An integrative review on the toxicity of Bisphenol A (BPA) released from resin composites used in dentistry.

The main aim of this study was to perform an integrative review on the release of bisphenol A (BPA) from resin-matrix composites and potential toxic effects. A bibliographic search was performed on the PubMed platform using the following keywords: "Bisphenol A" OR "BPA" AND "resin composite" OR "composite resin" AND "toxicity" OR "cytotoxicity" OR "release". Inclusion criteria involved in vitro and in vivo studies on the release and toxicity of BPA. Results highlighted the release of BPA from resin-matrix composites due to insufficient polymerization and/or degradation of the polymeric matrix. BPA is part of the organic matrix of resin-matrix composites and may be hydrolysed in human saliva, although studies report that low doses might not be detected by traditional chemical analysis. Studies exposing zebrafish embryos to different concentrations of Bis-GMA, showed 55% mortality at 10 µM Bis-GMA while 30% mortality was recorded at 1 µM Bis-GMA. In patients, a BPA concentration of around 2.09 × 10-2  µg/ml was found in the saliva after placement of lingual orthodontic retainers with resin-matrix composites. Also, the BPA molecule can be swallowed and absorbed by the oral/gastrointestinal mucosa, which might result in systemic toxicity. The degradation of resin-matrix composites and release of BPA in oral environment are dependent on the organic matrix content and on the polymerization method. A increased release of BPA can lead to the absorption into oral and gastrointestinal mucosa with high risks of local and systemic toxicity.

Mecanismo carcinogénico asociado a la exposición al Bisfenol A / Carcinogenic mechanism associated of Bisphenol A exposure

Resumen Introducción: El Bisfenol A (BPA) es un producto químico al que los seres humanos están expuestos ampliamente por la vía oral, inhalación y transdérmica. Justificación: Dada la importancia de la patología oncológica que puede estar asociada a exposición a este químico, resulta imprescindible comprender mejor sus posibles mecanismos de acción asociados a carcinogénesis. Objetivo General: Investigar el mecanismo carcinogénico asociado a la exposición a BPA. Resultados: Aunque la mayoría de las investigaciones se han orientado hacia el efecto disruptor endocrino, con la limitante que los estudios in vivo son realizados en animales, existen estudios recientes que muestran su posible efecto carcinogénico en tejidos humanos. Sin embargo, se requiere más investigación sobre el papel del BPA de dosis baja (como ocurre en condiciones ambientales normales) y su efecto en la regulación de los cambios globales de expresión génica y las alteraciones epigenéticas en las células, que permitan establecer vínculos con carcinogénesis; esta revisión demuestra que los estudios realizados hasta la fecha señalan varios factores que pueden estar involucrados, como efectos mutagénicos que incluyen cambios en la transcripción génica y enzimáticos que promueven la proliferación celular limitando la apoptosis y favorecen la angiogénesis y migración de células tumorales. Conclusión: Si bien en la actualidad se reconoce que la célula cancerígena adquiere características patológicas que le ayudan a sobrevivir en el organismo, estas características obedecen a mecanismos moleculares genéticos y epigéneticos, muchos de los cuales han sido descritos para el caso de la exposición humana al BPA.

Abstract Introduction: Bisphenol A (BPA) is a chemical to which humans are extensively exposed orally, inhaled and transdermally. Justification: Given the importance of the oncological pathology that may be associated with exposure to this chemical, it is essential to better understand its possible mechanisms of action associated with carcinogenesis. Objective: To investigate the carcinogenic mechanism associated with BPA exposure. Results: Although the majority of investigations have been oriented towards the endocrine disrupting effect, with the limitation that in vivo studies are carried out in animals, recent studies have shown that they can be carcinogenic in human tissues. However, more research is required on the role of low-dose BPA (as occurs under normal environmental conditions) and its effect on the regulation of global changes in gene expression and epigenetic alterations in cells, which allow establishing links with carcinogenesis; this review shows that the studies carried out to date point to several factors that may be involved, such as mutagenic effects that include changes in gene transcription and enzymes that promote cell proliferation, limiting apoptosis and promoting angiogenesis and migration of tumor cells. Conclusion: Although it is currently recognized that the cancer cell acquires pathological characteristics that help it to survive in the organism, these characteristics are due to genetic and epigenetic molecular mechanisms, many of which have been described for the case of human exposure to BPA.

Effect of Bisphenol A Glycol Methacrylate on Virulent Properties of Streptococcus mutans UA159.

Bisphenol A glycidyl methacrylate (bis-GMA), which is released into the oral environment by dental composites through incomplete polymerization, hydrolysis, and mechanical degradation, can significantly influence oral ecology around resin-based materials. The purpose of this study was to investigate how bis-GMA changes the virulence properties of Streptococcus mutans, a major cariogenic bacterium in humans. The results show that bis-GMA not only inhibited the planktonic growth of cells in medium containing glucose, fructose, or mannose, but also reduced the viability of S. mutans. However, the presence of bis-GMA increased sugar transport and intracellular polysaccharide accumulation in S. mutans, thereby increasing the potential of cell persistence. In addition, bis-GMA could enhance S. mutans's adhesion to hard surfaces and glucan synthesis, which could contribute to biofilm formation. Although free bis-GMA made cells vulnerable to acidic stress, it also provided increased resistance to hydrogen peroxide, which might confer an advantage in competition with other oral microorganisms during the early stage of biofilm development. Interestingly, the presence of bis-GMA did not change the ability of S. mutans to interact with saliva. The results suggest that leachable bis-GMA could contribute to biofilm-related secondary dental caries at the marginal interface between resin-based materials and teeth by altering the virulent properties of S. mutans, although bis-GMA reduced the planktonic growth and viability of S. mutans.

Negative effects of bisphenol A on testicular functions in albino rats and their abolitions with Tribulus terristeris L

ABSTRACT This study was conducted to find out the ameliorative properties of Tribulus terristeris L (TT) on BPA induced spermatotoxicity in male albino rats. Mature male albino rats were divided into five groups, Group A was taken as control for comparison group, whereas the other four groups namely B(vehicle control), C (toxic), D (preventive control) and Group E (amelioration group) received distilled water, olive oil, BPA, TT, and (TT + BPA) respectively. Macroscopic results revealed decreased body weight of rats, weight of testes, and the relative tissue weight index (RTWI) in BPA induced group. Hormonal (testosterone) assay results revealed the decreased values of BPA treated group. Microscopic examination of testis of BPA treated rats showed reduction in leydig cells, decreased diameter of seminiferous tubules and low values of Johnsen's scoring. Histological examination showed discontinuity and irregularity of basement membrane and sloughing of the germinal cell linage. Group E showed the body weights of rats, weight of testes, RTWI, and increased, while reduced level of testosterone, reduced number of Leydig cells, decreased diameter of seminiferous tubules and low values of Johnsen's scoring were restored near to normal. These results demonstrate that TT might be beneficial in combating the spermatotoxicity, induced by BPA.

Release of monomers from orthodontic adhesives.

INTRODUCTION: Most composite resins release both bisphenol A (BPA), which disrupts the endocrine balance, and triethylene glycol dimethacrylate (TEGDMA), which has high risks for human health: eg, allergies and cytotoxicity. The aim of this study was to characterize monomers released from orthodontic adhesives. METHODS: We studied samples of orthodontic adhesives by associating 2 techniques: gas phase chromatography and mass spectrometry. RESULTS: The in-vitro analysis detected significant quantities of BPA, TEGDMA, and other monomers in orthodontic adhesives used in daily practice: Transbond XT, Transbond Supreme LV (both, 3M Unitek, Monrovia, Calif), Blugloo (Ormco, Orange, Calif), and MonoLok 2 (Rocky Mountain Orthodontics, Denver, Colo). CONCLUSIONS: Clinicians should consider that orthodontic adhesives contain BPA, an endocrine disruptor; TEGDMA, an allergic and a cytotoxic compound; and carcinogenic genotoxic compounds. These molecules are not mentioned in the material safety data sheets. Manufacturers should declare all components of dental composites to identify these substances that may result in allergic or undesirable side effects for patients and dental staff.

El bisfenol A: un factor ambiental implicado en el daño nefrovascular / Bisphenol A: An environmental factor implicated in renal vascular damage

No disponible

Effect of beverages on color and translucency of new tooth-colored restoratives.

This investigation examined the susceptibility to staining and translucency changes of some new tooth-colored restorative materials after immersion in different beverages. The materials studied were 3M Filtek Z350XT (ZT), 3M Filtek 350XT Flowable Restorative (ZF), Shofu Beautifil Flow Plus (BF), Shofu Beautifil II (B2), 3M Ketac Nano (N100), and 3M Photac Fil (PF). Following the manufacturers' instructions, 42 samples were made from each material and placed in an incubator at 100% humidity and 37°Celsius for 24 hours. Baseline L*, a*, b* readings were taken against white and black backgrounds using a photospectrometer. The samples were then randomly assigned to be immersed in seven beverages, namely cola drink, orange juice, red wine, vodka, black coffee, green tea, and distilled water for a period of seven days. Color readings were taken again by recording the L*, a*, b* values. Data was analyzed using t-tests, one-way analysis of variance with Tukey post hoc and Pearson's correlation (p<0.05). BF generally performed as well as the conventional composite resin materials (ZT and ZF) but N100 and B2 did not. PF had the largest staining and translucency changes. Coffee, red wine, and tea resulted in the most staining and negative translucency changes. An inverse correlation between ΔE and ΔTP was observed for all materials and beverages with the exception of orange juice.

Demineralization adjacent to orthodontic brackets after application of conventional and self-etching primer systems.

OBJECTIVES: The goal of this work was to compare the demineralization of enamel associated with two different self-etching primers and traditional acid etching. MATERIALS AND METHODS: A total of 15 volunteers (23-32 years, 8 male and 7 female) were provided with a removable archwire/resin appliance to be worn 20 h/day for 28 days. The device was attached to the mandibular posterior teeth and included samples of human enamel (from extracted third molars) located in both posterior vestibules. Both sides featured the same distribution of samples, including one untreated control sample (group A) and three samples with brackets (Victory™ APC II) bonded to their surface after conditioning with a self-etching non-fluoride primer (iBond™ Gluma® Inside; group B), a self-etching fluoride-releasing primer (Transbond™ Plus; group C), or traditional acid-etching with 35% phosphoric acid and Transbond™ XT (group D). Mineral loss was assessed extraorally under standardized conditions using quantitative light-induced fluorescence (QLF) with a specialized camera system (Inspektor Pro). Results were expressed as relative fluorescence loss (ΔF in %). A baseline measurement (T0) was taken before the appliance was first inserted but with the brackets already bonded. Fluorescence loss was analyzed after 3 (T1), 7 (T2), 14 (T3), and 28 days (T4) and compared to the baseline loss (T0) for each of the four study groups (A to D). Kruskal-Wallis and Mann-Whitney U tests were used to compare the results for statistical significance. RESULTS: The lowest percentages of fluorescence loss both at baseline and during the follow-up assessments was found in group C. While all three experimental groups (B, C, D) presented total decreases in fluorescence loss after 28 days, indicating remineralization, the decrease in group C was the largest. The Kruskal-Wallis test yielded no significant differences between the three groups other than a significantly lower percentage of fluorescence loss in group C than in group D during the last assessment (T4). The untreated samples of control enamel (group A) revealed increasing percentages of fluorescence loss over the entire study period. CONCLUSION: Use of the self-etching primers (groups B and C) was not associated with patterns of enamel demineralization different from those noted after traditional etching with phosphoric acid (group D). The only significant difference we observed was between the self-etching fluoride-releasing primer (group C) and traditional etching (group D) at the final assessment (T4). Thus, the fluoride-releasing system Transbond™ Plus was advantageous.

Allergic contact stomatitis from bisphenol-a-glycidyl dimethacrylate during application of composite restorations: a case report.

Composite resins have revolutionized the field of esthetic dentistry. They are safe to use and usually do not cause any untoward reactions. Allergies to composites are rare, but they do occasionally occur as patients are briefly exposed to the resin before it is polymerized and becomes non-allergenic. Here, we present a case of allergic contact stomatitis due to bis-GMA.

Critical appraisal: dental amalgam update--part II: biological effects.

Dental amalgam restorations have been controversial for over 150 years. In Part I of this Critical Appraisal, the clinical efficacy of dental amalgam was updated. Here in Part II, the biological effects of dental amalgam are addressed.

Biology and cytotoxicity of dental materials: an in vitro study.

OBJECTIVE: The purpose of the experiment was to determine the degree of biocompatibility of a sealer (RO, laboratory made product) dental material in terms of cytotoxicity and animal tests. MATERIALS AND METHODS: In the present study, the biological compatibility of eight experimental composite materials was examined by in vitro methods. The bio-composites used for the cytotoxicity test were placed into direct contact with normal human fibroblasts in a cell-culture dish. After fibroblast bioassay was performed, a duplicate sample of biomaterial was placed in each well, and then the fibroblasts were incubated for 48 hours at 37°C and 5% carbon dioxide. Local reactions after the implantation of the material regarding preclinical evaluation have been carried out within the Biobase Laboratory of the "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania. The biocompatibility was studied using the tolerance test by the subcutaneous and intramuscular implantation of the cured specimens. RESULTS: The sealant C3 scored the highest value to the cell viability. The results of the present study showed that different dental materials had different effects on cells. The resin monomer TEGDMA, present in the sealer's composition, increased the amount of intracellular reactive oxygen species. Resin-based composites are cytotoxic before polymerization and immediately thereafter, whereas already set specimens cause almost no reaction. The test of tolerance showed that the composite materials do not contain any toxic, irritant substances or destructive ones for the living cells or tissues. CONCLUSIONS: The tests with experimental composite materials revealed that they are not cytotoxic for the living cells, in all versions of the materials used. All the samples of composite materials have maintained their integrity during the experiment, allowing the testing together with the embedded cells, which proved good viability, so they are suitable for dentistry use.

Assessing the biocompatibility of a dental composite product.

OBJECTIVE: The purpose of the study was to assess the biocompatibility of a composite material considering the reaction caused at the implant site during 21 days by daily observing the subjects' behavior as well as by macroscopic examination and histological examination upon expiry of the testing period. MATERIALS AND METHODS: We performed the tolerance test by implant of the composite material Dualcim. The implant test was made on two species of lab animals, Guinea pigs and Wistar rats in two versions: subcutaneous implant and intramuscular÷perimuscular implant. RESULTS: After a 21 days period, when the implant was in direct contact with the tissue, no change of the shape and consistency, color or surface of the implant occurred. Around the implants, the biocompatibility was kept under physiological limits. CONCLUSIONS: The product, in the structure and shape presented, could be easily placed under good conditions, both at the level of the subcutaneous tissue and at inter-muscular level. In case of both species and in all subjects, the histological exam proved a favorable development of the relationship between the implant body and the placing site.

Proinflammatory activation of macrophages by bisphenol A-glycidyl-methacrylate involved NFκB activation via PI3K/Akt pathway.

AIM: Bisphenol A-glycidyl-methacrylate (BisGMA), a dental composite resin and dentin bonding agent, might prompt inflammatory effects to adjacent tissues. Macrophages are a major cellular component of the inflammatory sites. Little is known about the mechanisms of BisGMA on macrophages activation. The aim of this study was to evaluate BisGMA on proinflammatory mediators generation of murine macrophage RAW264.7 cells. METHODS: IL-1ß and IL-6 were analyzed by enzyme-linked immunosorbent assay. Nitric oxide, extracellular superoxide anion, and intracellular reaction oxygen species were measured by Griess assay, ferricytochrome c, and 2',7'-dichlorofluorescein assay, respectively. Expression of iNOS, p-p65, IκB, and p-Akt was analyzed by Western blotting. RESULTS: BisGMA augmented the generation of IL-1ß, IL-6, nitric oxide and the expression of iNOS in a time- and dose-dependent manner (p<0.05). BisGMA enhanced the generation of intracellular and extracellular ROS in a dose-dependent manner (p<0.05). The levels of p65 phosphorylation, IκB degradation, and Akt phosphorylation were found to be increased in a time- and dose-dependent manner (p<0.05). CONCLUSIONS: These results indicate that BisGMA could induce nitric oxide, ROS, and inflammatory cytokines in macrophages. In addition, BisGMA may active macrophage via NF-κB activation, IκB degradation, and p-Akt activation.

Dental composite restorations and psychosocial function in children.

BACKGROUND AND OBJECTIVE: Resin-based dental materials may intraorally release their chemical components and bisphenol A. The New England Children's Amalgam Trial found that children randomized to amalgam had better psychosocial outcomes than those assigned to composites for posterior tooth restorations. The objective of this study was to examine whether greater exposure to dental composites is associated with psychosocial problems in children. METHODS: Analysis of treatment-level data from the New England Children's Amalgam Trial, a 2-group randomized safety trial comparing amalgam with the treatment plan of bisphenol A-glycidyl methacrylate (bisGMA)-based composite and urethane dimethacrylate-based polyacid-modified composite (compomer), among 534 children aged 6 to 10 years at baseline. Psychosocial function at follow-up (n = 434) was measured by using the self-reported Behavior Assessment System for Children (BASC-SR) and parent-reported Child Behavior Checklist (CBCL). RESULTS: Children with higher cumulative exposure to bisGMA-based composite had poorer follow-up scores on 3 of 4 BASC-SR global scales: Emotional Symptoms (ß = 0.8, SE = 0.3, P = .003), Clinical Maladjustment (ß = 0.7, SE = 0.3, P = .02), and Personal Adjustment (ß = -0.8, SE = 0.2, P = .002). Associations were stronger with posterior-occlusal (chewing) surfaces, where degradation of composite was more likely. For CBCL change, associations were not statistically significant. At-risk or clinically significant scores were more common among children with greater exposure for CBCL Total Problem Behaviors (16.3% vs 11.2%, P-trend = .01) and numerous BASC-SR syndromes (eg, ≥ 13 vs 0 surface-years, Interpersonal Relations 13.7% vs 4.8%, P-trend = .01). No associations were found with compomer, nor with amalgam exposure levels among children randomized to amalgam. CONCLUSIONS: Greater exposure to bisGMA-based dental composite restorations was associated with impaired psychosocial function in children, whereas no adverse psychosocial outcomes were observed with greater urethane dimethacrylate-based compomer or amalgam treatment levels.

Enamel loss and adhesive remnants following bracket removal and various clean-up procedures in vitro.

This study evaluated the enamel loss and composite remnants after debonding and clean-up. The tested null hypothesis is that there are no differences between different polishing systems regarding removing composite remnants without damaging the tooth surface. Brackets were bonded to 75 extracted human molars and removed after a storage period of 100 hours. The adhesive remnant index (ARI) was evaluated. The clean-up was carried out with five different procedures: 1. carbide bur; 2. carbide bur and Brownie and Greenie silicone polishers; 3. carbide bur and Astropol polishers; 4. carbide bur and Renew polishers; and 5. carbide bur, Brownie, Greenie and PoGo polishers. Silicone impressions were made at baseline (T0) and after debonding (T1) and polishing (T2) to produce plaster replicas. The replicas were analysed with a three-dimensional laser scanner and measured with analytical software. Statistical analysis was performed with the Kruskal-Wallis test and pairwise Wilcoxon tests with Bonferroni-Holm adjustment (α = 0.05). Enamel breakouts after debonding were detectable in 27 per cent of all cases, with a mean volume loss of 0.02 mm(3) (±0.03 mm(3)) and depth of 44.9 µm (±48.3 µm). The overall ARI scores was 3 with a few scores of 1 and 2. The composite remnants after debonding had a mean volume of 2.48 mm(3) (±0.92 mm(3)). Mean volume loss due to polishing was 0.05 mm(3) (±0.26 mm(3)) and the composite remnants had a mean volume of 0.22 mm(3) (±0.32 mm(3)). There were no statistically significant differences in volumetric changes after polishing (P = 0.054) between the different clean-up methods. However, sufficient clean-up without enamel loss was difficult to achieve.

Carboxylesterase expression in human dental pulp cells: role in regulation of BisGMA-induced prostanoid production and cytotoxicity.

Biocompatibility of dentin bonding agents (DBA) and composite resin may affect the treatment outcome (e.g., healthy pulp, pulpal inflammation, pulp necrosis) after operative restoration. Bisphenol-glycidyl methacrylate (BisGMA) is one of the major monomers present in DBA and resin. Prior studies focused on salivary esterase for metabolism and degradation of resin monomers clinically. This study found that human dental pulp cells expressed mainly carboxylesterase-2 (CES2) and smaller amounts of CES1A1 and CES3 isoforms. Exposure to BisGMA stimulated CES isoforms expression of pulp cells, and this event was inhibited by catalase. Exogenous addition of porcine esterase prevented BisGMA- and DBA-induced cytotoxicity. Interestingly, inhibition of CES by bis(p-nitrophenyl) phosphate (BNPP) and CES2 by loperamide enhanced the cytotoxicity of BisGMA and DBA. Addition of porcine esterase or N-acetyl-l-cysteine prevented BisGMA-induced prostaglandin E(2) (PGE(2)) and PGF(2α) production. In contrast, addition of BNPP and loperamide, but not mevastatin, enhanced BisGMA-induced PGE(2) and PGF(2α) production in dental pulp cells. These results suggest that BisGMA may induce the cytotoxicity and prostanoid production of pulp cells, leading to pulpal inflammation or necrosis via reactive oxygen species production. Expression of CES, especially CES2, in dental pulp cells can be an adaptive response to protect dental pulp against BisGMA-induced cytotoxicity and prostanoid release. Resin monomers are the main toxic components in DBA, and the ester group is crucial for monomer toxicity.

Short-term in situ/ex vivo study of the anticariogenic potential of a resin-modified glass-ionomer cement associated with adhesive systems.

OBJECTIVE: As resin-modified glass-ionomer cement (RMGIC) is an adhesive material, its association to dentin bonding agents (DBAs) was previously proposed. This study investigated the adjunctive behavior of an RMGIC with etch-and-rinse bonding systems under in situ/ex vivo cariogenic challenge. METHOD AND MATERIALS: Bovine enamel blocks (3 3 3 3 2 mm) were randomly assigned to group VP, Vitremer + its own primer (3M ESPE); group VSB, Vitremer + Single Bond (3M ESPE); and group VPB, Vitremer + Prime and Bond 2.1 (Dentsply). Two blocks of each group were randomly placed in an acrylic palatal appliance, so each appliance included six blocks. Volunteers (n = 10) wore these appliances according to given instructions to promote a sucrose challenge eight times/day for 15 days. After this period, the blocks were removed from the devices and cleaned, and demineralization was assessed through longitudinal microhardness analysis (Knoop indenter, 25 g/5 s). Data were submitted to three-way ANOVA and Tukey test (P < .05). RESULTS: No treatment was able to completely avoid demineralization. All materials showed a statistically significant difference in mineral loss when the microhardness on the outer enamel was compared with deeper regions (P < .05). CONCLUSION: Association of the tested RMGICs with etch-and-rinse DBAs did not seem to be more beneficial against caries than the conventional treatment with RMGIC.

Clinical experience using Cortoss for treating vertebral compression fractures with vertebroplasty and kyphoplasty: twenty four-month follow-up.

STUDY DESIGN: Forty patients were enrolled in 2 FDA-approved pilot Investigational Device Exemption (IDE) studies using Cortoss for the treatment of vertebral compression fractures (VCF). Twenty patients were treated at 3 centers, using vertebroplasty (VP) and 20 patients were treated at 5 centers, using kyphoplasty (KP). OBJECTIVE: To assess the feasibility and clinical outcomes using Cortoss to treat osteoporotic VCF. SUMMARY OF BACKGROUND DATA: Cortoss is an injectable bioactive, self-setting, radiopaque composite shown to stabilize and provide immediate weight bearing support to fractured vertebrae. Cortoss is approved for use in Europe for both screw and vertebral augmentation. METHODS.: Patient assessments were conducted before surgery and after surgery through 24 months using Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and quality-of-life assessment (SF-12) questionnaires. Extravasations were evaluated using radiographs and CT scans. RESULTS: Immediate pain improvement was seen in VP patients with VAS scores decreasing from 75.7 before surgery to 35.9 at 72 hours. Continued improvement from baseline was seen out to 2 years (average VAS of 48.9). Disability improved with average ODI scores decreasing from 52.2% preoperative to 38.3% at 2 years for VP patients. Immediate pain improvement was also seen in KP patients with VAS scores decreasing from 78.1 before surgery to 42.7 at 72 hours. Continued improvement from baseline was seen out to 2 years (average VAS of 25.4). ODI scores improved from 60.5% preoperative to 34.5% at 2 years for KP patients. Average material volumes injected were 1.85 mL for VP and 4.13 mL for KP. Extravasations from both techniques were minor, anatomically close to the treated vertebrae and asymptomatic. No cardiac irregularities or pulmonary emboli were observed. CONCLUSION: These studies indicate Cortoss is safe and effective in treating osteoporotic VCF using vertebroplasty or kyphoplasty. Pain relief and restoration of function with Cortoss is comparable to results found in the literature for polymethylmethacrylate.

The role of reactive oxygen species and hemeoxygenase-1 expression in the cytotoxicity, cell cycle alteration and apoptosis of dental pulp cells induced by BisGMA.

Biocompatibility of dentin bonding agents (DBAs) and resin composite is important to preserve the pulp vitality after operative restoration. Bisphenol-glycidyl-methacrylate (BisGMA) is one common monomer adding into DBAs and resin. In this study, we found that exposure of human dental pulp cells to BisGMA (>0.1 mM) led to cytotoxicity, G2/M cell cycle arrest and apoptosis as analyzed by propidium iodide (PI) and PI/annexin V dual fluorescent flow cytometry. These events were associated with a decline of cdc2, cdc25C and cyclinB1 expression at both mRNA and protein levels. BisGMA also induced the expression of hemeoxygenase-1 (HO-1), an oxidative stress responsive gene, in pulp cells. Catalase could prevent the BisGMA-induced alteration of cell cycle-related genes (cdc2, cdc25C, cyclinB1) and HO-1 expression in dental pulp cells. Interestingly, Zn-protoporphyrin (2.5-5 microM), a HO inhibitor, enhanced the BisGMA-induced reactive oxygen species (ROS) production and cytotoxicity. These results suggest that exposure to higher concentrations of BisGMA may stimulate ROS production, cell cycle arrest, apoptosis and cell death. Inducing the expression of HO-1 in dental pulp cells by BisGMA is mediated by ROS production and important to protect dental pulp against the toxicity by monomers present in composite resin and DBAs.

Effect of prerestorative home-bleaching on microleakage of self-etch adhesives.

BACKGROUND: Tooth bleaching has become a routine treatment due to patients' esthetic demands. PURPOSE: The aim of this study was to evaluate how prerestorative home-bleaching affected microleakage of resin composite restorations bonded with etch-and-rinse and self-etch adhesives. MATERIALS AND METHODS: Fifty extracted human premolar teeth were used. The bleaching agent (10% carbamide peroxide) was applied to the buccal surface of each tooth for 6 hours a day for 2 weeks. The lingual surfaces of the same teeth received no application (control). The teeth were stored in artificial saliva. After 14 days, standardized Class V cavity preparations (2 mm high, 3 mm wide, and 2 mm deep) were made on the buccal and lingual surfaces with all margins in the enamel. They were randomly divided into five groups according to the adhesive systems: an etch-and-rinse adhesive (Single Bond [SB]), two two-step self-etch adhesives (Adper SE Plus [ASE] and One Coat [OC]), and two one-step self-etch adhesives (Adper Easy One [EO] and G-Bond [GB]). All adhesives were applied according to the manufacturers' instructions. The preparations were then restored using the same hybrid composite (Filtek Z250) in one increment and light-cured. The teeth were thermocycled (5/55 degrees C, 1,000x) and immersed in dye, then sectioned, and dye penetration was scored. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U-tests. RESULTS: Although statistically significant differences were found between the adhesive systems in the bleached teeth, no differences were observed in the control groups (non-bleached teeth). There were significant differences between SB/GB, SB/EO, SB/OC, and GB/ASE in the bleached teeth (p < 0.05). When comparing bleached and non-bleached teeth within each adhesive system, only SB and EO produced higher leakage scores when bleaching was applied. The other groups showed no difference in terms of bleaching (p > 0.05). CONCLUSION: Prerestorative home-bleaching had an adverse effect on microleakage of SB and EO. CLINICAL SIGNIFICANCE: The effect of prerestorative home-bleaching agents on microleakage of composite resin restorations differs according to the type of adhesive material used.