ABSTRACT
INTRODUCTION: Solubility of root filling materials is heavily influenced by the environment they are in contact with. This study compared the solubility of ProRoot MTA in deionized water and synthetic tissue fluid. MATERIALS AND METHODS: Forty specimens of prepared MTA were immersed in deionized water and synthetic tissue fluid (20 samples each). The solubility was assessed after 7 and 28 days. Scanning electron microscope observation was also performed. The mean weight loss was evaluated using a digital scale. Data were analyzed using one-way ANOVA. Tukey test was performed for multiple comparisons. RESULTS: MTA solubility in synthetic tissue fluid was significantly lower than deionized water after 7 and 28 days (P<0.05). Secondary electron detectors revealed the presence of lumps and platelets on the surfaces of both specimens. Also, more voids were observed in specimen stored in deionized water. CONCLUSION: MTA dissolved faster in deionized water than synthetic tissue fluid. Despite this, the solubility of this material in both media was acceptable.
ABSTRACT
INTRODUCTION: Storage temperature influences the properties of Portland cement during mixing. Because of similarities between Portland cement and mineral trioxide aggregate, the aim of the present study was to evaluate surface microhardness, topography, and phase structure of white mineral trioxide aggregate (WMTA) after storage in a range of temperatures. METHODS: Thirty WMTA sachets were divided into 3 groups of 10. The 3 groups were stored at 4 degrees C, 25 degrees C, and 40 degrees C for 48 hours with accompanying ampules. Sachets were immediately mixed after removal from storage according to manufacturer's instructions and mixed and packed into cylindrical glass tubes at room temperature. Surface microhardness of each specimen was measured after 3 days. Four specimens from each group were prepared and observed under scanning electron microscope and x-ray diffraction. Data were subjected to one-way analysis of variance and a post hoc Tukey test at P <.05. RESULTS: Mean surface hardness +/- standard deviation after storage at 4 degrees C, 25 degrees C, and 40 degrees C were 25.23 +/- 5.99, 53.56 +/- 3.28, and 62.89 +/- 1.76, respectively. Statistically significant differences were observed among the groups (P < .001). More voids and a disorganized, flake-like topography were observed in specimens stored at 4 degrees C in comparison with those stored at 25 degrees C and 40 degrees C. X-ray diffraction meter generated similar peaks at 40 degrees C and 25 degrees C, but slight differences were observed at 4 degrees C. CONCLUSIONS: This study indicated that storage temperature might influence surface hardness and microstructure of WMTA.
Subject(s)
Aluminum Compounds/chemistry , Calcium Compounds/chemistry , Oxides/chemistry , Root Canal Filling Materials/chemistry , Silicates/chemistry , Carbon Compounds, Inorganic/chemistry , Chemical Phenomena , Cold Temperature , Crystallography , Dental Polishing/methods , Drug Combinations , Drug Storage , Hardness , Hot Temperature , Humans , Humidity , Materials Testing , Microscopy, Electron, Scanning , Phase Transition , Porosity , Silicon Compounds/chemistry , Surface Properties , Temperature , Time Factors , X-Ray DiffractionABSTRACT
INTRODUCTION: The aim of this study was to evaluate morphologic microstructure and surface hardness of white mineral trioxide aggregate (WMTA) after exposure to a range of alkaline environments during hydration. METHODS: WMTA was mixed and packed into 60 glass tubes. Four groups, each containing 15 tubes, were exposed to pH values of 7.4, 8.4, 9.4, and 10.4, respectively, for 3 days. In 12 tubes in each group, Vickers surface hardness was measured after exposure to alkaline environments. Data were subjected to one-way analysis of variance and a post hoc Tukey test. Three specimens in each group were prepared to be evaluated under a scanning electron microscope using scattered electron (SE) and backscattered electron (BSE) detectors. RESULTS: The mean surface hardness values +/- standard deviation after exposure to pH values of 7.4, 8.4, 9.4, and 10.4 were 58.28 +/- 8.21, 68.84 +/- 7.19, 67.32 +/- 7.22, and 59.22 +/- 9.14, respectively. The difference between these values was statistically significant (p = 0.000). There were statistically significant differences between pH values of 8.4 and 9.4 and pH values of 7.4 and 10.4 (p > 0.05). The SE detector revealed needle-shaped crystals at pH values of 7.4 and 8.4 and an amorphous microstructure at pH values of 9.4 and 10.4 on WMTA surface. The BSE detector showed more unhydrated structure and pores at pH values of 7.4 and 10.4 compared with pH values of 8.4 and 9.4. CONCLUSIONS: Surface hardness can be influenced by different alkaline pH values. The BSE detector can reveal more microstructure details of WMTA in conjunction with the SE detector. More porosity and unhydrated structure are observed in WMTA exposed to pH values of 7.4 and 10.4.
