Introduction: It has been shown that the cellular response; adhesion, proliferation and differentiation are influenced by the surface properties to which they come in contact, such as the topography. In particular, it has been shown that the differentiation of mesenchymal cells into the osteoblast lineage increases when the average surface roughness of titanium implants is about 2 microns. However it is unknown if this response is unique to the titanium or a general effect induced by the roughness. Objective: to compare the differentiation of periodontal ligament stem-cells (PDLSCs) into adipocytes, bone, cartilage and cement of different materials presenting a similar roughness.
Materials: Pure Titanium (cp-Ti, grade 2), medical grade stainless steel AISI316L (SS), dental porcelain (DP), zirconia (ZrO2), high density polyethylene (HDPE) and polymethacrylate-methyl (PMMA)
Methods: The samples were produced as discs of 14 x 2mm; (n= 30 for each material). A surface treatment was used to produce an average roughness of 2±0.5 mm for all samples. Surfaces properties such as wettability, composition and zero point of charge were measured in order to correlate with the biological response. The cell adhesion and proliferation were initially tested to assure non-toxic effects using the MTT assay. Finally, the differentiation pattern was evaluated using qRT-PCR for 5, 7 and 14 days without adding any induction method.
Discussion: None material showed toxic response; however, some differences in both the adhesion and the proliferation rate were detected. In terms of the qRT-PCR, differences were observed among the materials-type; metals expressed largely osteocalcin (SS) or collagen II (Ti), the ceramics showed larger amount of collagen II with respect to the control, while for the polymers, the larger expression was for the CAP protein, corresponding to differentiation into cement precursor cells.
Conclusion: Despite that the six materials have similar roughness; the differentiation pattern was completely different, suggesting that the roughness by itself cannot induce a specific differentiation pattern. It must be a synergic effect among other surface properties and the roughness.
Omar Novelo, Enrique Romo, Mercedes Bermudez.
References:
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