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Discoloration Improvement by Mechanically-Milled Binary Oxides as Radiopacifier for Mineral Trioxide Aggregates
oleh: Hsiu-Na Lin, Ling-Chi Wang, May-Show Chen, Pei-Jung Chang, Pin-Yu Lin, Alex Fang, Chin-Yi Chen, Pee-Yew Lee, Chung-Kwei Lin
Format: | Article |
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Diterbitkan: | MDPI AG 2022-11-01 |
Deskripsi
Mineral trioxide aggregates (MTA) have been widely used in endodontic treatments, but after some time, patients suffer tooth discoloration due to the use of bismuth oxide (Bi<sub>2</sub>O<sub>3</sub>) as a radiopacifier. Replacement of Bi<sub>2</sub>O<sub>3</sub> with high energy ball-milled single (zirconia ZrO<sub>2</sub>; hafnia, HfO<sub>2</sub>; or tantalum pentoxide, Ta<sub>2</sub>O<sub>5</sub>) or binary oxide powder was attempted, and corresponding discoloration improvement was investigated in the present study. Bi<sub>2</sub>O<sub>3</sub>-free MTA is expected to exhibit superior discoloration. The radiopacity, diametral tensile strength, and discoloration of MTA-like cements prepared from the as-milled powder were investigated. Experimental results showed that MTA-like cements prepared using Ta<sub>2</sub>O<sub>5</sub> exhibited a slightly higher radiopacity than that of HfO<sub>2</sub> but had a much higher radiopacity than ZrO<sub>2</sub>. Milling treatment (30 min to 3 h) did not affect the radiopacities significantly. These MTA-like cements exhibited superior color stability (all measured ΔE<sub>00</sub> < 1.0) without any perceptible differences after UV irradiation. MTA-like cements prepared using ZrO<sub>2</sub> exhibited the best color stability but the lowest radiopacity, which can be improved by introducing binary oxide. Among the investigated samples, MTA-like cement using (ZrO<sub>2</sub>)<sub>50</sub>(Ta<sub>2</sub>O<sub>5</sub>)<sub>50</sub> exhibited excellent color stability and the best overall performance with a radiopacity of 3.25 mmAl and a diametral tensile strength of 4.39 MPa.