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Use of Additive Manufacturing in Surgical Tools/Guides for Dental Implants
Published in Harish Kumar Banga, Rajesh Kumar, Parveen Kalra, Rajendra M. Belokar, Additive Manufacturing with Medical Applications, 2023
Himanshu Deswal, Anoop Kapoor, Komal Sehgal, Vishakha Grover
Cone beam computed tomography (CBCT) is an imaging method that enables a precise three-dimensional portrayal of mineralised hard tissue structures. This novel imaging modality permits a fine resolution (2 line pair/mm), enhanced diagnostic quality and reduced shorter scanning times. There is a huge difference in the radiation exposure dose from conventional CT scans for maxillofacial imaging, approximately to the amount of 10 times (68 μSv compared with 600 μSv of conventional CT) (Loubele et al. 2009). Further, the technique offers great dimensional accuracy with only about 2 per cent magnification permissible (Kumar et al. 2015). CBCT was preferred for the majority of dental and maxillofacial purposes both diagnostic and therapeutic as this high-resolution imaging facility, was much smaller in size as well as cost-effective as opposed to conventional CT scanning. In two-dimensional imaging, of each slice, every two-dimensional pixel represents a three-dimensional cube or vowels of the area imaged. This two-dimensional limitation was overcome by the use of a cone-shaped incident X-ray beam as compared to the fan-shaped beam of conventional CT. The radiation dose reduction was significant and amounted to approximately equivalent to radiation exposure as occurs in two and eight panoramic radiographs (0.035 to 0.10 mSv). Higher resolution was accomplished due to the smaller voxel size in CBCT scans as opposed to conventional CT. Contemporary commercial CBCT units include NewTom DVT 9000 (Quantitative Radiology, Verona, Italy), i-CAT (Imaging Sciences International, Hatfield, USA), and 3D Accuitomo (J. Morita, Kyoto, Japan) etc. (Siu et al. 2010).
Advances in Patient Setup and Target Localization
Published in Siyong Kim, John Wong, Advanced and Emerging Technologies in Radiation Oncology Physics, 2018
Although CBCT substantially improves anatomic visibility relative to 2D images, it also has several limitations: Scatter effects. The amount of X-ray scatter is proportional to the amount of volume being irradiated during imaging. Compared with fan-beam CT, CBCT irradiates a much larger image volume, which substantially increases the amount of scatter detected by the detector. Scatter has the doubly negative effect of increasing quantum noise while decreasing image contrast in the projection data. Thus, the contrast-to-noise ratio (CNR) in CBCT images is lower than the CNR in traditional fan-beam CT images. Scattered radiation also creates streak and cupping artifacts, which impairs the Hounsfield unit (HU) accuracies in the reconstructed CBCT images.High imaging dose. The imaging dose of CBCT can be as high as approximately 3 c Gy due to the large number of X-ray projections acquired (400 to 600 projections). (Hyer et al., 2010) If CBCT is taken daily, the accumulated imaging dose over a 30-fraction treatment course will be close to 1 Gy, which is not negligible, especially considering this imaging dose is delivered through a large volume of the body. This high imaging dose causes concerns for secondary cancer induction, especially for young patients.Long scanning time. A typical CBCT scan takes around 30 to 60 s depending on the scanning mode. The long scanning time makes CBCT prone to artifacts caused by respiratory motions of the patient.
Conebeam CT for Medical Imaging and Image-Guided Interventions
Published in Salim Reza, Krzysztof Iniewski, Semiconductor Radiation Detectors, 2017
Conebeam CT (CBCT) is an imaging technique that employs a divergent x-ray source and usually a large-area flat-panel detector to form a cone-shaped exposure to the imaged object. Such a configuration guarantees the volume coverage of one large object and achieves the volumetric imaging within one single scan. The first CBCT scanner entered the market in 1996 as the dental scanner by NewTom Corp. Subsequently, CBCT was extended to multiple clinical applications, including implantology, orthopedics, interventional radiology, and radiation oncology.
Computer-assisted surgery in medical and dental applications
Published in Expert Review of Medical Devices, 2021
Yen-Wei Chen, Brian W. Hanak, Tzu-Chian Yang, Taylor A. Wilson, Jenovie M. Hsia, Hollie E. Walsh, Huai-Che Shih, Kanako J. Nagatomo
Preoperative evaluation of the anatomical structures around the planned surgical site is the first critical step of sCAIS. Although CT scanning allows direct visualization of internal anatomical structures, the high radiation dose, long scanning time, and large-scale equipment needed limits its applications in dentistry. The introduction of CBCT provided an alternative with comparable accuracy to produce high-resolution imaging of hard tissue structures in the maxillofacial region, using lower radiation dosage [55]. Whereas effective radiation dose values have been reported within the range of 474 to 1160 μSv for multi-slice CT (MSCT) scans, effective dose values range from 13 to 82 μSv for CBCT scans [56]. In addition, shorter scanning time and reduced equipment size and cost have allowed CBCT to become a standard diagnostic tool for imaging of maxillofacial structures in otolaryngology, oral maxillofacial surgery, orthodontics, endodontics, and implant dentistry [57].
Review on 3D printing in dentistry: conventional to personalized dental care
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Shadaan Ahmad, Nazeer Hasan, Akash Gupta, Arif Nadaf, Lubna Ahmad, Mohd. Aqil, Prashant Kesharwani
CBCT rotates around the patient, capturing data using a cone-shaped X-ray beam [48]. CBCT makes it possible to provide volumetric image data for the 3D printer before surgery and to produce replicas of the patient’s jaw [4,6,49]. When compared to traditional gypsum models, 3D printed model offers you a great deal of advantages like they are lighter in weight, better durable, have high wear resistance [50]. The presence of the model has led to the advancement in the procedure and approach of the surgery [51]. By using 3D printer drills are produced which leads to more predictable, less invasive, and expedited procedures.