title: The influence of sample dimensions on hydroxyl ion release from calcium hydroxide products.
abstract: The purpose of this study was to compare the rate of hydroxyl ion release from commercially available setting and non-setting calcium hydroxide products. The rate of hydroxyl ion release is important, as this has been suggested to be the main factor in the therapeutic activity of these products. In total, hydroxyl ion release was measured from 1104 samples of Dycal, Life, Calasept and Hypocal in solution using in vitro titration. The rate of hydroxyl ion release was measured for up to 14 days, using two sizes of sample surface area. The dimensions of the exposed sample surface area was found to be an important physical constraint to the hydroxyl ion release from non-setting calcium hydroxide products, whereas this was not found to be the case with setting products. The range in hydroxide activity between products was found to be 298%. In rank order of hydroxide ion release, from the most to the least active was: Hypocal, Calasept, Life and Dycal. The differences in the rate of hydroxyl ion release from these products may have some implications for their clinical applications. It is suggested that in cases where the oral healing responses have been poorer than expected, the size and seal of prepared cavities could have negatively influenced the therapeutic release of hydroxyl ions from non-setting calcium hydroxide products.
authors.affiliation: School of Dentistry, University of Birmingham, Birmingham, UK.
authors.forename: P E
authors.initials: PE
authors.lastname: Murray
authors.forename: P J
authors.initials: PJ
authors.lastname: Lumley
authors.forename: A J
authors.initials: AJ
authors.lastname: Smith
authors.forename: H F
authors.initials: HF
authors.lastname: Ross
mesh_terms: D000704:Analysis of Variance; D001466:Barium Sulfate / Q000737:chemistry; D002122:Calcium Chloride; D002126:Calcium Hydroxide / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003785:Dental Pulp Capping; D004338:Drug Combinations; D006801:Humans; D006878:Hydroxides / Q000737:chemistry*; D016014:Linear Models; D008422:Materials Testing; D008903:Minerals / Q000737:chemistry; D015999:Multivariate Analysis; D011189:Potassium Chloride; D012387:Root Canal Filling Materials / Q000737:chemistry; D017693:Sodium Bicarbonate; D012965:Sodium Chloride; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003764:Dental Materials; D004338:Drug Combinations; D006878:Hydroxides; D008903:Minerals; D012387:Root Canal Filling Materials; C036086:calcium hydroxide, calcium chloride, potassium chloride, sodium bicarbonate, sodium chloride drug combination; D001466:Barium Sulfate; D012965:Sodium Chloride; C025702:Dycal; C088866:barium sulfate, calcium hydroxide drug combination; D011189:Potassium Chloride; C040408:Life (dental material); D017693:Sodium Bicarbonate; C031356:hydroxide ion; D002122:Calcium Chloride; D002126:Calcium Hydroxide