Ivana Nedeljkovic1, Kumiko Yoshihara2, Jan De Munck1, Wim Teughels3, Bart Van Meerbeek1, Kirsten L Van Landuyt4. 1. BIOMAT, Department of Oral Health Sciences, University of Leuven and Dentistry University Hospitals Leuven, Kapucijnenvoer 7, 3000, Leuven, Belgium. 2. Center for Innovative Clinical Medicine, Okayama University Hospital, 2-5-1 Shikata-cho, Okayama, Kita-ku, 700-8558,, Japan. 3. Oral Microbiology, Department of Oral Health Sciences, University of Leuven and Dentistry University Hospitals Leuven, Kapucijnenvoer 7, 3000, Leuven, Belgium. 4. BIOMAT, Department of Oral Health Sciences, University of Leuven and Dentistry University Hospitals Leuven, Kapucijnenvoer 7, 3000, Leuven, Belgium. kirsten.vanlanduyt@med.kuleuven.be.
Abstract
BACKGROUND: In spite of contradicting results, the high susceptibility of composites for secondary caries is still often associated with the bacterial growth-stimulating effect of released methacrylate monomers. However, most studies that showed this effect were performed with techniques having inherent limitations (spectrophotometry). OBJECTIVES: Therefore, our objective was to determine the effect of four methacrylate monomers (2-Hydroxyethyl methacrylate (HEMA), triethylene glycol dimethacrylate (TEGDMA), ethylene glycol dimethacrylate (EGDMA), diethylene glycol dimethacrylate (DEGDMA)) on the growth of two caries-associated bacteria, Streptococcus mutans and sobrinus, and one non-cariogenic species, Streptococcus sanguinis, using TaqMan quantitative polymerase chain reaction (qPCR) to quantify bacterial DNA. MATERIALS AND METHODS: Cultures were exposed to monomer solutions selected after spectrophotometric growth measurements. At baseline and predetermined time intervals, bacterial DNA was extracted and quantified with TaqMan qPCR. Biofilms grown in the presence of monomers were analyzed with scanning electron microscopy (SEM). RESULTS: Spectrophotometry indeed showed increased growth rates of all three strains with 5 mM TEGDMA, EGDMA, and DEGDMA and increased total biomass of S. sanguinis with 5 mM TEGDMA. However, qPCR failed to show any growth-stimulating effect of these monomers on S. mutans and S. sobrinus. In contrast, some monomers exhibited a growth-inhibiting effect on S. sanguinis. SEM revealed extracellular matter in S. sobrinus and S. sanguinis biofilms, which might be attributed to polymer formation. CONCLUSIONS: Techniques which quantify bacterial DNA are more appropriate to evaluate bacterial growth in the presence of monomers than spectrophotometry. CLINICAL RELEVANCE: Even though methacrylate monomers did not affect the growth of cariogenic species, growth inhibition of S. sanguinis, a non-cariogenic antagonistic species, may lead to ecological shifts towards higher cariogenicity.
BACKGROUND: In spite of contradicting results, the high susceptibility of composites for secondary caries is still often associated with the bacterial growth-stimulating effect of released methacrylate monomers. However, most studies that showed this effect were performed with techniques having inherent limitations (spectrophotometry). OBJECTIVES: Therefore, our objective was to determine the effect of four methacrylate monomers (2-Hydroxyethyl methacrylate (HEMA), triethylene glycol dimethacrylate (TEGDMA), ethylene glycol dimethacrylate (EGDMA), diethylene glycol dimethacrylate (DEGDMA)) on the growth of two caries-associated bacteria, Streptococcus mutans and sobrinus, and one non-cariogenic species, Streptococcus sanguinis, using TaqMan quantitative polymerase chain reaction (qPCR) to quantify bacterial DNA. MATERIALS AND METHODS: Cultures were exposed to monomer solutions selected after spectrophotometric growth measurements. At baseline and predetermined time intervals, bacterial DNA was extracted and quantified with TaqMan qPCR. Biofilms grown in the presence of monomers were analyzed with scanning electron microscopy (SEM). RESULTS: Spectrophotometry indeed showed increased growth rates of all three strains with 5 mM TEGDMA, EGDMA, and DEGDMA and increased total biomass of S. sanguinis with 5 mM TEGDMA. However, qPCR failed to show any growth-stimulating effect of these monomers on S. mutans and S. sobrinus. In contrast, some monomers exhibited a growth-inhibiting effect on S. sanguinis. SEM revealed extracellular matter in S. sobrinus and S. sanguinis biofilms, which might be attributed to polymer formation. CONCLUSIONS: Techniques which quantify bacterial DNA are more appropriate to evaluate bacterial growth in the presence of monomers than spectrophotometry. CLINICAL RELEVANCE: Even though methacrylate monomers did not affect the growth of cariogenic species, growth inhibition of S. sanguinis, a non-cariogenic antagonistic species, may lead to ecological shifts towards higher cariogenicity.
Authors: Kirsten L Van Landuyt; Johan Snauwaert; Jan De Munck; Marleen Peumans; Yasuhiro Yoshida; André Poitevin; Eduardo Coutinho; Kazuomi Suzuki; Paul Lambrechts; Bart Van Meerbeek Journal: Biomaterials Date: 2007-05-07 Impact factor: 12.479
Authors: W Kim Seow; Janice H C Lam; Annetta K L Tsang; Trevor Holcombe; Philip S Bird Journal: Int J Paediatr Dent Date: 2009-09-01 Impact factor: 3.455