Physicochemical properties of radiopaque dicalcium silicate cement as a root-end filling material in an acidic environment.
OBJECTIVE
To investigate the effect of two solutions differing by pH (7.4 and 4.0) on the physicochemical properties of a radiopaque dicalcium silicate cement.


METHODS
The cement was prepared by hand-mixing the dicalcium silicate powder with distilled water in a liquid-to-powder ratio of 0.4 mL g(-1) . A total of 253 cement specimens with dimension of 6 mm (diameter) × 3 mm (height) were used. The morphology, weight loss, porosity and diametral tensile strength of the cement were evaluated after soaking in a solution for different time intervals, in addition to pH changes in the cement-immersed solutions.


RESULTS
After soaking in a pH 7.4 solution for 1 day, the particle size of precipitated apatite spherulites on the cement surfaces was greater than that obtained in a pH 4.0 solution. Solution pH did not result in a significant difference (P > 0.05) in diametral tensile strength of cement specimens at the same soaking time-point. On day 30, the sample was associated with a weight loss of 0.8% in a pH 4.0 solution, whereas in a pH 7.4 solution, a weight increase of 0.2% occurred. A greater porosity of the cement soaked in a pH 4.0 was found compared with that in the solution with pH 7.4. Soaking time affected significantly (P < 0.05) the porosity, weight change and strength of the cements in an acidic environment more than at pH 7.4.


CONCLUSIONS
High apatite-forming activity and low degradation were the characteristics of a radiopaque dicalcium silicate cement.
Institute of Oral Science, Chung Shan Medical University, Taichung City, Taiwan.
T Y
TY
Chiang
S J
SJ
Ding
D001031:Apatites / Q000737:chemistry; D002122:Calcium Chloride; D017610:Calcium Compounds / Q000737:chemistry*; D055598:Chemical Phenomena; D003287:Contrast Media / Q000737:chemistry; D006801:Humans; D006851:Hydrochloric Acid / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007101:Immersion; D015636:Magnesium Chloride / Q000737:chemistry; D008422:Materials Testing; D008744:Methylamines / Q000737:chemistry; D010316:Particle Size; D010710:Phosphates / Q000737:chemistry; D016062:Porosity; D011189:Potassium Chloride / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D012184:Retrograde Obturation / Q000379:methods*; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012823:Silicate Cement / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D017693:Sodium Bicarbonate / Q000737:chemistry; D012965:Sodium Chloride / Q000737:chemistry; D013314:Stress, Mechanical; D013431:Sulfates / Q000737:chemistry; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors
D001031:Apatites; D017610:Calcium Compounds; D003287:Contrast Media; D008744:Methylamines; D010710:Phosphates; D017680:Potassium Compounds; D012387:Root Canal Filling Materials; D017640:Silicates; D013431:Sulfates; D015636:Magnesium Chloride; C012036:sodium sulfate; C013481:dicalcium silicate; D012823:Silicate Cement; D012965:Sodium Chloride; D011189:Potassium Chloride; D017693:Sodium Bicarbonate; C013216:potassium phosphate; C027451:methylamine; D002122:Calcium Chloride; D006851:Hydrochloric Acid