title: Development of novel dental adhesive with double benefits of protein-repellent and antibacterial capabilities.
abstract: OBJECTIVE
  Secondary caries at the tooth-restoration margins remains a main reason for restoration failure. The objectives of this study were to: (1) combine protein-repellent 2-methacryloyloxyethyl phosphorylcholine (MPC) with quaternary ammonium dimethylaminohexadecyl methacrylate (DMAHDM) to develop a new dental adhesive with double benefits of protein-repellent and antibacterial capabilities for the first time; and (2) investigate the effects on protein adsorption, anti-biofilm activity, and dentin bond strength.
  
  
  METHODS
  MPC and DMAHDM were incorporated into Scotchbond Multi-Purpose (SBMP) primer and adhesive. Dentin shear bond strengths were measured using extracted human molars. Protein adsorption onto the adhesive resin surfaces was determined by the micro bicinchoninic acid (BCA) method. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate biofilm metabolic activity, colony-forming unit (CFU) counts, lactic acid production and live/dead staining of biofilms on resins.
  
  
  RESULTS
  Incorporation of 7.5% MPC and 5% DMAHDM into primer and adhesive did not adversely affect the dentin shear bond strength (p>0.1). The resin with 7.5% MPC+5% DMAHDM had protein adsorption that was nearly 20-fold less than SBMP control (p<0.05). The resin with 7.5% MPC+5% DMAHDM had much stronger antibacterial effects than using MPC or DMAHDM alone (p<0.05). Biofilm CFU counts on the resin with 7.5% MPC+5% DMAHDM were reduced by more than 4 orders of magnitude, compared to SBMP control.
  
  
  CONCLUSIONS
  The use of double agents (protein-repellent MPC+antibacterial DMAHDM) in dental adhesive achieved much stronger inhibition of biofilms than using each agent alone. The novel protein-repellent and antibacterial bonding agent is promising to reduce biofilm/plaque buildup and reduce recurrent caries at the tooth-restoration margins.
authors.affiliation: Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing 100050, China; Biomaterials & Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA.
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Biomaterials & Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Weir
authors.affiliation: Biomaterials & Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA.
authors.forename: Elaine
authors.initials: E
authors.lastname: Romberg
authors.affiliation: Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing 100050, China. Electronic address: byuxing@263.net.
authors.forename: Yuxing
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Biomaterials & Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA; Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Mechanical Engineering, University of Maryland, Baltimore County, MD 21250, USA. Electronic address: hxu@umaryland.edu.
authors.forename: Hockin H K
authors.initials: HH
authors.lastname: Xu
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D019344:Lactic Acid / Q000378:metabolism; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry* / Q000494:pharmacology*; D008963:Molar; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D000644:Quaternary Ammonium Compounds / Q000737:chemistry* / Q000494:pharmacology*; D019279:Resin Cements; D033081:Shear Strength
chemical_list: D000900:Anti-Bacterial Agents; D003738:Dental Cements; D008689:Methacrylates; D000644:Quaternary Ammonium Compounds; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; D010767:Phosphorylcholine; D019344:Lactic Acid; C070638:2-methacryloyloxyethyl phosphorylcholine
keywords: 2-Methacryloyloxyethyl phosphorylcholine; Antibacterial activity; Caries inhibition; Dental adhesive; Dentin bond strength; Protein repellent