Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. Chapter 26 Three-Dimensional Digital Imaging

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 2 Dental Radiography  Questions  What are the basic concepts and indications of three-dimensional digital imaging?  What equipment is used?  What are advantages and disadvantages of digital radiography?

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 3 Basic Concepts  Eliminates deficiencies  Provides more detailed information

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 4 Terminology  Cone beam computed tomography (CBCT)  Computer assisted digital imaging in dentistry that uses cone shaped x-ray beam to acquire information and present it in three dimensions  Cone beam volume tomography (CBVT)  Term used to differentiate between dental and medical CT  DICOM data  The way data is formatted for handling, storing and transmitting three-dimensional images  Acronym: digital imaging and communications in medicine

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 5Terminology  Field of view: area that can be captured in image  Multiplanar reconstruction (MPR): raw data imported into viewing software to create three anatomic planes  Plane, axial: Horizontal plane  Divides body into superior and inferior parts; runs parallel to floor  Plane, coronal: Vertical plane  Divides body into anterior & posterior sides; runs perpendicular to the ground  Plane, sagittal: Vertical plane  Divides body into right and left sides; runs perpendicular to the ground

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 6 Terminology  Resolution, contrast  Number of gray scale colors available for each pixel  Resolution, spatial  Measurement of pixel size in multiplanar reconstruction  Three-dimensional digital imaging  Image that demonstrates the anatomy in 3D  Three-dimensional volume rendering  A 3D shape that is created from 2D images  Voxel: AKA: volume element or 3D pixel  Smallest element of a 3D image

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 7 Fundamentals  Three-dimensional digital imaging  A method designed to evaluate the oral- maxillofacial complex  Named because it uses a cone-shaped x-ray beam to acquire three-dimensional information  Source of radiation rotates around the head of the patient very similar to a panoramic machine

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 8 Fundamentals  DICOM images  These allow practitioner to see field of view in three dimensions.  They are viewed in three planes: axial plane, coronal plane, and sagittal plane.  When viewed together images are referred to as multiplanar reconstructed images.  They can be shared amongst dental professionals.

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 9 Equipment  Specialized equipment  CBCT Machine  Comparable in size to a panoramic machine  Patient sits, stands, or is placed in a supine position.  In one rotation, radiation and receptor capture field of view

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 10

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 11 Equipment  Computer  Accepts raw data and converts them into stack of axial images.  Technique is completed during the data reconstruction process.  Viewing Software  Allows dental practitioner to view axial, coronal, and sagittal images.

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 12 Purpose and Use  Greatly improve interpretation, diagnosis, and treatment planning of dental care  Implant placement  Extraction or exposure of impacted teeth  Definition of anatomic structures  Endodontic assessment  Airway and sinus analysis  Evaluation of temporomandibular joint (TMJ) disorders  Orthodontic evaluation  Pathology evaluation

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 13 Step-by-Step Procedures  It is critical to refer to the manufacturer- provided instruction booklet for information concerning the operation of the system, equipment preparation, patient preparation, and exposure.

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 14 Patient Preparation ● Patients may be asked to sit or stand or be placed in the supine position during radiation exposure. ● Instructions are given to the patient before exposure to remove jewelry, eyeglasses, and removable dental appliances. ● A guide may be placed in the patients mouth during the scanning process. ● Some specialists may ask that the upper and lower teeth be kept apart.

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 15 Patient Positioning  Patient is instructed to remain still.  Scan times vary from 7 to 30 seconds.  Ergonomic head and chin supports have been designed for improved patient comfort.  Laser beams may be installed to help with proper alignment of clinical structures and to ensure correct anatomic positioning.

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 16 Advantages of Three-Dimensional Imaging  Lower radiation dose compared to traditional CT scans; greater than full mouth dose  Brief scanning time  Anatomically accurate images: 1:1 relationship with anatomy; no magnification  Ability to save and easily transport images: able to be saved as jpg or bmp  Very easy to send to other doctors

Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 17 Disadvantages of Digital Radiography  Patient movement and artifacts: metals may causes areas of blockage on image  Size of the field of view: if too small areas of importance may be missed  Cost of equipment: $150,000 to $300,000  Lack of training in interpretation of image on data on areas outside the maxilla and the mandible