Cytotoxicity of monomers, plasticizer and degradation by-products released from dental hard chairside reline resins

Chaves, Carolina de Andrade Lima; Machado, Ana Lucia; Carlos, Iracilda Zeppone; Giampaolo, Eunice Teresinha; Pavarina, Ana Cláudia; Vergani, Carlos Eduardo

doi:10.1016/j.dental.2010.06.008

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Volume 26, Issue 10 , Pages 1017-1023, October 2010

Cytotoxicity of monomers, plasticizer and degradation by-products released from dental hard chairside reline resins

Carolina de Andrade Lima Chaves
- UNESP – Univ Estadual Paulista, Araraquara Dental School, Department of Dental Materials and Prosthodontics, Rua Humaitá, 1680, Araraquara, CEP 14801-903, São Paulo, Brazil
Ana Lucia Machado
- UNESP – Univ Estadual Paulista, Araraquara Dental School, Department of Dental Materials and Prosthodontics, Rua Humaitá, 1680, Araraquara, CEP 14801-903, São Paulo, Brazil
- Corresponding author at: UNESP – Univ Estadual Paulista, Araraquara Dental School, Department of Dental Materials and Prosthodontics, Rua Humaitá, 1680, Araraquara, CEP 14801-903, São Paulo, Brazil. Tel.: +55 16 3301 6410; fax: +55 16 3301 6406.
Iracilda Zeppone Carlos
- UNESP – Univ Estadual Paulista, Araraquara Pharmaceutical School, Department of Clinical Analysis, Araraquara, São Paulo, Brazil
Eunice Teresinha Giampaolo
- UNESP – Univ Estadual Paulista, Araraquara Dental School, Department of Dental Materials and Prosthodontics, Rua Humaitá, 1680, Araraquara, CEP 14801-903, São Paulo, Brazil
Ana Cláudia Pavarina
- UNESP – Univ Estadual Paulista, Araraquara Dental School, Department of Dental Materials and Prosthodontics, Rua Humaitá, 1680, Araraquara, CEP 14801-903, São Paulo, Brazil
Carlos Eduardo Vergani
- UNESP – Univ Estadual Paulista, Araraquara Dental School, Department of Dental Materials and Prosthodontics, Rua Humaitá, 1680, Araraquara, CEP 14801-903, São Paulo, Brazil

Received 18 May 2010; accepted 25 June 2010.

Abstract

Objectives

The aim of this study was to evaluate the cytotoxic effect of the monomers isobutyl methacrylate (IBMA) and 1,6-hexanediol dimethacrylate (1,6-HDMA), the plasticizer di-n-butyl phthalate (DBP), and the degradation by-products methacrylic acid (MA) and benzoic acid (BA) on L929 cells. Based on previous investigations on the release of these compounds from hard chairside reline resins, a range of concentrations (μmol/L) were selected for the cytotoxicity tests (IBMA, 5.49–1406.57; 1,6-HDMA, 1.22–39.32; DBP, 1.12–143.8; MA, 9.07–581; BA, 3.19–409).

Methods

Cytotoxic effects were assessed using MTT and ³H-thymidine assays after the cells had been exposed to the test compounds at the given concentrations for 24h. Cytotoxicity was rated based on cell viability relative to controls (cells exposed to medium without test substances).

Results

DNA synthesis activity was inhibited by all compounds. Mitochondrial dehydrogenase activity decreased in cells treated with monomers, plasticizer and MA by-product, whereas no cytotoxic effect was observed on contact with BA at the majority of concentrations tested. The ranges of suppression for ³H-thymidine assay were: IBMA, 25–95%; 1,6-HDMA, 95–98%; DBP, 40–98%; MA, 97–99%; BA, 54–71%. For MTT assay, the ranges of suppression were: IBMA, 0–96%; 1,6-HDMA, 26–89%; DBP, 17–80%; MA, 52–66%; BA, 0–27%. The ³H-thymidine assay was more sensitive than the MTT assay.

Significance

This study evaluated the cytotoxicity of a wide range of concentrations of monomers (IBMA and 1,6-HDMA), plasticizer (DBP) and degradation by-products (MA and BA), including those expected to be released from hard chairside reline resins. The differences observed in the cytotoxicity of these compounds, along with other properties, may assist the dental practitioners in the selection of reline materials with improved service life performance and low risk of adverse reactions in patients who wear relined dentures.

Keywords: Acrylic resins, Cytotoxicity, Monomer, Plasticizer, Degradation products, Fibroblasts