title: Development of novel self-healing and antibacterial dental composite containing calcium phosphate nanoparticles.
abstract: OBJECTIVE
  Fracture and secondary caries are the primary reasons for dental restoration failure. The objective of this study was to develop a self-healing composite to heal cracks, while containing dimethylaminohexadecyl methacrylate (DMAHDM) for antibacterial function and nanoparticles of amorphous calcium phosphate (NACP) for remineralization.
  
  
  METHODS
  Microcapsules were synthesized with poly(urea-formaldehyde) (PUF) shells containing triethylene glycol dimethacrylate (TEGDMA) and N,N-dihydroxyethyl-p-toluidine (DHEPT) as healing liquid. Composite contained 20 mass% of NACP and 35% glass fillers. In addition, composite contained 0%, 2.5%, 5%, 7.5%, or 10% of microcapsules. A single edge V-notched beam method measured fracture toughness (KIC) and self-healing efficiency. A dental plaque microcosm biofilm model was used to test the antibacterial properties.
  
  
  RESULTS
  Incorporation of microcapsules up to 7.5% into the composite did not adversely affect the mechanical properties (p > 0.1). Successful self-healing was achieved, with KIC recovery of 65-81% (mean ± sd; n = 6) to regain the load-bearing capability after composite fracture. The self-healing DMAHDM-NACP composite displayed a strong antibacterial potency, inhibiting biofilm viability and lactic acid production, and reducing colony-forming units by 3-4 orders of magnitude, compared to control composite without DMAHDM.
  
  
  CONCLUSIONS
  A dental composite was developed with triple benefits of self-healing after fracture, antibacterial activity, and remineralization capability for the first time.
  
  
  CONCLUSIONS
  The self-healing, antibacterial and remineralizing composite may be promising for tooth cavity restorations to combat bulk fracture and secondary caries. The method of using triple agents (self-healing microcapsules, DMAHDM, and NACP) may have wide applicability to other dental composites, adhesives, sealants and cements.
authors.affiliation: Department of Prosthodontics, School of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Biomedicine, Jinan 250012, China; Biomaterials & Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA.
authors.forename: Junling
authors.initials: J
authors.lastname: Wu
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: Mary Anne 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; 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 / Q000494:pharmacology; D018441:Biofilms; D001696:Biomechanical Phenomena; D002130:Calcium Phosphates / Q000494:pharmacology*; D002214:Capsules; D003188:Composite Resins / Q000737:chemistry* / Q000494:pharmacology; D003773:Dental Plaque / Q000382:microbiology; D008422:Materials Testing; D053758:Nanoparticles
chemical_list: D000900:Anti-Bacterial Agents; D002130:Calcium Phosphates; D002214:Capsules; D003188:Composite Resins; C020243:calcium phosphate
keywords: Antibacterial; Fracture toughness recovery; Mechanical properties; Microcapsules; Polymerizable healing liquid; Self-healing dental composite