Effect of print angulation on the accuracy and precision of 3D-printed orthodontic retainers

In this study, we characterize the lateral dimension, depth, and inclination of buried tilted rectangular heat sources from time domain temperature data measured at the surface. The heat sources are representative for planar defects that emit heat in thermographic tests with internal burst excitation. We present a semi-analytical expression for the evolution of the surface temperature distribution. The emitted flux, dimensions and inclination of the heat source are determined by fitting the model to two perpendicular surface temperature profiles and the temperature history at one point of the surface. We show that the sensitivity of the data to the geometrical parameters of the heat source decreases as the angle it makes with the surface increases. The study also shows that the optimum duration of the excitation corresponds to a thermal diffusion length covering the distance from the surface to the deepest end of the heat source. The accuracy and precision of the results for different noise levels and inclinations have been tested by fitting the model to synthetic data with added noise. Fittings of experimental induction thermography data on 3D printed photo-polymeric resin samples containing calibrated Cu slabs confirm that it is possible to characterize tilted rectangular heat sources from surface temperature data.

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Patient-Specific Guides for Total Hip Arthroplasty: A Paired Acetabular and Femoral Implantation Approach

Journal of Medical Devices ◽

10.1115/1.4028945 ◽

2015 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Jacob Stegman ◽

Chris Casstevens ◽

Todd Kelley ◽

Vasile Nistor

Keyword(s):

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Bone Geometry ◽

Patient Specific ◽

Total Hip ◽

Orthopedic Procedure ◽

Accuracy And Precision ◽

Patient Specific Instruments ◽

3D Printed ◽

Ct Data

While total hip arthroplasty (THA) is a common orthopedic procedure for treatment of hip arthritis, current techniques demonstrate poor implant alignment accuracy and precision, which is critical to the replacement's long-term survivorship. Patient-specific instruments to guide bone preparation and implantation could improve accuracy, thereby improving replacement survivorship. A single cadaver was CT (computer tomography) scanned to extract the 3D bone geometry, from which the operating surgeon planned a THA. Patient-specific guides were designed, 3D printed, and used in the cadaveric THA procedure. Postprocedural CT data were used to compare measured implant positioning versus the preprocedural template. Implanted component accuracy ranged from 1 deg–12 deg.

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3D Printed Models for Surgical Planning and Reconstructive Implant Design in Sphenoorbital Tumor Surgery

Journal of Neurological Surgery Part B Skull Base ◽

10.1055/s-0036-1592451 ◽

2016 ◽

Vol 77 (S 02) ◽

Author(s):

Hassan Othman ◽

Sam Evans ◽

Daniel Morris ◽

Saty Bhatia ◽

Caroline Hayhurst

Keyword(s):

Surgical Planning ◽

Implant Design ◽

Tumor Surgery ◽

3D Printed

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A in Vivo Assay for Standardizing Heparin Preparations

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646810 ◽

1979 ◽

Vol 41 (03) ◽

pp. 576-582

Author(s):

A R Pomeroy

Keyword(s):

In Vitro Assays ◽

British Pharmacopoeia ◽

In Vitro Method ◽

Standard Preparation ◽

Reliable Estimation ◽

Assay Procedure ◽

Accuracy And Precision ◽

Heparin Preparation

SummaryThe limitations of currently used in vitro assays of heparin have demonstrated the need for an in vivo method suitable for routine use.The in vivo method which is described in this paper uses, for each heparin preparation, four groups of five mice which are injected intravenously with heparin according to a “2 and 2 dose assay” procedure. The method is relatively rapid, requiring 3 to 4 hours to test five heparin preparations against a standard preparation of heparin. Levels of accuracy and precision acceptable for the requirements of the British Pharmacopoeia are obtained by combining the results of 3 to 4 assays of a heparin preparation.The similarity of results obtained the in vivo method and the in vitro method of the British Pharmacopoeia for heparin preparations of lung and mucosal origin validates this in vivo method and, conversely, demonstrates that the in vitro method of the British Pharmacopoeia gives a reliable estimation of the in vivo activity of heparin.

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