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سمنار اكس ري ميككسنطمطمميكسميككطميكيميميمميميمي
- 1. Cone beam computedtomography (CBCT) supervised by lamia Hamid ابهر ةيا يرون محمد ءارهز يمثم سمش مشاه ةمطاف
- 2. Introductio n STAR T FINISH What is CBCT ? What Does The EquipmentLook Like? CBCT VS CT CBCT Use in dentistry Field of view Advantages Disadvantag es Risks Subjects 2
- 3. Introduction Radiology is important inthe diagnostic assessment of the dental patient 3D diagnostic imaging of the jaws has been of interest since introduction of CT as a clinical tool. 3
- 4. What Is CBCT ?1Itis a technology used to take three dimensional (3-D) images of your teeth, maxillary sinus, nerve pathways, and bone in the maxillofacial region with a single scan. 2TheCBCT s y s t e mrotates around the patient in approximately 30 seconds, capturing datausing a cone-shapedx-ray beam. 4
- 5. When CBCT ? When CBCT? Dental cone beam computedtomography is used when regular two dimensional dental x-rayş are not sufficient 5
- 6. With CBCT, clinicianscan get highly detailed 3-D views of the facial region with lower radiation exposure than a conventional CT scan. This may help with thediagnosis, treatment planning and evaluation of certain conditions. Why CBCT? 6
- 7. Cone beam CTscanners are square- shaped machines that include either an upright chair for sitting or a moveable table so patients can lie down during the examination. Scanners that include a chair have a rotating C-arm, an x-rayimage intensifier that contains an x-ray source and detector. Cone beam CT machines with a table include a What Does The Equipment Look Like? CBCT Equipment 7
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- 9. 1)A 3D conebeam is directed through a central object onto a detector. 2)After a single two-dimensional projection is acquired by the detector, the x-ray source and detectorrotate a small distance around a trajectory arc. 3)At this second angular position another basis projection imageis captured. 4)This sequence continuesaroundthe object for the entire 360 degrees. HOW DOES A CBCT WORK ? 10
- 10. CBCT Use in dentistry Usein Dentistr y Implantology and prosthodontic s Oral and maxillofaci al surgery Endodontic s Periodontic s Orthodontic s 9
- 11. 01 02 03 To assess thequantity and quality of bone in edentulous ridges and implant cases Implant site evaluation. accurate measurements, accurate planning of implant in relation to vital structures, surgical guide, Evaluation roots of upper posterior teeth in to themaxillary sinus, sinus lift 11
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- 14. CBCT enables theanalysis of jaw pathology, the assessment of impacted teeth, supernumerary teeth and their relation to vital structures Oral and Maxillofacial surgery 14
- 15. 0 1 02 03 helpful in analysingand assessing paranasal sinuses •The assessment of bone grafts. •Orthognathic surgeries •Posttreatment esthetic evaluation TMJ, and condyle 04 •Cleft palate , Craniofacial reconstruction •Mid face fracture cases of fractures of the facial bones •Tooth auto transplants Oral and Maxillofacial surgery 15
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- 18. • CBCTis avery useful tool in diagnosing apical lesions • Crown morphology, pulp chamber, proximal caries • Root morphology. number of root canals,course and direction of canals, accessory canals, root resorption, root fractures Endodontic s 16
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- 20. •Obturation, filling, underand overfilling, sinus problems • Broken instruments •Useful in planning periapical endodontic surgery as theanatomical structures such as inferior dental canal, mental foramen,maxillary sinus can be easily differentiated and relation to root can be quantified Endodontic s 20
- 21. • CBCT canbe used in assessing a detailed morphologic description of the bone • Measuring of bony defects, furcation involvement, buccal & lingual defects Periodontic s 21
- 22. • Orthodontists canuse CBCT images in orthodontic •Complete hard tissue examination and record,type of dentition present, Arch size, arch shape, symmetry of arches, •anteroposterior and transverse maxillo mandibular relationship, • number, size of teeth, shape of teeth, Orthodontic s 22
- 23. •These depend onthe detector size and shape, beam projection geometry and the ability to collimate or not • It is desirable to limit the field size to the smallest volume that can accommodate the region of interest. Field of view 23
- 24. o Obtaining datafrom two or more separate scans and superimposing and overlapping theregions of the CBCT data using refrence points, o A software is used to stich or blend the images together. o Disadvantage being scanning the regions of interest double times so increase in doage of radiation. 24 Stitchin g
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- 26. 01 Medical CT:Slices are acquired then reconstructed to create the volume Medical CT 26
- 27. 02 CBCT: Thevolume is acquired then slices are reconstructed from the volume CBC T 27
- 28. Advantage s • Rapid scantime • Beam limitation • Image accuracy •Reduction in patient radiation dose when compared to medical ct (10 times less) •Economical comfortable and safe 28
- 29. Disadvantage s • Scatter • Artifacts •Motionartifacts due to Increased scan time • Scan volume in sufficiency • Image noise is detrimental 29
- 30. Risks 01 02 There isalwaysa slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk. Because children are more sensitive to radiation, they should have a CT exam only if it isessential for making a diagnosis and should not have repeated CT exams unless absolutely necessary. CT scans in children should always be done with low- dose technique. 30
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