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In the latter part of the 20th century, remarkable developments in new dental materials and technologies were achieved. However, regarding the impact of dental resin-based materials 3D-printed on cellular responses, there have been a limited number of published studies recently. The biocompatibility of dental restorative materials is a controversial topic, especially when discussing modern manufacturing technologies. Three-dimensional printing generates the release of residual monomers due to incomplete polymerization of materials and involves the use of potentially toxic substances in post-printing processes that cannot be completely eliminated. Considering the issue of biocompatibility, this article aims to establish an overview of this aspect, summarizing the different types of biocompatibility tests performed on materials used in 3D printing in dentistry. In order to create this comprehensive review, articles dealing with the issue of 3D printing in dentistry were analysed by accessing the main specialized search engines using specific keywords. Relevant data referring to types of materials used in 3DP to manufacture various dental devices, polymerization methods, factors affecting monomer release, cytotoxicity of unreacted products or post-curing treatments, and methods for assessing biocompatibility were analysed. Although the introduction of new restorative materials used in dental treatments is subject to national and international regulations and standards, it is necessary to investigate them regarding biocompatibility in order to support or deny the manufacturers' statements regarding this aspect. [ABSTRACT FROM AUTHOR]

Clinically, dentists are suggested to immerse autopolymerizing interim fixed restorations in hot water during fabrication. However, this suggestion, without including the best temperature, mostly comes from clinical experience instead of scientific evidence. This in vitro study evaluated the effect of water temperature on the cytotoxicity of interim partial fixed dental prostheses (FDPs) and examined its correlation with residual MMA. Tempron was chosen as the autopolymerizing polymethyl methacrylate material. Tempron was mixed and then soaked in water at different temperatures, except control group (Control air) was not being soaking in water. The specimens were incubated with conditioned medium. The concentration of residual MMA was determined by liquid chromatography-tandem mass spectrometry (LC-MS-MS). The cell viability of human gingival fibroblasts (HGFs) was evaluated by MTT assay. The 60 °C and 80 °C groups exhibited significantly higher cell viabilities than those of the other groups (P < 0.05) at 48 and 72 h. The concentration of residual MMA was highly correlated with this outcome: the higher the concentration of residual MMA detected in the eluates, the poorer the cell viability was; the longer the incubation time was, the stronger the correlation was between the concentration of residual MMA and the cell viability. Autopolymerizing PMMA interim FDPs that are polymerized in water up to at least 60 °C could reduce cell toxicity. Higher water temperature could certainly decrease the amount of residual MMA, which is closely correlated with the outcome of cell viability. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of our study was to determine the amount of eluted triethyleneglycol dimethacrylate (TEGDMA) and to compare the eluted TEGDMA in different composite resins after light curing with conventional halogen light curing unit and light emitting diode (LED). Materials and Methods: The present study was conducted on the two types of composite resins, which were divided equally into four groups – Group I: Denoted as Hybrid-LED, Group II: Denoted as Microhybrid-LED, Group III: Denoted as Hybrid-Halogen Group IV: Denoted as Microhybrid-Halogen. Polymerized specimens of hybrid and microhybrid composite resins were stored in air tight centrifuge tubes at 37°C for 24 h, then extract the monomers in high-performance liquid chromatography (HPLC) grade acetonitrile and water and incubated at 37°C for 24 h. All extracts were analyzed by HPLC. Eluted TEGDMA was detected by ultraviolet detector. The results obtained for TEGDMA were computed and analyzed using the one-way ANOVA and independent samples F -test at significance level 0.05. Results and Conclusions: Elution of TEGDMA from all the samples of Group III (Hybrid-Halogen) was greatest and from Group II (Microhybrid-LED) was lowest. The sequence of TEGDMA elution was Group III > Group I > Group IV > Group II. From our results, we can conclude that the LED light curing unit may be more efficient than standard halogen light curing unit. The extractable quantities of composite resin components should be minimized. Furthermore, all ingredients of a dental composite should be declared by the manufacturers, in order to identify those substances in a product which may cause adverse side effects in patients and dental personnel. [ABSTRACT FROM AUTHOR]

A novel biocomposite with poly(methyl methacrylate) as resin containing Salvadora persica powders was elaborated. In this study, for the first time, S. persica was used to enhance the bioactive performance of dental restoration materials. Material characterization was carried out both on bare materials and on the elaborated biocomposite (30 wt% of S. persica). X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, and high-performance liquid chromatography techniques were conducted to perform material characterization. The obtained results linked to dental material showed the presence of the organic chemical compounds of S. persica, which are responsible for biological activities, and the presence of mineral chemical compounds of S. persica, which are useful for dental applications and health. They also revealed the absence of toxic residual monomers. In addition, they proved the antioxidant activities proof of elaborated composite related to total polyphenol flavonoid content. Finally, they exhibited the antibacterial activity of S. persica and the composite. [ABSTRACT FROM AUTHOR]

Giomers are hybrid dental materials with controlled fluoride release properties. The aim of this study was to characterise a new experimental flowable giomer (G) in comparison to three commercial flowable giomers: Beautifil flow Plus X F00 (B-F00), Beautifil flow F02 (B-F02) and Beautifil flow Plus X F03 (B-F03), Shofu, Kyoto, Japan. The studied properties are fluoride ion release, residual monomers release and mechanical properties. The data analysis was performed using the ANOVA test and Tukey test for post hoc comparisons between groups. During the first day of the fluoride releasing measurement, the following classification resulted: B-F02 ˃ B-F03 ˃ B-F00 ˃ G and at the end of the investigation period, at 60 days: B-F02 ˃ B-F03 ˃ G ˃ B-F00. The experimental giomer released a lower percentage of total residual monomers than the commercial giomers. The highest value for the mechanical properties was recorded for the commercial giomers. The experimental giomer registered the lowest values for mechanical properties but higher than the imposed standard limit. There were statistically significant differences between the analyzed materials, in terms of fluoride releasing, residual monomer releasing and mechanical properties. [ABSTRACT FROM AUTHOR]

• Biocompatibility of 3 D printed splints versus milled and hand-made. • Elution of monomers from a 3 D printed splint polymer in water and methanol. • Residual monomers in 3 D printed splint. The elution of unpolymerized (co-)monomers and additives from methacrylic resin-based materials like polymethyl methacrylate (PMMA) can cause adverse side effects, such as mutagenicity, teratogenicity, genotoxicity, cytotoxicity and estrogenic activity. The aim of this study was to quantify the release and the cytotoxicity of residual (co-)monomers and additives from PMMA-based splint materials under consideration of real splint sizes. Three different materials used for additive (3D printing), subtractive (milling) and conventional (powder and liquid) manufacturing were examined. The splint materials SHERAprint-ortho plus (additive), SHERAeco-disc PM20 (subtractive) and SHERAORTHOMER (conventional) were analysed. 16 (n = 4) sample discs of each material (6 mm diameter and 2 mm height) were polished on the circular and one cross-section area and then eluted in both distilled water and methanol. The discs were incubated at 37 °C for 24 h or 72 h and subsequently analysed by gas chromatography/mass spectrometry (GC/MS) for specifying and quantifying released compounds. XTT-based cell viability assays with human gingival fibroblasts (HGFs) were performed for Tetrahydrofurfuryl methacrylate (THFMA), 1,4-Butylene glycol dimethacrylate (BDDMA) and Tripropylenglycol diacrylate (TPGDA). In order to project the disc size to actual splint sizes in a worst-case scenario, lower and upper jaw occlusal splints were designed and volumes and surfaces were measured. For SHERAeco-disc PM20 and for SHERAORTHOMER no elution was determined in water. SHERAprint-ortho plus eluted the highest THFMA concentration of 7.47 μmol/l ±2,77 μmol/l after 72 h in water. Six (co-)monomers and five additives were detected in the methanol eluates of all three materials tested. The XTT-based cell viability assays resulted in a EC 50 of 3006 ± 408 μmol/l for THFMA, 2569.5 ± 308 μmol/l for BDDMA and 596.7 ± 88 μmol/l for TPGDA. With the solvent methanol, released components from the investigated splint materials exceeded cytotoxic concentrations in HGFs calculated for a worst-case scenario in splint size. In the water eluates only the methacrylate THFMA could be determined from SHERAprint-ortho plus in concentrations below cytotoxic levels in HGFs. [ABSTRACT FROM AUTHOR]

Giomers are hybrid dental materials with controlled fluoride release properties. The aim of this study was to characterise a new experimental flowable giomer (G) in comparison to three commercial flowable giomers: Beautifil flow Plus X F00 (B-F00), Beautifil flow F02 (B-F02) and Beautifil flow Plus X F03 (B-F03), Shofu, Kyoto, Japan. The studied properties are fluoride ion release, residual monomers release and mechanical properties. The data analysis was performed using the ANOVA test and Tukey test for post hoc comparisons between groups. During the first day of the fluoride releasing measurement, the following classification resulted: B-F02 ˃ B-F03 ˃ B-F00 ˃ G and at the end of the investigation period, at 60 days: B-F02 ˃ B-F03 ˃ G ˃ B-F00. The experimental giomer released a lower percentage of total residual monomers than the commercial giomers. The highest value for the mechanical properties was recorded for the commercial giomers. The experimental giomer registered the lowest values for mechanical properties but higher than the imposed standard limit. There were statistically significant differences between the analyzed materials, in terms of fluoride releasing, residual monomer releasing and mechanical properties.

The synthesis of the poly(N-isopropylacrylamide-co-2-hydroxypropylmethacrylate) hydrogel along with the analysis of the residual monomers content and influence of monomer and crosslinker molar ratios on the swelling behaviour was investigated. Synthesis of thermosensitive hydrogel based on N-isopropylacrylamide was carried out with the molar ratios of 5, 10, 15 and 20 mol. % of monomer 2- hydroxypropyl-methacrylate, in the presence of ethylene glycol dimethacrylate as a crosslinker (1, 1.5, 2 and 3 mol. %) and 2,2'-azobis(2-methylpropionitril) as an initiator in acetone. The quantities of residual monomers in the synthesized copolymers were determined by HPLC method, ranging from 0.19 to 0.49 % for N-isopropylacrylamide and from 0.13 to 0.63 % for 2-hydroxypropyl-methacrylate, counting the amount of xerogel. The hydrogels swelling ratio depending on time at 20 and 40°C was examined. It was found that hydrogel with 5 mol. % 2-hydroxypropyl-methacrylate and 1 mol. % ethylene glycol dimethacrylate had the highest degree of swelling (α = 29.59) at 20°C, and that hydrogel with 20 mol. % 2-hydroxypropyl-methacrylate and 3 mol. % ethylene glycol dimethacrylate had the lowest swelling degree (α = 2.17) at 40°C.

Abstract: Objectives: The latest LED dental curing devices claim sufficient curing of restorative materials with short curing times. This study evaluates mechanical and chemical properties as a function of curing time of two commercial composite filling materials cured with three different LED lamps. Methods: The composites were Filtek Z250 (3M ESPE) and Tetric EvoCeram (Ivoclar Vivadent) and the LED curing devices were bluephase 16i (Ivoclar Vivadent), L.E.Demetron II (Kerr) and Mini L.E.D. (Satelec). Control samples were cured with a QTH-lamp (VCL 400, Kerr). The wear resistance after simulated tooth brushing, degree of conversion, curing depth, and amounts of residual monomers were measured after different curing times. Results: The results of this study show that short curing time with high-intensity LEDs may influence the bulk properties of the materials, resulting in lower curing depth and increased residual monomer content. The measured surface properties of the materials, degree of conversion and wear resistance, were not affected by short curing times to the same extent. Significance: This study demonstrates that reduced exposure time with high intensity LEDs can result in composite restorations with inferior curing depth and increased leaching of monomers. Dentists are recommended to use sufficient curing times even with high intensity LEDs to ensure adequate curing and minimize the risk of monomer leaching. [Copyright &y& Elsevier]

Abstract: The aim of this in vitro study was to assess different auto-curing resins based on methylmethacrylate (MMA) and new light-curing resins based on urethane dimethacrylate (UDMA) regarding the residual monomers remaining in the resin and their elution over time. Specimens from three auto-curing and three light-curing resins were produced following the manufacturer''s instructions. The concentration of residual MMA and UDMA monomers present in the resins as well as the quantity of the residual monomers released into artificial saliva solution after immersion times of 1, 3, and 7 days were analyzed by high-performance liquid chromatography (HPLC). Data were statistically analyzed using ANOVA and the post hoc Student-Newman–Keuls test. The highest and lowest amounts of residual monomers were found in the group of light-curing resins (p <0.05). The light-curing resins Triad Trans Sheet (0.06wt%) and Primosplint (0.06wt%) released over the entire immersion time of 7 days the smallest (p <0.05) quantity of UDMA. These two light-curing resins based on UDMA exhibited lower elution of residual monomers than auto-curing resins (MMA). The elution characteristics of the residual monomers do not seem to correlate with the residual monomer concentration in resins. These observations demonstrate that the quantitative determination of residual monomers alone - as required by the ISO specification 20795-1 – does not seem to be sufficient for an assessment of the biological properties of different resins. Instead, the evaluation of elution characteristics appears to be of higher clinical relevance. [Copyright &y& Elsevier]

Abstract: A simple and efficient method based on hollow fiber protected headspace liquid-phase in conjunction with high performance liquid chromatography has been introduced for extraction and determination of three residual monomers (2-ethylhexyl acrylate (EHA), vinyl acetate (VA), glycidyl methacrylate (GM)) in polymer latex. Using this methodology, the analytes of interest extracted from a sample are led into organic solvent located inside the porous hollow fiber membrane. Initially, several experimental parameters were controlled and optimized and the optimum conditions were reached with 8 cm neatly cut hollow fibers containing heptanol, which were exposed to the headspace of a 12 mL sample solution containing 20% (w/v) NaCl thermostated at 110 °C and stirred at 800 rpm for 20 min. Finally, 20 μL of the extraction solution was withdrawn into a syringe and injected into HPLC for analysis. The calibration curves were linear (r2 ≥ 0.994) over the concentration range of 0.05–10 mg L−1 for VA and 0.02–10 mg L−1 for other analytes. The relative standard deviation (RSD%) for three-replicate extractions and measurements was below 8.6%. The limits of detection of this method for quantitative determination of the analytes were found within the range of 0.005 to 0.011 mg kg−1 with the enrichment factors within the 5–164 range. The method was successfully applied for determination of residual monomers in polymer latex. [Copyright &y& Elsevier]

This work was intended to develop a new hydrogel of collagen-g-Poly (acrylamide-co-itaconic acid) through chemical cross-linking by graft copolymerization of acrylamide (AM) and itaconic acid (IA) on to collagen (CGN) via redox initiator system of ammonium persulfate (APS) and N, N, N', N'-tetramethylethylenediamine (TMED), in presence of N, N'-methylene bis acrylamide (MBA) as crosslinking agent. Characterization of the hydrogel was done by FT-IR, TGA, SEM, LCMS/MS and HPLC. Valsartan (VAL) was successfully loaded into the prepared hydrogel. CGN-g-P(AM-co-IA) (H10) formulation showed highest swelling capacity as well as VAL release in the biological media and release was controlled up to 24h. The release data of various formulations were fitted to Zero order, First order and Higuchi's kinetic models. It was observed that the release of drug from all the formulations followed Higuchi's kinetic model as its value of coefficient of determination is greater than that of others. [ABSTRACT FROM AUTHOR]

Abstract: Semi-interpenetrating network (SISH-GA) composed of gum arabic and crosslinked copolymer of poly(2-hydroxyethyl methacrylate-co-acrylic acid) was synthesized in the presence of initiator ammonium persulfate (APS), crosslinker N,N′-methylene bis acrylamide (MBA), catalyzed by [CuSO4/glycine] chelate complex and finally loaded nanoparticle inside the networks via in situ reduction of silver nitrate (AgNO3) using trisodium citrate (Na3C6H5O7) as reducing agent. Characterization of the product was performed along with its degradability in Escherichia coli medium. [Copyright &y& Elsevier]

The harmful residual monomers present in acrylic pressure sensitive adhesives (PSAs), used in transdermal drug delivery system (TDDS), should be quantified through a simple, rapid and accurate method. This paper introduces an optimized method for the determination of the residual monomers in acrylic polymers based on a gas chromatographic (GC) technique. Acetone was shown to be the optimum extraction solvent and the extraction time was 80 min. The recovery, precision, accuracy, limit of detection (LOD) and limit of quantification (LOQ) of the method were also studied. The method was relatively accurate and precise with recoveries ranging from 93.2 to 102.7% for each monomer with a relative standard deviation of (%RSD) < 7%. The method proposed in this paper for the determination of residual monomers in solvent-based acrylic PSAs is simple, accuracy and easy to carry out. [ABSTRACT FROM AUTHOR]

Dendrimer/methyl methacrylate co-polymers were studied for use in dental composites. The aim was to determine the effects of methyl methacrylate concentration in the resin mixture and polymerization method on the degree of conversion and residual monomer content of the co-polymers. Two dendrimers were studied, D12 with 12 reactive methacrylate groups and D24 with 24 reactive groups. The concentration of methyl methacrylate varied from 20 wt% to 50 wt% of monomers. Camphorquinone (CQ) was used as the light-activation initiator and 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) as the activator, both in the quantity of 3.0 wt%. Three polymerization methods were used: photo-polymerization, photo-polymerized immediately followed by post-polymerization at 120°C for 15 min, and photo-polymerization followed by post-polymerization after 7 days. The degree of conversion was determined using FT-IR. Residual monomers were extracted with tetrahydrofuran and methanol and analyzed with HPLC. The highest degrees of conversion were 65 and 62%, and the lowest residual monomer contents 1.0 and 1.5% for D12 and D24, respectively. These were measured after heat-induced post-polymerization. For D12, increasing the proportion of methyl methacrylate decreased the degree of conversion and increased the residual monomer content after photo-polymerization. Post-polymerization enhanced the polymerization of the dendrimer co-polymers in respect of degree of conversion and residual monomer content. The present study suggested that the tested dendrimer/methyl methacrylate co-polymers require heat-induced polymerization to reach the generally accepted levels of degree of conversion and residual monomers. [ABSTRACT FROM AUTHOR]

Full-evaporation head-space gas chromatography is a useful technique for the determination of free monomers and other volatile molecules contained in polymer dispersions. The method has a large working range and good repeatability. The absence of contamination in the syringe and the injection line makes it applicable in gas chromatographs equipped with autosamplers. A detailed description of the method and a comparison with the "traditional" head-space gas chromatographic technique and the liquid-injection technique described in ASTM D 4827-93 are presented. [ABSTRACT FROM AUTHOR]

Elution from polymer-based dental filling materials may have a potential impact on the biocompatibility of the materials. Since information from the manufacturers about ingredients in the materials often is incomplete, analyses of eluates from the materials are necessary for a better knowledge about possible harmful compounds. The aim of this study was to identify organic eluates from polymerized samples of two composites, one compomer and one resin-reinforced glass ionomer cement. Samples were immersed in ethanol or Ringer's solution. Organic leachables were analyzed by gas chromatography–mass spectrometry. Identification was confirmed with reference substances, if available. Among components detected were monomers, co-monomers, initiators, stabilizers, decomposition products and contaminants. Thirty-two substances were identified and 17 were confirmed with reference substances. From elution in Ringer's we identified 13 eluates from Tetric Ceram, 10 from Z250, 21 from Dyract and six from Fuji II LC; HEMA, HC and CQ were found in all samples. From elution in ethanol 12 eluates from Tetric Ceram, 18 eluates from Z250, 19 from Dyract and 10 from Fuji II LC were identified. The diversity of eluates from the four materials under study is demonstrated. Owing to variation between the materials, the biocompatibility including the allergenic potential may be different. [ABSTRACT FROM AUTHOR]

Previous studies have shown that extracts of various filling materials, e.g., resin composites, may influence the growth of cariogenic micro-organisms. The purpose of this study was to examine the effects of important resin composite (co)monomers (Bis-GMA, UDMA, TEGDMA, EGDMA) and extracts of two commercial dental composites with similar composition (composite A, Arabesk™; composite S, Superlux™) on the growth of the two cariogenic bacterial pathogens Streptococcus sobrinus and Lactobacillus acidophilus. It was found that neither the monomers Bis-GMA and UDMA, nor the comonomer EGDMA, nor the extract of composite A influenced the growth of S. sobrinus in the log phase. The comonomer TEGDMA and the extract of composite S were found to stimulate growth in the log phase, but this stimulation was not statistically significant. However, EGDMA, TEGDMA, and the extract of composite S did stimulate the total growth of S. sobrinus. In the assays with L. acidophilus, Bis-GMA, UDMA, and the extract of composite A inhibited the growth in the log phase, whereas TEGDMA stimulated it. Furthermore, EGDMA, TEGDMA, and the extract of composite S stimulated the biomass production of L. acidophilus. We conclude from our results that a release of EGDMA and TEGDMA from resin composites should be avoided due to their growth- stimulating effects on the caries-associated micro-organisms S. sobrinus and L. acidophilus. [ABSTRACT FROM AUTHOR]

Purpose: Incomplete polymerisation processes produce several leachable substances. The aim of this work was to review, through existing research and published literature, the genotoxic effect of residual monomers of polymers used in restorative dentistry., Materials and Methods: The selection of published studies was performed on six databases from January 2000 to June 2020. The keywords used were: 'genotoxicity' or 'DNA damage' and 'dental resin' or 'methacrylates' or 'residual monomers'. The selection was carried out according to the parameters and guidelines of the Preferred Reporting Items for Systematic Review and Metanalyses (PRISMA) and was based on patient, intervention, comparison, and outcome (PICO). The inclusion criteria were: in vitro and in vivo studies published in English that evaluated genotoxicity for residual monomers leached from polymers related to restorative dentistry. Case reports and review articles were excluded., Results: Twenty-seven studies met the eligibility criteria. Two categories were constructed based on the experimental design, in vivo and in vitro reports. For the in vitro research, two main methods of assessing DNA damage were reported in selected studies: micronucleus (MN) counting and alkaline comet assay. For in vivo reports, the main method for assessing genotoxic damage was MN counting., Conclusion: From the electronic search, structured data extraction, and analysis by different independent reviewers, results from the present systematic review allow us to conclude that DNA damage is induced by monomers/co-monomers (triethylene glycol dimethacrylate, bisphenol-A-glycidyl methacrylate, urethane dimethacrylate, and 2-hydroxyethyl methacrylate) that are used in restorative dentistry. This systematic review highlights the need for more research on the use of monomers/co-monomers to properly assess clinical biocompatibility.

Reconstructive bone surgery of the head and neck could prove challenging in terms of postoperative healing and recovery. Fighting infection during the healing period is one of the critical factors of the long-term survival of an implant. The aim of the study was to develop an innovative composition suitable for an antibacterial craniofacial implant that should have the capacity to continuously and constantly release the amount of gentamicin necessary to prevent the post-surgical infections. For this purpose, a series of composite materials based on dimethacrylic monomers, hydroxyapatite and ZrO2, with (series B) or without the addition of polymethyl methacrylate (series A), reinforced with woven E-glass fibers (FRC) were obtained using the laminate lay-up process. Gentamicin was included in all FRC sample matrices to confer an antimicrobial effect. The results show that after extraction of the residual monomers from the FRC samples in different solvents (chloroform, acetone and ethyl alcohol), the cumulative amount of released gentamicin after 12 days was between 7.05–11.38 mg for A samples and 11.21–14.52 mg for B samples. The microbiological protocol showed that gentamicin induces a two weeks-lasting antimicrobial effect maintained over the minimal inhibitory concentration for P. aeruginosa and S. aureus. [ABSTRACT FROM AUTHOR]

Objectives: This study aims at evaluating and comparing mechanical, chemical, and cytotoxicological parameters of a commercial brand name composite material against two 'own brand label' (OBL) composites., Methods: Parameters included depth of cure, flexural strength, degree of conversion, polymerization shrinkage, filler particle morphology and elemental analyzes, Vickers hardness, surface roughness parameters after abrasion, monomer elution, and cytotoxicity., Results: The conventional composite outperformed the OBLS in terms of depth of cure (p<0.001), degree of cure at the first and last time intervals (p<0.001), hardness (p<0.001), and post-abrasion roughness (p<0.05). The polymerization volumetric shrinkage ranged from 2.86% to 4.13%, with the highest shrinkage seen among the OBLs. Both Monomer elution from the OBLs was statistically significantly higher (p<0.001). Statistically significantly higher cytotoxicity combined with altered morphology and loss of confluence was detected in the cells exposed to extracts from the OBLs., Conclusions: The OBLs were in general outdone by the conventional composite., Clinical Significance: OBLs restorative materials have become pervasive in the dental market. Manufacturers often promise equal or better characteristics than existing brand-name composites, but at a lower price. Dentists are highly recommended to reconsider utilization of OBLs lacking sound scientific scrutiny, and our findings underscore this recommendation., (Copyright © 2016 Elsevier Ltd. All rights reserved.)