Fig. 5. Osteoblasts with an orientation tendency after 24 h of rotation (phallacidin fluorescence staining). On the left side with 200× and on the right side with 400× magnification. The yellow arrows show the orientation of the cells. The red arched arrow within the coloured circle shows the direction of rotation. The dashed white line oriented to the right stands for the resulting centrifug...
Fig. 4. Randomly orientated osteoblasts without influence of rotation (phallacidin fluorescence staining). On the left side with 200× and on the right side with 400× magnification. The white X on the coloured circle marks the location upon the plate where the osteoblasts were located. The red X marks the centre of the plate
Fig. 4. Randomly orientated osteoblasts without influence of rotati...
centrifugal force and the glass plates’ dimensions. For example, at a distance of 25 mm from the centre of the upper plate, the shear forces’ value is 8.33 dyn/cm2, together with an additional centrifugal force that has a value of 0.55 dyn/cm2
Fig. 3. Diagram for visualisation of the calculation of shear stress rates taking into account the centrifugal force and the glass plates’ dim...
earing gap and bottom plate are shown on the left side; rotation speed = 200 rpm; colour code bar (left edge) showing shear force values [Pa] [1 Pa = 10 dyn/cm2]; flow direction presented by arrows
Fig. 2. Side view of a computerized simulation, showing the flow chambers’ lower compartment and the flow profile in between the two plates; shearing gap and bottom plate are shown on ...
Fig. 1. Three-dimensional illustration (a–e) and photography (f) of the experimental setup with the components marked numerical. a as the lower plate); 2 Rotating glass panel [60 mm diameter (cell bearing)]; 3 Titanium axis. b4 Liquid medium (red). cGearwheel with set screw. eng ring with additional set screw
Fig. 1. Three-dimensional illustration (a–e) and photography (f) of the experim...
Culture medium/additives
Manufacturer
Order no.
Concentration
Dulbecco’s modified Eagle medium (DMEM) with l-glutamine, plus 4.5 g glucose,...
Component
Manufacturer
Order no.
Large petri dish
Becton Dickinson, Franklin Lakes, NJ, USA
...
Kämmerer, P.W., Thiem, D.G.E., Alshihri, A. et al. Cellular fluid shear stress on implant surfaces—establishment of a novel experimental set up.
Int J Implant Dent 3, 22 (2017). https://doi.org/10.1186/s40729-017-0085-3
Download citation
Received: 27 February 2017
Accepted: 22 May 2017
Published: 31 May 2017
DOI: https://doi.org/10.1186/s40729-017-0085-3
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were...
Correspondence to
D. G. E. Thiem.
Department of Oral and Maxillofacial Surgery, Facial Plastic Surgery, University Medical Centre Rostock, Schillingallee 35, 18057, Rostock, Germany
P. W. Kämmerer & D. G. E. Thiem
Department of Prosthetic and Biomaterial Sciences, King Saud University, Riyadh, Saudi Arabia
A. Alshihri
Harvard School of Dental Medicine, Boston, MA, USA
A. Alshihri
Department of Oral and Maxillofacial Surge...
The authors thank the Department of Hydraulic Machines, Faculty of Mechanical Engineering, Technical University of Munich, Germany, for helping with the computerised simulations.
Nothing to declare
The datasets supporting the conclusions of this article are available at the repository of the University Medical Centre Mainz, Germany, and can be provided on request.
PK had substantial contributio...
Papadaki M, Eskin SG. Effects of fluid shear stress on gene regulation of vascular cells. Biotechnol Prog. 1997;13(3):209–21.
James NL, Harrison DG, Nerem RM. Effects of shear on endothelial cell calcium in the presence and absence of ATP. FASEB J. 1995;9(10):968–73.
Kämmerer PW, Lehnert M, Al-Nawas B, Kumar VV, Hagmann S, Alshihri A, et al. Osseoconductivity of a specific streptavidin-biot...
Hughes-Fulford M. Signal transduction and mechanical stress. Sci STKE. 2004;2004(249):RE12.
Ruel J, Lemay J, Dumas G, Doillon C, Charara J. Development of a parallel plate flow chamber for studying cell behavior under pulsatile flow. ASAIO J. 1995;41(4):876–83.
Kazakidi A, Sherwin SJ, Weinberg PD. Effect of Reynolds number and flow division on patterns of haemodynamic wall shear stress near br...
Becker J, Kirsch A, Schwarz F, Chatzinikolaidou M, Rothamel D, Lekovic V, et al. Bone apposition to titanium implants biocoated with recombinant human bone morphogenetic protein-2 (rhBMP-2). A pilot study in dogs. Clin Oral Investig. 2006;10(3):217–24.
Hung CT, Allen FD, Pollack SR, Brighton CT. What is the role of the convective current density in the real-time calcium response of cultured bon...
Ehrlich PJ, Lanyon LE. Mechanical strain and bone cell function: a review. Osteoporos Int. 2002;13(9):688–700.
Vaughan TJ, Haugh MG, Mcnamara LM. A fluid-structure interaction model to characterize bone cell stimulation in parallel-plate flow chamber systems. J R Soc Interface. 2013;10(81):20120900.
Weinbaum S, Cowin SC, Zeng Y. A model for the excitation of osteocytes by mechanical loading-in...
To create fluid shear stress under in vitro conditions, several flow chambers have been developed in the past. The experimental setup of the flow chamber in the centre of this study offers advantages such as simplicity to assemble and ease of use as well as the creation of reproducible fluid shear forces on cells. Due to the new design, different cell types could be simultaneously analysed under r...
Besides, in the model reported in this study, microscopic examinations are possible after completing the experiment only. Nevertheless, an advantage of the new flow chamber is the possibility of testing different cell colonies simultaneously in one single experiment by placing cells in different radial locations on the spinning disc. Due to the current flow gradient from the centre to the peripher...
Due to the fact that constant flows were generated within the parallel flow chamber only, the situations of in vitro experiments differ from in vivo setting where dynamic flow profiles are particular [33]. As the constant laminar flow profile is not physiological in bones [34], vessels and other tissues [35], the informative value of the experimental setting is limited but it could be used for var...
The aim of this study was to establish a new FSS model that is easy to use as well as simple to assemble in order to create reproducible fluid shear forces on cells close to implant material surfaces. Todays’ commonly used commercial flow devices differ in geometry and function, which makes comparisons between experiments difficult [4, 10, 26, 27]. The benefits of this novel testing device are r...
in which ρ = density, h = height, ω = angular velocity and r = radius.
Figure 3 shows the respective physical force and its dependence on a bigger radius and higher rotational speed. The results of this study indicate that the centrifugal force represents only a little proportion of effective forces. Hence, the centrifugal forces’ impacts on the tested cells are considered to be insignifican...
Our analysis was focused on two main aspects:
Simulation of the fluid flow characteristics as well as quantification of the arising shear forces at the plate/plate flow chamber with reliable reproducibility
Assessment of the impact of fluid shear stress on osteoblast cells in terms of altered cell morphology and intracellular structural changes
The computational fluid dynamic analysis and the q...
For constant and fully developed laminar flow between the two parallel plates, the magnitude of the wall shear stress (τ) in between was calculated by formula 1:
in which η is the dynamic fluid viscosity (dyn/cm2), r is the radius of the plate (cm), ω stands for angular velocity and H for height (vertical distance in between the two plates).
To get information whether the flow is laminar or t...
A three-dimensional illustration and photography of the plate/plate flow chamber model is shown in Fig. 1. A detailed list of used parts can be found in Appendix 1.
The circulation within the flow chamber was generated by an externally attached electric motor, which rotates up to 500 rounds per minute (rpm). A commercial grade 4 pure medical titanium gear shaft (length = 40 mm, diameter =...
Therefore, the aim of the present study was to establish a new cell chamber model for FSS simulation and stimulation. In addition to its ease of use, the reported model in this study should meet the requirements of a simple design, generating reproducible flow characteristics next to laminar flows and clearly defined flow gradients on implant surfaces.
Cells can be influenced by different mechanostimuli, which lead to an activation of cellular and inter-cellular responses. These reactions may be caused by either a direct stimulation of the cell body (mechanoreception) or indirect cellular stimulation (response) [1,2,3]. Extracellular fluid movement induces fluid shear stress (FSS) that can result in different cellular processes including prolife...
Mechanostimuli of different cells can affect a wide array of cellular and inter-cellular biological processes responsible for dental implant healing. The purpose of this in vitro study was to establish a new test model to create a reproducible flow-induced fluid shear stress (FSS) of osteoblast cells on implant surfaces.
As FSS effects on osteoblasts are detectable at 10 dyn/cm2, a custom-made f...
Fig. 5. Osteoblasts with an orientation tendency after 24 h of rotation (phallacidin fluorescence staining). On the left side with 200× and on the right side with 400× magnification. The yellow arrows show the orientation of the cells. The red arched arrow within the coloured circle shows the direction of rotation. The dashed white line oriented to the right stands for the resulting centrifug...
Fig. 4. Randomly orientated osteoblasts without influence of rotation (phallacidin fluorescence staining). On the left side with 200× and on the right side with 400× magnification. The white X on the coloured circle marks the location upon the plate where the osteoblasts were located. The red X marks the centre of the plate
Fig. 4. Randomly orientated osteoblasts without influence of rotati...
to account the centrifugal force and the glass plates’ dimensions. For example, at a distance of 25 mm from the centre of the upper plate, the shear forces’ value is 8.33 dyn/cm2, together with an additional centrifugal force that has a value of 0.55 dyn/cm2
Fig. 3. Diagram for visualisation of the calculation of shear stress rates taking into account the centrifugal force and the glas...
e in between the two plates; shearing gap and bottom plate are shown on the left side; rotation speed = 200 rpm; colour code bar (left edge) showing shear force values [Pa] [1 Pa = 10 dyn/cm2]; flow direction presented by arrows
Fig. 2. Side view of a computerized simulation, showing the flow chambers’ lower compartment and the flow profile in between the two plates; shearing gap...
Fig. 1. Three-dimensional illustration (a–e) and photography (f) of the experimental setup with the components marked numerical. a lower plate); 2 Rotating glass panel [60 mm diameter (cell bearing)]; 3 Titanium axis. b4 Liquid medium (red). cwheel with set screw. e ring with additional set screw
Fig. 1. Three-dimensional illustration (a–e) and photography (f) of the experimental setup w...
Culture medium/additives
Manufacturer
Order no.
Concentration
Dulbecco’s modified Eagle medium (DMEM) with l-glutamine, plus 4.5 g glucose,...
Component
Manufacturer
Order no.
Large petri dish
Becton Dickinson, Franklin Lakes, NJ, USA
...
Kämmerer, P.W., Thiem, D.G.E., Alshihri, A. et al. Cellular fluid shear stress on implant surfaces—establishment of a novel experimental set up.
Int J Implant Dent 3, 22 (2017). https://doi.org/10.1186/s40729-017-0085-3
Download citation
Received: 27 February 2017
Accepted: 22 May 2017
Published: 31 May 2017
DOI: https://doi.org/10.1186/s40729-017-0085-3
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were...
Correspondence to
D. G. E. Thiem.
Department of Oral and Maxillofacial Surgery, Facial Plastic Surgery, University Medical Centre Rostock, Schillingallee 35, 18057, Rostock, Germany
P. W. Kämmerer & D. G. E. Thiem
Department of Prosthetic and Biomaterial Sciences, King Saud University, Riyadh, Saudi Arabia
A. Alshihri
Harvard School of Dental Medicine, Boston, MA, USA
A. Alshihri
Department of Oral and Maxillofacial Surge...
The authors thank the Department of Hydraulic Machines, Faculty of Mechanical Engineering, Technical University of Munich, Germany, for helping with the computerised simulations.
Nothing to declare
The datasets supporting the conclusions of this article are available at the repository of the University Medical Centre Mainz, Germany, and can be provided on request.
PK had substantial contributio...
Papadaki M, Eskin SG. Effects of fluid shear stress on gene regulation of vascular cells. Biotechnol Prog. 1997;13(3):209–21.
James NL, Harrison DG, Nerem RM. Effects of shear on endothelial cell calcium in the presence and absence of ATP. FASEB J. 1995;9(10):968–73.
Kämmerer PW, Lehnert M, Al-Nawas B, Kumar VV, Hagmann S, Alshihri A, et al. Osseoconductivity of a specific streptavidin-biot...
Hughes-Fulford M. Signal transduction and mechanical stress. Sci STKE. 2004;2004(249):RE12.
Ruel J, Lemay J, Dumas G, Doillon C, Charara J. Development of a parallel plate flow chamber for studying cell behavior under pulsatile flow. ASAIO J. 1995;41(4):876–83.
Kazakidi A, Sherwin SJ, Weinberg PD. Effect of Reynolds number and flow division on patterns of haemodynamic wall shear stress near br...
Becker J, Kirsch A, Schwarz F, Chatzinikolaidou M, Rothamel D, Lekovic V, et al. Bone apposition to titanium implants biocoated with recombinant human bone morphogenetic protein-2 (rhBMP-2). A pilot study in dogs. Clin Oral Investig. 2006;10(3):217–24.
Hung CT, Allen FD, Pollack SR, Brighton CT. What is the role of the convective current density in the real-time calcium response of cultured bon...
Ehrlich PJ, Lanyon LE. Mechanical strain and bone cell function: a review. Osteoporos Int. 2002;13(9):688–700.
Vaughan TJ, Haugh MG, Mcnamara LM. A fluid-structure interaction model to characterize bone cell stimulation in parallel-plate flow chamber systems. J R Soc Interface. 2013;10(81):20120900.
Weinbaum S, Cowin SC, Zeng Y. A model for the excitation of osteocytes by mechanical loading-in...
To create fluid shear stress under in vitro conditions, several flow chambers have been developed in the past. The experimental setup of the flow chamber in the centre of this study offers advantages such as simplicity to assemble and ease of use as well as the creation of reproducible fluid shear forces on cells. Due to the new design, different cell types could be simultaneously analysed under r...
Besides, in the model reported in this study, microscopic examinations are possible after completing the experiment only. Nevertheless, an advantage of the new flow chamber is the possibility of testing different cell colonies simultaneously in one single experiment by placing cells in different radial locations on the spinning disc. Due to the current flow gradient from the centre to the peripher...
Due to the fact that constant flows were generated within the parallel flow chamber only, the situations of in vitro experiments differ from in vivo setting where dynamic flow profiles are particular [33]. As the constant laminar flow profile is not physiological in bones [34], vessels and other tissues [35], the informative value of the experimental setting is limited but it could be used for var...
The aim of this study was to establish a new FSS model that is easy to use as well as simple to assemble in order to create reproducible fluid shear forces on cells close to implant material surfaces. Todays’ commonly used commercial flow devices differ in geometry and function, which makes comparisons between experiments difficult [4, 10, 26, 27]. The benefits of this novel testing device are r...
in which ρ = density, h = height, ω = angular velocity and r = radius.
Figure 3 shows the respective physical force and its dependence on a bigger radius and higher rotational speed. The results of this study indicate that the centrifugal force represents only a little proportion of effective forces. Hence, the centrifugal forces’ impacts on the tested cells are considered to be insignifican...
Our analysis was focused on two main aspects:
Simulation of the fluid flow characteristics as well as quantification of the arising shear forces at the plate/plate flow chamber with reliable reproducibility
Assessment of the impact of fluid shear stress on osteoblast cells in terms of altered cell morphology and intracellular structural changes
The computational fluid dynamic analysis and the q...
For constant and fully developed laminar flow between the two parallel plates, the magnitude of the wall shear stress (τ) in between was calculated by formula 1:
in which η is the dynamic fluid viscosity (dyn/cm2), r is the radius of the plate (cm), ω stands for angular velocity and H for height (vertical distance in between the two plates).
To get information whether the flow is laminar or t...
A three-dimensional illustration and photography of the plate/plate flow chamber model is shown in Fig. 1. A detailed list of used parts can be found in Appendix 1.
The circulation within the flow chamber was generated by an externally attached electric motor, which rotates up to 500 rounds per minute (rpm). A commercial grade 4 pure medical titanium gear shaft (length = 40 mm, diameter =...
Therefore, the aim of the present study was to establish a new cell chamber model for FSS simulation and stimulation. In addition to its ease of use, the reported model in this study should meet the requirements of a simple design, generating reproducible flow characteristics next to laminar flows and clearly defined flow gradients on implant surfaces.
Cells can be influenced by different mechanostimuli, which lead to an activation of cellular and inter-cellular responses. These reactions may be caused by either a direct stimulation of the cell body (mechanoreception) or indirect cellular stimulation (response) [1,2,3]. Extracellular fluid movement induces fluid shear stress (FSS) that can result in different cellular processes including prolife...
Mechanostimuli of different cells can affect a wide array of cellular and inter-cellular biological processes responsible for dental implant healing. The purpose of this in vitro study was to establish a new test model to create a reproducible flow-induced fluid shear stress (FSS) of osteoblast cells on implant surfaces.
As FSS effects on osteoblasts are detectable at 10 dyn/cm2, a custom-made f...
Fig. 6. Roughness (Sa) box plot
Fig. 6. Roughness (Sa) box plot
Fig. 5. 3D profile
Fig. 5. 3D profile
Fig. 4. CLSM
Fig. 4. CLSM
Fig. 3. SEM for localization of EDX analysis
Fig. 3. SEM for localization of EDX analysis
Fig. 2. SEM. White arrow (→) exemplary mark the droplet like shape of surface as described in the text
Fig. 2. SEM. White arrow (→) exemplary mark the droplet like shape of surface as described in the text
Fig. 1. Diagram of different implant areas used for sampling. 1) Machined (untreated) area. 2) rough (treated) area
Fig. 1. Diagram of different implant areas used for sampling. 1) Machined (untreated) area. 2) rough (treated) area
Amplitude parameters
Group
Name
Sa (μm)
Machined area
WhiteSKY
...
Element composition/semi-quantitative evaluation
Location
Type
Zr at %min–at %max
Hf at %
Y at %min–at %max...
NoneTable 1 Five commercially available ceramic implants and surface characteristics
Beger, B., Goetz, H., Morlock, M. et al. In vitro surface characteristics and impurity analysis of five different commercially available dental zirconia implants.
Int J Implant Dent 4, 13 (2018). https://doi.org/10.1186/s40729-018-0124-8
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Received: 11 December 2017
Accepted: 08 February 2018
Published: 26 April 2018
DOI: https://doi.org/10.1186/s40729-018...
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were m...
Not applicable.
Not applicable.
Beger B, Goetz H, Morlock M, Schiegnitz E, and Al-Nawas B declare that they have no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Department of Maxillofacial Surgery, University Medical Center of the Johannes Gutenberg-University Mainz, Augustusplatz 2, 55131, Mainz, Germany
B. Beger, M. Morlock, E. Schiegnitz & B. Al-Nawas
Biomaterials in Medicine (BioAPP), University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
H. Goetz
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Papanagiotou HP, Morgano SM, Giordano RA, Pober R. In vitro evaluation of low-temperature aging effects and finishing procedures on the flexural strength and structural stability of Y-TZP dental ceramics. J Prosthet Dent. 2006;96(3):154–64.
Ewais OH, Al Abbassy F, Ghoneim MM, Aboushelib MN. Novel zirconia surface treatments for enhanced osseointegration: laboratory characterization. Int J Dent....
Ong JL, Carnes DL, Cardenas HL, Cavin R. Surface roughness of titanium on bone morphogenetic protein-2 treated osteoblast cells in vitro. Implant Dent. 1997;6(1):19–24.
Schwartz Z, Kieswetter K, Dean DD, Boyan BD. Underlying mechanisms at the bone-surface interface during regeneration. J Periodontal Res. 1997;32(1 Pt 2):166–71.
Al-Nawas B, Gotz H. Three-dimensional topographic and metrologic...
Jacobi-Gresser E, Huesker K, Schutt S. Genetic and immunological markers predict titanium implant failure: a retrospective study. Int J Oral Maxillofac Surg. 2013;42(4):537–43.
Wenz HJ, Bartsch J, Wolfart S, Kern M. Osseointegration and clinical success of zirconia dental implants: a systematic review. Int J Prosthodont. 2008;21(1):27–36.
Shulte W. The intra-osseous Al2O3 (Frialit) Tuebingen...
Aluminum oxide
Ceramic injection molding
Confocal laser scanning microscopy
Energy-dispersive X-ray spectroscopy
Hot isostatic pressing
Implant
Kilovolt
Millibar
Megapascal
Nanometer
Area roughness parameter
Scanning electron microscopy
Sandblasted, Large-grit, Acid-etched
Yttrium-stabilized tetragonal zirconium polycrystalline
Micrometer
New ceramic implants are showing a variety of surface characteristics due to different manufacturing processes as shown by other groups [2, 28]. The surface structures of the investigated implants are close to titanium implants. If the surface characteristics really have a high influence on osseointegration, ceramic implants cannot yet compare to the long experience with titanium. However, there a...
The semi-quantitative energy-dispersive X-ray spectroscopy (EDX) can be used to further analyze the components of the implant surface. None of the implants showed any impurity or unexpected results. Implants 4 and 5 showed yttrium under the detection limit in the EDX analysis. This could be caused by the lower dosage of yttrium endowment in the stabilization processing in comparison to other impla...
The surface shape (droplet-like surface), which was observed in the SEM samples, can be caused due to the sintering process in which ceramic powder was melted and then formed. Different particle, immersion, and droplet sizes can also change due to possible reasons like usage of various types and dosages of acid for the etching process and change of exposure time to acid effect. A longer exposure t...
Implant surface characteristics are of ongoing scientific interest. Implants made from titanium are still the most common to be used. Titanium implants are made from alpha-beta alloy which consists of 6% aluminum and 4% vanadium (Ti-6Al-4V). These materials have low density, high strength, and resistance to fatigue and corrosion, and their modulus of elasticity is closer to the bone than any other...
Implant 2 (Sa 1.27 μm ± 0.24) and implant 5 (Sa 1.22 μm ± 0.36) show the highest roughness values (Sa) of all tested implants: Straumann’s pure ceramic implant was blasted and etched and shows the overall highest Sa value in the rough area. Implant 3 (vitaclinical) shows correspondingly lower Sa around 1.05 μm (± 0.17) (Table 3). The lowest Sa value could be found in implant ...
SEM micrographs presented in Fig. 2 demonstrate the dissimilarity of the sample surface microstructure. Implant 1 shows an overall smoother surface and a slaty-like surface without evidence of a typical etching process. The surface shows sparse roughness. Implants 2–4 show deep markings from their brand’s specific etching and sandblasting processes. In × 10,000 magnification, immersions ca...
Subsequently, the depth map images are imported in the SPIP™ 4.2.6 (Image Metrology) software for roughness and texture evaluation. According to the ISO 25178-2 reference, all surface roughness parameters implemented in SPIP™ are evaluated and classified as amplitude, hybrid, functional, and spatial parameters. Selected values are shown in Table 3.
Analysis of the element composition of the implant surfaces by means of energy-dispersive X-ray spectroscopy (EDX) was performed with an INCA Energy 350 system (Oxford Instruments, Wiesbaden, Germany) coupled with the SEM Quanta 200 FEG (Fig. 2). Similar to the micro-morphological presentation, each implant was divided into comparable sites of interest. Typical areas were selected and evaluated (...
The following five commercially available dental zirconia implants were used in this study (Table 1). Bredent whiteSKY™ implant (I1) is made from unground Brezirkon™, an yttrium oxide (Y2O3)-stabilized tetragonal polycrystalline zirconium oxide and is sandblasted. Zirconium oxide is endowed with 3 mol% yttrium oxide to gain a rectangle and room temperature stable structure [17]. Straumann® ...
Dental implants have become a well-established treatment method for oral rehabilitation after tooth loss. Pure titanium is still the material of choice when it comes to dental intraosseous implants and has been used for decades. However, titanium implants have esthetic limitations, especially in the front aspect of the maxillary jaw. The recession of the gingiva can lead to visible implant necks. ...
The aim of this study was to assess surface characteristics, element composition, and surface roughness of five different commercially available dental zirconia implants.
Five zirconia implants (Bredent whiteSKY™ (I1), Straumann® PURE Ceramic (I2), ceramic.implant vitaclinical (I3), Zeramex® (I4), Ceralog Monobloc M10 (I5)) were evaluated.
The evaluation was performed by means of scanning el...
Figure 5. Osteoblasts with an orientation tendency after 24 h of rotation (phallacidin fluorescence staining). On the left side with 200× and on the right side with 400× magnification. The yellow arrows show the orientation of the cells. The red arched arrow within the coloured circle shows the direction of rotation. The dashed white line oriented to the right stands for the r...
Figure 4. Randomly orientated osteoblasts without influence of rotation (phallacidin fluorescence staining). On the left side with 200× and on the right side with 400× magnification. The white X on the coloured circle marks the location upon the plate where the osteoblasts were located. The red X marks the centre of the plate
Figure 3. Diagram for visualisation of the calculation of shear stress rates taking into account the centrifugal force and the glass plates’ dimensions. For example, at a distance of 25 mm from the centre of the upper plate, the shear forces’ value is 8.33 dyn/cm2, together with an additional centrifugal force that has a value of 0.55 dyn/cm2
Figure 2. Side view of a computerized simulation, showing the flow chambers’ lower compartment and the flow profile in between the two plates; shearing gap and bottom plate are shown on the left side; rotation speed = 200 rpm; colour code bar (left edge) showing shear force values [Pa] [1 Pa = 10 dyn/cm2]; flow direction presented by arrows
Figure 1. Three-dimensional illustration (a–e) and photography (f) of the experimental setup with the components marked numerical. a 1 Lower petri dish (s’ bottom serving as the lower plate); 2 Rotating glass panel [60 mm diameter (cell bearing)]; 3 Titanium axis. b 4 Liquid medium (red). c 5 Reversed upper petri dish. d 6 Gearwheel with set screw. e 7 Closing; 8 Electronic motor device and ...
References
Ehrlich PJ, Lanyon LE. Mechanical strain and bone cell function: a review. Osteoporos Int. 2002;13(9):688–700.
Vaughan TJ, Haugh MG, Mcnamara LM. A fluid-structure interaction model to characterize bone cell stimulation in parallel-plate flow chamber systems. J R Soc Interface. 2013;10(81):20120900.
Weinbaum S, Cowin SC, Zeng Y. A model for the excitation of osteocytes by mec...
Besides, in the model reported in this study, microscopic examinations are possible after completing the experiment only. Nevertheless, an advantage of the new flow chamber is the possibility of testing different cell colonies simultaneously in one single experiment by placing cells in different radial locations on the spinning disc. Due to the current flow gradient from the centre to the pe...
Due to the fact that constant flows were generated within the parallel flow chamber only, the situations of in vitro experiments differ from in vivo setting where dynamic flow profiles are particular. As the constant laminar flow profile is not physiological in bones, vessels and other tissues, the informative value of the experimental setting is limited but it could be used for various cell...
Further on, the simulations indicated that the flow profile in between the two plates was not influenced by peripheral turbulences alongside the peripheral regions. To verify a cellular realignment towards the shear direction, cells were microscopically examined prior and after exposure to shear forces for 24 h upon a spinning disc at a speed level of 200 rpm. Even if not sufficiently ...
Discussion
The aim of this study was to establish a new FSS model that is easy to use as well as simple to assemble in order to create reproducible fluid shear forces on cells close to implant material surfaces. Todays’ commonly used commercial flow devices differ in geometry and function, which makes comparisons between experiments difficult. The benefits of this novel testing device are...
Regarding the upper compartment, peripheral turbulent flow along the outer edges was similar to the fluid movements within the area in between the plates. At the top, the turbulent flow directed from the centre to the periphery whereas the turbulences at the bottom were orientated in reverse to that. Moreover, the effect of the shear forces on the osteoblast cells was also influenced by the centri...
Results
Our analysis was focused on two main aspects:
Simulation of the fluid flow characteristics as well as quantification of the arising shear forces at the plate/plate flow chamber with reliable reproducibility
Assessment of the impact of fluid shear stress on osteoblast cells in terms of altered cell morphology and intracellular structural changes
Evaluation of the f...
Test procedure
The experimental process involved three steps. First, a count of n = 50.000 commercially available osteoblasts (PromoCell, Heidelberg, Germany) per millilitre of culture medium were cultured on the bottom of the cell-bearing surface (glass panel). Therefore, cells were seeded in a culture medium (cf. Appendix 2 for a detailed composition) at 37 °C. Prior to the test proce...
Analytical formula for evaluating the flow characteristics
Frequently used flow chambers are characterised by an internal fluid flow along a stationary cell-bearing surface, whereas the osteoblast test cells of this newly developed model are circulating within a resting culture medium.
For constant and fully developed laminar flow between the two parallel plates, the magnitude of the wall sh...
Methods
Experimental setup
A three-dimensional illustration and photography of the plate/plate flow chamber model is shown in Fig. 1. A detailed list of used parts can be found in Appendix 1.
The circulation within the flow chamber was generated by an externally attached electric motor, which rotates up to 500 rounds per minute (rpm). A commercial grade 4 pure medical titanium gear shaft (len...
Abstract
Background
Mechanostimuli of different cells can affect a wide array of cellular and inter-cellular biological processes responsible for dental implant healing. The purpose of this in vitro study was to establish a new test model to create a reproducible flow-induced fluid shear stress (FSS) of osteoblast cells on implant surfaces.
Methods
As FSS effects on osteoblasts are detectabl...