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The Role of Nanoscale Roughness on Cell Attachment Following Titanium‐based Instrumentation of Titanium, Titanium‐Zirconium, and Zirconia Surfaces
Author(s) -
Cerutis D. Roselyn,
Fischer Nicholas G.,
Gnabasik Ryan,
Lang Melissa S.,
Baruth Andrew
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1034.7
Subject(s) - titanium , materials science , cubic zirconia , surface roughness , nanoscopic scale , scanning electron microscope , surface finish , zirconium , curette , adhesion , biomedical engineering , nanotechnology , composite material , ceramic , metallurgy , surgery , medicine
This study aimed to evaluate the nanoscale characteristics of human gingival fibroblast (HGF) adhesion to disks composed of several dental implant and healing abutment materials following repeated (100x) instrumentation with a titanium (Ti) curette, as commonly used in dental implant surface cleaning, using atomic force microscopy (AFM) in contact mode. Sterile Ti Grade 2, Zirconia (ZrO 2 ) and Ti‐zirconium (Ti‐Zr, Roxolid®) disks (Straumann®, Andover, MA, USA) with a machined surface, 5 mm in diameter, were used in this study. Optical laser profilometry (1 – 5 μm lateral resolution) over a length of 4.4 mm revealed a statistical increase (over control) in average roughness for Ti and Ti‐Zr, but not for ZrO 2 . The disks were then placed in 96‐well cell culture plates and seeded with 0.3 ml of an HGF suspension at a density of 10 4 cells / ml of cell culture media. The units were incubated for 24 h at 37 °C in a humidified CO 2 incubator. The units were removed from the 96 well dishes, rinsed in phosphate buffered saline, fixed by immersion in 95% ethanol for 5 min, and air‐dried. Scanning electron microscopy revealed that HGF adhesion was statistically higher (over control) for Ti, Ti‐Zr, but not for ZrO 2 . We employed AFM (5 – 10 nm lateral resolution) to explicate the role of nanoscale roughness on cellular attachment; in particular, whether the nanoscale roughness played a dominant role in adhesion. AFM was performed on an Agilent 5420 SPM/AFM, in ambient conditions, housed in an acoustic and mechanical vibration isolation chamber and analyzed with Agilent's PicoView software package. Images were obtained in constant force mode with a 1 Hz scan rate, at 512 lines per image, with a Silicon Nitride cantilever (spring constant of 0.08 N/m and a tip radius of ≤ 10 nm). Images taken at size scales of 2 to 100 μm revealed an instrumented surface of Ti and Ti‐Zr that was coated with 50 – 100 nm pits and fissures, while ZrO 2 remained relatively unchanged and smooth. Critically, these nanoscale features would have been difficult, if not impossible, to identify using traditional optical profilometry methods. Following cell plating, AFM clearly shows protruding cells on the control surface and a “planarizing” of the nanoscopically rough surfaces of instrumented Ti and Ti‐Zr. This likely occurs by filling of the pits and fissures with extracellular matrix during cell attachment. Alternatively, on ZrO 2 , the cells protruded from the surface for both the control and instrumented surface. In conclusion, the increase in nanoscale roughness following instrumentation, along with macroscale roughness, may play a significant role in HGF attachment and adhesion for dental implant and healing abutment materials, as it is more consistent with cellular size scales. Support or Funding Information This research was partially supported by a research grant from Straumann USA (IIS 15‐12).