title: An in vitro study of the pH of three calcium hydroxide dressing materials.
abstract: Calcium hydroxide is widely used as a root canal dressing material because of its favorable alkalinizing effect. It has been suggested that the action comes from diffusion of hydroxyl ions through the apical foramen. The purpose of this in vitro study was to test the pH changes that occurred over a period of 30 days using a mixture of calcium hydroxide and distilled water and two commercial calcium hydroxide products in a simulated periapical environment. The materials were inserted in glass tubes closed at one end, which were placed in individual vials containing distilled water at a pH 7.4. Unfilled glass tubes were used as controls. Alkalinity changes of the medium were measured at 1 and 24 h and 15 and 30 days. The alkalinizing properties of all materials showed a rapid increase at 1 and 24 h followed by a continuous but more gradual increase from 15 to 30 days. The control tubes did not cause a change in pH of the medium, which remained at pH 7.4. At the end of the observation period, the alkalinizing properties of Calasept and Ultracal XS were significantly higher (P < 0.05) than the calcium hydroxide/distilled water paste.
authors.affiliation: Department of Adult Dental Care, Faculty of Odontology, University of Buenos Aires, Argentina. zmener@infovia.com.ar
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Zmener
authors.forename: Cornelis H
authors.initials: CH
authors.lastname: Pameijer
authors.forename: Gladys
authors.initials: G
authors.lastname: Banegas
mesh_terms: D000704:Analysis of Variance; D002122:Calcium Chloride; D002126:Calcium Hydroxide / Q000737:chemistry*; D003736:Dental Cavity Lining; D004338:Drug Combinations; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000032:analysis*; D009824:Ointments; D011189:Potassium Chloride; D012387:Root Canal Filling Materials / Q000737:chemistry*; D017693:Sodium Bicarbonate; D012965:Sodium Chloride
chemical_list: D004338:Drug Combinations; D006878:Hydroxides; D009824:Ointments; D012387:Root Canal Filling Materials; C531021:UltraCal XS; C036086:calcium hydroxide, calcium chloride, potassium chloride, sodium bicarbonate, sodium chloride drug combination; D012965:Sodium Chloride; D011189:Potassium Chloride; D017693:Sodium Bicarbonate; D002122:Calcium Chloride; D002126:Calcium Hydroxide