Physicomechanical properties of strontium and fluoride modified biodentineTM
Objectives: To investigate the effect of bioactive glass addition on the physicomechanical properties of BiodentineTM. The study compares the setting time, compressive strength and radiopacity of BiodentineTM modified by three different compositions of bioactive glasses
Design: This was an exploratory lab based quasi-experimental study
Setting: The study was conducted in the laboratory at Queen Mary, University of London Dental Physical Sciences Unit.
Materials and methods: Dental cements based on BiodentineTM and its modifications were used in the study. Original unmodified BiodentineTM cement was coded BO. Three bioactive glasses based on high fluoride (Q), high strontium (I) and high fluoride + strontium (H)were synthesized and 0.07g of each of the bioactive glasses added to BiodentineTM powder to yield 3 additional types of cements which were coded BQ, BI and BH respectively. A set mass of each cement type was prepared by adding 5 drops of the liquid supplied with BiodentineTM to the powders and triturating for 30 seconds in a 4000rpm electric amalgamator. These cements were subjected to setting time determination, compressive strength testing and radiopacity testing according to ISO 9917-1: 2007.Setting time and compressive strength were statistically analysed using T-test at 95% confidence level at a significance level of 0.05.
Results: Bioactive glass addition resulted in initial setting times of11.31+0.18, 12:22+ 0.11, 11:59+ 0.15 and 13:35+0.23 minutes for BO, BQ, BI and BH respectively. The increased setting time of BQ and BH were statistically significant. Student t-test analysis of compressive strength demonstrated statistically higher 14 day compressive strengths for BI (p=0.036) and BH (p=0004). BH cement had the highest grey scale value equivalent to 2.9mm of aluminium, which was consistent with the best radiopacity among the 4 BiodentineTM based cements.
Conclusion: Bioactive glass addition to BiodentineTM improved the radiographic detectability and compressive strength of the cement. This is important since current use of BiodentineTM is limited owing to inadequate strength and detection on radiographs. However, further studies are needed to explore alternative modifications that could shorten the setting time of this cement.