Radiology Project

There are two main types of dental X-rays: intraoral (meaning the X-ray film is inside the mouth) and extra oral (meaning the X-ray film is outside the mouth). •

•

Intraoral X-rays are the most common type of X-ray taken. You've probably had many sets of these X-rays taken in your life already. These X-rays provide a lot of detail and allow your dentist to find caries, check the health of the tooth root and bone surrounding the tooth, check the status of developing teeth, and monitor the general health of your teeth and jawbone. Extraoral X-rays show teeth, but their main focus is the jaw and skull. These Xrays do not provide the detail found with intraoral X-rays and therefore are not used for detecting caries or for identifying problems with individual teeth. Instead, extraoral X-rays are used to look for impacted teeth, monitor growth and development of the jaws in relation to the teeth, and to identify potential problems between teeth and jaw and the temporomandibular joint (TMJ) or other bones of the face. (See the document, "Temporomandibular Disorders" for more information.)

There are several types of intraoral X-rays, each of which shows different aspects of teeth. •

•

•

Bite-wing X-rays show details of the upper and lower teeth in one area of the mouth. Each bite-wing shows a tooth from its crown to about the level of the supporting bone. Bite-wing X-rays are used to detect decay between teeth and changes in bone density caused by gum disease. They are also useful in determining the proper fit of a crown (or cast restoration) and the marginal integrity of fillings. Periapical X-rays show the whole tooth, from the crown to beyond the end of the root to where the tooth is anchored in the jaw. Each periapical X-ray shows this full tooth dimension and includes all the teeth in one portion of either the upper or lower jaw. Periapical X-rays are used to detect any abnormalities of the root structure and surrounding bone structure. Occlusal X-rays are larger and show full tooth development and placement. Each X-ray reveals the entire arch of teeth in either the upper or lower jaw.

Periapical Radiography: Paralleling technique is mostly the same for both bitewing and periapical techniques: Long cone is used to take x-rays with paralleling exposure techniques. Periapical film is held parallel to t h e long axis of t h e tooth using film-holding instruments. The central ray is directed to pass at a perpendicular angle to both t h e tooth a n d t h e film. Since t h e slope a n d curvature of t h e dental arches a n d t h e alveolar processes will n o t permit t h e film to be held close to t h e teeth a n d still be parallel to their long axes, t h e film m u s t be held a w a y from t h e teeth. This method provides a target-film distance of approximately 16 inches, in contrast to 8 inches for t h e bisecting technique. The increase in t h e target-film distance is related to t h e size of t h e image produced. If t h e film is held a w a y from t h e tooth a n d t h e target-film distance kept at 8inches, enlargement of t h e image would be unavoidable. Enlargement is minimized, however, by increasing t h e target-film distance

to 16 inches, thus using t h e parallel rays. An extension cone is used to increase t h e target-film distance. ASSEMBLY OF FILM-HOLDING INSTRUMENTS The instruments used to hold t h e film parallel to t h e teeth are plastic biteblocks, Indicator rods, a n d plastic locator rings. Placing the Device Once you have assembled the posterior paralleling device, place it in the patient's mouth. Be very careful not to injure the oral tissue. If the patient gags, use the Guide the bite-block and the film packet into position, centering the packet behind the area being X- rayed. The film packet should be positioned far enough behind the tooth so it will be parallel to the long axis of the tooth. After positioning the film packet, slide the locator ring down the indicator rod until the ring almost touches the surface of the patient's face. Then, position the tube head cylinder. The end of the cylinder should be parallel with the locator-ring, and its side should be parallel with the indicator rod. Once these procedures have been accomplished, the film packet and the tube head are in proper alignment. You are now ready to expose the film. EXPOSURE ROUTINE FOR FULL MOUTH PERIAPICAL EXAMINATION The full mouth periapical examination consists of 14 periapical radiographs (7 maxillary and 7 mandibular). The series includes the following films and sequence starting with the maxillary arch and proceeding to the mandibular arch: • • • • • • •

Incisor area Left cuspid area Left bicuspid area Left molar area Right cuspid area Right bicuspid area Right molar area

GUIDELINES FOR TAKING PERIAPICAL RADIOGRAPHS, PARALLELING TECHNIQUE The following guidelines apply if you are taking either a full mouth series, or an individual periapical radiograph. For training purposes, infection control barriers are not used in the photographs in this section. In most cases, the X-ray machine is set at 10 mA for dental radiographs. The kVp may vary, depending upon the thickness or the region being radiographed. If the area being radiographed is edentulous (no teeth present), reduce the recommended kVp by 5. When you are taking radiographs on a child, reduce the recommended kVp to 70. Always consult the dentist before taking radiographs on a child. Because of the different types of X-ray equipment in use, the exposure time selector you use may not have the settings suggested. Consult the film manufacturer's instructions regarding the desired time setting to use. Before you perform an individual radiograph or a full mouth periapical examination, prepare the patient, using the procedures explained earlier.

When you are using the parallel film placement technique, the position of the patient's head is not critical. But, it is best to adjust the head rest on the dental chair so that the patient's "plane of occlusion" is parallel with the floor and the "midsagittal plane" is perpendicular to the floor . It is important to properly position the paralleling devices and the tube head cylinder when using the paralleling placement technique. When taking a full mouth series or an individual periapical radiograph, follow the given guidelines for the specific area listed: NOTE: • •

After each exposure, put the exposed film in a clean paper cup or disposable container. Then place the cup or disposable container in a lead container or behind a protective screen.

Maxillary Incisor Area 1. 2. 3. 4.

Set the exposure time selector to manufacturer's suggested impulses. Prepare the anterior paralleling device. Position the paralleling device with film in the patient's mouth. Center the film on the midline so that it is parallel with the long axis of the incisors. Place a cotton roll under the bite-block. 5. Have the patient close gently but firmly. 6. Adjust the locator ring and align the tube head cylinder as previously described. 7. Make the exposure. Maxillary Cuspid Area 1. 2. 3. 4. 5. 6. 7.

Set the exposure time selector to manufacturer's suggested impulses. Prepare the anterior paralleling device. Position the paralleling device with film in the patient's mouth. Center the film on the cuspid and parallel with the tooth's long axis. Place a cotton roll under the bite-block and have the patient close. Adjust the locator ring and align the tubehead cylinder. Make the exposure.

Maxillary Bicuspid Area 1. Set the exposure time selector to the manufacturer's suggested impulses. 2. Prepare the posterior paralleling device. 3. Position the paralleling device with film in the patient’s mouth. 4. Center the second bicuspid and parallel with the tooth's long axis. 5. Place a cotton roll under the bite-block and have the patient close. 6. Adjust the locator ring and align the tubehead cylinder. 7. Make the exposure. Maxillary Molar Area

1. Set the exposure time selector to the manufacturer's suggested impulses Prepare the posterior paralleling device. 2. Position the paralleling device with film in the patient's mouth. 3. Center the film on the second molar, so the anterior edge of the film includes at least the distal half of the second bicuspid. 4. The film should be parallel with the long axis of the molars. 5. Place a cotton roll under the bite-block and have the patient close. 6. Adjust the locator ring and align the tubehead cylinder. 7. Make the exposure. Mandibular Incisor Area 1. Set the exposure time selector to the Manu- facture's suggested impulses. 2. Prepare the anterior paralleling device. 3. Position the paralleling device with film in the patient's mouth. 4. Position the film packet so that it is centered on the midline and parallel with the long axis of the incisors. 5. Place a cotton roll on the upper surface of the bite-block and have the patient close. 6. Adjust the locator ring and align the tubehead cylinder. 7. Make the exposure. Mandibular Cuspid Area 1. Position the paralleling device with film in the. 2. Set the exposure time selector to the manufacturer's suggested impulses. 3. Assemble the anterior paralleling device. Patient's mouth. 4. Center the film on the cuspid and parallel with its long axis. 5. Place a cotton roll on the upper surface of the bite-block and have the patient close. 6. Adjust the locator ring and align the tubehead cylinder. 7. Make the exposure. Mandibular Bicuspid Area 1. Set the exposure time to the manufacturer's suggested impulses. 2. Assemble the posterior paralleling device. 3. Position the paralleling device with film in the patient's mouth. Position the film packet so that it is centered on the second bicuspid and parallel with its long axis. 4. Place a cotton roll on the upper surface of the bite-block and have the patient close. 5. Adjust the locator ring and align the tubehead cylinder. 6. Make the exposure. Mandibular Molar Area

1. Set the exposure time to the manufacturer's suggested impulses. 2. Assemble the posterior paralleling device. 3. Position the paralleling device with film in the patient’s mouth. Position the film packet. 4. Center the film on the second molars, so the anterior edge of the film includes at least the distal half of the second bicuspid. 5. The film should be parallel with the long axis of the molars. 6. 4. Place a cotton roll on the upper surface of the bite-block and have the patient close. 7. Adjust the locator ring and align the tubehead cylinder.

1. Bisecting Angle technique GENERAL A short cone is used to take x-rays with bisecting angle exposure techniques. The target-film distance is 8 inches. The resulting image x-ray is somewhat larger using the short cone rather than using a long cone. The bisecting plane is halfway between the plane of the dental film and the longitudinal axis of the tooth. The average angle of projection is the angle between the occlusal plane and the angle of the central ray. The angle of the central ray is in relation to the bisecting plane. POSITIONING THE PATIENT Standard radiographic procedures include precise positioning of the patient's head as one step in placing film. The tissues to be radiographed and the x-ray beam must be in proper relationship to produce an accurate radiographic image. This is particularly important when using the bisecting angle technique. In adjusting the backrest and headrest, it is important to make the patient as comfortable as possible to minimize movement during exposure. As in photography, movement during exposure will result in a blurred image. Blurring may be greatly reduced through the use of ultra-speed film. a. Head Positioning in Radiography of the Maxilla Using the Bisecting Technique. In radiography of the maxilla, the head should be positioned so that the occlusal surfaces of the maxillary teeth are in a horizontal plane. This is done by adjusting the headrest so that the median plane (sagittal plane) is vertical and a line from the ala of the nose to the tragus of the ear is horizontal. b. Head Positioning in Radiography of the Mandible Using the Bisecting Technique. In periapical radiography of the mandible, the head should be positioned so that the occlusal surfaces of the mandibular teeth will be horizontal when the mouth is opened to the position in which the radiographs are to be made. This is done by adjusting the

headrest so the median plane is vertical and a line from the corner of the mouth to the tragus of the ear is horizontal. c. Angulation. When the cone is adjusted to project the central beam upward, it will be set at a negative (-) degree angulation. When it is adjusted to project the central beam downward, it will be set at a positive (+) angulation. CENTRAL RAY ANGULATION The angle of the x-ray beam, the average angle of projection of the central ray, is essential for successful use of the bisecting exposure techniques. Both vertical and horizontal angulations must be considered. a. Vertical angulation Is the up-and-down movement of the tube head or x-ray beam. The correct vertical angulation exists when the central ray is directed perpendicular to the bisector of the angle formed by the long axis of the tooth and the plane of the film. When this angulation is correct, the vertical dimension of the tooth will be as realistic as possible. Incorrect vertical angulation may cause two problems--foreshortening or elongation. Correct projection of central ray. (1) Foreshortening exists if the vertical angulation is larger than necessary. The image of the teeth appears smaller than normal (2) Elongation exists if the vertical angulation is less than is necessary. The image of the teeth appears larger than normal. Foreshortened image caused by projection of central ray from an angle that is too great. Elongated image caused by projection of central ray from an angle that is too small. b. Horizontal angulation. Is the side-to-side movement of the tube head or x-ray beam. Correct horizontal angulation for successful radiographs exists when the central ray is perpendicular to the facial surfaces of the teeth and parallel to the mesial and distal surfaces. If the horizontal angulation is incorrect, overlapping will occur on the radiograph. Overlapping results when the proximal surfaces of adjacent teeth are superimposed over one another. When this occurs, there will be a light area where the two teeth are overlapped or superimposed. The resultant light area is the inability of the x-ray beam to penetrate the two dense surfaces. Correct horizontal and vertical angulation of the x-ray beam is necessary to obtain radiographs of diagnostic quality.

Correct image resulting from proper horizontal projection of the central ray. Overlapping images caused by incorrect horizontal projection of the central ray.

OVERVIEW OF THE BISECTING ANGLE EXPOSURE TECHNIQUES a. The bisecting method of periapical radiography is used to varying degrees in Army dental clinics. The dental specialist should be familiar with its techniques. The following paragraphs describe techniques using this method to produce a 14-exposure set of radiographs of an adult dentition. Discussion of the techniques for exposure of each area of the mouth will include illustrations and descriptions of film placement, film holding, direction of the central ray, and average angulation. Slight contouring of a corner may facilitate film placement in restricted areas of the mouth, such as those of the maxillary incisors or the maxillary third molar, and make it more comfortable. To shape the film, press it over the rounded contour of a finger to pre-adapt it to the position in the mouth. Use only slight contouring to prevent distortion of the image. (A flat image produces the best image.) Paragraph 4-7 covers proper head positioning and other instructions for intraoral radiography. b. Various film holding devices may be used to secure the film in place when using the bisecting technique: the Rinn EEZEE-GRIP Film Holder, a hemostat, a plastic or Styrofoam film holder (with 105º angle). When such film holding devices are not available, the finger or thumb may be used.

MAXILLARY MOLARS Adjust the head as described for radiographs of maxillary teeth. Place the film packet in the mouth so that its long axis is horizontal, the anterior border of the film is lingual to the mesial border of the second bicuspid, and the lower border of the film is parallel to and slightly below (approximately 1/4 inch) the occlusal surfaces of the molars. The upper corner of the packet may be contoured slightly but the film packet should not be bent. Adjust the tube to an average angulation of +20º. Direct the central ray straight through the interproximal spaces in the area of the second molar and perpendicular to the bisecting plane. Follow the manufacturer's instructions for all exposure times.

MAXILLARY BICUSPIDS Adjust the head as described for radiographs of maxillary teeth. Place the film packet in the mouth so that its long axis is horizontal and its anterior border is lingual to the mesial surface of the cuspid. Have its lower border paralleled to, and slightly below, the occlusal surfaces of the teeth (approximately 1/4-inch). Adjust the cone to an average angulation of +30º. Direct the central ray straight through the interproximal spaces of the first and second bicuspids at the center of the film and perpendicular to the bisecting plane. Follow the manufacturer's instructions for all exposure times.

MAXILLARY CUSPIDS Adjust the head as described for radiographs of maxillary teeth. Place the film packet in the mouth so that its long axis is vertical and its lower border is parallel to and slightly below (approximately 1/8 inch) the incisal edges of the lateral incisor and cuspid teeth. The anterior border of the film should lie lingual to the central incisor of the same side. The upper anterior corner of the film may be contoured slightly to fit the curvature of the maxillary arch. Adjust the cone to an average angulation of +45º. Direct the central ray straight at the cuspid at the level of the root and perpendicular to the bisecting plane. Follow the manufacturer's instructions for exposure times. MAXILLARY INCISORS Adjust the head as described for radiography of maxillary teeth. Gently contour both long borders of the film slightly in the direction of the curvature of the palate. Place the film packet in the mouth so that its long borders are vertical and its center is in line with the median plane of the upper arch. Have the lower border of the packet slightly below (approximately 1/8 inch) and parallel to the incisal edges. Adjust the tube to an average angulation of +40º. Direct the central ray to pass through the tip of the nose in line with the median plane and perpendicular to the bisecting plane. Follow the manufacturer's instruction for exposure times. MANDIBULAR MOLARS Adjust the head as described for radiographs of mandibular teeth (paragraph 4-7b). Place the packet in the mouth with the long axis horizontal and the upper border of the film parallel to, and slightly above (approximately 1/4 inch) the occlusal surfaces of the molar teeth. Relieve the lower anterior border by contouring. Place the packet alongside the tongue and far enough distally to include the entire third molar area. Impacted or malposed mandibular teeth may require special positioning of the film packet. Adjust the tube to an average angulation of -5º. Direct the central ray straight through the interproximal spaces at the center of the film and perpendicular to the bisecting plane. Follow the manufacturer's instructions for exposure times. MANDIBULAR BICUSPIDS Adjust the head as described for radiographs of mandibular teeth. Place the film packet in the mouth with its long axis horizontal and its upper border parallel to and slightly above (approximately 1/4 inch) the occlusal surfaces of the teeth. Locate the anterior border of the film lingual to the mesial surface of the cuspid. The lower anterior border of the film should be contoured slightly to fit the curvature of the mandibular arch. Adjust the tube to an average angulation of -10º. Direct the central ray straight through the interproximal spaces at the center of the film and perpendicular to the bisecting plane. Follow the manufacturer's instructions for exposure times. MANDIBULAR CUSPIDS Adjust the head as described for radiographs of mandibular teeth. Place the film packet in the mouth with its long axis vertical and its upper border parallel to and

slightly above (approximately 1/8 inch) the incisal edges of the lateral incisor and cuspid teeth. The film's anterior border should be located lingual to the distal surface of the opposite central incisor. Adjust the tube to an average angulation of -20º. Direct the central ray straight through the bisecting plane. Follow the manufacturer's instructions for exposure times. MANDIBULAR INCISORS Adjust the head as described for radiographs of mandibular teeth. Place the film packet in the mouth with the long axis vertical. Both the long borders of the packet should be placed under the tongue with the center of the film opposite the midline of the arch and the upper border parallel to and slightly above (approximately 1/8 inch) the incisal edges of the incisor teeth. Adjust the tube to an average angulation of -15º. Direct the central ray straight through the interproximal spaces at the center of the film and perpendicular to the bisecting plane. Follow the manufacturer’s instructions for exposure times. Bitewing Radiographic Technique: Radiographs are an important part of dental diagnosis and treatment planning. Patients may be prescribed radiographs that will be used along with a clinical examination. Bitewing radiography is a commonly used dental x-ray technique and may be a component of the radiologic examination. Bitewing radiographs provide vital information to aid in the diagnosis of the most common dental diseases; specifically tooth decay and periodontal bone loss or gum disease. Additional important findings may be detected on bitewings, including the condition of fillings and the presence of calculus or tartar. Background Bitewing radiographs provide an image of the crowns of the top and bottom teeth on a single film. The type of film used for this examination provides a high resolution image that is able to detect the subtle changes that occur with dental diseases. Bitewings are usually prescribed in a series of 4 films, positioned on both sides of the mouth, examining the structures from the eye teeth, or canines, back. Bitewing Procedure 1) The patient is seated in an upright position in the dental chair. 2) The patient is covered with a lead apron and thyroid collar. Accepted standards for infection control will be followed, with the operator wearing gloves and some of the surfaces covered in a protective barrier. 3) A film is placed into the patient’s mouth using a cardboard film holding device. This device holds the film in position while the patient bites his or her teeth together onto a portion of the cardboard tab. It is important that the patient closes his or her teeth completely in their natural bite. Sometimes a plastic film holder with an attached ring may also be used.

4) Once the film is in position, the operator directs the cone of the x-ray unit toward the film. 5) The patient is instructed to hold still while maintaining the correct position. The operator leaves the room where he or she will press a button, to expose the film, which produces an audible beep. 6) The operator re-enters the operatory and removes the film from the patient’s mouth. This procedure may be repeated for different areas of the mouth as required. 7) Once the series of bitewing radiographs has been completed, the operator will remove the thyroid collar and lead apron and ensure that the patient is comfortable, while waiting for the films to be processed. 8) Following film processing, the films are examined. This initial assessment does not examine the films for disease; rather, the films are assessed to determine whether all areas can be visualized adequately. Anatomical variations, as well as local restorations may obscure the image so that all the required areas cannot be clearly seen, necessitating a re-take of that film. The patient exposure dose of radiation is kept as low as possible in order to maximize diagnostic value while minimizing risk. Radiation doses from dental radiography are considered comparable to the levels of radiation that we are exposed to every day from natural sources, such as the earth and space. Bitewing radiographs provide the dental professional with important information that is vital in the diagnosis and treatment planning for patients.

Paralleling TECHNIQUE The following procedures describe this technique: 1. Program the X-ray machine for he discussed time, mA settings, and kVp settings. 2. Prepare the inter-proximal paralleling device. Fold the bitewing tab against the film packet and insert the packet into the bite-block so that the printed side faces the backing support. Insert the end of the indicator rod into the holes in the bite-block. Slide the locator ring onto the indicator rod. Look through the locator ring to see if the bite-block is centered in the ring. If it is, the paralleling device is ready for positioning in the patient's mouth. 3. Position the paralleling device with film in the patient’s mouth so that the anterior edge of the film touches the distal surface of the mandibular cuspid. Have the patient close gently but firmly on the bite-block to hold the film in position. 4. Slide the locator ring down the indicator rod until the ring almost touches the surface of the patient's face. Then, align the tube head using the same technique as previously described for the paralleling device.

5. Make the exposure. After making the exposure, put the exposed film in a lead lined container or behind a protective screen. You are now ready to take the radiograph on the opposite side of the patient's mouth. BISECTING-ANGLE TECHNIQUE The following procedures describe this technique: 1. Program the X-ray machine for the discussed time, mA settings, and kVp settings. 2. Position the patient so that the ala-tragus line is parallel with the floor, and the midsagittal plane is perpendicular to the floor. 3. Position the film packet in the patient's mouth. Hold the wing of the packet between your thumb and index finger. Place the lower edge of the packet between the tongue and the lingual surfaces of the mandibular teeth. Position the packet so that its anterior edge touches the distal surface of the mandibular cuspid. Rest the wing of the packet on the occlusal surfaces of the mandibular teeth. Instruct the patient to close slowly. As the patient's maxillary teeth contact your index finger, roll your finger out facially, permitting the patient's teeth to close on the wing. The film packet is now positioned. 4. set the vertical angulation of the tube head at +5° to +l0°. The occlusal packet contains two X-ray films. This allows different developing times to be used for these films. The finished radiographs can then be compared for diagnostic purposes. Occlusal radiographs are exposed using the bisected angle technique. MAXILLARY OCCLUSAL RADIOGRAPHS Maxillary occlusal radiographs are taken by using the following procedures: 1. set the X-ray machine at 10 mA, 90 kVp, and 60 impulses (1 second). (Reduce the kilovoltage 5 kVp if the arch is edentulous. Use 70 kVp if the patient is a child.) 2. Position the patient so that the ala-tragus line is parallel with the floor, and the mid-sagittal plane is perpendicular to the floor. 3. Place the film in the patient's mouth. Occlusal films are normally very comfortable. Have the patient relax the muscles of the mouth and cheek as much as possible. The pebbled surface of the packet should be toward the occlusal surfaces of the maxillary teeth, and the narrow side of the packet toward the patient’s cheeks. To place the packet, retract one corner of the patient’s mouth until the packet can be inserted. Position the packet far enough in the mouth so that it covers all the teeth. Special care must be taken to avoid gagging the patient. Have the patient close gently but firmly on the packet to hold it in place. 4. Position the tube head. a. For maxillary anterior occlusal radiographs, set the vertical angulation of the tube head at +65°. Center the tube head cylinder on the bridge of the.—Projection of central ray (CR) for maxillary anterior occlusal

radiographs. patient's nose so that the central X-ray beam will be projected as shown in For maxillary posterior occlusal radiographs, set the vertical angulation of the tube head at +75°. Center the tube head at the top of the patient's nose so that the central X-ray beam will be projected as shown in. 5. Make the exposure. MANDIBULAR OCCLUSAL RADIOGRAPHS Mandibular occlusal radiographs are taken by using the following procedures: 1. Program the X-ray machine for 10 mA, 90 kVp, and 60 impulses (1 second). (Reduce the kVp setting for edentulous patients and children as discussed earlier.).— Projection of central ray (CR) for maxillary posterior occlusal radiographs.

2. Position the patient. a. For mandibular anterior occlusal radiographs, position the patient so that the ala-tragus line is at a 45° angle with the floor, and the midsagittal plane is perpendicular to the floor. b. For mandibular posterior occlusal radiographs, position the patient so that the ala-tragus line and mid-sagittal plane are perpendicular to the floor. 3. Place the film packet in the patient's mouth with the pebbled surface toward the occlusal surfaces of the mandibular teeth, and the short sides of the packet are toward the patient's cheeks. Have the patient close gently on the packet to hold it in place. 4. Position the tube head. a. For mandibular anterior occlusal radio- graphs, set the vertical angulation of the tube head at - 10°. Center the tube head cylinder on the tip of the patient’s chin so that the central X-ray beam will be projected as shown in. b. For mandibular posterior occlusal radiographs, set the vertical angulation of the tube head at 0°. Center the tube head cylinder beneath the patient's chin so that the central X-ray beam will be projected as shown in. 5. Make the exposures. Extraoral radiographs example: Panoramic X-ray: Is one X-ray that provides a full picture of your whole mouth- complete upper and lower jaw; sinuses and jaw joint. It is not as specific as the other X-rays because its purpose is to show the general condition of all the teeth. It is used to help viewWhen

taking a full mouth series or an individual periapical radiograph, follow the given guidelines for the specific area listed: NOTE: After each exposure, put the exposed film in a clean paper cup or disposable container. Then place the cup or disposable container in a lead container or behind a protective screen. 1. 2. 3. 4. 5. 6. 1. 2. 3. 4. Maxillary Incisor Area Set the exposure time selector to manufacturer's suggested impulses. Prepare the anterior paralleling device. Position the paralleling device with film in the patient's mouth. Center the film on the midline so that it is parallel with the long axis of the incisors (fig. 1-14). Place a cotton roll under the bite-block. Have the patient close gently but firmly. Adjust the locator ring and align the tubehead cylinder as previously described. Make the exposure. Maxillary Cuspid Area Set the exposure time selector to manufacturer's suggested impulses. Prepare the anterior paralleling device. Position the paralleling device with film in the patient's mouth. Center the film on the cuspid and parallel with the tooth's long axis (fig. 1-15). Place a cotton roll under the bite-block and have general tooth development; trauma; jaw joint pain;

wisdom teeth and certain abnormalities. It will give a broad view but does not provide the fine detail that Bite-Wings or P.A.s provide. This X-ray is to be taken every 5-7 years