Dr. MH. Nekoofar

DDS, MSc, DoIBoE, PhD

Tag: BioAggregate

  • Acid and Microhardness of Mineral Trioxide Aggregate and Mineral Trioxide Aggregate–like Materials

    The aim of this study was to compare the surface microhardness of BioAggregate, ProRoot MTA, and CEMCement when exposed to an acidic environment or phosphate-buffered saline (PBS) as a synthetic tissue fluid. Methods: Ninety cylindrical molds made of polymethyl methacrylate with an internal diameter of 6 mm and height of 4 mm (according to ASTM E384 standard for microhardness tests) were fabricated and filled with BioAggregate (n = 30), tooth-colored ProRoot MTA (n = 30), or CEM Cement (n = 30). Each group was then divided into 3 subgroups of 10 specimens consisting of those exposed to distilled water, exposed to PBS (pH = 7.4), or exposed to butyric acid (pH = 5.4). After 1 week the Vickers surface microhardness test was performed. Statistical analysis included 2-way analysis of variance, followed by post hoc Dunnett T3 in cases with lack of homoscedasticity and Tukey honestly significant difference in cases with homoscedasticity. 
    Results: The indentations obtained from the CEM Cement specimens exposed to an acidic pH were not readable because of incomplete setting. There was a significant difference between the microhardness of the materials regardless of the environmental conditions (P < .001). In all the environmental conditions, MTA had significantly higher and CEM Cement had significantly lower microhardness values (P < .001). All experimental cements had significantly higher microhardness values when exposed to PBS (P < .001) and had significantly lower microhardness values when exposed to butyric acid (P < .001). Conclusions: The surface microhardness of BioAggregate, ProRoot MTA, and CEM Cement was reduced significantly by exposure to butyric acid and increased significantly by exposure to PBS. In all environmental conditions, MTA had significantly higher microhardness values. (J Endod 2014;40:432–435)

     Acid and Microhardness of Mineral Trioxide Aggregate.pdf

  • Bioactivity of EndoSequence Root Repair Material and Bioaggregate

    Aim: To evaluate the bioactivity of Bioaggregate (BA), EndoSequence Root Repair Material (ERRM), and white ProRoot Mineral trioxide aggregate (MTA). Methodology Sixty horizontal root sections with standardized canal spaces were divided randomly into 3 groups (n = 20) and filled with white ProRoot MTA (groups 1 and 2), BA (groups 3 and 4) or ERRM putty (groups 5 and 6). The specimens of groups 1, 3 and 5 (each of 10) were immersed in phosphatebuffered saline (PBS) for 1 week and those of groups 2, 4 and 6 (each of 10) for 2 months. After the experimental periods, the specimens were processed for scanning electron microscopy (SEM) observations. Precipitation of apatite crystals on the surfaces of the cements and/or at the dentine–cement interface was evaluated and analysed elementally by energy dispersive X-ray (EDX) instrument.
    Results: Analysis of specimens revealed various surface morphologies that were dependent on the material and immersion time in PBS. The formation of precipitates was observed on the surfaces of all materials at 1 week, which increased substantially over time. After 2 months, the surface of the cements was changed dramatically and consisted of a substantially greater amount of apatite aggregates. Interfacial layers in some areas of the dentine–cement interface were found only following 2 months of immersion. Precipitates on MTA revealed high peaks of Ca, Si and O after 1 week of immersion; after 2 months, high peaks of Ca, P and O were present. Precipitates on BA and ERRM displayed high Ca, P O peaks after both 1 week and 2 months.
    Conclusion: Exposure of MTA, BA and ERRM to PBS resulted in precipitation of apatite crystalline structures that increased over time. This suggests that the tested materials are bioactive.

     Bioactivity of EndoSequence Root Repair Material.pdf