Dental Radiography Types & Geometry - PDF

Infection control in dental radiography  Infection control during intraoral radiograph taking procedure  The authors recommendations ; the use of plastic coverage of the X-Rays equipment (cone, tube head, control panel, exposure button) or an efficient disinfection of these surfa...

Infection control in dental radiography  Infection control during intraoral radiograph taking procedure  The authors recommendations ; the use of plastic coverage of the X-Rays equipment (cone, tube head, control panel, exposure button) or an efficient disinfection of these surfaces before or after each patient.; the use of plastic barriers over the high- touch surfaces, the disinfection and sterilization of film-holding devices, the removal of contaminated overgloves in the darking room and film processing with new gloved hands. Infection control of intraoral dental film  The use of a sealed plastic bag for radio graphic dental film and its storage for ready access when needed.  Sections of plastic bag are cut to a size larger than that of the dental film to be covered.  The film is then sealed between the pieces of plastic using heat sealer. After the radio graphic technique, it is recommended that plastic bag must be removed and afterwards, the uncontaminated film process.  Theradiographic film,it can be a source of contamination, so, it must be protected with plastic barrier. If the barrier is not available, the dental film should be disinfected with alcohol 70%.  The steps of the recommended protocol for the dental film handling are:  1. Protect every dental film with plastic barrier previously to its use  2. Place carefully the protected film inside the patient's mouth wearing glove  3. Take the patient to the work area and place the lead apron and thyroid collar  4. After the exposure, take the dental film out of the patient's mouth and remove the plastic barrier, avoiding touching the dental film package  5. Place the uncontaminated film inside a plastic cup  6. Discard contaminated gloves and wash hands or wear overgloves  7. Take the cup with uncontaminated films to the processing chamber. The protocols to be followed during the intraoral conventional exposure are:  1. Protect with barrier all the surfaces that can be touched by saliva contaminated gloves during exposure such as X-Rays equipment tubehead, cone, control panel, start button, chair and headrest adjustment controls and work area surfaces.  2. Prepare all the devices and radiographic films that will be used, properly cleaned and protected with plastic barrier.  3. Take the patient to the work area and place the lead apron and thyroid collar  4. Wear gown, mask, eyewear and disposable new gloves in front of the patient.  5. Insert the radiographic film into the film holder device or directly in patient's mouth.  6. Execute the X-Rays exposure, avoiding touching any unprotected surface.  7. Remove the film holder device or radiographic film from patient's mouth and place the contaminated materials on a protected surface.  8. Remove contaminated gloves and wash hands  9. Take the lead apron and thyroid collar off the patient  10. Wear new gloves or overgloves and discard all contaminated protection barriers from the surfaces. Also, remove the film barrier or disinfect the film and film holder and if necessary, disinfect all surfaces that were not protected and could have had contact with oral fluids. The types of dental radiographs Intraoral Radiographs  Intraoral radiographs are radiographs taken with the dental film placed inside the oral cavity. Intraoral radiographs remain one of dentistry's most important imaging modalities to the dental practitioner. The intraoral technique provides high spatial resolution imaging of teeth and potential associated dental and jawbone diseases. 1.Materials we need when taking  The following are the materials used to take intraoral radiographs  1. X-ray Machine (including the tube head and control panel)  2. X-ray Film or Digital Sensor  3. Film Holder/Sensor Holder (e.g., Rinn XCP holder)  4. Lead Apron with Thyroid Collar  5. Positioning Devices (bite blocks or stabilizers)  6. Cotton Rolls (for patient comfort and sensor stabilization)  Cont’  7. X-ray Processing Equipment:  - Film radiography: Developer, fixer, and darkroom.  - Digital radiography: Computer with imaging software.  8. Disposable Plastic Barriers (for sensor or film)  9. Patient Safety Supplies:  - Disposable gloves  - Protective eyewear (optional)  10. Beam Alignment Device (to ensure proper angulation of the X-ray beam)  11. Mouth Mirrors or Tongue Depressors (to help position the film/sensor properly)  12. Beam aiming devices( locator ring and metal arm) There are 3 main types of intraoral Radiographs  Periapical Radiograph  Periapical radiographs are used to detect any abnormalities of the root structure and surrounding bone structure. These types of radiographs are taken in a selected region. Each PA shows the full tooth dimension and includes all the teeth in one portion of either the upper or lower jaw.  When taking this Radiograph, we use two techniques namely Bisecting and paralleling techniques.  2. Paralleling techniques: The tooth and the sensor are both kept on a parallel plane. This technique provides less image distortion and reduces excess radiation to the patient.  The way of taking paralleling technique: The Image is taken with the image receptor placed parallel to the long axis of the tooth. There must be a distance between the tooth and the receptor to take a good image.  3. Bisecting angle techniques: The bisecting angle technique is accomplished by placing the receptor as close to the tooth as possible. The central ray of the X-ray beam should be directed perpendicularly to an imaginary line that bisects or divides the angle formed by the long axis of the tooth and the plane of the receptor.  The way of taking Bisecting angle technique: The image receptor is placed diagonally to the long axis of the tooth. The beam projects at a right angle at the imaginary line that bisects the point to contact of the image receptor and long axis of the tooth. Indications of Periapical Radiographs  Detection of apical infection/inflammation  Assessment of the periodontal status  After trauma to the teeth and associated alveolar bone  Assessment of the presence and position of unerupted teeth  Assessment of root morphology before extractions  During endodontics Cont’  Preoperative assessment and postoperative appraisal of apical surgery  Detailed evaluation of apical cysts and other lesions within the alveolar bone  Evaluation of implants postoperatively. Contraindications  To the patient with multiple carries  I can’t record the soft tissues. the same case as the others.  Pregnant women  Non-cooperating patients like children Advantages of Periapical X-rays  They can record the teeth from the tip to the root.  They can record the anterior teeth where bitewing is contraindicated  Can show the detailed morphology of the tooth since it takes few teeth in one image Disadvantages  By taking periapical radiographs, it is not possible to take 3 dimensional radiographs which can lead to the limitation of diagnosis.  This type of radiograph does not record the teeth from both jaws at the same time. Thus, it is not possible to notice the relationship between the teeth in both jaws. 2. Bitewing radiograph  Bitewing radiographs are a type of intraoral dental X-ray that captures images of both the upper and lower teeth simultaneously. They are particularly useful for diagnosing specific dental conditions, especially those affecting the crowns of the teeth and the areas between teeth. Indications for Bitewing Radiographs:  1. Detection of Interproximal Caries: Bitewing radiographs are particularly useful for diagnosing cavities between the teeth that are not visible during a clinical exam.  2. Monitoring Existing Restorations: They are used to evaluate the integrity of existing dental restorations, such as fillings or crowns, and to check for recurrent decay under restorations.  3. Assessment of Bone Levels: These X-rays are indicated for assessing bone loss in patients with periodontal disease, providing an overview of the bone supporting the teeth. Cont’  4. Routine Dental Check-ups: Bitewings are typically recommended during routine dental exams to identify early signs of tooth decay or other dental issues.  5. Follow-up After Treatment: They are often used to monitor the progress of dental treatments, such as fillings or periodontal therapy, and to ensure there are no complications. Contraindications for Bitewing Radiographs  1. Pregnancy: Although radiation exposure is low, bitewing radiographs are generally avoided in pregnant women, particularly during the first trimester, unless necessary for urgent treatment.  2. Severe Gag Reflex: Patients with a strong gag reflex may find it difficult to tolerate the intraoral placement of the sensor or film, making the procedure uncomfortable and potentially inaccurate. Cont’  3. Limited Mouth Opening: Conditions such as trismus or temporomandibular joint disorders that restrict mouth opening can make it difficult to properly position the bitewing film or sensor.  4. Severe Periodontal Disease: If teeth are significantly mobile or gums are severely inflamed, bitewing radiographs may be difficult to take without causing discomfort, and alternative imaging methods may be preferred.  5. Young Children or Uncooperative Patients:  Bitewings may not be suitable for very young children or patients who cannot cooperate with the procedure due to cognitive or physical impairments. Other imaging methods may be considered. Advantages of Bitewing X-ray  It is quick and easy to perform  Minimal radiation exposure  It can show the relationship between upper and lower teeth by recording them in the same radiograph.  It is good at discovering newly formed caries on the tooth.  Disadvantages  Like the periapical one, it cannot give the 3-dimensional image  It does not record the whole tooth. So, it can’t be effective in dealing with root problems. This is limited diagnostic use. 3. Occlusal radiographs  Occlusal radiographs are a type of intraoral dental X- ray that captures a broad view of the teeth and the supporting structures, primarily focusing on the upper and lower teeth' occlusal (biting) surfaces. They provide images of larger areas of the mouth than periapical or bitewing radiographs.  By taking the bitewing we focus the x-ray beam perpendicular to the image receptor by horizontal angulation, and at 5 to 10 degrees downward by vertical angulation to ensure the proper record of both jaws without distortion.  Incorrect vertical angulation can result in elongation or foreshortening of the teeth in the X-ray image. Indication of occlusal radiographs  1. Detecting Pathological Conditions: Useful for identifying cysts, tumors, and other lesions in the jawbone or soft tissues.  2. Locating Impacted or Unerupted Teeth: Commonly used to locate impacted teeth, such as third molars (wisdom teeth), or unerupted teeth that have not yet broken through the gums.  3. Fracture Detection: Helpful in identifying fractures of the jaw, particularly in the anterior (front) portion of the maxilla or mandible.  4. Evaluating Tooth Development in Children: Frequently used to monitor tooth development and eruption patterns, especially in pediatric patients.  5. Locating Foreign Bodies: This can be used to locate foreign objects that may have become embedded in the soft tissues of the mouth or jaws.  6. Assessing Cleft Palate: Useful for evaluating the extent and location of cleft palates and other congenital abnormalities.  7. Monitoring Orthodontic Treatment: Used to assess the alignment of the teeth and their relationship to the jaws, aiding in orthodontic treatment planning. Contraindications for Occlusal Radiographs  1. Pregnancy: Although the radiation exposure is minimal, occlusal radiographs are typically avoided during pregnancy unless necessary to prevent harm to the developing fetus.  2. Patients with Severe Gag Reflex: The large size of the film or sensor used in occlusal X-rays may trigger a gag reflex, making the procedure difficult for some patients.  3. Uncooperative Patients (Young Children or Patients with Cognitive Impairments): Some patients, especially young children or those with cognitive impairments, may be unable to tolerate the procedure, making it challenging to obtain a clear image.  4. Limited Mouth Opening (Trismus): Patients with conditions like trismus, where the mouth cannot open wide enough, may struggle to accommodate the film or sensor needed for occlusal radiographs.  5. Severe Oral Infections: In cases of acute oral infections, particularly in soft tissues, the procedure may cause discomfort or worsen the condition, so it may be contraindicated until the infection is resolved. Extra oral dental radiographs  Thistype of X-ray still shows the teeth but can also provide important information about the jaw and skull. Think of these X- rays like the “big picture” of oral cavity, they are used to see how everything comes together. Panoramic Radiograph (Panorex)  A panoramic radiograph is a two-dimensional dental X-ray that provides a broad, comprehensive view of the entire mouth in a single image, including the upper and lower teeth, both jaws, and the surrounding bone structures. The X-ray machine rotates around the patient’s head to capture the image, offering a“panoramic” view of the dental arches How It Works  The patient stands or sits with their chin on a rest, while the machine moves in a semi-circle from one side of the head to the other. The X-ray beam captures a continuous image of the dental structures, providing a wide view of the entire oral cavity. Uses:  Detecting impacted or unerupted teeth (e.g., wisdom teeth)  Diagnosing dental and jawbone abnormalities, such as cysts, tumors, or fractures  Planning for orthodontic treatments (e.g., braces) and evaluating jaw development  Assessing bone structure for dental implant planning  Identifying and diagnosing periodontal (gum) disease and monitoring bone loss  Advantages:  Provides a full view of both dental arches, including hard- to-reach areas (such as the back of the mouth)  Quick and non-invasive, making it easy to capture a complete picture of the mouth in a few seconds  Useful for initial diagnosis and broad evaluation of dental and jaw issues  Limitations:  Lacks the detail of more focused intraoral X-rays, so small cavities or early-stage periodontal disease may not be visible  Slight distortion or magnification can occur, meaning it may not be ideal for precise measurements 2. Cephalometric Radiograph (Cephalogram) A cephalometric radiograph is a side-view X- ray of the head that shows the teeth, jaws, facial bones, and soft tissues. Unlike other dental X-rays, it captures the entire skull and is mainly used in orthodontics to evaluate the alignment of the teeth and jaws in relation to the facial structure. 3. Tomograph Radiograph (Dental Tomography)  A tomograph radiograph, often referred to as tomography, is a specialized type of X-ray that provides a detailed, layered view of a specific section of the body. In dental tomography, this technique is used to capture a detailed image of a particular layer or "slice" of the jaw, teeth, or other oral structures, without interference from the surrounding tissues. Conventional Radiography Overview  Conventional radiograph: Uses a stationary X-ray source.  Displays a 2D image of the body part.  Also known as plain or projection views (unlike ultrasound, CT, MRI).  Projects all tissue between X-ray source and image receptor (digital sensor/film) onto a 2D image. Radiograph Interpretation  Clinicians must understand normal anatomy.  They mentally reconstruct a 3D image from 2D views.  High-quality radiographs improve accuracy Projection Geometry  Defines effects of focal spot size and object- image receptor position on clarity, magnification, and distortion.  Clinicians use this to: o Maximize image clarity. o Minimize distortion. o Localize objects in the image field. Image Sharpness and Resolution  Sharpness: Measures boundary clarity between areas of differing radiodensity.  Resolution: Measures the ability to reveal small objects close together.  Sharpness and resolution are related and influenced by the same geometric factors. Factors Affecting Image Sharpness 1. Focal Spot Size: X-rays originate from different points within the focal spot, causing blurring at the edges.  Larger focal spot = more unsharpness. 2. Distance from Focal Spot to Object: Increased distance reduces blurring by limiting X-ray beam divergence. 3. Distance from Object to Image Receptor: Minimizing this distance decreases unsharpness and improves clarity. FIGURE 6-3 Increasing the distance between the focal spot and the object results in an image with increased sharpness and less magnification of the object as seen on the right. Fig: Decreasing the distance between the object and the image receptor increases the sharpness and results in less magnification of the object as seen on the left.  Image Size Distortion  Magnification: Image size distortion caused by divergent X-ray beams.  Minimized by:  Increasing focal spot-to-image receptor distance.  Decreasing object-to-image receptor distance.  Image Shape Distortion  Unequal magnification of different object parts results in shape distortion.  Can occur due to differences in focal spot-to-object distance. Minimizing Shape Distortion  1. Align image receptor parallel to the long axis of the object. Prevents foreshortening and elongation of the image.  2. Orient the central ray perpendicular to both the object and image receptor to reduce distortion.