scholarly journals Sinus Hemodynamics in Representative Stenotic Native Bicuspid and Tricuspid Aortic Valves: An In-Vitro Study

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 56 ◽  
Author(s):  
Hoda Hatoum ◽  
Lakshmi Prasad Dasi
Keyword(s):  
Aortic Valve ◽  
In Vitro Study ◽  
Patient Specific ◽  
Shear Stresses ◽  
Flow Shear ◽  
Aortic Sinus ◽  
Image Velocimetry ◽  
3D Printed ◽  
Sinus Flow

(1) The study’s objective is to assess sinus hemodynamics differences between stenotic native bicuspid aortic valve (BAV) and native tricuspid aortic valve (TrAV) sinuses in order to assess sinus flow shear and vorticity dynamics in these common pathological states of the aortic valve. (2) Representative patient-specific aortic roots with BAV and TrAV were selected, segmented, and 3D printed. The flow dynamics within the sinus were assessed in-vitro using particle image velocimetry in a left heart simulator at physiological pressure and flow conditions. Hemodynamic data calculations, vortex tracking, shear stress probability density functions and sinus washout calculations based on Lagrangian particle tracking were performed. (3) (a) At peak systole, velocity and vorticity in BAV reach 0.67 ± 0.02 m/s and 374 ± 5 s−1 versus 0.49 ± 0.03 m/s and 293 ± 3 s−1 in TrAV; (b) Aortic sinus vortex is slower to form but conserved in BAV sinus; (c) BAV shear stresses exceed those of TrAV (1.05 Pa versus 0.8 Pa); (d) Complete TrAV washout was achieved after 1.5 cycles while it was not for BAV. 4) In conclusion, sinus hemodynamics dependence on the different native aortic valve types and sinus morphologies was clearly highlighted in this study.

scholarly journals The congenital bicuspid aortic valve can experience high-frequency unsteady shear stresses on its leaflet surface

2012 ◽  
Vol 303 (6) ◽  
pp. H721-H731 ◽  
Author(s):  
Choon Hwai Yap ◽  
Neelakantan Saikrishnan ◽  
Gowthami Tamilselvan ◽  
Nikolai Vasilyev ◽  
Ajit P. Yoganathan
Keyword(s):  
Aortic Valve ◽  
Bicuspid Aortic Valve ◽  
High Frequency ◽  
Shear Stresses ◽  
Fluid Shear ◽  
Flow Loop ◽  
Model Flow ◽  
Image Velocimetry ◽  
Vitro Model

The bicuspid aortic valve (BAV) is a common congenital malformation of the aortic valve (AV) affecting 1% to 2% of the population. The BAV is predisposed to early degenerative calcification of valve leaflets, and BAV patients constitute 50% of AV stenosis patients. Although evidence shows that genetic defects can play a role in calcification of the BAV leaflets, we hypothesize that drastic changes in the mechanical environment of the BAV elicit pathological responses from the valve and might be concurrently responsible for early calcification. An in vitro model of the BAV was constructed by surgically manipulating a native trileaflet porcine AV. The BAV valve model and a trileaflet AV (TAV) model were tested in an in vitro pulsatile flow loop mimicking physiological hemodynamics. Laser Doppler velocimetry was used to make measurements of fluid shear stresses on the leaflet of the valve models using previously established methodologies. Furthermore, particle image velocimetry was used to visualize the flow fields downstream of the valves and in the sinuses. In the BAV model, flow near the leaflets and fluid shear stresses on the leaflets were much more unsteady than for the TAV model, most likely due to the moderate stenosis in the BAV and the skewed forward flow jet that collided with the aorta wall. This additional unsteadiness occurred during mid- to late-systole and was composed of cycle-to-cycle magnitude variability as well as high-frequency fluctuations about the mean shear stress. It has been demonstrated that the BAV geometry can lead to unsteady shear stresses under physiological flow and pressure conditions. Such altered shear stresses could play a role in accelerated calcification in BAVs.

In Vitro Study of Pulsatile Flow Through a Motionless Diode Valve in the Pulmonary Position

2009 ◽  
Author(s):  
Tiffany A. Camp ◽  
Richard Figliola ◽  
Donald Beasley ◽  
Timothy Conover ◽  
Tim McQuinn ◽  
...  
Keyword(s):  
Shear Stress ◽  
In Vitro Study ◽  
Mechanical Valve ◽  
Field Analysis ◽  
Shear Stresses ◽  
Flow Shear ◽  
Flow Through ◽  
Flow Field Analysis ◽  
Stress Patterns

Pulmonary circulation shows a tolerance for mild regurgitation and pressure gradient. [1]. Given these tolerances, we have explored using a fluid diode as a pulmonary valve. Camp et al showed that diode valves are able to regulate flow in the pulmonary position with promising results and could be tolerated using a pig model [2, 3]. Flow and shear stress patterns are two other hemodynamic concerns that must be considered during heart valve design. Elevated bulk flow shear stresses, wall shear stresses, and turbulent stresses within bioprostheses and mechanical valve flow fields are recognized as a cause of cell and platelet damage, initiating platelet activation and triggers for thrombogenesis [4–7]. In this study, we conduct in vitro flow field analysis of the flow downstream of a proposed prototype diode valve in order to observe the flow and shear stress patterns.

scholarly journals Accuracy of Guided Implant Surgery in the Edentulous Jaw Using Desktop 3D-Printed Mucosal Supported Guides

2021 ◽  
Vol 10 (3) ◽  
pp. 391
Author(s):  
Rani D’haese ◽  
Tom Vrombaut ◽  
Geert Hommez ◽  
Hugo De Bruyn ◽  
Stefan Vandeweghe
Keyword(s):  
In Vitro Study ◽  
Angular Deviation ◽  
Implant Surgery ◽  
Implant Position ◽  
Surgical Guides ◽  
Negative Effect ◽  
Bone Level ◽  
3D Printed ◽  
Implant Alignment

Purpose: The aim of this in vitro study is to evaluate the accuracy of implant position using mucosal supported surgical guides, produced by a desktop 3D printer. Methods: Ninety implants (Bone Level Roxolid, 4.1 mm × 10 mm, Straumann, Villerat, Switzerland) were placed in fifteen mandibular casts (Bonemodels, Castellón de la Plana, Spain). A mucosa-supported guide was designed and printed for each of the fifteen casts. After placement of the implants, the location was assessed by scanning the cast and scan bodies with an intra-oral scanner (Primescan®, Dentsply Sirona, York, PA, USA). Two comparisons were performed: one with the mucosa as a reference, and one where only the implants were aligned. Angular, coronal and apical deviations were measured. Results: The mean implant angular deviation for tissue and implant alignment were 3.25° (SD 1.69°) and 2.39° (SD 1.42°) respectively, the coronal deviation 0.82 mm (SD 0.43 mm) and 0.45 mm (SD 0.31 mm) and the apical deviation 0.99 mm (SD 0.45 mm) and 0.71 mm (SD 0.43 mm). All three variables were significantly different between the tissue and implant alignment (p < 0.001). Conclusion: Based on the results of this study, we conclude that guided implant surgery using desktop 3D printed mucosa-supported guides has a clinically acceptable level of accuracy. The resilience of the mucosa has a negative effect on the guide stability and increases the deviation in implant position.

scholarly journals Biochemical Interactions Between Polymeric Resins Used for Occlusal Splints and Saliva A pilot study comparing the CAD/CAM technology and the conventional approach

2019 ◽  
Vol 56 (2) ◽  
pp. 409-412 ◽  
Author(s):  
Marina Melescanu-Imre ◽  
Mihaela Pantea ◽  
Alexandra Totan ◽  
Ana Maria Cristina Tancu ◽  
Maria Greabu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Uric Acid ◽  
In Vitro Study ◽  
Acrylic Resin ◽  
Occlusal Splints ◽  
Oral Environment ◽  
Cad Cam ◽  
3D Printed ◽  
Polymeric Resins

The CAD/CAM technology has been successfully integrated in clinical and laboratory aspects of dental medicine. The present in vitro study focuses on the biochemical interactions between saliva and three types of polymeric resins for occlusal splints. Dental material samples were produced from 3D printed, milled and self-cured resins and were incubated with saliva samples from 20 healthy volunteers. The results showed that the 3D printed and milled polymeric resins did not produce any significant changes in oxidative stress parameters (uric acid, TAC, GGT, OXSR-1) or inflammatory markers (IL-2, IL-6). On the other hand, the self-cured acrylic resin produced a significant decrease in the salivary TAC and uric acid, the most important antioxidants in saliva, affecting the capacity of saliva to protect the oral environment against oxidative stress.

scholarly journals Accuracy of a workflow using sleeveless 3D printed surgical guides made from a cost‐effective and biodegradable material: An in vitro study

2019 ◽  
Vol 30 (S19) ◽  
pp. 519-519 ◽  
Author(s):  
Valentin Hromadnik ◽  
Stefano Pieralli ◽  
Benedikt Spies ◽  
Florian Beuer ◽  
Christian Wesemann
Keyword(s):  
In Vitro Study ◽  
Cost Effective ◽  
Vitro Study ◽  
Biodegradable Material ◽  
Surgical Guides ◽  
3D Printed

scholarly journals Evaluation of the 3D Printing Accuracy of a Dental Model According to Its Internal Structure and Cross-Arch Plate Design: An In Vitro Study

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5433
Author(s):  
Seung-Ho Shin ◽  
Jung-Hwa Lim ◽  
You-Jung Kang ◽  
Jee-Hwan Kim ◽  
June-Sung Shim ◽  
...  
Keyword(s):  
3D Printing ◽  
Internal Structure ◽  
Three Dimensional ◽  
In Vitro Study ◽  
Thick Shell ◽  
Plate Design ◽  
Dental Model ◽  
3D Printed ◽  
Modeling Data

The amount of photopolymer material consumed during the three-dimensional (3D) printing of a dental model varies with the volume and internal structure of the modeling data. This study analyzed how the internal structure and the presence of a cross-arch plate influence the accuracy of a 3D printed dental model. The model was designed with a U-shaped arch and the palate removed (Group U) or a cross-arch plate attached to the palate area (Group P), and the internal structure was divided into five types. The trueness and precision were analyzed for accuracy comparisons of the 3D printed models. Two-way ANOVA of the trueness revealed that the accuracy was 135.2 ± 26.3 µm (mean ± SD) in Group U and 85.6 ± 13.1 µm in Group P. Regarding the internal structure, the accuracy was 143.1 ± 46.8 µm in the 1.5 mm-thick shell group, which improved to 111.1 ± 31.9 µm and 106.7 ± 26.3 µm in the roughly filled and fully filled models, respectively. The precision was 70.3 ± 19.1 µm in Group U and 65.0 ± 8.8 µm in Group P. The results of this study suggest that a cross-arch plate is necessary for the accurate production of a model using 3D printing regardless of its internal structure. In Group U, the error during the printing process was higher for the hollowed models.

Accuracy and precision of 3D-printed implant surgical guides with different implant systems: An in vitro study

2020 ◽  
Vol 123 (6) ◽  
pp. 821-828 ◽  
Author(s):  
Matthew Yeung ◽  
Aous Abdulmajeed ◽  
Caroline K. Carrico ◽  
George R. Deeb ◽  
Sompop Bencharit
Keyword(s):  
In Vitro Study ◽  
Vitro Study ◽  
Surgical Guides ◽  
Accuracy And Precision ◽  
3D Printed
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