Surface roughness of titanium disks influences the adhesion, proliferation and differentiation of osteogenic properties derived from human

Abstract

Purpose: The aim of this study was to investigate the response of osteogenic cell lineage and gingival fibroblastic cells to different surface treatments of grade IV commercially pure Titanium (cpTi) disks.

Material and methods: Grade IV cpTi disks with different surfaces were produced: machined (M), sandblasting (B), sandblasting and acid subtraction (NP), and hydrophilic treatment (ACQ). Surface microtopography characteristics and chemical composition were investigated by scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDS). Adhesion and proliferation of SC-EHAD (human surgically-created early healing alveolar defects) and HGF-1 (human gingival fibroblasts) on Ti disks were investigated at 24 and 48 h, and osteogenic differentiation and mineralization were evaluated by assessing alkaline phosphatase (ALP) activity and alizarin red staining, respectively.

Results: No significant differences were found among the various surface treatments for all surface roughness parameters, except for skewness of the assessed profile (Rsk) favoring M (p = 0.035 ANOVA). M disks showed a slightly higher (p > 0.05; Kruskal-Wallis/Dunn) adhesion of HGF-1 (89.43 ± 9.13%) than SC-EHAD cells (57.11 ± 17.72%). ACQ showed a significantly higher percentage of SC-EHAD (100%) than HGF-1 (69.67 ± 13.97%) cells adhered at 24 h. SC-EHAD cells expressed increased ALP activity in osteogenic medium at M (213%) and NP (235.04%) surfaces, but higher mineralization activity on ACQ (54.94 ± 4.80%) at 14 days.

Conclusion: These findings suggest that surface treatment influences the chemical composition and the adhesion and differentiation of osteogenic cells in vitro.

Clinical relevance: Hydrophilic surface treatment of grade IV cpTi disks influences osteogenic cell adhesion and differentiation, which might enhance osseointegration.

Keywords: Cell adhesion; Fibroblasts; Surface analysis; Titanium; cell proliferation.

Fig. 1

SEM photomicrographs. Titanium disks with machined (M), sandblasted (B), Neoporos® (NP), and Acqua® (ACQ) surfaces

Fig. 2

3D surface plot. a M, b B, c NP, and d ACQ groups obtained by Interactive 3D, Surface Plot plugin (ImageJ, NIH, USA)

Fig. 3

EDS analysis. Chemical composition of titanium disks with different surface treatment. a M. b B. c NP. d ACQ

Fig. 4

SEM photomicrographs of HGF and SC-EHAD cell adhesion and proliferation. SEM images of HGF-1 and BG-1 cells cultivated on M, B, N,P and ACQ surfaces after 24 and 48 h of culture (× 500 magnification)

Fig. 5

Percentage area of the disks covered by cells (mean ± standard deviation) at 24 and 48 h, according to groups. Equal symbols in columns HGF-1 represent *significant differences between groups B and NP, ACQ, and M (p < 0.01; Kruskal-Wallis post hoc Dunn). Equal symbols in columns SC-EHAD represent ⁺significant differences between M and groups B and ACQ (p < 0.001; Kruskal-Wallis post hoc Dunn); ^**significant differences between NP and groups B and ACQ (p < 0.001; Kruskal-Wallis post hoc Dunn)

Fig. 6

Mineralization activity of SC-EHAD cells at 14 days in the different groups. a Standard medium. b Osteogenic medium. *Squared images represent ¼ of disk surface

Fig. 7

ALP activity of HGF-1 and SC-EHAD cells [DMEM (standard) and osteogenic media]