title: Physicochemical basis of the biologic properties of mineral trioxide aggregate.
abstract: This study characterized the interactions of mineral trioxide aggregate with a synthetic tissue fluid composed of a neutral phosphate buffer saline solution and root canal dentin in extracted human teeth using inductively coupled plasma-atomic emission spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, and X-ray diffraction. Mineral trioxide aggregate exposed to synthetic tissue fluid at 37 degrees C released its metallic constituents and produced precipitates with a composition and structure similar to that of hydroxyapatite [Ca10(PO4)6(OH)2-HA]. Endodontically prepared teeth filled with mineral trioxide aggregate and stored in synthetic tissue fluid at 37 degrees C for 2 months produced at the dentin wall an adherent interfacial layer that resembled hydroxyapatite in composition. The authors conclude that Ca, the dominant ion released from mineral trioxide aggregate, reacts with phosphates in synthetic tissue fluid, yielding hydroxyapatite. The dentin-mineral trioxide aggregate interfacial layer results from a similar reaction. The sealing ability, biocompatibility, and dentinogenic activity of mineral trioxide aggregate is attributed to these physicochemical reactions.
authors.affiliation: Operative Dentistry and Biomaterials Department, LSU, School of Dentistry, 1100 Florida Ave, New Orleans, LA 70119, USA. nsarka@lsuhsc.edu
authors.forename: N K
authors.initials: NK
authors.lastname: Sarkar
authors.forename: R
authors.initials: R
authors.lastname: Caicedo
authors.forename: P
authors.initials: P
authors.lastname: Ritwik
authors.forename: R
authors.initials: R
authors.lastname: Moiseyeva
authors.forename: I
authors.initials: I
authors.lastname: Kawashima
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D002021:Buffers; D002118:Calcium / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003804:Dentin / Q000737:chemistry; D004338:Drug Combinations; D017886:Durapatite / Q000737:chemistry; D004577:Electron Probe Microanalysis; D006801:Humans; D007474:Ion Exchange; D008274:Magnesium / Q000737:chemistry; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D012387:Root Canal Filling Materials / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D012996:Solutions
chemical_list: D017607:Aluminum Compounds; D002021:Buffers; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D010710:Phosphates; D012387:Root Canal Filling Materials; D017640:Silicates; D012996:Solutions; C086631:mineral trioxide aggregate; D017886:Durapatite; D008274:Magnesium; D002118:Calcium