scholarly journals Characterising the Mould Rectification Process for Designing Scoliosis Braces: Towards Automated Digital Design of 3D-Printed Braces

2021 ◽  
Vol 11 (10) ◽  
pp. 4665
Author(s):  
Inigo Sanz-Pena ◽  
Shanika Arachchi ◽  
Dhammika Halwala-Vithanage ◽  
Sanjaya Mallikarachchi ◽  
Jeewantha Kirumbara-Liyanage ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Plaster Cast ◽  
Concave Side ◽  
Digital Design ◽  
Alternative Methods ◽  
Lateral Tilt ◽  
Cad Cam ◽  
Surface Deviation ◽  
Two Parameters ◽  
Rectification Process

The plaster-casting method to create a scoliosis brace consists of mould generation and rectification to obtain the desired orthosis geometry. Alternative methods entail the use of 3D scanning and CAD/CAM. However, both manual and digital design entirely rely on the orthotist expertise. Characterisation of the rectification process is needed to ensure that digital designs are as efficient as plaster-cast designs. Three-dimensional scans of five patients, pre-, and post-rectification plaster moulds were obtained using a Structure Mark II scanner. Anatomical landmark positions, transverse section centroids, and 3D surface deviation analyses were performed to characterise the rectification process. The rectification process was characterised using two parameters. First, trends in the external contours of the rectified moulds were found, resulting in lateral tilt angles of 81 ± 3.8° and 83.3 ± 2.6° on the convex and concave side, respectively. Second, a rectification ratio at the iliac crest (0.23 ± 0.04 and 0.11 ± 0.02 on the convex and concave side, respectively) was devised, based on the pelvis width to estimate the volume to be removed. This study demonstrates that steps of the manual rectification process can be characterised. Results from this study can be fed into software to perform automatic digital rectification.

Applications of Scanning Microscopy in Biomedical Research

1968 ◽  
Vol 26 ◽  
pp. 354-355
Author(s):  
T. L. Hayes
Keyword(s):  
Information Content ◽  
Biomedical Research ◽  
Biomedical Applications ◽  
Three Dimensional ◽  
Dental Enamel ◽  
Resolving Power ◽  
Whole Mount ◽  
Two Parameters ◽  
Content Information ◽  
Sectioned Tissue

Biomedical applications of the scanning electron microscope (SEM) have increased in number quite rapidly over the last several years. Studies have been made of cells, whole mount tissue, sectioned tissue, particles, human chromosomes, microorganisms, dental enamel and skeletal material. Many of the advantages of using this instrument for such investigations come from its ability to produce images that are high in information content. Information about the chemical make-up of the specimen, its electrical properties and its three dimensional architecture all may be represented in such images. Since the biological system is distinctive in its chemistry and often spatially scaled to the resolving power of the SEM, these images are particularly useful in biomedical research.In any form of microscopy there are two parameters that together determine the usefulness of the image. One parameter is the size of the volume being studied or resolving power of the instrument and the other is the amount of information about this volume that is displayed in the image. Both parameters are important in describing the performance of a microscope. The light microscope image, for example, is rich in information content (chemical, spatial, living specimen, etc.) but is very limited in resolving power.

scholarly journals Virtual Surgical Planning, Stereolitographic Models and CAD/CAM Titanium Mesh for Three-Dimensional Reconstruction of Fibula Flap with Iliac Crest Graft and Dental Implants

2021 ◽  
Vol 10 (9) ◽  
pp. 1922
Author(s):  
Carlos Navarro Cuéllar ◽  
Manuel Tousidonis Rial ◽  
Raúl Antúnez-Conde ◽  
Santiago Ochandiano Caicoya ◽  
Ignacio Navarro Cuéllar ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Surgical Planning ◽  
Iliac Crest ◽  
Three Dimensional ◽  
Titanium Mesh ◽  
Iliac Crest Graft ◽  
Virtual Surgical Planning ◽  
Fibula Flap ◽  
Dimensional Reconstruction ◽  
Cad Cam

Mandibular reconstruction with fibula flap shows a 3D discrepancy between the fibula and the remnant mandible. Eight patients underwent three-dimensional reconstruction of the fibula flap with iliac crest graft and dental implants through virtual surgical planning (VSP), stereolitographic models (STL) and CAD/CAM titanium mesh. Vertical ridge augmentation and horizontal dimensions of the fibula, peri-implant bone resorption of the iliac crest graft, implant success rate and functional and aesthetic results were evaluated. Vertical reconstruction ranged from 13.4 mm to 10.1 mm, with an average of 12.22 mm. Iliac crest graft and titanium mesh were able to preserve the width of the fibula, which ranged from 8.9 mm to 11.7 mm, with an average of 10.1 mm. A total of 38 implants were placed in the new mandible, with an average of 4.75 ± 0.4 implants per patient and an osseointegration success rate of 94.7%. Two implants were lost during the osseointegration period (5.3%). Bone resorption was measured as peri-implant bone resorption at the mesial and distal level of each implant, with a variation between 0.5 mm and 2.4 mm, and with a mean of 1.43 mm. All patients were rehabilitated with a fixed implant prosthesis with good aesthetic and functional results.

scholarly journals An actin network is present in the cytoplasm throughout the cell cycle of carrot cells and associates with the dividing nucleus.

1987 ◽  
Vol 105 (1) ◽  
pp. 387-395 ◽  
Author(s):  
J A Traas ◽  
J H Doonan ◽  
D J Rawlins ◽  
P J Shaw ◽  
J Watts ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Three Dimensional ◽  
Preprophase Band ◽  
Alternative Methods ◽  
Cell Periphery ◽  
Actin Network ◽  
Suspension Cells ◽  
Daucus Carota L ◽  
Culture Cells ◽  
Transvacuolar Strands

We have studied the F-actin network in cycling suspension culture cells of carrot (Daucus carota L.) using rhodaminyl lysine phallotoxin (RLP). In addition to conventional fixation with formaldehyde, we have used two different nonfixation methods before adding RLP: extracting cells in a stabilizing buffer; inducing transient pores in the plasma membrane with pulses of direct current (electroporation). These alternative methods for introducing RLP revealed additional features of the actin network not seen in aldehyde-fixed cells. The three-dimensional organization of this network in nonflattened cells was demonstrated by projecting stereopairs derived from through-focal series of computer-enhanced images. F-actin is present in interphase cells in four interconnected configurations: a meshwork surrounding the nucleus; thick cables in transvacuolar strands and deep in the cytoplasm; a finer network of bundles within the cortical cytoplasm; even finer filaments that run in ordered transverse array around the cell periphery. The actin network is organized differently during division but it does not disappear as do the cortical microtubules. RLP stains a central filamentous cortical band as the chromatin begins to condense (preprophase); it stains the mitotic spindle (as recently shown by Seagull et al. [Seagull, R. W., M. Falconer, and C. A. Weerdenburg, 1987, J. Cell Biol., 104:995-1004] for aldehyde fixed suspension cells) and the cytokinetic apparatus (as shown by Clayton, L., and C. W. Lloyd, 1985, Exp. Cell Res., 156:231-238). However, it is now shown that an additional network of F-actin persists in the cytoplasm throughout division associating in turn with the preprophase band, the mitotic spindle, and the cytokinetic phragmoplast.

scholarly journals Evaluation of the Effect of the Sulcus Angle and Lateral to Medial Facet Ratio of the Patellar Groove on Patella Tracking in Aging Subjects with Stable Knee Joint

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
Jianghui Qin ◽  
Dongyang Chen ◽  
Zhihong Xu ◽  
Dongquan Shi ◽  
Jin Dai ◽  
...  
Keyword(s):  
Lower Limb ◽  
Lateral Displacement ◽  
Three Dimensional ◽  
Trochlear Groove ◽  
Patellar Tilt ◽  
Sulcus Angle ◽  
Lateral Tilt ◽  
Computed Tomography Images ◽  
Three Dimensional Models ◽  
Patella Tracking

Purpose.To determine whether the sulcus angle and the lateral to medial facet ratio correlate with patella lateral displacement and tilt in patients without patella instability.Methods.Computed tomography images of the lower limb of 64 patients without known arthropathy were collected. Three-dimensional models of the lower limb with a unified coordinate system were rebuilt by using Mimics software. The sulcus angle, lateral to medial facet ratio, lateral trochlear inclination of the patellar groove, tibial tuberosity-trochlear groove (TT-TG) distance, bisect offset index, and lateral tilt of the patella were measured. Pearson’s correlation test was used to determine the relationship between the aforementioned parameters.Results.Data from 51 patients were analyzed. The sulcus angle was negatively correlated with lateral tilt inclination (p<0.001,r=0.8406) and positively correlated with the bisect offset index (p=0.003,r=0.634) and patellar tilt (p=0.03,r=0.551); the lateral to medial facet ratio was positively correlated with TT-TG distance (p=0.003,r=0.643) and bisect offset index (p=0.026,r=0.559).Conclusion.The sulcus angle and lateral to medial facet ratio of the patellar groove can influence patella tracking in patients with stable knee joints.

A CAD/CAM Representation Model Applied to Tolerance Transfer Methods

1998 ◽  
Author(s):  
Alain Desrochers
Keyword(s):  
Three Dimensional ◽  
Dimensional Representation ◽  
One Dimensional ◽  
Dimensional Tolerance ◽  
Representation Model ◽  
Three Dimensional Representation ◽  
Tolerance Chart ◽  
Cad Cam ◽  
Tolerance Charts

Abstract This paper presents the adaptation of tolerance transfer techniques to a model called TTRS for Technologically and Topologically Related Surfaces. According to this model, any three-dimensional part can be represented as a succession of surface associations forming a tree. Additional tolerancing information can be associated to each TTRS represented as a node on the tree. This information includes dimensional tolerances as well as tolerance chart values. Rules are then established to simulate tolerance chains or stack up along with tolerance charts directly from the graph. This way it becomes possible to combine traditional one dimensional tolerance transfer techniques with a powerful three-dimensional representation model providing high technological contents.

scholarly journals In-House, Open-Source 3D-Software-Based, CAD/CAM-Planned Mandibular Reconstructions in 20 Consecutive Free Fibula Flap Cases: An Explorative Cross-Sectional Study With Three-Dimensional Performance Analysis

2021 ◽  
Vol 11 ◽  
Author(s):  
Lucas M. Ritschl ◽  
Paul Kilbertus ◽  
Florian D. Grill ◽  
Matthias Schwarz ◽  
Jochen Weitz ◽  
...  
Keyword(s):  
Open Source ◽  
Dimensional Analysis ◽  
Open Source Software ◽  
Three Dimensional ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Free Fibula Flap ◽  
Cross Sectional ◽  
Cad Cam ◽  
Free Fibula

BackgroundMandibular reconstruction is conventionally performed freehand, CAD/CAM-assisted, or by using partially adjustable resection aids. CAD/CAM-assisted reconstructions are usually done in cooperation with osteosynthesis manufacturers, which entails additional costs and longer lead time. The purpose of this study is to analyze an in-house, open-source software-based solution for virtual planning.Methods and MaterialsAll consecutive cases between January 2019 and April 2021 that underwent in-house, software-based (Blender) mandibular reconstruction with a free fibula flap (FFF) were included in this cross-sectional study. The pre- and postoperative Digital Imaging and Com munications in Medicine (DICOM) data were converted to standard tessellation language (STL) files. In addition to documenting general information (sex, age, indication for surgery, extent of resection, number of segments, duration of surgery, and ischemia time), conventional measurements and three-dimensional analysis methods (root mean square error [RMSE], mean surface distance [MSD], and Hausdorff distance [HD]) were used.ResultsTwenty consecutive cases were enrolled. Three-dimensional analysis of preoperative and virtually planned neomandibula models was associated with a median RMSE of 1.4 (0.4–7.2), MSD of 0.3 (-0.1–2.9), and HD of 0.7 (0.1–3.1). Three-dimensional comparison of preoperative and postoperative models showed a median RMSE of 2.2 (1.5–11.1), MSD of 0.5 (-0.6–6.1), and HD of 1.5 (1.1–6.5) and the differences were significantly different for RMSE (p &lt; 0.001) and HD (p &lt; 0.001). The difference was not significantly different for MSD (p = 0.554). Three-dimensional analysis of virtual and postoperative models had a median RMSE of 2.3 (1.3–10.7), MSD of -0.1 (-1.0–5.6), and HD of 1.7 (0.1–5.9).ConclusionsOpen-source software-based in-house planning is a feasible, inexpensive, and fast method that enables accurate reconstructions. Additionally, it is excellent for teaching purposes.

scholarly journals Digital planning and guided surgery in oral rehabilitation

2020 ◽  
Author(s):  
Larissa Braga dos Santos ◽  
Adriano Relvas Barreira de Oliveira ◽  
Mauro Lefrançois ◽  
Marcos Venício Azevedo ◽  
Pablo Sotelo ◽  
...  
Keyword(s):  
Surgical Planning ◽  
Three Dimensional ◽  
Oral Rehabilitation ◽  
Digital Workflow ◽  
Surgical Guide ◽  
Surgical Guides ◽  
Digital Planning ◽  
Cad Cam ◽  
Correct Understanding ◽  
Plaster Model

Digital planning of the prosthesis associated with surgical planning increased predictability, since surgical guides indicate the best place for implant installation, thus reducing the number of complications, and the CAD/CAM system provides predictability in the preparation of final restorations, according to the procedure previously planned. Our study reported a digital workflow used for the guided installation of two dental implants in regions 14 and 16, extraction of tooth 15 and installation of a fixed prothesis over implants. After anamnesis and clinical evaluation, intra- and extra-oral photographs of the patient were performed, molding the upper arch with polyvinylsiloxane (2-step putty/light-body technique) and requesting computed tomography. The plaster model obtained was sent to the laboratory and scanned. The generated file (STL) was used to create a diagnostic wax-up that was aligned to the tomography (in DICOM format), enabling the three-dimensional planning of the implants, which generated a partial printed surgical guide after approval of the dentist. After six months, the patient received the provisional fixed prosthesis printed in PMMA (polymethylmethacrylate) on an intermediate in PEEK (polyetheretherketone) aiming to condition an emergency profile to receive a definitive prosthesis two months later, with zirconia-milled infrastructure on a ti-base. The correct understanding of the operator about the steps of the digital workflow (diagnosis, prosthetic planning, surgical planning, guide preparation, temporary and final restorations) gives the operator improved predictability at the time of surgery as well as satisfactory aesthetic and functional result of definitive restorations.

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