Apatite formation on bioactive calcium-silicate cements for dentistry affects surface topography and human marrow stromal cells proliferation

• Published in: Dental materials 2010-10, Vol.26 (10), p.974-992
• Main Authors: Gandolfi, Maria Giovanna, Ciapetti, Gabriela, Taddei, Paola, Perut, Francesca, Tinti, Anna, Cardoso, Marcio Vivan, Van Meerbeek, Bart, Prati, Carlo
• Format: Article
• Language: English
• Subjects: Advanced Basic Science; Alpha-TCP; Apatite; Apatite spherulites; Apatites - chemical synthesis; Apatites - pharmacology; Biocompatible Materials - chemistry; Biocompatible Materials - pharmacology; Bismuth - pharmacology; Bone Marrow Cells - drug effects; Calcium Compounds - chemistry; Calcium Compounds - pharmacology; Calcium Phosphates - pharmacology; Calcium-silicate cement; Cell Proliferation - drug effects; Cell Survival - drug effects; Cells, Cultured; Cements; Collagen - biosynthesis; Collagens; Contrast Media - pharmacology; Dentistry; Drug Storage; Human; Humans; Hydrophobic and Hydrophilic Interactions; Interferometry; Materials Testing; MTA; Nanocomposites; Nanospheres; Nanostructure; Photoelectron Spectroscopy; Root-end filling materials; Silicate Cement - chemistry; Silicate Cement - pharmacology; Silicates - chemistry; Silicates - pharmacology; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; Stromal Cells - drug effects; Surface chemistry; Surface Properties - drug effects; Topography
• ISSN: 0109-5641; 1879-0097
• DOI: 10.1016/j.dental.2010.06.002

Abstract The effect of ageing in phosphate-containing solution of bioactive calcium-silicate cements on the chemistry, morphology and topography of the surface, as well as on in vitro human marrow stromal cells viability and proliferation was investigated. A calcium-silicate cement (wTC) mainly based on dicalcium-silicate and tricalcium-silicate was prepared. Alpha-TCP was added to wTC to obtain wTC-TCP. Bismuth oxide was inserted in wTC to prepare a radiopaque cement (wTC-Bi). A commercial calcium-silicate cement (ProRoot MTA) was tested as control. Cement disks were aged in DPBS for 5 h (‘fresh samples’), 14 and 28 days, and analyzed by ESEM/EDX, SEM/EDX, ATR-FTIR, micro-Raman techniques and scanning white-light interferometry. Proliferation, LDH release, ALP activity and collagen production of human marrow stromal cells (MSC) seeded for 1–28 days on the cements were evaluated. Fresh samples exposed a surface mainly composed of calcium-silicate hydrates CSH (from the hydration of belite and alite), calcium hydroxide, calcium carbonate, and ettringite. Apatite nano-spherulites rapidly precipitated on cement surfaces within 5 h. On wTC-TCP the Ca-P deposits appeared thicker than on the other cements. Aged cements showed an irregular porous calcium-phosphate (Ca-P) coating, formed by aggregated apatite spherulites with interspersed calcite crystals. All the experimental cements exerted no acute toxicity in the cell assay system and allowed cell growth. Using biochemical results, the scores were: fresh cements > aged cements for cell proliferation and ALP activity (except for wTC-Bi), whereas fresh cements < aged cements for collagen synthesis. Summarizing (1) non-aged cements showed higher cell proliferation than aged cements, probably favoured by the presence of Si–OH gel and the early formation of apatite nano-spherulites; (2) the alpha-TCP doped cement aged for 28 days displayed the highest bioactivity and cell proliferation; (3) the deleterious effect of bismuth on cell proliferation was reduced by the progressive increase of the biocoating thickness on aged cement. In conclusion, the experimental cements have adequate biological properties to be used as root-end/root repair filling materials or pulp capping materials. The alfa-TCP doped cement represents a new potential bioactive material for expanded applications in dentistry.