite failure. The aim of this study was to evaluate the microvoid potential and microleakage of two bulk-fill and a microhybrid resin composite applied with different adhesive materials. Materials and Methods: MOD cavities were prepared in 60 endodontically treated maxillary premolars. The teeth were divided into six different groups (n = 10) according to adhesive systems (Gluma (Kulzer), OptiBond FL (Kerr) and resin composite materials EverX Posterior (GC) and Filtek One Bulk Fill (3M ESPE). An aging procedure with 5000 cycles of thermal cycling was applied. All teeth were individually scanned with micro-computed tomography. A Shapiro–Wilk test, two-way MANOVA, and Bonferroni analysis were used for statistical tests. Results: Self-etch groups showed more microleakage than total-etch groups. Minimum microleakage was observed in Filtek One Bulk Fill groups, whereas G-aenial Posterior groups showed maximum microleakage. Conclusions: Filtek One Bulk Fill (3M ESPE) resin composite was found to be more effective in reducing microvoid formation in MOD cavities when applied with total-etch adhesive systems. However, EverX Posterior (GC) and G-aenial Posterior (GC) showed less microvoid formation with self-etch adhesive systems.

Dentin adhesion of bulk-fill composites and universal adhesives in class I-cavities with high C-factor

ObjectivesThe aim of this study was to compare the dentin adhesion of bulk-fill composites in high C-factor class I-cavities before and after thermocycling to a control group using incremental layering technique. MethodsA standardized class I-cavity was prepared into 195 human molars, then different universal adhesives were applied either in self-etch or etch & rinse mode, and the cavity was filled according to each materials application protocol. The material combinations used were a conventional layered composite as control, the respective bulk-fill product, two other bulk-fill composites made by different manufacturers, with one of them being tested using two different polymerization times. Furthermore, one thermoviscous bulk-fill composite and one self-adhesive restorative were examined of which the latter can only be applied in self-etch mode. In each group the dentin adhesion to the cavity bottom was measured using microtensile bond strength test initially (24 h water storage) and after thermocycling. All results were statistically analyzed using STATA 17.0. ResultsThe statistical analysis showed significant differences between the control and the experimental groups (p < 0.001). The highest mean bond strength before (14.8 ± 10.7 MPa) and after aging (14.2 ± 11.5 MPa) was measured for the etch & rinse-control group. Among the bulk-fill groups, the etch & rinse technique consistently showed higher bond strengths. Bond strength of groups with shortened polymerization did not exceed 2.1 MPa. The bond strength of the self-adhesive restoration material was low before and after thermocycling (2.7 MPa/ 0.0 MPa). Groups with low bond strength values showed a high number of pre-testing-failures. ConclusionsBulk-fill materials used in high C-factor class I-cavities showed lower bond strength during self-etch application. The same applies for a shortened polymerization regime, which cannot be recommended for high C-factor cavities. Clinical significanceToday, a large variety of materials and application techniques can be used when placing an adhesive restoration. Whether new instead of established procedures should be applied in high C-factor cavities has to be critically assessed, as they are a demanding scenario for adhesive restorations.

Postoperative sensitivity in posterior restorations restored with self-adhesive and conventional bulk-fill resin composites: A randomized clinical split-mouth trial

ObjectiveTo compare the postoperative sensitivity (POS) of a self-adhesive bulk-fill resin composite with that of a conventional bulk-fill resin composite in posterior restorations. MethodsClass I and II (n = 166) cavities of at least 3 mm depth, in 83 participants were restored by: (TEST: Surefil one™ Self-Adhesive bulk-fill (n = 83); and CONTROL: Filtek™ Bulk-Fill posterior composites (n = 83). The presence and intensity of POS associated with the restorations was evaluated at 24 h, 1 week and 1 month intervals using the Visual Analogue Scale (VAS). Comparisons of POS presence between the two treatment groups were made using the Chi-square and Fisher exact tests, while Mann-Whitney and Friedman tests were used to compare the intensity of POS (α=0.05). ResultsForty-two of participants (25.3%; 95% CI 19.3 to 32.4) reported presence of POS after 24 h and none of the participants reported POS after 1 month. The presence of POS was not significantly affected by the restorative material after 24 h, 1 week and 1 month (p>0.05). After 1 week, the participants in the Surefil one™ group reported significantly less intensity of POS than the participants in the Filtek™ Bulk-Fill group (p = 0.02). ConclusionsThe use of Surefil one™ self-adhesive resin composite did not significantly increase the presence of POS compared to the use of the conventional bulk-fill resin composite. However, the intensity of POS was significantly less in the Surefil one ™ group after one week. Clinical significanceThe use of a self-adhesive bulk-fill resin composite in posterior restorations did not increase the presence of POS more than the use of a conventional bulk-fill resin composite. However, it decreased the intensity of POS after one week. This clinical trial was registered at ClinicalTrials.gov; the registration number is NCT05567263.

The strength of restorations of hard tooth tissues with changes in atmospheric pressure, &lt;i&gt;in vitro&lt;/i&gt; studies

BACKGROUND: It is known that the development of the carious process is promoted by microorganisms that secrete waste products that penetrate into the tooth tissue during the depressurization of the filling material. That is why high-quality restoration prevents the development of secondary caries.&#x0D; AIM: Based on the study of the edge fit of restorations made of various types of filling materials, when restoring the chewing surface of the tooth, to determine the most optimal method of filling, which reduces the likelihood of violation of the edge fit of the seal in cases of significant changes in atmospheric pressure.&#x0D; MATERIALS AND METHODS: The removed teeth were prepared and treated with the Single Bond Universal adhesive system, the samples were divided into 4 groups, the cavities were filled according to the classical method with traditional composite materials Estelite Sigma Quick (Tokuyama Dental), OptiShade (Kerr) and materials of the bulk fill Tetric N-Ceram (Ivoclar Vivadent), SonicFill (Kerr). After sealing, groups 3 and 4 were placed in a pressure chamber (the study was conducted at the Department of Aviation and Space Medicine) and exposed to low atmospheric pressure. Next, the restoration slots were made and the study was carried out using a scanning electron microscope JEOL JSM-6380LV.&#x0D; RESULTS: As a result of microscopic studies, a violation of the marginal fit along the filling-tooth border was determined in all samples sealed with traditional composite materials (Estelite Sigma Quick, OptiShade) 65 9.18% (p 0.05) and bulk fill group materials (Tetric N-Ceram, SonicFill) 98 2.69%, (p 0.05) in cases of exposure to low atmospheric pressure. In the samples that were not exposed to atmospheric pressure, the marginal depressurization was 12 6.25% (p 0.05) Estelite Sigma Quick, OptiShade and 21 7.84% (p 0.05) Tetric N-Ceram, SonicFill.&#x0D; CONCLUSION: It has been proved by laboratory method that traditional composite materials and bulk fill group materials are rational to use only in persons who are not associated with extreme effects on the body, since in cases of exposure to atmospheric pressure, there are violations of the marginal fit of the material along the sealtooth border.

Performance of bulk-fill versus conventional nanocomposite resin restorations supporting the occlusal rests of removable partial dentures: An in vitro investigation

Statement of problemPlacing removable partial denture (RPD) rests on composite resin restorations has long been a debatable issue. Despite developments in composite resins such as nanotechnology and bulk-filling techniques, studies investigating the performance of composite resin restorations when used to support occlusal rests remain scarce. PurposeThe purpose of this in vitro study was to investigate the performance of bulk-fill versus incremental (conventional) nanocomposite resin restorations when they are used to support RPD rests under functional loading. Material and methodsThirty-five caries-free intact maxillary molars of similar coronal size were collected and divided into 5 equal groups (n=7): Enamel (Control) group: rest seats prepared entirely in enamel; Class I Incremental group: Class I cavities restored with incrementally placed nanohybrid resin composite resin (Tetric N-Ceram); Class II Incremental group: Mesio-occlusal (MO) Class II cavities restored with Tetric N-Ceram; Class I Bulk-fill group: Class I cavities restored with high-viscosity bulk-fill hybrid resin composite (Tetric N-Ceram Bulk-Fill); and Class II Bulk-fill group: MO Class II cavities restored with Tetric N-Ceram Bulk-Fill. Occlusal rest seats were prepared mesially in all groups, and clasp assemblies were fabricated and cast in cobalt chromium alloy. Specimens with their clasp assemblies were subjected to thermomechanical cycling using a mechanical cycling machine (250000 masticatory cycles) and 5000 thermal cycles (5 °C to 50 °C). Surface roughness (Ra) was measured with a contact profilometer before and after cycling. Fracture analysis was done using stereomicroscopy, and margin analysis was done with a scanning electron microscope (SEM) before and after cycling. Statistical analysis of Ra was conducted using ANOVA followed by the Scheffé test for between-group comparison and paired t test for within-group comparison. The Fisher exact probability test was used for fracture analysis. The Mann–Whitney test was used for between-group comparison and Wilcoxon signed rank test for within-group comparison for the SEM images (α=.05). ResultsMean Ra increased significantly after cycling in all groups. Significant differences in Ra were found between enamel and all 4 resin groups (P<.001), with no significant differences between incremental and bulk-fill resin groups for both Class I and II specimens (P>.05). No significant differences were found between the 2 resin groups with regard to fracture and margin analysis (P>.05). ConclusionsThe surface roughness of enamel was significantly lower than that of both incremental and bulk-fill nanocomposite resins before and after functional loading. Incremental and bulk-fill nanocomposite resins showed comparable performance in terms of surface roughness, fracture behavior, and marginal adaptation.

A comparative study on microleakage of two low shrinkage composite materials in Class II cavities: A stereomicroscopic analysis.

To compare the microleakage of Filtek bulk fill posterior and Beautifil II LS composites in Class II cavities using stereomicroscope. A total of 34 extracted teeth were randomly divided into two groups. Teeth were prepared and mounted on a plaster block. In each tooth, Class II cavities were prepared, following which the cavities were etched and bonded. In Group I, 17 teeth were restored with Filtek bulk fill posterior composite in bulk fill technique and in Group II, 17 teeth were restored with Beautifil II LS following manufacture's instructions. The samples were then thermocycled and then the tooth were immersed in 1% methylene blue for 24 h and were divided into two halves mesiodistally using a diamond disc at low speed. Then, all the sections were observed under a stereomicroscope at ×10 magnification. Mann-Whitney U-test displayed a statistically significant higher mean rank among Filtek bulk fill group (mean rank = 23.09) when compared to Beautifil II LS composite group (mean rank = 11.91). The study concluded that in Class II restorations, Beautifil II LS showed significantly less microleakage than Filtek bulk fill posterior.

Effect of thickness on the degree of conversion, monomer elution, depth of cure and cytotoxicity of bulk-fill composites

Today, bulk-fill composites are used as a single layer with a thickness of up to 4-5 mm. However, is proper polymerization achieved with this increased thickness? This study was designed to investigate the effect of thickness on the degree of conversion (DC) (n = 6), the elution of monomers (n = 6), depth of cure (DoC) (n = 10) and cytotoxicity (n = 6) of the bulk-fill composites SDR Flow Plus (SDR), SonicFill2 SingleFill (SF) and ACTIVA Bioactive Restorative (ACT) in comparison to the conventional G-aenial Posterior (GC). Two-way analysis of variance (ANOVA) was used to assess the interaction between materials and surfaces, and one-way ANOVA and Tukey tests were used to compare the degree of conversion, monomer elution and cytotoxicity values (P < 0.05). The highest DC was found at the top surface of SDR, while the lowest DC was found at SF. The V2 mm/V0 mm DoC ratios of the composites except ACTs were appropriate according to the threshold. None of the composites were cytotoxic on day 1. In bulk-fill composites, DC decreased and monomer elution increased with increasing depth. The V4 mm/V0 mm ratios of all bulk-fill groups were not appropriate. Additionally, only ACTs had a cell viability of <70% on day 7.

Postoperative Sensitivity of Composite Replacement of Amalgam Restoration: A Randomized Clinical Trial

This randomized clinical trial aimed to evaluate the postoperative sensitivity of different resin composite/adhesive materials, placed either by an incremental or bulk-fill technique in posterior resin composite replacement of amalgam restorations. A total of 47 patients with good overall health and at least four class I or class II amalgam restorations to be replaced participated in this study. The characteristics of 188 cavities were registered and randomly restored using incremental (Z350XT, 3M) or bulk-fill (Filtek Bulk Fill, 3M; Sonic Fill, Kerr; and Opus Bulk Fill, FGM) technique. The postoperative sensitivity was assessed using a Visual Analog Scale (0-100) after 24 hours, 7 days, and 30 days. Pain scores were temporally analyzed using Friedman test followed by Dunn post hoc test (α=0.05). The frequency of tests was calculated according to the frequency and percentage of the McNemar test. The restorative technique and the bulk-fill system used did not affect the postoperative sensitivity, except for Filtek Bulk Fill group, which presented less postoperative sensitivity after 24 hours (p=0.037). Regardless of the restorative material, the postoperative sensitivity decreased after 24 hours, and no differences were found after 7 and 30 days. After 1 week, the filling technique and the bulk-fill system have no influence on the postoperative sensitivity.

Fracture Resistance and Microleakage around Direct Restorations in High C-Factor Cavities.

The aim of this research was to evaluate the mechanical impact of different direct restorations in terms of fracture resistance, and subsequent fracture pattern, in occlusal high C-factor cavities. Furthermore, the adaptation of different direct restorations in the form of gap formation was also evaluated. Seventy-two intact mandibular molars were collected and randomly distributed into three groups (n = 24). Class I occlusal cavities with standardized dimensions were prepared in all specimens. After adhesive treatment, the cavities were restored with direct restorations utilizing three different materials. Group 1: layered conventional packable resin composite (Filtek Ultimate), Group 2: bulk-fill resin composite (SDR), Group 3: bulk-fill short fibre-reinforced composite (SFRC; everX Posterior) covered with packable composite occlusally. Half of the restored specimens underwent static load-to fracture testing (n = 12/group), while the rest underwent sectioning and staining for microleakage evaluation and gap formation analysis. Fracture patterns were evaluated visually among the mechanically tested specimens. The layered composite restoration (Group 1) showed significantly lower fracture resistance compared to the bulk fill groups (Group 2, p = 0.005, Group 3, p = 0.008), while there was no difference in fracture resistance between the other groups. In terms of gap formation values, the layered composite restoration (Group 1) produced significantly higher gap formation compared to the bulk-fill groups (Group 2, p = 0.000, Group 3, p = 0.000). Regarding the fracture pattern, SFRC (Group 3) produced the highest number, while SDR (Group 2) produced the lowest number of repairable fractures. The use of bulk-fill resin composite (fibre or non-fibre-reinforced) for occlusal direct restorations in high C-factor cavities showed promising achievements regarding both fracture resistance and microleakage. Furthermore, the use of short fibre-reinforced bulk-fill composite can also improve the fracture pattern of the restoration-tooth unit. Bulk-fill materials provide a simple and effective solution for restoring and reinforcing high C-factor occlusal cavities.

Evaluation of different composite resin finishing and polishing protocols by confocal laser scan microscopy

Aim: This study aimed to analyze the influence of finishing and polishing (F/P) protocols on resin surface through roughness (Ra) values and laser scan microscopy observations. Methods: Forty-eight (n=48) resin specimens were sorted into four groups (n=12), according to the type of resin used: Filtek Z250 (Z250), Filtek Z350 (Z350), Filtek One Bulk Fill (BF), Filtek P60 (P60). The specimens were sorted into six groups according to the type of F/P system used (n=2/group): Control group, Diamond bur (KG Sorensen), Soflex Pop-On Discs (3M ESPE), Soflex Spiral (3M ESPE), Dura Gloss (American Burs), and Praxis (TDV). Results: The highest roughness values (Ra) were attributed to BF group for all F/P systems, except for the Soft-Lex PopOn discs. The Soft-Lex PopOn, Spiral, and Praxis discs presented a better performance for the surface treatment of the tested composite resins. Regardless of the restorative material, the use of diamond bur or single-step abrasive rubber (Dura Gloss) were associated with the highest Ra values. Conclusion: The effect of F/P systems on Ra is material-dependent and instrument or system-dependent.

A comparative study of the 5 mm-layer Vickers hardness model with bulk-fill resin-based composites

Aim: The aim of this study was to compare the Vickers hardness numbers (VHNs) of two bulk-fill resin-based composites (BFRBC) and a conventional hybrid resin-based composite (RBC) through the layers of a 5mm thickness model with two different light-curing time intervals.&#x0D; Methodology: In the present study, a sonic-activated and dual-cure BFRBC, and a conventional hybrid RBC were used. Semi-cylindrical specimens 4 mm in radius and 5 mm in height were prepared using a two-piece stainless-steel mold (n=10). The BFRBCs allowed a single 5mm increment to be introduced into the molds, whereas hybrid RBC was incremented (2+2+1 mm). Two different time intervals were applied for the light-curing (irradiance of 1200 mW/cm2) of each material (hybrid-sonic-activated bulk-fill, 20 s and 40 s; dual-cure bulk-fill, 7 s and 15 s). VHN measurements were carried out from top to bottom at every 1 mm of the specimen thickness. Data were analyzed using three-way and two-way ANOVA for the VHN and bottom/top ratios and Bonferroni correction for multiple comparisons (p=0.05).&#x0D; Results: For each layer and time interval groups, there was a significant difference between the materials. The highest VHN was found within hybrid groups, whereas dual-cure bulk-fill groups showed the lowest results. Sonic-activated bulk-fill had the lowest bottom/top ratios, which were significantly different from those of the other materials. There was no significant difference between the different time intervals for bottom/top ratios within each material.&#x0D; Conclusion: Increased irradiation intervals positively affected the VHN of hybrid and dual-cure bulk-fill. BFRBCs showed clinically acceptable bottom/top hardness ratios.&#x0D; &#x0D; How to cite this article: Aytaç Bal F, Ağaccıoğlu M, Demir O. A comparative study of the 5 mm-layer Vickers hardness model with bulk-fill resin-based composites. Int Dent Res 2021;11(2):172-9. https://doi.org/10.5577/intdentres.2021.vol11.no3.6&#x0D; &#x0D; Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Laboratory studies of heated Bulk Fill composite in the tooth cavity during filling of teeth with carious defects

Aim. To study with the help of a microscope the marginal fit of Bulk-Fill group composite materials to the hard tissues of the tooth. Optimize the method of heating the composite in the cavity.Materials and methods. The marginal fit of the composite material of the Bulk-Fill group, sealed in 30 teeth of chewing anatomical and functional accessories extracted according to various indications, was studied. Materials used in the laboratory experiment: 3M ESPE Filtek posterior restorative Bulk Fill, SDR (Dentsply Sirona), Sonic Fill (Kerr). According to the manufacturers, the materials are used with the method of single-portion sealing. The research was conducted at the Department of General Dentistry of the S.M.Kirov Military Medical Academy of the Ministry of Defense of the Russian Federation.Results. 30 teeth extracted according to various indications of chewing anatomical and functional accessories were indicators were shown by the Sonic Fill (Kerr) system, due to heating and changing the viscosity of the material.Conclusions. It was proved in the laboratory that the heated composites of the Bulk-Fill group had the best edge fit during sealing than composites at normal room temperature. A nozzle was developed for heating the composite in the tooth cavity (priority application No. 2021120658 dated 12.07.2021).

Comparison of restorative materials and surface alterations after prebiotic and probiotic beverages: A nanoindentation and SEM study.

The purpose was to investigate the surface characteristics of various resin-based materials by immersing in probiotic beverages. A total of 420 disc-shaped samples (5 mm × 2 mm) were prepared from resin-based composites. Samples were divided into four groups and immersed for 10 min/day for 1 month in either a probiotic sachet, kefir, kombucha, or artificial saliva (control). Surface roughness was measured at baseline and 1 month. One sample of each of the tested materials was examined under nanoindentation to evaluate the reduced elasticity modulus and nanohardness scores. Scanning electron microscopy (SEM) was used to compare surface differences. Data were analyzed statistically using one-way ANOVA test and the significance was set at p < .05. The lowest roughness scores were observed in Z250, Estelite Bulk Fill, and HRi ENA in most of the test groups. Among conventional composites, Z250 group had the highest nanohardness and elasticity modulus scores. Among bulk-fill composites, Estelite Bulk Fill Flow had the lowest surface roughness after immersion in probiotic beverages and the highest nanohardness values. Reveal HD, as a bulk-fill group showed higher surface roughness and considerably lower nanohardness and elasticity modulus scores. Maximum height levels of samples were recorded. SEM images revealed voids and microcracks on the surfaces of test materials. Dentists may prefer Z250 as microhybrid and Estelite Bulk Fill Flow as bulk-fill composites for the restorations of patients who consume gut-friendly drinks regularly. When there are various types of materials, nanoindentation is a useful method for evaluating surface alterations and sensible comparisons.

Resistência à compressão de compósitos de preenchimento único

A new class of composite resins called single fill resins (Bulk-Fill) was proposed to simplify restorative procedures. They allow filling dental cavities in layers of approximately 4mm. This study aims to compare the compression strength of single fill composites with different polymerization times. Four Bulk-Fill composites were used Filtek Bulk-Fill, Filtek Bulk-Fill Flow, Tetric N-Ceram Bulk-Fill, and Tetric N-Flow Bulk-Fill, and also a conventional composite Filtek Z350 XT as a control group. One hundred cylinders were manufactured in a matrix with 4.7mm diameter and 4mm height for Bulk-Fill compounds, and 2mm height for the control group. Half of the specimens of each material was photopolymerized for 10 seconds and the other half for 20 seconds (n = 10). The samples were stored in distilled water for 48 hours at 37°C and subjected to compression testing in a universal test machine. Variance analysis was performed with t-test of multiple comparisons between groups and student t-test for the different polymerization times with significance index p=0.05. The results did not show statistically significant difference in relation to polymerization time. However, there was a statistically significant difference between the control and Filtek Bulk-Fill Flow groups, which presented higher strenght to compression than the Filltek Bulk-Fill, Tetric N-Ceram Bulk-Fill, and Tetric N-Flow Bulk-Fill groups. The type of resin can influence its resistance to fracture. The polymerization time did not have any influence in the materials strength.

Influence of etching mode and composite resin type on bond strength to dentin using universal adhesive system.

Adhesive bond strength at the composite/dentin interface is influenced by various factors, including the etching mode and composite resin type. The purpose of this study was to evaluate the influence of the total-etch and self-etch mode on the microtensile bond strength (μTBS) of conventional and bulk-fill composite to dentin, using the universal adhesive system. Sixty non-carious human teeth were sectioned parallel to their longitudinal axis, using a low-speed diamond saw to obtain a flat dentin surface. According to the etching technique and composite resin type used, teeth were randomly divided into four different groups (n=15): TC (total-etch/conventional composite), TB (total-etch/bulk-fill composite), SC (self-etch/conventional composite), and SB (self-etch/bulk-fill composite). Cylindric composite build-ups were made with 3M Filtek Z250 and 3M Filtek Bulkfill Posterior, using a plastic mold, 4 mm in diameter and 4 mm in height. The specimens were subjected to the μTBS test in a universal testing machine and failure force was recorded. Failure modes were determined using stereoscopic and scanning electron microscopy. Data were analyzed using the two-way ANOVA and Student's t test. The μTBS was significantly affected by the etching technique. A significant statistical difference was determined between total-etch and self-etch groups, irrespective of the composite resin type used. Higher bond strength was obtained in total-etch groups. The μTBS was not affected by the composite resin type. No significant statistical difference was determined between the conventional and bulk-fill groups, irrespective of the etching-mode.

Comparative Evaluation of Retention and Antibacterial Efficacy of Compomer and Glass Hybrid Bulk Fill Restorative Material as a Conservative Adhesive Restoration in Children with Mixed Dentition-An In Vivo Two-arm Parallel-group Double-blinded Randomized Controlled Study.

Aim and objectiveTo compare and evaluate the retention along with antibacterial efficacy of colored compomer and glass hybrid bulk fill glass ionomer restorative material as a conservative adhesive restoration in children of age 6–12 years.Materials and methodsSixty children were selected fulfilling the inclusion and exclusion criteria falling in the age group of 6–12 years with mixed dentition and two groups were formed: group I—colored compomer and group II—glass hybrid bulk fill material. Initially, oral prophylaxis was carried out and baseline collection of saliva was completed. Then, the restorative treatment was completed. Retention of the material and antibacterial count [colony-forming units (CFU)/mL of saliva] was estimated at 1, 3, and 6 months after the restorative procedure.ResultsIt was seen that retention rate with glass hybrid bulk fill group was 100%, whereas with colored compomer group it was 90% at end of 6 months. Although good antibacterial activity was shown by both the group at 1, 3, and 6 months follow-up but statistically significant drop was seen in the glass hybrid bulk fill group at 3-month intervals than the colored compomer group with a p value of 0.0001 (p < 0.05).ConclusionAmong both the materials, glass hybrid bulk fill restorative material showed good retention compared to Colored compomer material but it was not statistically very significant. Also, both the materials have shown good antimicrobial activity at 1, 3, and 6 months follow-up.How to cite this articleMundada MV, Hugar SM, Hallikerimath S, et al. Comparative Evaluation of Retention and Antibacterial Efficacy of Compomer and Glass Hybrid Bulk Fill Restorative Material as a Conservative Adhesive Restoration in Children with Mixed Dentition—An In Vivo Two-arm Parallel-group Double-blinded Randomized Controlled Study. Int J Clin Pediatr Dent 2020;13(S-1):S45–S54.

The effect of different obturation methods on sealer penetration alongside apically separated rotary nickel–titanium instruments: A confocal laser scanning microscopy study

The effects of different obturation techniques on calcium silicate-based sealer penetration in the presence of apically separated rotary files were evaluated. Forty-eight extracted mandibular incisors were used. ProTaper F2 rotary files were separated at the apical thirds. Samples were divided into four groups (n = 12) according to obturation technique used: (a) cold lateral compaction (CLC); (b) single cone; (c) bulk-fill (BF) without a core material; and (d) thermoplastic injection (TI). Specimens were sectioned horizontally at 1 and 3 mm from the apex and studied using a confocal scanning laser microscope. The maximum tubule penetration depth and percentage of penetration were measured. Data were statistically analyzed using parametric and nonparametric tests with a significance level of 5%. Regarding penetration depth, a significant difference was found at 1 mm (p < .05), while no significant difference was found at 3 mm (p > .05). At the 3 mm level, all of the obturation techniques showed similar penetration depths. Regarding penetration percentage, the values of the CLC and TI groups were statistically less when compared with the BF group at 1 and 3 mm levels, respectively (p < .05). Under the limitations of this in vitro study, results suggest that the obturation technique may present a significant effect on sealer penetration.

Fracture resistance of pulpotomized and composite-restored primary molars: Incremental versus bulk-fill techniques

The aim of this study was to assess the fracture resistance of pulpotomized primary molars restored with incremental and bulk-fill composite application techniques. In this in-vitro experimental study, 36 extracted primary molars were nonrandomly (selectively) divided into three groups of 12 each. All teeth underwent conventional pulpotomy treatment, and mesio-occluso-distal cavities were prepared in such a way that the buccolingual width of the preparation was two-thirds of the intercuspal distance, and the depth of the buccal and lingual walls was 4 mm. The teeth were then restored as follows: Group 1 (control) was restored with amalgam, Group 2 was restored with Tetric N-Ceram composite using the incremental technique, and Group 3 was restored with Tetric N-Ceram composite using the bulk-fill technique. The restored teeth were subjected to thermocycling and then underwent fracture resistance testing in a universal testing machine at a crosshead speed of 1 mm/min. Fracture resistance of groups was compared using the one-way ANOVA and Tukey's honestly significant difference test. The mean fracture resistance was 1291.47 ± 603.88 N in the amalgam, 1283.08 ± 594.57 N in the Tetric N-Ceram incremental, and 1939.06 ± 134.47 N in the Tetric N-Ceram bulk-fill group. The difference in this regard between Group 3 and Groups 1 and 2 was statistically significant (P = 0.019 and P= 0.035, respectively). Bulk-fill composite is recommended for reinforcing the remaining tooth structure after the primary molar pulpotomy procedure. Time-saving characteristics of this material are clinically important for reducing appointment time for children.

Fracture Resistance and Marginal Adaptation of Capped and Uncapped Bulk-fill Resin-based Materials.

This study tested the fracture resistance of capped and uncapped bulk-fill composite restorations and compared them to a conventional composite. Also, the effect of different radiant exposure was investigated. Flowable and high-viscosity bulk-fill composites (SureFil SDR, Filtek Bulk-Fill Posterior, and Tetric N-Ceram Bulk-Fill) and a nanohybrid resin composite (Filtek Z350 XT) were used. Standardized class II cavities were prepared on extracted premolars, and different restoration protocols were used. In protocol 1 (control), restoration was applied using a layering technique; in protocol 2, restoration was applied in bulk with a capping layer; in protocol 3, restoration was applied in bulk without a capping layer; and in protocol 4, restoration was applied in bulk without a capping layer, and the light curing time was extended. After thermocycling, the restorations were examined for marginal gaps and then subjected to the fracture resistance test using a universal testing machine. Statistical analysis was carried out using two-way analysis of variance (ANOVA) followed by one-way ANOVA at a significance level of α = 0.05. A statistically significant difference in the fracture resistance of the tested materials and protocols was detected. Filtek Bulk-Fill Posterior achieved the highest fracture resistance values regardless of the protocol used, and its results were comparable to those of Filtek Z350. SDR and Tetric N-Ceram Bulk-Fill achieved their highest strengths when a capping layer was added. Tetric N-Ceram Bulk-Fill showed improvement in fracture resistance with extended light curing, while SDR and Tetric N-Ceram Bulk-Fill achieved similar results with the addition of a capping layer. The uncapped bulk-fill group showed more gap-free margins than the capped group. The new high-viscosity bulk-fill composite restorations seem to have adequate fracture resistance. However, the results are material dependent, and some materials perform better with a capping layer and extended light curing.