Elution study of unreacted TEGDMA from bulk-fill composite (SDR™ Dentsply) using HPLC

PURPOSE

The study evaluates the dynamics of unreacted TEGDMA monomer elution from new generation of flowable bulk fill composite resin (SDR™ Dentsply).

MATERIAL AND METHODS

Polymerised specimens of SDR™ composite (7mm diameter and 4mm thick) were placed in four solutions: 100% ethanol, 75% ethanol, distilled water and 100% methanol. The concentration of the eluted TEGDMA was measured using the HLPC method after 0.5, 1, 2 and 3h as well as after 1, 3, 7, 14, 21 and 31 days.

RESULTS

During the first 24h of storage in each medium, a significant elution of TEGDMA was observed (100% ethanol - 12.5μg/g, 75% ethanol - 8.4μg/g, distilled water - 5.4μg/g and 100% methanol - 7μg/g). The elution time of the TEGDMA into 100% ethanol, 75% ethanol, distilled water and 100% methanol was 14, 7, 3 and 1 day, respectively. After 31 days, total concentrations of TEGDMA were as follows: 100% ethanol - 16μg/g, 75% ethanol - 9.4μg/g, distilled water - 6μg/g and 100% methanol - 7μg/g.

CONCLUSIONS

The TEGDMA was released from the SDR™ composite into each solution used. The TEGDMA concentration and the time of its elution depend on the type of the solvent. In an aqueous environment, the SDR™ composite exhibits a high chemical stability compared to other solutions. The direct toxicity towards to the dental pulp is established during the first hours after the placement of resin.

The effect of mouth rinses on the color stability of sonicfill and a nanohybrid composite

PURPOSE

The aim of this study was to evaluate the effects of 4 mouth rinses on the color stability of two different resin composites.

MATERIALS AND METHODS

A2 shade sonic-activated bulk fill material SonicFill (Kerr) and conventional nanohybrid composite Filtek Z550 (3M ESPE) were used. Forty disc-shaped specimens (10 mm x 2 mm) were fabricated for both composites and finished using 400-grit SiC paper and polished. After polishing and immersing in distilled water for 24h all specimens were subjected to color measurements. The baseline color values (L*, a*, b*) of each specimen were measured with a colorimeter. Following baseline measurement each composite group was divided into 5 groups: Oral-B Pro Expert Clinic Line Alcoholfree (Oral-B) group, Listerine Tooth Defense Rinse (Listerine) group, Pharmol Zn Mouth rinse (Çözümilaç) group, Nilera Mouth rinse (Nilera) group and Distilled water (control) group. The specimens were incubated in mouth rinses (20 ml) at 37°C for 12 hours and subjected to color measurement. Two-way ANO VA was used for statistical analysis (p<0.05).

RESULTS

SonicFill showed significantly higher discoloration when exposed to Oral-B Pro Expert Clinic Line Alcohol-free, Listerine Tooth Defense Rinse and Pharmol Zn Mouth rinse. The color differences of two resin composites were not statistically significant for distilled water and Nilera Mouth rinse.

CONCLUSION

Within the limits of this study it can be concluded that the SonicFill showed higher discoloration than nanohybrid resin composite Filtek Z550.

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

Context

In pediatric clinic practice, bulk fill composite is gaining importance for shortened clinical time with a limited shrinkage.

Aims

The present study evaluated the 1 year clinical performance of bulk fill composite and conventional composite material in occlusal caries of primary molars.

Settings and Design

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.

Materials and Methods

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.

Statistical Analysis Used

Besides the descriptive statistical methods, the Friedman test and the Wilcoxon Signed Ranks were used.

Results

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).

Conclusions

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.

Mechanical Behaviour of Novel Nanohybrid Resin Composite Using Two Light Cure Systems

INTRODUCTION

Zein-incorporated magnesium oxide nanoparticles (zMgO NPs) were found to be effective against the bacteria S. mutans, S. aureus, E. faecalis and C. albicans, and can impart this antimicrobial effect on the resin composite it is integrated with. However, the effect of different light curing systems on the mechanical properties of this novel biomaterial has yet to be investigated. The objective of this study was to assess the effect of light-emitting diode (LED) and quarts-tungsten halogen (QTH) light curing systems on the compressive strength, flexural strength, and microhardness of bulk-fill resin composite modified with zMgO NPs.

METHODOLOGY

A Teflon mold was used to fabricate 180 bulk-fill composite samples with concentrations of zMgO NPs at 0%, 0.3% and 0.5% (n = 60). Samples of each group were allocated to light curing by LED or QTH, after which 10 samples of each group were allotted to a mechanical test. Characterization of the specimens was performed by X-ray diffraction, field emission scanning electron microscopy and Fourier transform infrared spectroscopy. Two-way ANOVA and Tukey's post-hoc test was conducted at P = .05 to determine significance.

RESULTS

The characterization revealed a uniform distribution of nanoparticles in the matrix and the formation of a new hybrid composite that maintained its properties. The compressive strength of the 0.3% zMgO composite for the QTH group significantly increased, while the remaining groups underwent no significant change. There was no significant difference among the groups for the flexural strength and microhardness tests.

CONCLUSION

The modified composites' compressive strength, flexural strength, and microhardness improved or remained consistent. Long-term clinical studies can further substantiate the enhanced resin composite.

CLINICAL RELEVANCE

The modified composite will exhibit similar or improved mechanical properties whether an LED or QTH light cure device is used. The addition of an antimicrobial effect to bulk-fill resin composite will aid in the prevention of secondary caries.

Effects of different surface treatments and adhesive self-etch functional monomers on the repair of bulk fill composites: A randomised controlled study

OBJECTIVE

To evaluate the effect of different adhesive protocols on the microtensile bond strength (μTBS) and integrity of the repaired bulk fill composite interface.

METHODS

Two hundred and seventy composite blocks made of bulk fill composites of different viscosity were randomly assigned to 18 surface conditioning groups (n = 15/group). The universal adhesive systems used were Heliobond™, Tokuyama bond force II™ and Scotchbond Universal™. A nanohybrid resin composite was applied as the repair material. Negative and positive control groups were included. Stick shape specimens of each group were subjected to μTBS testing. Representative samples from all test groups were subjected to microscopic, profilometric and SEM examination to determine their mode of failure. The data were analysed statistically using two-way ANOVA test, Tukey's test and the independent t-test (α = 0.05).

RESULTS

The mean μTBS of all test groups ranged between 28.5 and 46.8 MPa and varied with the type of adhesive system employed. Significantly highest μTBS values were obtained when Tokuyama bond force II™ and Scotchbond Universal™ adhesives were used (p < 0.01) which were comparable to the coherent strength of the bulk fill resin composite in the positive control groups (p > 0.05). The viscosity of the bulk fill composite did not significantly influence repair bond strength. The microscopy and SEM examination of the failed interfaces revealed a mixture of adhesive and cohesive failures.

CONCLUSIONS

Under the tested conditions, significantly greater μTBS of repaired bulk fill composite was achieved when the substrate surface was treated with adhesive systems containing a functional monomer.

CLINICAL SIGNIFICANCE

Eff ;ecting a repair of a bulk fill resin composite restoration with the application of a functional monomer containing adhesive system, such as Tokuyama Bond Force II™ or Scotchbond Universal™, would seem to enhance the interfacial bond strength and integrity of the repaired resin composite interface.

Bond Strength and Fracture Resistance of Flowable Bulk Fill Composite Posts and Cores in Endodontically Treated Teeth

OBJECTIVES

Smart dentin replacement (SDR) is a new flowable bulk fill composite with many useful characteristics such as low viscosity and higher depth of cure. This study aimed to evaluate the bond strength and fracture resistance of flowable bulk fill composite posts and cores versus that of fiber posts and cores.

MATERIALS AND METHODS

Forty intact, extracted human maxillary central incisor roots were endodontically treated. Group A (n = 20) was prepared for the composite space and group B (n = 20) was prepared for the fiber post space. Group A and B were divided into two subgroups A1 and A2 and B1 and B2, respectively (10 roots for each subgroup). Root canal spaces of group A1 were filled with SDR composite, X-Post fiber post with Core X Flow composite was inserted into the root canal spaces of group B1. Group A2 was restored using SDR and group B2 was restored using post and core composite. Five hundred thermocycles were applied for the sample. Bond strength values were measured for segments in A1 and B1. Fracture force values were measured for specimens of A2 and B2.

RESULTS

No significant difference was observed between the two paired groups (A1 and B1) and (A2 and B2) in bond strength and fracture force values.

CONCLUSION

SDR could be used for restoring endodontically treated teeth.

Clinical performance of polyethylenefiber reinforced resin composite restorations in endodontically treated teeth: (a randomized controlled clinical trial)

AIM

The purpose of this study was to evaluate the performance of polyethylene fiber reinforced resin composite fillings compared to bulk fill resin composite fillings in endodontically treated teeth over a two-year monitoring period.

METHOD

A total of 240 individuals with endodontically treated lower molars and a moderate amount of tooth structure were divided into two equal groups of 120 each. One group received polyethylene fiber reinforced bulk fill resin composite restorations while the other group received only bulk fill resin composite restorations, both applied as per manufacturer guidelines. Two proficient experienced blinded assessors assessed the restorations using modified USPHS criteria at baseline, 6, 12, and 24 months.

STATISTICAL ANALYSIS USED

Data analysis involved the utilization of Mann-Whitney U, Friedman's test, and Nemenyi post hoc test, with age data being displayed as mean and standard deviation. The significance level was established as p < 0.05, and R software was utilized for statistical analysis.

RESULTS

There were no notable distinctions in any parameters or scores between the intervention and comparator groups at various time points. Alpha scores were present for retention, gross fracture, and secondary caries at all follow up intervals.

CONCLUSION

Both direct resin composite restorations reinforced with polyethylene fibers and direct bulk fill resin composite restorations placed in endodontically treated molars with moderate remaining tooth structure demonstrated satisfactory clinical outcomes during a 24-month follow-up period.

CLINICAL RELEVANCE

Bulk fill resin composites directly placed in endodontically treated molars with moderate remaining tooth structure showed promise as a treatment option over a two-year period.

CLINICAL TRIAL REGISTRATION

(06-01-2022) on https://ClinicalTrials.gov with the ID (NCT05180903).

Fracture resistance of endodontically treated teeth restored with Zirconia filler containing composite core material and fiber posts

Objectives:

To assess the fracture resistance of endodontically treated teeth with a novel Zirconia (Zr) nano-particle filler containing bulk fill resin composite.

Methods:

Forty-five freshly extracted maxillary central incisors were endodontically treated using conventional step back preparation and warm lateral condensation filling. Post space preparation was performed using drills compatible for fiber posts (Rely X Fiber Post) on all teeth (n=45), and posts were cemented using self etch resin cement (Rely X Unicem). Samples were equally divided into three groups (n=15) based on the type of core materials, ZirconCore (ZC) MulticCore Flow (MC) and Luxacore Dual (LC). All specimens were mounted in acrylic resin and loads were applied (Universal testing machine) at 130° to the long axis of teeth, at a crosshead speed of 0.5 mm/min until failure. The loads and the site at which the failures occurred were recorded. Data obtained was tabulated and analyzed using a statistical program. The means and standard deviations were compared using ANOVA and Multiple comparisons test.

Results:

The lowest and highest failure loads were shown by groups LC (18.741±3.02) and MC (25.16±3.30) respectively. Group LC (18.741±3.02) showed significantly lower failure loads compared to groups ZC (23.02±4.21) and MC (25.16±3.30) (p<0.01). However groups ZC (23.02±4.21) and MC (25.16±3.30) showed comparable failure loads (p=0.23).

Conclusions:

Fracture resistance of endodontically treated teeth restored with Zr filler containing bulk fill composite cores was comparable to teeth restored with conventional Zr free bulk fill composites. Zr filled bulk fill composites are recommended for restoration of endodontically treated teeth as they show comparable fracture resistance to conventional composite materials with less catastrophic failures.

An evaluation of dental paste-like bulk-fill composite wear using intra-oral scanner

This study evaluates the wear resistance of dental paste-like bulk-fill composites compared to conventional paste-like composite resins using an intraoral scanner and 3-D analyzing software. Six different dental composite materials, including five bulk-fill composites and one conventional composite, were tested alongside natural human enamel as a control group. A computer-controlled chewing simulator for wear testing. A one-way ANOVA test was used to identify any significant differences between the means of the tested dental composite materials α=0.05. The results showed variability among bulk-fill composites, with some demonstrating wear resistance similar to conventional composites (p<0.05). Human enamel displayed the lowest wear values, but some bulk-fill composites matched this resistance(p>0.05). Significant variability was observed among bulk-fill composites but the results were comparable to those of conventional composites. The enamel control group demonstrated the lowest wear values, with some bulk-fill composites showing similar wear resistance. This study provides valuable information about the wear resistance of contemporary bulk-fill composite materials, commonly used in current clinical practice, contributing to enhancing clinical procedures.

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.

Comparison of Cuspal Deflection and Microleakage of Premolar Teeth restored with Three Restorative Materials

AIM

This study aimed to assess cuspal deflection and micro-leakage of mesio-occluso-distal (MOD) cavities in premolar teeth restored with three different tooth-colored restorative materials to determine the effect of polymerization shrinkage stress over time.

MATERIALS AND METHODS

The MOD cavities (4 mm depth) were prepared in 30 sound human maxillary premolars. The teeth were randomly divided into three groups (n = 10). The teeth were then restored with Filtek P60 (group I), X-tra fil (group II), and Admira Fusion x-tra (group III). Cuspal deflection was assessed after 5 minutes, 24 hours, 48 hours, and 7 days by measuring the intercuspal distance. After restoring the teeth, they were subjected to 1,000 thermal cycles and were then immersed in 2% methylene blue for 24 hours. After vertical section of teeth, they were observed under a stereomicroscope to assess micro-leakage. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey's honest significant difference (HSD) post hoc test. Friedman test was used to compare different time points in each group and nonparametric Mann-Whitney test was applied to assess microleakage (a < 0.05).

RESULTS

The mean cuspal deflection was significantly different in the three groups (p < 0.001). The highest deflection was noted in Filtek P60 (14.8 ± 1.9) and the lowest was noted in Admira Fusion x-tra (7.4 ± 1.4 μm). Cuspal deflection significantly decreased after 7 days, but did not return to the baseline value. Admira Fusion x-tra showed significantly less deflection after 7 days (p < 0.001), but the other two groups were the same (p = 0.3). Microleakage was not significantly different among the three groups (p > 0.05).

CONCLUSION

The lowest cuspal deflection was noted in Admira Fusion x-tra, although marginal microleakage was not significantly different among the groups.

CLINICAL SIGNIFICANCE

As the lowest cusp deflection was noted in Admira Fusion x-tra, this restorative material can be suitable for esthetic restoration of extensive posterior cavities.

Analysis of the bond strength between conventional, putty or resin-modified calcium silicate cement and bulk fill composites

BACKGROUND

The aim of this study was to evaluate the shear bond strength of three different calcium silicate-based cements (CBCs) with two different bulk-fill composite resins (CRs).

METHODS

Plexiglas moulds with a diameter of 4 mm and a thickness of 2 mm were prepared (n = 60). The Biodentine, NeoPutty and MTA Cem LC samples were randomly divided into two subgroups containing 10 samples each. Surfaces of samples were air dried and Single Bond universal adhesive was applied. Cylindrical plastic capsules of 4 mm height and 2 mm inner diameter belonging to Filtek Bulk-fill and EverX Posterior CRs were centred on coating material and polymerized for 20 s. After shear bond strength (SBS) testing, all samples were examined by scanning electron microscopy (SEM) to identify failure patterns. Three samples, one from each group, were prepared to evaluate chemical composition of CBCs and examined with an energy dispersive X-ray spectroscopy for surface elemental analysis.

RESULTS

The values obtained from the tests were evaluated as statistically significant (P < 0.05). After SBS testing, the difference between all CBCs was statistically significant in both CRs.

CONCLUSION

According to the findings in this study, it was concluded that MTA Cem LC had highest SBS values in both CRs. © 2023 Australian Dental Association.

Effect of Ionizing Radiation on the Mechanical Properties of Two Dental Materials Commonly Used in Primary Teeth

Aim

The purpose of this in vitro study was to evaluate the effect of radiotherapy on flexural strength, microhardness, and surface roughness of bulk fill composite (X-tra fil) and glass ionomer (EQUIA Forte HT).

Materials and methods

A total of 40 specimens were prepared for each test and were divided into two groups according to the material used (composite or glass ionomer cement), and each group was divided into two subgroups (n = 10) according to radiation condition, irradiated subgroup, subjected to 50 Gy by multienergy linear accelerator delivered in one shot and control subgroup.

Results

Control samples of flexural strength and microhardness had a significantly higher value than irradiated samples in both materials. Regarding the surface roughness, irradiated samples had a significantly higher value than the control samples in both materials.

Conclusion

Irradiation with a linear accelerator had a negative impact on the flexural strength and microhardness of both materials. Moreover, it increased the surface roughness for both materials. Bulk fill composite is the dental restorative material of choice in head and neck cancer patients undergoing radiotherapy due to its high mechanical properties before and after radiation.

How to cite this article

Nagi BM, El-Korashy DI, Amin A El-S, et al. Effect of Ionizing Radiation on the Mechanical Properties of Two Dental Materials Commonly Used in Primary Teeth. Int J Clin Pediatr Dent 2023;16(5):758-762.

Effect of carbonated beverages on the color stability of bulk and flowable composite resin

Tooth discoloration is considered as one of the most common dental problems among people, and in dentistry, the most common cases are claimed after the restoration. Therefore, in this research, we aim to evaluate the effect of carbonated beverages on the color stability of bulk and flowable composite resin. For the study, 12 composite disc samples were made using the standard dimensions of 10 mm diameter and 2 mm thick. To find the color stability, we used a VITA Easyshade spectrophotometer. We used two different composites of bulk fill and flowable composite resin; the composite brand we used was Tetric ecom plus; as an immersion medium, we used two different carbonated beverages, and the chosen beverages were Appy Fizz and 7Up. 24-h and 7-day postimmersion color stability was evaluated. In the results of postimmersion, we have found the Delta E value for 24 h immersion of flowable and bulk fill composite as 5.8115 and 7.4378, respectively; similarly, the Delta E value for 7 days immersion of flowable and bulk fill composite was 9.9559 and 10.1028, respectively. Using the independent "t"-test, we found that the significance is 0.633 and 0.328, which was statistically not significant. In the present study, when immersed in Appy Fizz juice and 7Up juice, bulk fill composite resins have shown greater discoloration when compared to flowable composite resin material. Thus, the flowable composite resin samples were more color stable.

Clinical, radiographic and biochemical assessment of proximal cavities restored with composite resin using incremental vs. bulk packing techniques: One-year randomized clinical trial

BACKGROUND

Bulk-fill resin composites may suffer from recurrent caries around compound proximal restorations in posterior teeth, especially at the proximo-gingival interface.Over 12 months, will the bulk fill technique affect the caries recurrence rate at gingival margins when compared to the conventional incremental packing technique? How early will the first clinical, radiographical, and biochemical evidence of caries recurrence occur?

METHODS

After randomization, in 30 patients with two compound (OM or OD) supragingival lesions, one tooth was restored using the bulk fill technique on one side (group 1) (n = 15). In contrast, the other tooth on the other side was restored utilizing the incremental layering technique (group 2) (n = 15). Both teeth received restorative material (X-tra fil, Voco, Cuxhaven, Germany). The FDI criteria were used to evaluate restorations. As for the periodontal assessment, the gingival index, plaque index, papillary bleeding scoring index and periodontal pocket depth were evaluated. The gingival crevicular fluid (GCF) specimens were gathered, and MMP-9 was extracted and quantitated by ELISA. A customized radiographic template was designed, and 3D printed digital bitewing radiographs were taken. Assessments were done clinically, radiographically and biochemically at baseline (1 week) and after 3, 6 and 12 months. Data was statistically analyzed.

RESULTS

The null hypothesis was accepted clinically; no statistically significant differences appeared between bulk and incrementally filled posterior restorations. As for the radiographic assessment, the null hypothesis was accepted except for increased periodontal ligament width at 3 months. The null hypothesis for the biochemical evaluation was rejected as there were significant changes in levels of MMP-9 at different testing times.

CONCLUSIONS

1. With similar results but less sensitivity and significant time saving, the bulk fill technique can be considered an efficient alternative to the incremental fill technique in restoring proximal cavities. 2. Early evidence of caries recurrence can be correlated to an increase in the MMP-9 level in gingival crevicular fluid, followed by an increase in radiographic periodontal ligament width measurement.

TRIAL REGISTRATION

An ethical approval from the Research Ethics Committee at the Faculty of Dentistry, October 6 University, (Approval No. RECO6U/5-2022). The study was registered at the Pan African Clinical Trials Registry on 24/07/2023 with an identification number (PACTR202307573531455).