Evaluation of the strength and radiopacity of Portland cement with varying additions of bismuth oxide.
OBJECTIVE
To study the effect of addition of various proportions of bismuth oxide on compressive strength and radiopacity of Portland cement.


METHODS
The compressive strength of white Portland cement and cement replaced with 10, 15, 20, 25 and 30% bismuth oxide was evaluated by testing cylinders 6 mm in diameter and 12 mm high. Twelve cylinders were tested for each material under study. The radiopacity of the cements tested was evaluated using an aluminium step-wedge and densitometer. The optical density was compared with the relevant thickness of aluminium (Al). Statistical analysis was performed using Analysis of Variance (ANOVA) with P = 0.05 and Tukey test to perform multiple comparison tests.


RESULTS
Various additions of bismuth oxide had no significant effect on the strength of the material when compared with the unmodified Portland cement (P > 0.05). The radiopacity of the cements tested ranged from 2.02 mm Al for Portland cement to 9.79 mm Al for the highest bismuth replacement.


CONCLUSIONS
Addition of bismuth oxide did not affect the compressive strength of Portland cement. All the bismuth oxide cement mixtures had radio-opacities higher than 3 mm thickness of aluminium.
Saliba
E
E
Department of Oral and Dental Science, Bristol Dental School, University of Bristol, Bristol, UK.
Abbassi-Ghadi
S
S
Vowles
R
R
Camilleri
J
J
Hooper
S
S
Camilleri
J
J
D017607:Aluminum Compounds / Q000737:chemistry; D001729:Bismuth / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry; D019245:Compressive Strength; D003287:Contrast Media; D003738:Dental Cements / Q000737:chemistry*; D003799:Dental Stress Analysis; D004338:Drug Combinations; D016014:Linear Models; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry; D012387:Root Canal Filling Materials / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry
D017607:Aluminum Compounds; D017610:Calcium Compounds; D003287:Contrast Media; D003738:Dental Cements; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C472247:accelerated Portland cement; C086631:mineral trioxide aggregate; C033301:bismuth oxide; D001729:Bismuth