title: Development of a multifunctional adhesive system for prevention of root caries and secondary caries.
abstract: OBJECTIVE
  The objectives of this study were to: (1) develop a novel adhesive for prevention of tooth root caries and secondary caries by possessing a combination of protein-repellent, antibacterial, and remineralization capabilities for the first time; and (2) investigate the effects of 2-methacryloyloxyethyl phosphorylcholine (MPC), dimethylaminohexadecyl methacrylate (DMAHDM), and nanoparticles of amorphous calcium phosphate (NACP) on dentin bond strength, protein-repellent properties, and dental plaque microcosm biofilm response.
  
  
  METHODS
  MPC, DMAHDM and NACP were added into Scotchbond Multi-Purpose primer and adhesive. Dentin shear bond strengths were measured. Adhesive coating thickness, surface texture and dentin-adhesive interfacial structure were examined. Protein adsorption onto adhesive resin surface was determined by the micro bicinchoninic acid method. A human saliva microcosm biofilm model was used to investigate biofilm metabolic activity, colony-forming unit (CFU) counts, and lactic acid production.
  
  
  RESULTS
  The resin with 7.5% MPC+5% DMAHDM+30% NACP did not adversely affect dentin shear bond strength (p>0.1). The resin with 7.5% MPC+5% DMAHDM+30% NACP produced a coating on root dentin with a thickness of approximately 70μm and completely sealed all the dentinal tubules. The resin with 7.5% MPC+5% DMAHDM+30% NACP had 95% reduction in protein adsorption, compared to SBMP control (p<0.05). The resin with 7.5% MPC+5% DMAHDM+30% NACP was strongly antibacterial, with biofilm CFU being four orders of magnitude lower than that of SBMP control. Significance The novel multifunctional adhesive with strong protein-repellent, antibacterial and remineralization properties is promising to coat tooth roots to prevent root caries and secondary caries. The combined use of MPC, DMAHDM and NACP may have wide applicability to bonding agents, cements, sealants and composites to inhibit caries.
authors.affiliation: Biomaterials & Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA; Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing, China.
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: Mary A S
authors.initials: MA
authors.lastname: Melo
authors.affiliation: Biomaterials & Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA; State Key Laboratory of Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.affiliation: Biomaterials & Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Liu
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: Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing, 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*; D018441:Biofilms; D002130:Calcium Phosphates; D003738:Dental Cements / Q000737:chemistry*; D003773:Dental Plaque / Q000382:microbiology*; D003804:Dentin / Q000737:chemistry; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008689:Methacrylates; D053758:Nanoparticles / Q000737:chemistry*; D010767:Phosphorylcholine / Q000031:analogs & derivatives; D019279:Resin Cements; D017213:Root Caries / Q000382:microbiology / Q000517:prevention & control*
chemical_list: D000900:Anti-Bacterial Agents; D002130:Calcium Phosphates; D003738:Dental Cements; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C519480:amorphous calcium phosphate; D010767:Phosphorylcholine; C070638:2-methacryloyloxyethyl phosphorylcholine
keywords: Antibacterial; Calcium phosphate nanoparticles; Dental adhesive; Dentin bond strength; Protein repellent; Tooth root caries inhibition