title: Novel antibacterial orthodontic cement containing quaternary ammonium monomer dimethylaminododecyl methacrylate.
abstract: OBJECTIVE
  Demineralized lesions in tooth enamel around orthodontic brackets are caused by acids from cariogenic biofilm. This study aimed to develop a novel antibacterial orthodontic cement by incorporating a quaternary ammonium monomer dimethylaminododecyl methacrylate (DMADDM) into a commercial orthodontic cement, and to investigate the effects on microcosm biofilm response and enamel bond strength.
  
  
  METHODS
  DMADDM, a recently-synthetized antibacterial monomer, was incorporated into orthodontic cement at 0%, 1.5%, 3% and 5% mass fractions. Bond strength of brackets to enamel was measured. A microcosm biofilm model was used to measure metabolic activity, lactic acid production, and colony-forming units (CFU) on orthodontic cements.
  
  
  RESULTS
  Shear bond strength was not reduced at 3% DAMDDM (p > 0.1), but was slightly reduced at 5% DMADDM, compared to 0% DMADDM. Biofilm viability was substantially inhibited when in contact with orthodontic cement containing 3% DMADDM. Biofilm metabolic activity, lactic acid production, and CFU were much lower on orthodontic cement containing DMADDM than control cement (p < 0.05).
  
  
  CONCLUSIONS
  Therefore, the novel antibacterial orthodontic cement containing 3% DMADDM inhibited oral biofilms without compromising the enamel bond strength, and is promising to reduce or eliminate demineralization in enamel around orthodontic brackets.
authors.affiliation: Biomaterials & Tissue Engineering Division, Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA. Electronic address: Mmelo@umaryland.edu.
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; Department of Prosthodontics, School of Stomatology, Shan Dong University, Jinan 250012, China; Shandong Provincial Key Laboratory of Oral Biomedicine, Jinan 250012, China.
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; Center for Stem Cell Biology & Regenerative Medicine, 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: D000134:Acid Etching, Dental / Q000379:methods; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D058491:Bacterial Load / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure; D003773:Dental Plaque / Q000382:microbiology; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D019344:Lactic Acid / Q000032:analysis; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry* / Q000494:pharmacology; D050296:Microbial Viability / Q000187:drug effects; D016910:Orthodontic Brackets; D000644:Quaternary Ammonium Compounds / Q000737:chemistry* / Q000494:pharmacology; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry* / Q000494:pharmacology; D012463:Saliva / Q000382:microbiology; D033081:Shear Strength; D013295:Streptococcus mutans / Q000187:drug effects; D013314:Stress, Mechanical
chemical_list: D000900:Anti-Bacterial Agents; D003188:Composite Resins; D008689:Methacrylates; D000644:Quaternary Ammonium Compounds; D019279:Resin Cements; C477790:Transbond XT; C516047:Transbond XT Light Cure Adhesive Primer; C586974:dimethylaminododecyl methacrylate; D019344:Lactic Acid
keywords: Antibacterial; Bond strength; Lactic acid; Metabolic activity; Microcosm biofilm; Quaternary ammonium methacrylate