title: Evaluation of antimicrobial and physical properties of orthodontic composite resin modified by addition of antimicrobial agents--an in-vitro study.
abstract: BACKGROUND
  This study was designed to investigate the antimicrobial and physical properties of orthodontic composite resin modified by the addition of antimicrobial agents.
  
  
  METHODS
  Unite bonding adhesive (3M Unitek, Monrovia, Calif), a chemically cured composite resin, modified by the addition of benzalkonium chloride (BAC), chlorhexidine, and triclosan in concentrations of 0.1 wt%, 0.2 wt%, and 0.3 wt%, respectively, was formed into tablets for testing. The tablets of each group and a control group were subjected to the agar plate diffusion test to measure the zone of bacterial inhibition. In addition, they were incubated for 24 hours in tryptic soy broth inoculated with Streptococcus mutans and examined for bacterial growth. A total of 80 extracted premolars were collected and divided into 2 sets of 40 teeth each. Stainless steel Begg brackets were bonded by using control and experimental composites. A universal testing machine was used to determine shear bond strength. The first set of teeth was tested after 24 hours and the second set after 25 days of storage in distilled water. Time-dependent release of antimicrobial agents from the modified composites was monitored spectrophotometrically.
  
  
  CONCLUSIONS
  The findings indicated that (1) addition of BAC to the orthodontic composite resin enhanced its antimicrobial properties, (2) there was no significant difference in the bond strengths of the control and the experimental resin tested after 24 hours and 25 days, and (3) maximum release of BAC from the modified resin was higher than that of chlorhexidine or triclosan, and was much higher than the minimum inhibitory concentration level.
authors.affiliation: Department of Orthodontics, DAV Dental College, Yamunanagar, Haryana, India. docvikas79@rediffmai1.com
authors.forename: Vikas
authors.initials: V
authors.lastname: Sehgal
authors.forename: V Surendra
authors.initials: VS
authors.lastname: Shetty
authors.forename: Subraya
authors.initials: S
authors.lastname: Mogra
authors.forename: Gopalkrishna
authors.initials: G
authors.lastname: Bhat
authors.forename: Montu
authors.initials: M
authors.lastname: Eipe
authors.forename: Shery
authors.initials: S
authors.lastname: Jacob
authors.forename: Laxman
authors.initials: L
authors.lastname: Prabu
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D000890:Anti-Infective Agents / Q000627:therapeutic use*; D001641:Bicuspid; D002710:Chlorhexidine / Q000627:therapeutic use; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D006801:Humans; D016910:Orthodontic Brackets; D011140:Polyurethanes / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D012822:Silicon Dioxide / Q000737:chemistry*; D013295:Streptococcus mutans / Q000187:drug effects*; D013997:Time Factors; D014260:Triclosan / Q000627:therapeutic use
chemical_list: D000180:Acrylic Resins; D000890:Anti-Infective Agents; C029012:Composite Dental Resin; D003188:Composite Resins; D003764:Dental Materials; D011140:Polyurethanes; D019279:Resin Cements; D014260:Triclosan; D012822:Silicon Dioxide; C073908:Unite resin; D002710:Chlorhexidine