title: Concentration of hydrogen ions in several calcium hydroxide pastes over different periods of time.
abstract: The purpose of this in vitro study was to measure the concentration of hydrogen ions (pH) of calcium hydroxide [(Ca(OH)2] pastes combined with different vehicles over 7 periods of time. The Ca(OH)2 was manipulated with the following vehicles: i: sterile water; ii: iodoform plus sterile water; iii: local anesthetics (Lydocaine 2% with 1: 100,000 epinephrine); iv: polyethyleneglycol; v: glycerin; vi: 2.0% chlorhexidine gel; vii: camphorated paramonochlorophenol (CMCP); viii: (CMCP) + glycerin; and ix: polyethyleneglycol plus CMCP. The pastes were made on a glass plate to toothpaste consistency and the pH was measured at the following times: 5 min, 1, 24, 48 h; 7, 14 and 28 days. The data were statistically analyzed (Kruskal-Wallis at p<0.05). At 5 min, 1 and 24 h, the pH of all tested pastes ranged from 13.05 to 11.16. At 48 h and 7 days the pH of all tested pastes ranged from 11.66 to 8.92. At 14 and 28 days almost all pastes had pH means lower than 10. In conclusion, the mean pH of all tested calcium hydroxide pastes decreased with the time. Pastes made with aqueous vehicles (especially with sterile water), followed by oily vehicles (especially with CMCP + glycerin), held the highest pH means over the periods of time tested.
authors.affiliation: Eastman Dental Institute, Unit of Endodontology, University College London, London, UK.
authors.forename: Morgana Eli
authors.initials: ME
authors.lastname: Vianna
authors.forename: Danila M
authors.initials: DM
authors.lastname: Zilio
authors.forename: Caio Cezar Randi
authors.initials: CC
authors.lastname: Ferraz
authors.forename: Alexandre Augusto
authors.initials: AA
authors.lastname: Zaia
authors.forename: Francisco José
authors.initials: FJ
authors.lastname: de Souza-Filho
authors.forename: Brenda Paula Figueiredo de Almeida
authors.initials: BP
authors.lastname: Gomes
mesh_terms: D000779:Anesthetics, Local / Q000494:pharmacology; D000891:Anti-Infective Agents, Local / Q000737:chemistry / Q000494:pharmacology; D002126:Calcium Hydroxide / Q000737:chemistry* / Q000494:pharmacology; D002164:Camphor / Q000494:pharmacology; D002710:Chlorhexidine / Q000494:pharmacology; D002733:Chlorophenols / Q000494:pharmacology; D004338:Drug Combinations; D005990:Glycerol / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008012:Lidocaine / Q000494:pharmacology; D008422:Materials Testing; D014677:Pharmaceutical Vehicles / Q000737:chemistry; D011092:Polyethylene Glycols / Q000494:pharmacology; D012388:Root Canal Irrigants / Q000737:chemistry* / Q000494:pharmacology; D012391:Root Resorption / Q000517:prevention & control; D013997:Time Factors; D014089:Tooth Remineralization / Q000379:methods; D014783:Viscosity; D014867:Water
chemical_list: D000779:Anesthetics, Local; D000891:Anti-Infective Agents, Local; D002733:Chlorophenols; D004338:Drug Combinations; D014677:Pharmaceutical Vehicles; D012388:Root Canal Irrigants; D014867:Water; D011092:Polyethylene Glycols; D002164:Camphor; C029804:camphorated parachlorophenol; D008012:Lidocaine; D005990:Glycerol; D002126:Calcium Hydroxide; D002710:Chlorhexidine