title: Antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles.
abstract: BACKGROUND
  Conventional spray and the immersion disinfection of irreversible hydrocolloid impression materials may lead to dimensional changes.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to investigate the antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles.
  
  
  METHODS
  The antimicrobial activity and properties of 2 commercially available irreversible hydrocolloid impression materials were evaluated after incorporating varying concentrations of silver nanoparticles. Antimicrobial activity was determined using the disk diffusion method. The gel strength, permanent deformation, flow, and gelation time were measured according to American Dental Association specification #18. Analysis of variance was used to identify the significant differences within and across the groups (α=.05).
  
  
  RESULTS
  Adding silver nanoparticles to irreversible hydrocolloid impression materials resulted in superior antimicrobial activity without adversely affecting their properties. Adding silver nanoparticles to Zelgan significantly increased the gel strength compared with the control group, except at 5 wt%. However, the gel strength of Tropicalgin was unaffected except at 5 wt%. An increase in the permanent deformation was found with the incorporation of silver nanoparticles in both Zelgan and Tropicalgin. The flow of Zelgan increased with the incorporation of silver nanoparticles, whereas a decrease in the flow of Tropicalgin was observed at 1 wt% and 2 wt%. An increase in the gelation time of both Zelgan and Tropicalgin was observed with the incorporation of silver nanoparticles.
  
  
  CONCLUSIONS
  Based on this in vitro study, silver nanoparticles can be incorporated into irreversible hydrocolloid impression materials as antimicrobial agents without adversely affecting their properties.
authors.affiliation: Associate Professor, Department of Dental Materials, Manipal College of Dental Sciences, Manipal University, Manipal, India. Electronic address: kishore.gp@manipal.edu.
authors.forename: Kishore
authors.initials: K
authors.lastname: Ginjupalli
authors.affiliation: Assistant Professor, Department of Dental Materials, Vishnu Dental College, Bhimavaram, India.
authors.forename: Rama Krishna
authors.initials: RK
authors.lastname: Alla
authors.affiliation: Senior Research Fellow, Directorate of Research (Health Sciences), Manipal University, Manipal, India.
authors.forename: Chaitanya
authors.initials: C
authors.lastname: Tellapragada
authors.affiliation: Reader, Department of Prosthodontics and Crown and Bridge, Manipal College of Dental Sciences, Manipal University, Manipal, India.
authors.forename: Lokendra
authors.initials: L
authors.lastname: Gupta
authors.affiliation: Associate Professor, Department of Dental Materials, Manipal College of Dental Sciences, Manipal University, Manipal, India.
authors.forename: Nagaraja
authors.initials: N
authors.lastname: Upadhya Perampalli
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects; D003102:Colloids / Q000737:chemistry / Q000494:pharmacology*; D003760:Dental Impression Materials / Q000737:chemistry / Q000494:pharmacology*; D052978:Disk Diffusion Antimicrobial Tests; D004926:Escherichia coli / Q000187:drug effects; D053768:Metal Nanoparticles / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000890:Anti-Infective Agents; D003102:Colloids; D003760:Dental Impression Materials