Comparison of microleakage between bulk-fill flowable and nanofilled resin-based composites

Effects of different removal methods of excess resin adhesive on the microleakage of alumina all-ceramic crowns

BACKGROUND

Microleakage is a common problem that affects the quality and longevity of all-ceramic crowns. It is influenced by factors such as the resin cement, crown margin design and curing technique. However, few studies focus on the effect of different methods of removing excess resin adhesive on the microleakage of all-ceramic crowns. This study aimed to compare two methods of removing excess resin adhesive (the small brush and sickle methods) on the microleakage of all-ceramic crowns with different marginal clearances.

METHODS

Forty extracted third molars were prepared with a 90° shoulder margin and randomly divided into four groups according to their marginal lift (30, 60, 90 or 0 μm). Procera alumina crowns were fabricated using computer-aided design/computer-aided modelling and cemented onto the teeth with 3 M RelyX Unicem (3 M Company, United States) resin cement. Excess resin cement was removed by either the small brush or the sickle scalpel method. The marginal adaptation was observed with a digital microscope. After thermal cycling of the teeth, microleakage was assessed using the dye penetration test under a stereomicroscope. The Mann-Whitney U test and Kruskal-Wallis H test were used to compare the microleakage scores among different groups.

RESULTS

The small-brush group showed significantly better marginal adaptation and lower microleakage scores than the sickle group (p < 0.05). There was no significant difference in the microleakage score (grade 0) among different marginal clearances within each group (p > 0.05).

CONCLUSION

The small-brush method was more effective than the sickle scalpel method in reducing the microleakage of all-ceramic crowns with different marginal clearances. This method can improve the marginal adaptation and sealability of all-ceramic crowns, thus preventing secondary caries and other complications.

Effect of Prolonged Water Aging on the Bond Strength and Marginal Seal of Three Novel Restorative Materials

AIM

To assess and contrast the shear bond strength (SBS) and microbial leakage of Cention-N, Fuji IX, and nanohybrid composite restorative materials after being exposed to prolonged water aging.

MATERIALS AND METHODS

A total of 30 self-curing acrylic blocks were prepared for SBS analysis. Extracted teeth were affixed on the acrylic resin to incorporate the root section. To expose the occlusal dentin, 3 mm of the midcoronal portion was sectioned. The sectioned samples were allocated into the following three groups: Group I: Fuji IX; group II: Filtek Z350; and group III: Cention-N. Cylindrical plastic tubing was used to place each material as directed by the manufacturer and water aging for 7, 14, and 28 days at 37°C. Also, a universal testing machine (UTM) was utilized for testing followed by a scanning electron microscope (SEM). For microleakage analysis, a total of 30 class-V cavities were prepared. The prepared samples were allotted to respective groups; Later, 200 thermocycles at 5°C and 55°C were applied for 30 seconds to mimic the oral environment. The root apices sealed with sticky wax and the exception of a 1-mm around the edges of the restorations were then painted twice with clear nail varnish and submerged in 0.5% basic fuchsin dye at 37°C. Samples were washed, dried, and sectioned longitudinally followed by stereomicroscopic evaluation.

RESULTS

Groups I (0.083), group II (0.083), and group III (0.102) did not show significant variation in the SBS after water degradation. At the end of 28 days of water aging, group III showed 33.3% adhesive failure and 66.7% mixed failure mode. For marginal leakage in group III, the mean and standard deviation (SD) were 334.90 ± 418.454 with the p = 0.001 showing a significant difference compared to groups I and II.

CONCLUSION

Compared to nanohybrid composite and Fuji IX, Cention-N showed a superior SBS after being exposed to water aging and exhibited lesser marginal leakage.

CLINICAL SIGNIFICANCE

Cention-N outperformed in its marginal adaptation with superior shear resistance and can be considered as an alternative bulk filling material.

Dental restoration operative time and analysis of the internal gap of conventional resins (Incremental Technique) vs. Bulk Fill (Single-Increment Technique): In vitro study

Background

To determine the operative time and the internal restoration gap in the restoration-tooth interface in the cavity floor using an incremental technique for conventional resins and the single-increment technique for the bulk fill resin.

Material and Methods

In this in vitro experimental study, the internal gaps of the restoration-tooth interfaces in the cavity floors of two conventional resins and two bulk fill resins were microscopically analyzed, and the restoration times of the single-increment technique and the incremental technique were determined.

Results

Bulk fill resins had smaller internal gap (63.31 µm) than conventional resins (333.14 µm). Regarding the restoration time, the single-increment technique obtained the best results in operative time (3.52 minutes), with significant differences relative to the incremental technique.

Conclusions

The Tetric N-Ceram bulk fill resin presented better performance than conventional resins relative to the internal gap of the restoration-tooth interface in the cavity floor. In addition, the single-increment technique presented a short clinical restoration time. Key words:Composite, internal gap, restoration technique.

In vitro microleakage at the enamel and dentin margins of class II cavities of primary molars restored with a bulk-fill and a conventional composite

OBJECTIVES

This study assessed the enamel and dentin margin microleakage of class II cavities of primary molars restored with a bulk-fill and a conventional composite.

MATERIALS AND METHODS

In this in vitro, experimental study, standard class II cavities were created in the proximal surfaces of 60 extracted primary molars. The teeth were randomly divided into two groups, and restored with SonicFill bulk-fill and Filtek Z250 conventional composite along with Single Bond 2 adhesive. The teeth were coated with two layers of nail varnish to 1 mm around the restoration margins, and the apices were sealed with wax. The teeth underwent 1500 thermal cycles and incubated at 37°C for 24 h. They were then immersed in 1 M silver nitrate in the dark, rinsed with water, immersed in developing solution for 12 h, and exposed to fluorescent light. Next, they were mesiodistally sectioned, and digitally photographed under a stereomicroscope at ×10 magnification. The dye penetration depth was measured by a blind observer, and analyzed by the Mann-Whitney U test (α = .05).

RESULTS

No significant difference existed in microleakage between the two composite groups at the enamel (p = .76) or dentin (p = .16) margins. In both composite groups, microleakage at the dentin margins was significantly greater than that at the enamel margins (p = .000).

CONCLUSION

Considering the absence of a significant difference in microleakage, SonicFill bulk-fill composite can be used as an alternative to Filtek Z250 conventional composite for restoration of primary molars to benefit from its advantages such as simpler and faster application.

Does Bleaching Affect the Microleakage of Class II Restoration with Bulk-Fill Composite?

Introduction

The use of technology in bulk-fill composites (BCs) has reduced the stresses caused by polymerization shrinkage, debonding, microleakage, or posttreatment sensitivity in them. This study was conducted to determine whether bleaching affects the microleakage of class II restoration with bulk-fill material.

Materials and Methods

This laboratory study was performed on 40 normal human premolars in 4 groups (n = 20). Class II cavities were prepared in mesial and distal surfaces of the teeth with dimensions of 2 × 2 × 4 mm. Then, based on the bleaching process by 20% carbamide peroxide gel and using two types of composites, the restored cavities were randomly divided into 4 groups: (1) CC without bleaching (CC group), (2) BC without bleaching (BC group), (3) CC with bleaching (CCB group), and (4) BC with bleaching (BCB group). Then, the samples were thermocycled for 1000 cycles at a temperature range of 5–55°C, and they were immersed in 0.6% alkaline fuchsine in order to penetrate into the pigment for 24 h. After cutting, the samples were placed under a stereomicroscope (40%) to determine microleakage. The data were analyzed using one-way analysis of variance (ANOVA), and a p value <0.05 was considered as statistically significant.

Results

Microleakage was determined in the CC group (0.97 ± 0.42), BC group (1.08 ± 0.54), CCB group (1.19 ± 0.37), and BCB group (0.30 ± 0.47). There were also no significant differences in the mean microleakage between the groups. No cases with zero microleakage (no microleakage) and grade 3 of microleakage (pigment penetration into the axial wall) were observed in the samples. Also, a two-by-two comparison of significant differences between CC and BC groups (p=0.89), CC and CCB groups (p=0.45), CC and BCB groups (p=0.11), BC and CCB groups (p=0.87), BC and BCB groups (p=0.41), and CCB and BCB groups (p=0.86) showed that the difference was not statistically significant.

Conclusion

Results showed no difference between microleakage of BC and CC with and without bleaching, and bleaching had the same effect on microleakage of these two types of composites.

Comparative Evaluation of Internal Margin Adaptation and Integrity of Class I Preparations using Two Composites: An In Vitro Study

Aim and Objectives:

The aim of this study is to evaluate the internal margin adaptation and integrity of Class 1 preparations using two composites types (bulk fill/conventional) with two placement methods (4/2 mm increments).

Materials and Methods:

Class 1 preparations of 4 mm × 4 mm dimensions were made on 30 extracted human mandibular molars. They were randomly divided into three groups; among them, in Group 1 (n = 10), cavities were filled with SureFil SDR Bulk Fill, Group 2 (n = 10) cavities were filled with Filtek Bulk Fill of 4 mm increments in both groups, and in Group 3 (n = 10), cavities were filled with conventional composite Filtek Z350 with 2 mm increments. Samples were sectioned occlusogingivally. Then, dye was on internal margins, and images of each specimen were recorded using a digital camera to evaluate the marginal integrity and adaptation of restorative material to the tooth surface with image analysis software. Then, collected data were put under the statistical analysis with analysis of variance test and post hoc Tukey's test.

Results:

There was no significant difference in overall dye penetration in bulk fill and conventional (incremental fill) composite resins; however, when dye penetration was evaluated at different locations, within enamel and mid-dentin, significantly more gap-free margins were found than at the pulpal interface. Filtek Bulk Fill and conventional composite (Filtek Z350) showed comparatively more dye penetration toward the pulpal interface compared to SDR Bulk Fill.

Conclusion:

There were no significant differences in percentage of gap-free margins between fill types for any of the composite materials. The proportions of gap-free margin were less at the pulpal interface and mid-dentin portions and enamel when filled with 4 and 2 mm increments.

Microhardness Assessment of Two Nanohybrid Composite Resins with Two Curing Technologies

AIM:This study evaluated the influence of two light sources on the microhardness of two recent composite resins. MATERIALS AND METHODS: A total of 120 specimens were prepared and divided into two groups according to the composite resin restoration used (Tetric EvoCeram Bulk fill) and (Universal Nanohybrid Mosaic). Each group was subdivided into four subgroups according to the curing sources used with different curing duration’s laser curing system (SIROLaser) for 10, 15, and 20 s and conventional blue light system (LED) for 20 s. A microhardness testing machine was used to assess the microhardness of Tetric EvoCeram Bulk fill and Universal Nanohybrid Mosaic. Two-way ANOVA statistical test was used for comparing resin composite and curing energy effect on different variable studied. One-way ANOVA followed by pair-wise Tukey’s post hoc tests was performed to detect significance between each composite subgroups and t-test for subgroups. P ≤ 0.05 is considered statistically significant in all tests. RESULTS: LED cured Tetric EvoCeram Bulk fill composite resin recorded higher bottom to top ratio (B/T ratio) than laser cured one and the difference in B/T ratio between both energies was statistically non-significant. LED cured Mosaic composite resin recorded higher B/T ratio than laser cured one . The difference in bottom to top ratio between both curing devices was statistically significant. CONCLUSION: SIROLaser Blue laser device increases the degree of polymerization and achieves better curing of composite resins than LED. RECOMMENDATION: Different types of curing systems are present in the dental practice. The use of SIROLaser Blue laser to photopolymerize composite resin will offers proper polymerization properties.

Functional and aesthetic rehabilitation in posterior tooth with bulk-fill resin composite and occlusal matrix

The restorative procedure in posterior teeth involves clinical steps related to professional skill, especially when using the incremental technique, which may fail in the long term. A recent alternative is bulk-fill resins, which can reduce polymerization shrinkage, decreasing clinical problems such as marginal leakage, secondary caries, and fracture. This scientific study aims to report a clinical case using bulk-fill resin with an occlusal matrix. As determined in the treatment plan, an acrylic resin matrix was produced to establish an improved oral and aesthetic rehabilitation of the right mandibular first molar, which presented a carious lesion with dentin involvement. The occlusal matrix is a simple technique that maintains the original dental anatomy, showing satisfactory results regarding function and aesthetic rehabilitation.