title: Synthesis of antibacterial and radio-opaque dimethacrylate monomers and their potential application in dental resin.
abstract: OBJECTIVE
  In this study, three dimethacrylate quaternary ammonium compounds N,N-bis[2-(3-(methacryloyloxy)propanamido)ethyl]-N-methyldodecyl ammonium iodide (QADMAI-12), N,N-bis[2-(3-(methacryloyloxy)propanamido)ethyl]-N-methylhexadecyl-ammonium iodide (QADMAI-16), and N,N-bis[2-(3-(methacryloyloxy)propanamido)ethyl]-N-methyloctadectyl ammonium iodide (QADMAI-18) were synthesized and proposed to be used as antibacterial and radio-opaque agents in dental resin.
  
  
  METHODS
  All QADMAIs were synthesized through a 2-steps reaction route, and their structures were confirmed by FT-IR and 1H NMR spectra. Antibacterial activities against Streptococcus mutans (S. mutans) of QADMAIs were measured by agar diffusion test. Each QADMAI was mixed with TEGDMA (50/50, w/w) and photoinitiation system (0.7 wt% of CQ and 0.7 wt% of DMAEMA) to form resin system. Degree of monomer conversion (DC) was determined by FT-IR analysis. The flexural strength (FS) and modulus (FM) of the polymer were measured using a three-point bending set up. Radiograph was taken to determine the radio-opacity of the polymer, and aluminum step-wedge (0.5-4 mm) was used as calibration standard. Surface charge density was measured using fluorescein binding. A single-species biofilm model with S. mutans as the tests organism was used to evaluate the antibacterial property of the polymer. Bis-GMA/TEGDMA resin system was used as control material in all of the tests.
  
  
  RESULTS
  FT-IR and 1H NMR spectra showed that the structures of QADMAIs were the same as designed. ANOVA analysis revealed that antibacterial activity of QADMAI decreased with the increasing of alkyl chain length (p<0.05). QADMAI containing polymers had higher DC (p<0.05) but lower FS and FM (p<0.05) than control polymer. Alkyl chain length had no influence on DC (p>0.05), but FS and FM of QADMAI-12 containing polymer were better than those of QADMAI-16 and QADMAI-18 containing polymers (p<0.05). QADMAI containing polymers had much better radio-opacity than control polymer (p<0.05), and the radio-opacity of polymer decreased with the increasing of alkyl chain length (p<0.05). All of QADMAIs containing polymers had higher surface charge density than control polymer (p<0.05), and surface charge densities of QADMAI-12 and QADMAI-16 containing polymers were nearly the same (p>0.05) which were higher than that of QADMAI-18 containing polymer (p<0.05). All of QADMAI containing polymers had good inhibitory effect on biofilm formation.
  
  
  CONCLUSIONS
  QADMAIs had no miscibility problem with TEGDMA, and QADMAIs could endow dental resin with both antibacterial activity and radio-opacity. Formulation of QADMAI containing resin should be optimized in terms of mechanical stregth to satisfy the requirements of dental resin for clinical application.
authors.affiliation: Department of Biomaterials Science, Institute of Dentistry and Biocity Turku Biomaterial Research Program, University of Turku, Turku 20520, Finland; Turku Clinical Biomaterials Centre-TCBC, University of Turku, Turku 20520, Finland; College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China. Electronic address: hejin@utu.fi.
authors.forename: Jingwei
authors.initials: J
authors.lastname: He
authors.affiliation: Institute of Dentistry, University of Turku, Turku 20520, Finland.
authors.forename: Eva
authors.initials: E
authors.lastname: Söderling
authors.affiliation: Turku Clinical Biomaterials Centre-TCBC, University of Turku, Turku 20520, Finland; College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China; Institute of Dentistry, University of Turku, Turku 20520, Finland.
authors.forename: Lippo V J
authors.initials: LV
authors.lastname: Lassila
authors.affiliation: Turku Clinical Biomaterials Centre-TCBC, University of Turku, Turku 20520, Finland; College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China; Institute of Dentistry, University of Turku, Turku 20520, Finland.
authors.forename: Pekka K
authors.initials: PK
authors.lastname: Vallittu
mesh_terms: D000180:Acrylic Resins / Q000138:chemical synthesis* / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000494:pharmacology*; D018441:Biofilms; D003188:Composite Resins; D008689:Methacrylates / Q000138:chemical synthesis* / Q000494:pharmacology*; D066244:Proton Magnetic Resonance Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared; D013295:Streptococcus mutans / Q000187:drug effects
chemical_list: D000180:Acrylic Resins; D000900:Anti-Bacterial Agents; D003188:Composite Resins; D008689:Methacrylates; C041289:Radio-Opaque acrylic resin
keywords: Antibacterial activity; Dental resin; Dimethacrylate quaternary ammonium; Radio-opacity