Uncompleted polymerization and cytotoxicity of dental restorative materials as potential health risk factors

Abstract

Małkiewicz K, Wychowański P, Olkowska-Truchanowicz J, Tykarska M, Czerwiński M, Wilczko M, Owoc A. Uncompleted polymerization and cytotoxicity of dental restorative materials as potential health risk factors. Ann Agric Environ Med. 2017; 24(4): 618-623. doi: 10.5604/12321966.1235159 Abstract Introduction. Composite materials used in dentistry indicate adverse biological effects in laboratory conditions. One reason for this activity is incomplete conversion of their polymer matrix, favoring chemical instability and release of biologically harmful components to the external environment. Aim. The aim of the study was to assess the degree of conversion of restorative materials commonly available on the European market and to examine the cytotoxic effects of their eluates in vitro. Material and methods. Using the Fournier transform infrared spectroscopy (FTIR) technique of analysis, the degree of polymer matrix conversion of 6 restorative materials was examined: Gradia Direct, Arkon, Filtek Z550, Herculite XRV, Tetric Evo Ceram, Charisma, polymerized with LED light. In order to assess the cytotoxicity of eluates of the studied materials obtained after 1 hour, 24 hours and 7 days, the MTT assay was used in cultured 3T3 cells. The results were statistically analyzed at significance level of p=0.05. Results. The conversion degree of the assessed polymers ranged from 31.56% for Tetric Evo Ceram to 75.84% for Arcon. The strongest (p=0.05) cytotoxic effect was demonstrated after 7-day observation of Tetric Evo Ceram eluates, reducing the metabolic activity of cells down to 56%. A positive correlation (r(x, y)=0.62) between the degree of conversion of composite materials and cytotoxic effects of their eluates on cell cultures was confirmed. Conclusions.1. Restorative dental materials are chemically unstable in the conditions of the present study. 2. Polymer-based restorative dental materials available on the European market demonstrate cytotoxic properties constituting a potential threat to the patients' health.

Poly (Methyl Methacrylate)-Containing Silver-Phosphate Glass Exhibits Potent Antimicrobial Activity without Deteriorating the Mechanical and Biological Properties of Dental Prostheses

“…Cell viability was assessed by applying the extractions of the control and experimental samples to L929 cells according to the international standard for biocompatibility evaluation, namely MTT analysis [ 6 , 9 ]. Because the denture base is in direct contact with the oral mucosa, it is essential to use a biocompatible material that does not cause hypersensitivity or toxicity [ 30 , 36 , 37 , 38 ]. Based on the findings of the MTT assay, there was no statistically significant difference in cell viability between the experimental and control groups.…”

Cytotoxicity and degree of conversion of methacrylate and silorane

“…The cytotoxicity of the resin composites has been mainly attributed to the release of monomers such as UDMA, HEMA and TEGMA, which are frequently added to the chemical composition of resins 15 . Both the resin content and percentage of monomer conversion of dental materials were considered as potential causes of cytotoxicity 11 . These unconverted monomers, such as TEGMA and UDMA, and photo-initiators, such as camphoroquinone, are known to be cytotoxic for cells 16 .…”

“…The cytotoxicity of a composite is related both to its chemical composition and to the conversion percentage of its monomers. As it is known, a high conversion percentage is vital for good mechanical properties and biocompatibility 11,12 . Low values of double bond conversion involve a large number of residual monomers trapped in the polymeric matrix, reducing its biocompatibility.…”

Cytotoxic Evaluation and Determination of Organic and Inorganic Eluates from Restorative Materials

“…Cell populations that simulate oral conditions have been used in order to study the cytotoxicity of dental materials [ 34 ]. Usually gingival fibroblast, keratinocytes of the oral epithelium and standardized strains of mouse L-929 or 3T3 fibroblasts are used for cytotoxicity studying [ 18 ].…”

“…Usually gingival fibroblast, keratinocytes of the oral epithelium and standardized strains of mouse L-929 or 3T3 fibroblasts are used for cytotoxicity studying [ 18 ]. The cytotoxic effects of the eluted substances have been studied by tests that estimate the severity of apoptotic action, the damage to ribonucleic acid and glutathione level in cells [ 34 ].…”