نتایج جستجو برای: توموگرافی کامپیوتری cone beam
تعداد نتایج: 150299 فیلتر نتایج به سال:
objectives: to compare the thickness of the lateral wall of the maxillary sinus in individuals with and without teeth to determine if extraction of the teeth can lead to a significant reduction in the thickness of the maxillary sinus lateral wall or not. patients and methods: in a retrospective study on fifty patients with an edentulous space, the thickness of the lateral wall of the maxillary ...
objectives: bone quality and quantity assessment is one of the most important steps in implant treatment planning. different methods such as computed tomography (ct) and recently suggested cone beam computed tomography (cbct) with lower radiation dose and less time and cost are used for bone density assessment. this in vitro study aimed to compare the tissue density values in hounsfield units (...
objectives: this study aimed to evaluate the location and characteristics of mental foramen, anterior loop and mandibular incisive canal using cone beam computed tomography (cbct). materials and methods: this retrospective cross-sectional study evaluated 200 mandibular cbct scans for the location of mental foramen, anterior loop prevalence and mandibular incisive canal visibility, its mean leng...
introduction: vertical root fracture (vrf) is a common failure in endodontically treated teeth. due to vrf’s poor prognosis, a reliable and valid detection method is critical for treatment planning. conventional and digital radiographs are limited in vrf detection. recently, cone beam ct (cbct) system has been introduced. this study aimed to compare the diagnostic accuracy of these three imagin...
objective: diagnosis of vertical root fractures (vrfs) is critical in endodontics which most of the times occurs in endodontically treated teeth with root canal fillings such as gutta percha. despite cone beam computed tomography (cbct) has significantly enhanced image quality compared to digital radiography (dr) which aid the diagnosis, artifacts has remained as a problem in vrf detection . th...
زمینه: یکی از خطاهای رایج در تصویربرداری های پزشکی و دندانپزشکی، انحراف از موقعیت استاندارد است. مطالعه ها نشان دادهاند انحراف موقعیت فک پایین حین تصویربرداری به کمک سیتی اسکن پزشکی میتواند بر روی دقت اندازهگیری های خطی اثر منفی داشته باشد. هدف: مطالعه به منظور تعیین اثر زاویه قرارگیری سر بیمار بر اندازهگیری های زاویه ای به دست آمده از تصاویر cbct در نمونه های جمجمه های خشک انسانی انجا...
زمینه و هدف : هنگام جراحی دندان های مولر سوم نهفته در صورت نزدیکی عصب آلوئولار تحتانی به این دندان ریسک آسیب به این عصب وجود دارد. هدف از این مطالعه بررسی تأثیر عوامل مختلف بر میزان این آسیب پذیری توسط تصویربرداری (cone beam computed tomography) cbct بود. روش بررسی : رادیوگرافی cbct از 191 بیمار مراجعه کننده برای ارزیابی دقیق تر رابطه کانال مندیبولار و مولر سوم نهفته مندیبل انتخاب و موقعیت ای...
Cone beam computed tomography is a state-of-the-art imaging tool, initially developed for dental and maxillofacial application. With its high resolution and low radiation dose, cone beam tomography has been expanding its application fields, for example, to diagnosis of traumata and fractures in the head and neck area. In this study, we demonstrate superior and satisfactory performance of cone b...
Conventional radiographs provide important information for dental disease diagnosis. However, they represent 2-D images of 3-D objects with significant structure superimposition and unpredictable magnification. Cone beam computed tomography, however, allows true 3-D visualization of the dentoalveolar structures, avoiding major limitations of conventional radiographs. Cone beam computed tomograp...
This paper presents analytical fan-beam and cone-beam reconstruction algorithms that compensate for uniform attenuation in single photon emission computed tomography. First, a fan-beam algorithm is developed by obtaining a relationship between the two-dimensional (2D) Fourier transform of parallel-beam projections and fan-beam projections. Using this relationship, 2D Fourier transforms of equiv...
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