Apatite-like calcium phosphate deposition and physicochemical properties of an aspartic acid-functionalized hydraulic cement.

چکیده اصلی

OBJECTIVES: This study evaluated the effects of aspartic acid modification on the physicochemical properties and phosphate-associated surface response of a hydraulic calcium silicate cement. MATERIALS AND METHODS: White mineral trioxide aggregate (MTA) was mixed using 0%, 25%, 50%, 75%, or 100% (v/v) of a 4 g/L aspartic acid stock solution. Final setting time, solubility, pH, and Ca²⁺ concentration in the immersion solution were evaluated after seven days in deionized water (n = 10). Surface roughness, morphology, elemental composition, and phosphate- and carbonate-associated spectral features were assessed after 30 days of storage in deionized water or phosphate-buffered saline (PBS). The Ap/C spectral ratio was calculated from the integrated ATR-FTIR band areas. Data were analyzed using one- or two-way ANOVA followed by Tukey's test (α = 0.05). RESULTS: The 25% formulation showed the shortest setting time, whereas the 100% formulation showed the longest (p < 0.001). All aspartic acid-containing formulations exhibited greater solubility and lower Ca²⁺ concentrations than the control (p < 0.05), and the 50%, 75%, and 100% formulations exceeded the recommended solubility limit. The 25% formulation had the lowest pH, whereas the control, 75%, and 100% formulations maintained similar alkaline values. Surface roughness was lowest for the 25% formulation and highest for the 100% formulation, with no significant effect of storage medium. EDS detected negligible surface phosphorus after storage in deionized water but marked phosphorus content after PBS storage. Ap/C analysis showed significant main effects of cement formulation and storage medium, without a significant interaction. The 25%, 50%, and 75% formulations exhibited higher marginal Ap/C ratios than the 0% and 100% formulations. CONCLUSIONS: Aspartic acid produced non-linear and formulation-dependent changes in the evaluated properties. Higher Ap/C ratios reflected differences in relative spectral composition but did not confirm increased apatite formation or a crystalline apatite phase. Ca-P-rich surface deposition depended on phosphate supplied by the storage medium, and no formulation improved all evaluated outcomes.

ترجمه فارسی چکیده

این مطالعه اثرات اصلاح با اسید آسپارتیک بر خواص فیزیوشیمیایی و پاسخ سطحی مرتبط با فسفات سیمان کلسیم سیلیکاتی هیدرولیک را ارزیابی کرد. سیمان مینرال تری‌اکسید آگریکیت سفید با استفاده از 0، 25، 50، 75 یا 100 درصد (v/v) محلول مایع اسید آسپارتیک 4 گرم بر لیتر مخلوط شد. زمان سخت‌شدگی نهایی، حل‌پذیری، pH و غلظت کلسیم در محلول غوطه‌وری پس از هفت روز در آب مقطر ارزیابی شد. خشکی سطح، ظاهر، ترکیب عناصر و ویژگی‌های طیفی مرتبط با فسفات و کربنات پس از ۳۰ روز ذخیره در آب مقطر یا فسفات-بیس‌ففات سدیم بررسی شد. نسبت آپاتیت/کلسیم (Ap/C) از مناطق نوارهای طیفی FTIR-ATR یکپارچه محاسبه شد. داده‌ها با استفاده از آنالیز واریانس یک‌جهته یا دوجهته و سپس آزمون Tukey تحلیل شد.

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