Evaluation of the propylene glycol association on  some physical and chemical properties of mineral  trioxide aggregate.
OBJECTIVE
To evaluate the influence of propylene glycol (PG) on the flowability, setting time, pH and calcium ion release of mineral trioxide aggregate (MTA).


METHODS
Mineral trioxide aggregate was mixed with different proportions of PG, as follows: group 1: MTA + 100% distilled water (DW); group 2: MTA + 80% DW and 20% PG; group 3: MTA + 50% DW and 50% PG; group 4: MTA + 20% DW and 80% PG; group 5: MTA + 100% PG. The ANSI/ADA No. 57 was followed for evaluating the flowability and the setting time was measured by using ASTM C266-08. For pH and calcium release analyses, 50 acrylic teeth with root-end cavities were filled with the materials (n = 10) and individually immersed in flasks containing 10 mL deionized water. After 3 h, 24 h, 72 h and 168 h, teeth were placed in new flasks and the water in which each specimen was immersed had its pH determined by a pH metre and the calcium release measured by an atomic absorption spectrophotometer with a calcium-specific hollow cathode lamp. Data were analysed by using one way anova test for global comparison and by using Tukey’s test for individual comparisons.


RESULTS
The highest value of flowability was observed with MTA + 20% DW and 80% PG and the lowest values were found with MTA + 100% DW. They were significantly different compared to the other groups (P < 0.05). The presence of PG did not affect the pH and calcium release. The MTA + 100% PG favoured the highest (P < 0.05) pH and calcium release after 3 h. Increasing the PG proportion interfered (P < 0.05) with the setting time; when used at the volume of 100% setting did not occur.


CONCLUSIONS
The addition of PG to MTA-Angelus increased its setting time, improved flowability and increased the pH and calcium ion release during the initial post-mixing periods. The ratio of 80% DW–20% PG is recommended.
Department of Operative Dentistry, Dental Materials and Endodontics, Dental School of Bauru, University of São Paulo, Bauru, Brazil. mhungaro@fob.usp.br
M A H
MA
Duarte
K
K
Alves de Aguiar
M A
MA
Zeferino
R R
RR
Vivan
R
R
Ordinola-Zapata
M
M
Tanomaru-Filho
P H
PH
Weckwerth
M C
MC
Kuga
D017607:Aluminum Compounds / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry*; D055598:Chemical Phenomena; D004338:Drug Combinations; D006244:Hardness; D006801:Humans; D006863:Hydrogen-Ion Concentration; D017736:Ion-Selective Electrodes; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry*; D014677:Pharmaceutical Vehicles / Q000737:chemistry*; D019946:Propylene Glycol / Q000737:chemistry*; D012212:Rheology; D017640:Silicates / Q000737:chemistry*; D013054:Spectrophotometry, Atomic; D013997:Time Factors; D014783:Viscosity; D014867:Water / Q000737:chemistry
D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D014677:Pharmaceutical Vehicles; D017640:Silicates; C086631:mineral trioxide aggregate; D014867:Water; D019946:Propylene Glycol; D002118:Calcium