scholarly journals A Study on the Errors of 2D Circular Trajectories Generated on a 3D Printer

2021 ◽  
Vol 11 (24) ◽  
pp. 11695
Author(s):  
Adriana Munteanu ◽  
Dragos-Florin Chitariu ◽  
Mihaita Horodinca ◽  
Catalin-Gabriel Dumitras ◽  
Florin Negoescu ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Error Compensation ◽  
Computer Assisted ◽  
Experimental Setup ◽  
3D Printer ◽  
Closed Curves ◽  
Computer Aided ◽  
Low Pass ◽  
Precision And Accuracy

This paper presents a study on the movement precision and accuracy of an extruder system related to the print bed on a 3D printer evaluated using the features of 2D circular trajectories generated by simultaneous displacement on x and y-axes. A computer-assisted experimental setup allows the sampling of displacement evolutions, measured with two non-contact optical sensors. Some processing procedures of the displacement signals are proposed in order to evaluate and to describe the circular trajectories errors (e.g., open and closed curves fitting, the detection of recurrent periodical patterns in x and y-motions, low pass numerical filtering, etc.). The description of these errors is suitable to certify that the 3D printer works correctly (keeping the characteristics declared by the manufacturer) for maintenance purpose sand, especially, for computer-aided correction of accuracy (e.g., by error compensation).

scholarly journals In-house 3D-printed surgical guides for osseous lesions of the lower jaw: an experimental study

2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Lukas Postl ◽  
Thomas Mücke ◽  
Stefan Hunger ◽  
Oliver Bissinger ◽  
Michael Malek ◽  
...  
Keyword(s):  
Control Group ◽  
Head Model ◽  
Computer Assisted ◽  
3D Printer ◽  
Surgical Guide ◽  
Surgical Guides ◽  
Lower Jaw ◽  
Bony Lesion ◽  
3D Printed ◽  
Phantom Head

Abstract Background The accuracy of computer-assisted biopsies at the lower jaw was compared to the accuracy of freehand biopsies. Methods Patients with a bony lesion of the lower jaw with an indication for biopsy were prospectively enrolled. Two customized bone models per patient were produced using a 3D printer. The models of the lower jaw were fitted into a phantom head model to simulate operation room conditions. Biopsies for the study group were taken by means of surgical guides and freehand biopsies were performed for the control group. Results The deviation of the biopsy axes from the planning was significantly less when using templates. It turned out to be 1.3 ± 0.6 mm for the biopsies with a surgical guide and 3.9 ± 1.1 mm for the freehand biopsies. Conclusions Surgical guides allow significantly higher accuracy of biopsies. The preliminary results are promising, but clinical evaluation is necessary.

A Suggestion for an Effective Use of a Computer-aided Diagnosis System in Screening for Hyperthyroidism

1977 ◽  
Vol 16 (02) ◽  
pp. 93-95 ◽  
Author(s):  
A. Alpérovitch ◽  
P. Fragu
Keyword(s):  
Clinical Signs ◽  
Test Sample ◽  
Bayes Theorem ◽  
Computer Assisted ◽  
Thyroid Status ◽  
Screening Strategies ◽  
Computer Aided ◽  
Using Data ◽  
Effective Use ◽  
Aided Diagnosis

A computer-assisted program for diagnosing hyperthyroidism, specially devoted to the screening of functional thyroid status, has been written using data provided by 359 patients, 282 euthyroid and 77 hyperthyroid. The model is based on Bayes’ theorem.Using only 9 clinical signs and the free thyroxin index, the program achieved, on a test-sample of 117 new patients, an overall accuracy of 90% ; 10% of the cases were in the zone of uncertainty, and none was misdiagnosed.Different screening strategies are examined and their results discussed.

scholarly journals Chairside CAD/CAM Materials: Current Trends of Clinical Uses

Biology ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1170
Author(s):  
Giulio Marchesi ◽  
Alvise Camurri Piloni ◽  
Vanessa Nicolin ◽  
Gianluca Turco ◽  
Roberto Di Lenarda
Keyword(s):  
Clinical Outcome ◽  
Computer Aided Design ◽  
Fabrication Process ◽  
Computer Assisted ◽  
Current Trends ◽  
Computer Aided ◽  
Restorative Materials ◽  
Cad Cam ◽  
Aided Design

Restorative materials are experiencing an extensive upgrade thanks to the use of chairside Computer-aided design/computer-assisted manufacturing (CAD/CAM) restorations. Therefore, due to the variety offered in the market, choosing the best material could be puzzling for the practitioner. The clinical outcome of the restoration is influenced mainly by the material and its handling than by the fabrication process (i.e., CAD/CAM). Information on the restorative materials performances can be difficult to gather and compare. The aim of this article is to provide an overview of chairside CAD/CAM materials, their classification, and clinically relevant aspects that enable the reader to select the most appropriate material for predictable success.

scholarly journals Gender imbalance in medical imaging datasets produces biased classifiers for computer-aided diagnosis

2020 ◽  
Vol 117 (23) ◽  
pp. 12592-12594 ◽  
Author(s):  
Agostina J. Larrazabal ◽  
Nicolás Nieto ◽  
Victoria Peterson ◽  
Diego H. Milone ◽  
Enzo Ferrante
Keyword(s):  
Medical Imaging ◽  
Medical Image ◽  
Computer Aided Diagnosis ◽  
Computer Assisted ◽  
Gender Imbalance ◽  
Gender Balance ◽  
Computer Aided ◽  
Medical Image Computing ◽  
Assisted Diagnosis ◽  
Aided Diagnosis

Artificial intelligence (AI) systems for computer-aided diagnosis and image-based screening are being adopted worldwide by medical institutions. In such a context, generating fair and unbiased classifiers becomes of paramount importance. The research community of medical image computing is making great efforts in developing more accurate algorithms to assist medical doctors in the difficult task of disease diagnosis. However, little attention is paid to the way databases are collected and how this may influence the performance of AI systems. Our study sheds light on the importance of gender balance in medical imaging datasets used to train AI systems for computer-assisted diagnosis. We provide empirical evidence supported by a large-scale study, based on three deep neural network architectures and two well-known publicly available X-ray image datasets used to diagnose various thoracic diseases under different gender imbalance conditions. We found a consistent decrease in performance for underrepresented genders when a minimum balance is not fulfilled. This raises the alarm for national agencies in charge of regulating and approving computer-assisted diagnosis systems, which should include explicit gender balance and diversity recommendations. We also establish an open problem for the academic medical image computing community which needs to be addressed by novel algorithms endowed with robustness to gender imbalance.

scholarly journals Computer-Aided Planning in Orthognathic Surgery: A Comparative Study with the Establishment of Burstone Analysis-Derived 3D Norms

2019 ◽  
Vol 8 (12) ◽  
pp. 2106 ◽  
Author(s):  
Cheng-Ting Ho ◽  
Rafael Denadai ◽  
Hsin-Chih Lai ◽  
Lun-Jou Lo ◽  
Hsiu-Hsia Lin
Keyword(s):  
Orthognathic Surgery ◽  
Three Dimensional ◽  
Computer Assisted ◽  
Class Iii ◽  
Facial Soft Tissue ◽  
Skeletal Class ◽  
Nasolabial Angle ◽  
Normal Occlusion ◽  
Computer Aided ◽  
Cephalometric Measurements

Three-dimensional (3D) computer-aided simulation has revolutionized orthognathic surgery treatment, but scarce 3D cephalometric norms have been defined to date. The purposes of this study were to (1) establish a normative database of 3D Burstone cephalometric measurements for adult male and female Chinese in Taiwan, (2) compare this 3D norm dataset with the two-dimensional (2D) Burstone norms from Caucasian and Singaporean Chinese populations, and (3) apply these 3D norms to assess the outcome of a computer-aided simulation of orthognathic surgery. Three-dimensional Burstone cephalometric analysis was performed on 3D digital craniofacial image models generated from cone-beam computed tomography datasets of 60 adult Taiwanese Chinese individuals with normal occlusion and balanced facial profile. Three-dimensional Burstone analysis was performed on 3D image datasets from patients with skeletal Class III pattern (n = 30) with prior computer-aided simulation. Three-dimensional Burstone cephalometric measurements showed that Taiwanese Chinese males had significantly (p < 0.05) larger anterior and posterior facial heights, maxillary length, and mandibular ramus height than females, with no significant (p > 0.05) difference for facial soft-tissue parameters. The 3D norm dataset revealed Taiwanese Chinese-specific facial characteristics, with Taiwanese presenting (p < 0.05) a more convex profile, protrusive maxillary apical bases, protruding mandible, protruding upper and lower lips, and a shorter maxillary length and lower facial height than Caucasians. Taiwanese had significantly (p < 0.05) larger maxillary projection, vertical height ratio, lower face throat angle, nasolabial angle, and upper lip protrusion than Singaporean Chinese. No significant (p > 0.05) difference was observed between 3D norms and computer-aided simulation-derived 3D patient images for horizontal skeletal, vertical skeletal, and dental measurements, with the exception of two dental parameters (p < 0.05). This study contributes to literature by providing gender- and ethnic-specific 3D Burstone cephalometric norms, which can assist in the multidisciplinary-based delivery of orthodontic surgical care for Taiwanese Chinese individuals worldwide, including orthodontic management, computer-assisted simulation, and outcome assessment.

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