Cytotoxicity and cytokine expression induced by silorane and methacrylate-based composite resins.

OBJECTIVE: The aim of this study was to evaluate cytotoxicity and cytokine production induced by light-cured or non-light-cured methacrylate-based and silorane composite resins in RAW 264.7 macrophages. MATERIAL AND METHODS: Cells were stimulated with the extracts from light-cured or non-light-cured composite resins. After incubation for 24 h, cytotoxicity was assessed with the lactate dehydrogenase (LDH) and methyl thiazolyl tetrazolium (MTT) assays, and total protein was quantified using the Lowry method. TNF-α detection was examined with an enzyme-linked immunosorbent assay (ELISA) conducted with cell supernatants after cell stimulation for 6, 12, and 24 h. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey's post hoc test (α=0.05). RESULTS: KaloreTM and FiltekTM Silorane were cytotoxic with or without light curing (p<0.05) after 24 h of incubation. KaloreTM stimulated the early production of TNF-α in comparison with control (p<0.05), whereas FiltekTM Silorane did not affect TNF-α levels after 6 and 12 h (p>0.05). However, after 24 h FiltekTM Silorane inhibited the production of TNF-α (p<0.05). CONCLUSIONS: KaloreTM and FiltekTM Silorane were cytotoxic regardless of light curing. The extract obtained from KaloreTM after 15 days of incubation stimulated the production of TNF-α, unlike that obtained from FiltekTM Silorane.

Cytotoxicity and cytokine expression induced by silorane and methacrylate-based composite resins

ABSTRACT The successful use of composite resins in Dentistry depends on physicochemical properties, but also on the biological compatibility of resins, because of the close association between pulp and dentin. Objective The aim of this study was to evaluate cytotoxicity and cytokine production induced by light-cured or non-light-cured methacrylate-based and silorane composite resins in RAW 264.7 macrophages. Material and Methods Cells were stimulated with the extracts from light-cured or non-light-cured composite resins. After incubation for 24 h, cytotoxicity was assessed with the lactate dehydrogenase (LDH) and methyl thiazolyl tetrazolium (MTT) assays, and total protein was quantified using the Lowry method. TNF-α detection was examined with an enzyme-linked immunosorbent assay (ELISA) conducted with cell supernatants after cell stimulation for 6, 12, and 24 h. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test (α=0.05). Results KaloreTM and FiltekTM Silorane were cytotoxic with or without light curing (p<0.05) after 24 h of incubation. KaloreTM stimulated the early production of TNF-α in comparison with control (p<0.05), whereas FiltekTM Silorane did not affect TNF-α levels after 6 and 12 h (p>0.05). However, after 24 h FiltekTM Silorane inhibited the production of TNF-α (p<0.05). Conclusions KaloreTM and FiltekTM Silorane were cytotoxic regardless of light curing. The extract obtained from KaloreTM after 15 days of incubation stimulated the production of TNF-α, unlike that obtained from FiltekTM Silorane.

Correlation of elution and sensitivity of cell lines to dental composites.

OBJECTIVES: The aim of the present study was to understand the role played by composition on the elution of dental composites and the subsequent cytotoxicity, the sensitivity of different cell lines to eluates on a temporal basis and the correlation of the two parameters elution and cytotoxicity. METHODS: LC-MS was done to analyze the eluates. MTT assay was done to assess cytotoxicity on two cell lines. RESULTS: Eluates were found to have matrix monomers, photoinitiators and their degradation products. The short-term viability of other mammalian cell line was inferior to human cell line. However human cell line became more sensitive to long-term incubation with composites. There was a strong inverse correlation to elution of monomers and photoinitiators and cell viability for both cell lines. Bisphenol A elution did not correlate to cell viability. SIGNIFICANCE: Other mammalian cell lines may be more sensitive to acute toxin build-up than human cell line while the latter may be more sensitive to prolonged toxin exposure. Dimethacrylate based composites elute more and exert strong cytotoxicity than Ormocer and Silorane based composites. Most of the eluates correlated linearly to cytotoxicity.

Gene expression analysis of conventional and interactive human gingival cell systems exposed to dental composites.

OBJECTIVES: The aim of this study was the detection of putative gene expression-related effects of dental composites in conventional and interactive gingival cell systems. METHODS: Conventional monoculture (MC) and interactive cell systems (ICS) comprising human gingival fibroblast (HGF) and immortalized human gingival keratinocytes (IHGK) were exposed for 24h and 7 days according to ISO10993-12:2012 manufactured eluates of different composites (Ceram X(®), Filtek™ Supreme XT, Filtek™ Silorane, Fusio™ Liquid Dentin, and Vertise™ Flow). qRT-PCR-based mRNA analysis for biomarkers indicating cell proliferation, differentiation, apoptosis, inflammation, and adhesion was performed. Apoptotic cells were quantified by annexin-V labeling. RESULTS: Due to low RNA amounts, qPCR could not be performed for Vertise™ Flow and Fusio™ Liquid Dentin at day 7. At 24h, flowables yielded increased transcription for biomarkers of inflammation and apoptosis in IHGK, irrespective of the cell system. HGF cultures displayed lower transcription for cell adhesion markers in both cell systems. Filtek™ Supreme XT showed increased differentiation by elevated filaggrin gene expression in both cell systems for IHGK at day 7, while Filtek™ Silorane and Ceram X(®) yielded elevation of inflammation biomarkers in both cell types. Annexin-V labeling revealed high apoptosis rates for both flowables and Filtek™ Supreme XT for IHGK, while low rates were detected for Filtek™ Silorane and Ceram X(®). SIGNIFICANCE: Among the composites evaluated, exposition of IHGK and HGF in conventional and interactive cell systems demonstrated most pronounced gene expression alterations in response to flowables, coinciding with elevated levels of apoptosis.

Cytotoxic effect of silorane and methacrylate based composites on the human dental pulp stem cells and fibroblasts

OBJECTIVES: The aim of this study was to compare the cytotoxic effect of a methacrylate-based and a siloranebased composite on the human dental pulp stem cells (DPSCs) versus human dental pulp fibroblasts (DPFs).Study DESIGN: Samples of the Filtek Z250 and P90 were polymerized and immersed in the culture medium to obtain extracts after incubation for one, seven and 14 days. Magnetic cell sorting based on the CD146 expression was performed to purify DPSCs and DPFs. After incubation of both cells with the extracts, cytotoxicity was determined using the MTT test. RESULTS: For the extracts of first and seventh day, both composites showed significantly lower cytotoxicity on DPSCs than DPFs (p = 0.003). In addition, there was a significant difference in the time-group interaction of both materials indicating different cytotoxic behaviours (p = 0.014). In contrast to Z250, exposure to the 14th day extract of P90 resulted in higher cell viability compared to that of day seven. CONCLUSIONS: DPSCs are less susceptible to the cytotoxic effect of the composites than DPFs. Compared to Z250, the cytotoxic effect of silorane-based composite decreases as the time passes on. This difference should be considered, particularly in deep cavities, in order to preserve the regenerative capacity of the pulp

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Effects of leached components from silorane and methacrylate-based dental composites on the male mice reproductive system.

BACKGROUND: This study aimed to investigate the potential toxic effects of leached components from either a methacrylate-based composite (Filtek Z250) or a silorane-based composite (Filtek P90) on the male mice reproductive system. METHODS: Sixty adult Syrian male mice were divided into six groups. In test groups, leached components from composite specimens in artificial saliva or 75% aqueous ethanol solution were administered intragastrically daily for 28 days. The mice were then euthanized and the following reproductive parameters recorded: body weight changes; weight of paired testes; testis volume; Gonadosomatic Index (GSI); sperm motility; sperm viability; daily sperm production and epididymal sperm count. RESULTS: There were no significant differences in body weight changes, weight of paired testes, GSI, testis volume, epididymal sperm count, and daily sperm production between groups. Sperm motility and sperm viability were significantly lower in all the test groups in comparison to the control groups. In addition, they were significantly lower in the test groups in which composite samples were immersed in aqueous ethanol solution. CONCLUSIONS: Within the limitations of this study, the present data indicate that leached components from dental composites could affect sperm quality and therefore could potentially cause adverse effects on the male mice reproductive system.

Human gingival keratinocyte response to substances eluted from silorane composite material reveal impact on cell behavior reflected by RNA levels and induction of apoptosis.

OBJECTIVES: The aim of this study was the characterization of siloran-derived composite eluates in conjunction with their putative impact on human gingival keratinocytes (HGK), i.e. levels of total RNA and induction of apoptosis compared to a methacrylate-based material. METHODS: Standardized Filtek™ Silorane specimens (n = 20) were subjected to scanning ion monitoring to detect monomer masses between 100 and 1000, after storage in human saliva, and 75% ethanol for up to 28 days. In order to evaluate the effect on cells, HGK were exposed to eluates from Filtek™ Silorane, Filtek™ Supreme XT and control medium for 1 and 4 days, prior to isolation of total RNA, and Annexin-5 fluorescence labeling indicating induction of apoptosis. RESULTS: Irrespective of the mode and storage time, SIM identified discrete peaks, corresponding to masses of "393" and "337". In response to both composite eluates, an effect on HGK was reflected by drastically reduced levels of isolated total RNA at each time period (after 1 day: control: 302 ng/µl; Filtek™ Silorane: 128 ng/µl, Filtek™ Supreme XT: 129 ng/µl and after 4 days: control: 528 ng/µl; Filtek™ Silorane: 162 ng/µl, Filtek™ Supreme XT: 166 ng/µl). Exposure to eluates from both composite materials yielded apoptosis induction in HGK, as demonstrated by a significant increase of cells exhibiting Annnexin-5 fluorescence. SIGNIFICANCE: Two distinct peaks were identified, which indicated the presence of corresponding substances. The composite-derived effects on HGK strongly suggest a negative impact on cells, as revealed by a clear reduction of total RNA levels, and significant increase in induction of apoptosis.