SU-E-J-13: A Study to Establish the Effect of CBCT Image Rotational Displacement on IGRT and ART Lung SBRT Treatments

To improve the mechanical performances of joints in prefabricated construction, a type of connection structure with long-fiber and metal laminated bolts (referred to as a fiber-metal connector) is proposed and investigated by simulation and theoretical methods. The results include the following: (1) The fiber layer in bolts can form a second stiffness during rotation. This mechanical characteristic improves the bearing capacities and energy dissipation ability of the connector relative to the conventional metal connector, which are expected to effectively limit the elastoplastic rotational displacement of a structure. (2) For the reason, the fiber layer can bear load in the plastic phase due to its high-strength characteristic in the length direction. (3) A bilinear model for the bearing curve of the fiber-metal connector is proposed, and equations for optimization of fiber layer thickness are obtained with a target on bearing capacity and energy dissipation ability which are approximately higher 30% and 13% than that of the conventional metal connector, respectively. This research is expected to provide a theoretical basis for the application of this fiber-metal connector in engineering and improve the safety of prefabricated structures.

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Application of 3D tooth model for monitoring of implant space and inter-root distance without radiographs: a proof of concept study

International Journal of Implant Dentistry ◽

10.1186/s40729-020-00253-3 ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Kyungmin Lee ◽

Gyu-Hyoung Lee

Keyword(s):

Computed Tomography ◽

Radiation Exposure ◽

Cone Beam Computed Tomography ◽

Alveolar Bone ◽

Tooth Movement ◽

Treatment Evaluation ◽

Cone Beam ◽

Proof Of Concept ◽

Cbct Image ◽

Root Position

Abstract Background Radiographs are integral in evaluating implant space and inter-root distance. The purpose of this report is to introduce a method for evaluating the 3D root position with minimal radiation using a 3D tooth model composed of an intraoral-scanned crown and a cone-beam computed tomography (CBCT)-scanned root. Materials and methods Intraoral scan and CBCT scan of the patient were obtained before treatment. In the CBCT image, tooth segmentation was performed by isolating individual teeth from the maxillary and mandibular alveolar bone using software program. The 3D tooth model was fabricated by combining segmented individual teeth with the intraoral scan. Results A post-treatment intraoral scan was integrated into the tooth model, and the resulting position of the root could be predicted without additional radiographs. It is possible to monitor the root position after a pretreatment CBCT scan using a 3D tooth model without additional radiographs. Conclusion The application of the 3D tooth model benefits the patient by reducing repeated radiation exposure while providing the clinician with a precise treatment evaluation to monitor tooth movement.

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