title: Mechanical properties and microstructure analysis of mineral trioxide aggregate mixed with hydrophilic synthetic polymer.
abstract: BACKGROUND
  In dentistry, mineral trioxide aggregate (MTA) has been widely used for root perforation, retrograde filling, pulp capping and regenerative endodontics. Despite its superior sealing ability and biocompatibility, MTA has critical drawbacks regarding handling property such as sandy property, lacking cohesive properties and wash-out tendency. So, it is necessary to improve the fluidity of MTA in order to improve its handling properties. In this study, we applied modified liquid to improve handling properties of MTA.
  
  
  METHODS
  Polyvinyl alcohol (PVA; 3 and 5 wt %) aqueous solutions were prepared and the samples were divided into three groups: DW group (MTA mixed with distilled water), P3 group (MTA mixed with 3% PVA), and P5 group (MTA mixed with 5% PVA). Handling property, initial setting time, and compressive strength were evaluated. The microstructures were observed by Field emission scanning electron microscope (FE-SEM) and X-ray diffractometer (XRD) phase analyses were performed.
  
  
  RESULTS
  PVA modified group showed similar behavior of IRM compared to DW group. The initial setting time of P3 or P5 group was significantly longer than that of DW group (p < 0.05). The compressive strength of DW group was higher than that of P3 or P5 groups (p < 0.05). Experimental groups (P3 and P5) showed no microstructural differences compared with DW group when the fractured surfaces were observed by FE-SEM with XRD patterns after 3 and 14 days.
  
  
  CONCLUSIONS
  Polyvinyl alcohol, a modified liquid for MTA, improved the handling properties of the material without violating its microstructure.
authors.affiliation: Department of Conservative Dentistry, Dental Research Institute and School of Dentistry, Seoul National University, Seoul, Korea.
authors.forename: Young-Seok
authors.initials: YS
authors.lastname: Noh
authors.forename: Shin-Hye
authors.initials: SH
authors.lastname: Chung
authors.forename: Kwang Shik
authors.initials: KS
authors.lastname: Bae
authors.forename: Seung-Ho
authors.initials: SH
authors.lastname: Baek
authors.forename: Kee-Yeon
authors.initials: KY
authors.lastname: Kum
authors.forename: Woo-Cheol
authors.initials: WC
authors.lastname: Lee
authors.forename: Won-Jun
authors.initials: WJ
authors.lastname: Shon
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Rhee
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D004338:Drug Combinations; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry*; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D017640:Silicates; C086631:mineral trioxide aggregate; D011142:Polyvinyl Alcohol
keywords: dental/craniofacial material; microstructure; polymer; stress; viscosity