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From Bis-GMA-Based Composites and Sealants by High Performance Liquid Chromatography Rosa Pulgar,1 M

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From Bis-GMA-Based Composites and Sealants by High Performance Liquid Chromatography Rosa Pulgar,1 M CORE Metadata, citation and similar papers at core.ac.uk Provided by PubMed Central Articles Determination of Bisphenol A and Related Aromatic Compounds Released from Bis-GMA-Based Composites and Sealants by High Performance Liquid Chromatography Rosa Pulgar,1 M. Fatima Olea-Serrano,2 Arancha Novillo-Fertrell,2 Ana Rivas,3 Patricia Pazos,3 Vicente Pedraza,3 Jose-Manuel Navajas,1 and Nicolas Olea3 1Department of Stomatology, School of Odontology; 2Department of Nutrition and Food Sciences, School of Pharmacy; 3Laboratory of Medical Investigations, Department of Radiology, School of Medicine; HUSC-University of Granada, Granada, Spain used in dentistry; they leached into the sali- Most of the composites and sealants used in dentistry are based on bisphenol A diglycidylether va of treated patients (16). These results methacrylate (Bis-GMA). Reports revealed that in situ polymerization is not complete and that have been confirmed by Arenholt-Bindslev free monomers can be detected by different analytic methods. Concerns about the estrogenicity of et al. (32) and Fung et al. (33), who found bisphenol A (BPA) and other aromatic components leached from commercial products have been BPA in saliva samples collected immediately expressed. We studied biphenolic components-eluted from seven composites and one sealant after the placement of Delton LC (batch no. before and after in vitro polymerization using HPLC and gas chromatography/mass spectrometry 940218; Dentsply, York, PA). A yeast-based and we investigated how pH modifications affect the leaching of these components. We found bioassay confirmed the estrogenic activity of BPA (maximal amount 1.8 p/mg dental material), its dimethacrylate derivative (Bis-DMA, 1.15 these saliva samples (32). In addition to pg/mg), bisphenol A diglycidylether (6.1 pg/mg), Bis-GMA (2.0 pg/mg), and ethoxylate and BPA (16,32,33), Bis-DMA and Bis-GMA propoxylate of bisphenol A in media in which samples of different commercial products were also leached from polymerized composites maintained under controlled pH and temperature conditions. Our results confirm the leaching of and sealants, and their presence among elut- estrogenic monomers into the environment by Bis-GMA-based composites and sealants in con- ed compounds was demonstrated after in centrations at which biologic effects have been demonstrated in in vivo experimental models. The vitro polymerization (34-39). Leaching of main issue with implications for patient care and dentist responsibility is to fuirther determine the components from composites and sealants clinical relevance of this estrogenic exposure. Key words Bis-GMA, bisphenol A, bisphenol A may occur during the setting period of the dimethacrylate, dental composites and sealants. Environ Health Perspect 108:21-27 (2000). resin and by the degradation of polymerized [Online 1 December 1999] materials (40). Bis-DMA can also be a hap://ehpnetl.niehs.nib.gov/docs/2000/108p21-27pulgar/abstract.html source of BPA because the enzymatic activi- ty of saliva, esterases, extreme pH, and saliva storage can hydrolyze the dimethacrylate Polycarbonates, epoxy, and methacrylic diphenylmethane-derived compounds with derivative (8,41). Figure 1 shows the chemi- resins are synthesized by reactions between estrogenic activity, including molecular cal structure of BPA and related aromatic individual chemicals, resulting in polymers modifications of BPA with different hor- compounds. with distinct physicochemical characteristics. monal activity. BPA mimics 1713-estradiol The aim of the present study was to As biomaterials they have multiple uses in in vitro (10,13-16) as well as in estrogen tar- determine aromatic components eluted by human health applications; for instance, as get organs in animal models (17-19). BPA in vitro polymerized Bis-GMA-based com- manufactured products, for example, intraoc- mimicked natural and synthetic estrogens posites and sealants, to investigate how pH ular lenses (1), cements for trauma surgery such as diethylstilbestrol in experimental modifications affect the leaching of these (2,3), or bisphenol A (BPA)-based filling models other than breast and uterine tissue components from the initial commercial materials in preventive (4,5) and restorative (20-22). Besides BPA, its dimethacrylate product, and to assess their presence prior to dentistry (6). The latter requires extensive derivative Bis-DMA (16,23,24), BADGE polymerization. We found that BPA, Bis- manipulation and in situ polymerization. (16), and related diphenylalkanes (25) are DMA, BADGE, and Bis-GMA, among From a toxicologic standpoint, the estrogenic in different bioassays and sys- other aromatic components, leached from migration of oligomers, monomers, and the tems. Bis-GMA increased uterine wet composites and sealants both before and precursors of synthetic polymers and other weight and uterine collagen content in after polymerization; their presence was low-weight molecules from polymer net- ovariectomized mice (26) and induced cell always confirmed by gas chromatography/ works must be carefully controlled because proliferation on MCF-7 cells (27), although mass spectrometry (GC/MS). some of them can react with biologically previous works were unable to show any important molecules. This is the case with proliferative effect of Bis-GMA except BPA and bisphenol A diglycidylether under extreme pH conditions (16). Address correspondence to N. Olea, Laboratory of (BADGE), which form adducts on DNA BPA was detected in a culture medium Medical Investigations, Department of Radiology, (7-9). BPA also binds to the estrogen for yeasts as an estrogenic contaminant that University of Granada, 18071 Granada, Spain. Telephone: 34 58 24 2864. Fax: 34 58 24 9953. E- receptor (10). leached from polycarbonate bottles during mail: [email protected] The estrogen receptor-mediated effects autoclaving (10). Also, BPA and other aro- We thank R. Davies for editorial assistance. A. of BPA and related diphenyls make their matic monomers are contaminants in wine Rivas and P. Pazos are on fellowships frotim the detection an important issue. A study pub- and mineral water stored in plastic contain- Spanish Ministry of Education and the Spaniish lished in 1936 (11) demonstrated that ers (28,29), in microwave susceptors (30), in Association Against Cancer, respectively. and had estro- food from cans coated with epoxy resin lac- This research was supported by grants from the diphenyl diphenylmethanes Spanish Ministry of Health (FIS, 95/1959) and genic activity in ovariectomized rats. Both quers (15), and in canned oily foods (31). Fducation (CICYT, AMB97-1194-CE) and the compounds contained two hydroxyl groups More recently, we found that BPA and Bis- Andalusian Regionial Governmiiienit, Department of in para positions. Later, Reid and Wilson DMA were responsible for the estrogenicity Health (Consejeria de Salud, JA, 231/97). (12) characterized further 4,4'-dihydroxy of some commercial composites and sealants Received 25 March 1999; accepted 30 July 1999. Environmental Health Perspectives * Volume 108, Number 1, Januay 2000 21 Articles * Pulgar et al. Materials and Methods * Pekalux (batch 1891D; Bayern Leverkusen, Dental methodology. Nonpolymerized Germany) samples were weighed (100 mg of each com- Equipment. F6r HPLC we used a Konik * Polofil (batch 3318; Voco, Cuxhaven, posite and 50 mg ofthe sealant), and samples model KNK-500 series A apparatus (Konik Germany) were carefully decanted into the appropriate Instruments, Barcelona, Spain) connected * Silux-Plus (batch 5702Y; 3M, St. Paul, MN) topaz glass vial to which 1 mL of distilled with a Konik detector UVIS-200 and an HP * Z-100 (batch 5904B3; 3M, St. Paul, MN) water was then added. A glass distillator and integrator HP-3394A (Hewlett-Packard, * Tetric (batch 460180; Ivoclar, Schaan, glass containers were used for water treat- Seville, Spain). For GC/MS we used a Fisons Liechtenstein) ment and storage. After vigorous agitation, Carlo Erba 8000 chromatograph (Fisons * Brillant (batch CH596; Coltene Whaledent, samples were left to settle for 24 hr. Carlo Erba, Milan, Italy) and Fisons VG Alstatten, Switzerland) Polymerized samples (100 mg) of each platform mass spectrometer. * Delton (batch 940218). composite studied were compacted into a Reagents. Acetonitrile (Panreac Quimica HPLC analysis. For HPLC analysis, we small glass cylinder to take on its geometric SA., Barcelona, Spain) was the HPLC used a C-18 column (flow of 1 mL/min) form. The cylinder was placed on a petri plate reagent. Reference standards BPA (4,4'-iso- and a UV detector at 280 nm. We used the for compacting. The composite was polymer- propopylidenediphenol, FW 228.31), Bis- following solvents: acetonitrile/water 1/1 ized to a 2-mm depth. Fifty milligrams of the DMA (FW 364.44), bisphenol A etoxylate (v/v) for phase A and acetonitrile for phase sealant product was placed on a petri dish. (EBPA; FW 316), and bisphenol A propoxy- B. We used helium gas, a temperature of Polymerization was immediately performed late (PBPA; FW 344) were purchased from 25°C, and an injection volume of20 pL. The for 40 sec by situating the front ofthe lamp in Aldrich-Chemie (Albuch, Germany). gradient was 100% at 0 min (phase A), close contact with the opposite side of the BADGE (FW 340.45) was a gift from 100% at 15 min (phase B), and 100% at 17 glass to that on which the cylinder was placed. Gairesa, S.A. (La Corufna, Spain); Bis-DMA min (phase A). The total duration of the Samples were extracted from the cylinder by (FW 364.44) was
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