title: Effect of various chemicals as solvents on the dissolution of set white mineral trioxide aggregate: an in vitro study.
abstract: BACKGROUND
  The main disadvantages of mineral trioxide aggregate (MTA) are its prolonged setting time and the difficulty in retrieving it from the root canal. Because MTA is alkaline in nature, it might interact with acids or chemicals and could disintegrate. The aim of this study was to assess the effect of various chemicals on dissolution of white MTA (WMTA).
  
  
  METHODS
  Stainless steel molds were prepared and filled with WMTA that was exposed to carbonic acid, 2% chlorhexidine gluconate solution, 17% ethylenediaminetetraacetic acid (EDTA) solution, and saline on days 1 and 21. The surface hardness was measured before and after 5-, 10-, 15-, and 20-minute intervals after exposure to chemicals. The samples were probed with a #16 endodontic explorer after 20 minutes of chemical exposure and hardness testing.
  
  
  RESULTS
  Both qualitative and quantitative analysis showed that carbonic acid was effective in significantly reducing the surface hardness of set WMTA on both days 1 and 21; 2% chlorhexidine gluconate reduced the surface hardness of set WMTA significantly on day 1 only.
  
  
  CONCLUSIONS
  Carbonic acid can be effectively used as an adjunct to dissolve set WMTA even after 21 days, whereas 2% chlorhexidine gluconate showed significant surface dissolution only within 24 hours of WMTA placement. Thus, usage of chlorhexidine gluconate as a root canal irrigant in which WMTA is used during endodontic procedure should be avoided for 24 hours. Solutions with EDTA have no effect on surface hardness of WMTA.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Meenakshi Ammal Dental College, Maduravoyal, Chennai, Tamil Nadu, India. nandini_80@hotmail.com
authors.forename: Suresh
authors.initials: S
authors.lastname: Nandini
authors.forename: Velmurugan
authors.initials: V
authors.lastname: Natanasabapathy
authors.forename: Sushmita
authors.initials: S
authors.lastname: Shivanna
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D002255:Carbonic Acid / Q000737:chemistry; D002710:Chlorhexidine / Q000031:analogs & derivatives / Q000737:chemistry; D017005:Dental Debonding / Q000379:methods; D004338:Drug Combinations; D004492:Edetic Acid / Q000737:chemistry; D006244:Hardness; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry*; D019233:Retreatment; D012387:Root Canal Filling Materials / Q000737:chemistry*; D018915:Root Canal Preparation / Q000379:methods; D017640:Silicates / Q000737:chemistry*; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D013997:Time Factors
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; D012997:Solvents; C086631:mineral trioxide aggregate; D002255:Carbonic Acid; D004492:Edetic Acid; C010882:chlorhexidine gluconate; D002710:Chlorhexidine