title: Structure and chemical composition of an experimentally formed apical barrier after the application of calcium-glycerophosphate.
abstract: Transformation in the structure and composition of calcium-glycerophosphate (Ca-GP) was investigated using a scanning electron microscope fitted with an energy dispersive X-ray microanalysis (EDX) system. Ca-GP was packed inside roots that were subsequently implanted into the mandibles of rats to stimulate the formation of an apical barrier. Scanning electron microscopic observations of packed Ca-GP revealed three types of structures: globular aggregates, plate or flake-like aggregates, and granular aggregates. The average Ca/P molar ratios of EDX by area mode--postoperatively obtained at days 1, 3, 5, and 7--were 1.300, 1.533, 1.472, and 1.495 (analytic area: 0.01 to 0.03 mm2) and those of EDX by point mode were 1.220, 1.451, 1.487, and 1.467 (analytic point: 0.05 micron 2). The magnesium (Mg) weight percentage was found to be approximately 1.9 at days 3, 5, and 7, similar to Mg-substituted whitlockite. These findings suggest that Ca-GP are transformed, over a period of 3 days into Mg-substituted whitlockite as a result of being hydrolyzed by tissue fluid.
authors.affiliation: Department of Endodontics and Operative Dentistry, Nagasaki University School of Dentistry, Sakamoto 1-7-1, Nagasaki 852-8588, Japan.
authors.forename: I L
authors.initials: IL
authors.lastname: Viloria
authors.forename: K
authors.initials: K
authors.lastname: Yanagiguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Hayashi
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002118:Calcium / Q000032:analysis; D002130:Calcium Phosphates / Q000032:analysis; D011232:Chemical Precipitation; D016001:Confidence Intervals; D003461:Crystallography; D003786:Dental Pulp Cavity / Q000737:chemistry / Q000187:drug effects / Q000473:pathology; D004577:Electron Probe Microanalysis; D005994:Glycerophosphates / Q000378:metabolism / Q000627:therapeutic use*; D006868:Hydrolysis; D008274:Magnesium / Q000032:analysis; D008297:Male; D008334:Mandible / Q000601:surgery; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D010758:Phosphorus / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D019227:Tooth Apex / Q000737:chemistry / Q000187:drug effects* / Q000473:pathology; D014074:Tooth Calcification / Q000187:drug effects; D014961:X-Ray Diffraction
chemical_list: D002130:Calcium Phosphates; D005994:Glycerophosphates; C021767:whitlockite; D010758:Phosphorus; D008274:Magnesium; D002118:Calcium