D90: the strongest contributor to setting time in mineral trioxide aggregate and Portland cement

Ha, William N., Bentz, Dale P., Kahler, Bill and Walsh, Laurence J. (2015) D90: the strongest contributor to setting time in mineral trioxide aggregate and Portland cement. Journal of Endodontics, 41 7: 1146-1150. doi:10.1016/j.joen.2015.02.033

Author Ha, William N.
Bentz, Dale P.
Kahler, Bill
Walsh, Laurence J.
Title D90: the strongest contributor to setting time in mineral trioxide aggregate and Portland cement
Journal name Journal of Endodontics   Check publisher's open access policy
ISSN 0099-2399
Publication date 2015-07
Year available 2015
Sub-type Article (original research)
DOI 10.1016/j.joen.2015.02.033
Open Access Status Not yet assessed
Volume 41
Issue 7
Start page 1146
End page 1150
Total pages 5
Place of publication Philadelphia, PA, United States
Publisher Elsevier
Collection year 2016
Language eng
Formatted abstract
Introduction:  The setting times of commercial mineral trioxide aggregate (MTA) and Portland cements vary. It was hypothesized that much of this variation was caused by differences in particle size distribution.

Methods:  Two gram samples from 11 MTA-type cements were analyzed by laser diffraction to determine their particle size distributions characterized by their percentile equivalent diameters (the 10th percentile, the median, and the 90th percentile [d90], respectively). Setting time data were received from manufacturers who performed indentation setting time tests as specified by the standards relevant to dentistry, ISO 6786 (9 respondents) or ISO 9917.1 (1 respondent), or not divulged to the authors (1 respondent). In a parallel experiment, 6 samples of different size graded Portland cements were produced using the same cement clinker. The measurement of setting time for Portland cement pastes was performed using American Society for Testing and Materials C 191. Cumulative heat release was measured using isothermal calorimetry to assess the reactions occurring during the setting of these pastes. In all experiments, linear correlations were assessed between setting times, heat release, and the 3 particle size parameters.

Results:  Particle size varied considerably among MTA cements. For MTA cements, d90 was the particle size characteristic showing the highest positive linear correlation with setting time (r = 0.538). For Portland cement, d90 gave an even higher linear correlation for the initial setting time (r = 0.804) and the final setting time (r = 0.873) and exhibited a strong negative linear correlation for cumulative heat release (r = 0.901).

Conclusions:  Smaller particle sizes result in faster setting times, with d90 (the largest particles) being most closely correlated with the setting times of the samples.
Keyword Hydration
Mineral trioxide aggregate
Particle size
Portland cement
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
School of Dentistry Publications
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