Dental Radiography: Principles and Techniques

The dental radiographer must master a variety of intraoral imaging techniques. The bite-wing technique is used to examine the interproximal surfaces of teeth. A bite-wing image includes the crowns of maxillary and mandibular teeth, interproximal areas, and areas of crestal bone on the same image. Bite-wing images are used to detect interproximal caries (tooth decay) and are particularly useful in detecting early carious lesions that are not clinically evident. Bite-wing images are also useful in examining crestal bone levels between teeth.

Before the dental radiographer can use this important technique, an understanding of the basic concepts, including the terminology and principles relating to the bite-wing technique, is necessary. In addition, the dental radiographer must understand patient preparation, equipment preparation, exposure sequencing, and the receptor placement procedures used in the bite-wing technique.

The purpose of this chapter is to present basic concepts and to describe patient preparation, equipment preparation, and the receptor placement procedures used in the bite-wing technique. This chapter also outlines the advantages and disadvantages of the bite-wing technique and reviews helpful hints.

Basic Concepts

The bite-wing technique (also known as the interproximal technique) is a method used to examine the interproximal surfaces of teeth. Before the dental radiographer can competently use this technique, a thorough understanding of the terminology, principles, and basic rules of the bite-wing technique is necessary. In addition, a knowledge of the beam alignment devices, sizes of receptors, and angulations of the position-indicating device (PID) used with the bite-wing technique is also required.

Terminology

An understanding of the following basic terms is necessary before describing the bite-wing technique:

Interproximal: Between two adjacent surfaces.

Interproximal examination: Intraoral examination used to inspect the crowns of both maxillary and mandibular teeth on a single image.

Bite-wing receptor: Type of receptor used in interproximal examination. The bite-wing receptor has a “wing,” or tab, and the patient “bites” on the wing to stabilize the receptor.

Alveolar bone: Bone that supports and encases the roots of teeth (Figure 19-1).

FIGURE 19-1 Alveolar bone. (Adapted from Haring JI, Lind LJ: Radiographic interpretation for the dental hygienist, Philadelphia, 1993, Saunders.)

Crestal bone: Coronal portion of alveolar bone found between teeth; also known as the alveolar crest (Figure 19-2).

FIGURE 19-2 Crestal bone is the most coronal portion of alveolar bone found between teeth. (Adapted from Haring JI, Lind LJ: Radiographic interpretation for the dental hygienist, Philadelphia, 1993, Saunders.)

Contact areas: The area of a tooth that touches an adjacent tooth; the area where adjacent tooth surfaces contact each other (Figure 19-3).

FIGURE 19-3 Contact areas are areas where adjacent tooth surfaces contact each other. (From Haring JI, Lind LJ: Radiographic interpretation for the dental hygienist, Philadelphia, 1993, Saunders.)

Horizontal bite-wing: The bite-wing receptor is placed in the mouth with the long portion of the receptor in a horizontal direction.

Opened contacts: On a dental image, opened contacts appear as thin radiolucent lines between adjacent tooth surfaces (Figure 19-4).

FIGURE 19-4 The opened contacts in the premolar region appear as thin radiolucent lines. Note that the occlusal plane is positioned horizontally along the midline of the long axis of the image. (From Haring JI, Lind LJ: Radiographic interpretation for the dental hygienist, Philadelphia, 1993, Saunders.)

Overlapped contacts: On a dental image, the area where the contact area of one tooth is superimposed over the contact area of an adjacent tooth is referred to as overlapped contacts (Figure 19-5).

FIGURE 19-5 A nondiagnostic bite-wing image with overlapped interproximal contacts. (From Haring JI, Lind LJ: Radiographic interpretation for the dental hygienist, Philadelphia, 1993, Saunders.)

Vertical bite-wing: The bite-wing receptor is placed in the mouth with the long portion of the receptor in a vertical direction.

Principles of Bite-Wing Technique

The basic principles of the bite-wing technique can be described as follows (Figure 19-6):

FIGURE 19-6 Positions of the receptor, bite-wing tab, and central ray in the bite-wing technique. The receptor is parallel to the crowns in the maxillary and mandibular teeth. The central ray is directed downward (+10 degrees of vertical angulation).

1. The receptor is placed in the mouth parallel to the crowns of both maxillary and mandibular teeth.

2. The receptor is stabilized when the patient bites on the bite-wing tab or the bite-wing beam alignment device.

3. The central ray of the x-ray beam is directed through the contacts of teeth, using a vertical angulation of +10 degrees.

Beam Alignment Device and Bite-Wing Tab

In the bite-wing technique, either a beam alignment device or a bite-wing tab is used to stabilize the receptor.

Bite-Wing Beam Alignment Device

A beam alignment device is a device used to position an intraoral receptor in the mouth and maintain the receptor in position during the radiographic procedure (see Chapter 6). Beam alignment devices eliminate the need for the patient to stabilize the receptor with a bite-wing tab. An example of a commercially available intraoral bite-wing beam alignment device is the XCP bite-wing instrument; this instrument may be used to stabilize the bite-wing receptor in a horizontal or vertical direction.

• Rinn XCP bite-wing instruments (Rinn Corporation, Elgin, IL). The XCP bite-wing instruments include plastic horizontal and vertical bite-blocks, plastic aiming rings, and metal indicator arms (Figure 19-7, A, B). To reduce the amount of radiation the patient receives, a snap-on ring collimator can be added to the plastic aiming ring. These beam alignment devices are reusable and must be sterilized after each use.

FIGURE 19-7 A, Beam alignment device for horizontal bite-wings. Note external localizing ring used for the position-aiming tube of the x-ray machine to ensure that the entire receptor is covered by the x-ray beam. B, Beam alignment device for vertical bite-wings. C, Rectangular collimation used with a bite-wing exposure.

The Rinn XCP bite-wing instruments with collimators are recommended for bite-wing exposures. These devices include aiming rings that assist in the alignment of the PID and collimators, significantly reducing the amount of radiation exposure. These instruments are simple to position and easy to sterilize. As mentioned in Chapter 17, the American Dental Association (ADA) and the American Academy of Oral and Maxillofacial Radiology recommend the use of a rectangular collimator to reduce the amount of radiation the patient receives (Figure 19-7, C). For information about the use of the Rinn XCP bite-wing instruments, the dental radiographer should refer to the instructions provided by the manufacturer.

Bite-Wing Tab

As an alternative to a beam alignment device, a receptor can be fitted with a bite-wing tab (also called a bite loop or bite tab). The bite-wing tab is a heavy paperboard tab or loop that is fitted around an intraoral receptor and is used to stabilize the receptor during the procedure (Figure 19-8, A). When using film, the bite-wing is oriented in the bite loop so that the tab portion extends from the white side (tube side) of the film. Bite-wing receptors may be purchased with the tabs attached, or they may be constructed by assembling a periapical receptor and a bite-wing tab. Bite-wing tabs may be used on horizontal or vertical bite-wing projections. Bite loops are available in various sizes; adhesive bite tabs are also available (Figure 19-8, B).

FIGURE 19-8 A, Bite-wing tabs. B, Adhesive bite-wing tabs.

Bite-Wing Receptors

As described in Chapter 7, three sizes of bite-wing receptors (0, 2, and 3) are available. Figure 7-14 (pp. 69–70) summarizes the measurements and uses of these receptors.

• Size 0 is used to examine the posterior teeth of children with primary dentitions. This receptor is always placed with the long portion of the receptor in a horizontal (sideways) direction.

• Size 2 is used to examine the posterior teeth in adults and may be placed horizontally or vertically. For most bite-wing exposures, a size 2 receptor is placed with the long portion of the receptor in a horizontal direction. When a vertical posterior bite-wing exposure is indicated, a size 2 receptor is placed with the long portion of the receptor in a vertical direction.

• Size 3 is longer and narrower than the standard size 2 receptor and is used only for bite-wing exposures. One receptor is exposed on each side of the arch to examine all the premolar and molar contact areas. A size 3 receptor is placed with the long portion of the receptor in a horizontal direction.

In the adult patient, a size 2 receptor is recommended for bite-wing exposures. The size 3 receptor is not recommended. With a size 3 receptor, overlapped contacts often result because of the difference in the curvature of the arch between the premolar and molar areas. In addition, the crestal bone areas may not be adequately seen on the dental images of patients with bone loss because of the narrow shape of the receptor.

Position-Indicating Device Angulation

In the bite-wing technique, the angulation of the PID is critical. As defined in Chapter 18, angulation is a term used to describe the alignment of the central ray of the x-ray beam in both horizontal and vertical planes. Angulation can be varied by moving the PID in a horizontal or vertical direction. Use of the XCP bite-wing instruments with aiming rings dictates the proper PID angulation. However, when a bite-wing tab is used, the dental radiographer must determine both horizontal and vertical angulations.

Horizontal Angulation

As described in Chapter 18, horizontal angulation refers to the positioning of the central ray in a horizontal, or side-to-side, plane (see Figure 18-7). The bite-wing, paralleling, and bisecting techniques all use the same principles of horizontal angulation.

Correct Horizontal Angulation: With correct horizontal angulation, the central ray is directed perpendicular to the curvature of the arch and through the contact areas of teeth (see Figure 18-8). As a result, the contact areas on the exposed image appear “opened” and can be examined for evidence of caries (see Figure 19-4).

Incorrect Horizontal Angulation: Incorrect horizontal angulation results in overlapped (“unopened”) contact areas (see Figure 18-9). An image with overlapped interproximal contact areas cannot be used to examine the interproximal areas of teeth for evidence of caries (see Figure 19-5).

Vertical Angulation

As described in Chapter 18, vertical angulation refers to the positioning of the PID in a vertical, or up-and-down, plane (Figure 19-9). Vertical angulation may be positive or negative and is measured in degrees as viewed on the outside of the tubehead (Figure 19-10). If the PID is positioned above the occlusal plane and the central ray is directed downward, the vertical angulation is termed positive (+). If the PID is positioned below the occlusal plane and the central ray is directed upward, the vertical angulation is termed negative (−).

FIGURE 19-9 All vertical angulations above the occlusal plane are termed positive. Vertical angulations below the occlusal plane are termed negative. Zero angulation is achieved when the position-indicating device (PID) and the central ray are parallel to the floor.

FIGURE 19-10 Vertical angulation is measured in degrees on the outside of the tubehead.

Correct Vertical Angulation: When a bite-wing tab is used, a vertical angulation of +10 degrees is recommended for the bite-wing image. The +10-degree vertical angulation is used to compensate for the slight bend of the upper portion of the receptor and the slight tilt of maxillary teeth (Figure 19-11).

FIGURE 19-11 A vertical angulation of +10 degrees is used to compensate for the slight bend of the upper portion of the receptor and the tilt of maxillary teeth.

Incorrect Vertical Angulation: Incorrect vertical angulation used in the exposure of a bite-wing results in a distorted image. For example, if a negative vertical angulation is used, the occlusal surfaces of maxillary teeth are evident, and the apical regions of mandibular teeth are seen (Figure 19-12). A bite-wing image exposed with an excessive negative vertical angulation is nondiagnostic.

FIGURE 19-12 Negative vertical angulation.

Rules of Bite-Wing Technique

Five basic rules must be followed when using the bite-wing technique.

1. Receptor placement. The bite-wing receptor must be positioned to cover the prescribed area of teeth to be examined. Specific placements are detailed in the procedures described in the next section.

2. Receptor position. The bite-wing receptor must be positioned parallel to the crowns of both maxillary and mandibular teeth. The receptor must be stabilized when the patient bites on the bite-wing tab or on the bite-wing beam alignment device.

3. Vertical angulation. When a bite-wing tab is used, the central ray of the x-ray beam must be directed at +10 degrees (see Figure 19-6).

4. Horizontal angulation. When a bite-wing tab is used, the central ray of the x-ray beam must be directed through the contact areas between teeth.

5. Receptor exposure. The x-ray beam must be centered on the receptor to ensure that all areas of the receptor are exposed. Failure to center the x-ray beam results in a partial image on the bite-wing receptor or a cone-cut.

Step-By-Step Procedures

Step-by-step procedures for the exposure of bite-wing receptors include patient preparation, equipment preparation, and receptor placement methods. Before exposing any dental bite-wings, infection control procedures (as described in Chapter 15) must be completed.

Patient Preparation

After completion of infection control procedures and preparation of the treatment area and supplies, the patient should be seated. After seating the patient, the dental radiographer must prepare the patient for the radiographic procedure (Procedure 19-1).

PROCEDURE 19-1 Patient Preparation for Bite-Wing Images

1. Briefly explain the imaging procedure to the patient before starting the procedure.

2. Position the patient upright in the chair. Adjust the level of the chair to a comfortable working height.

3. Adjust the headrest to support and position the patient’s head. The patient’s head must be positioned such that the maxillary arch is parallel to the floor and the midsagittal (midline) plane is perpendicular to the floor.

4. Place and secure the lead apron with a thyroid collar on the patient.

5. Have the patient remove all objects from the mouth (e.g., dentures, retainers, chewing gum) that may interfere with the procedure. Eyeglasses must also be removed.

Equipment Preparation

After patient preparation, equipment must also be prepared before exposure of any receptors (Procedure 19-2).

PROCEDURE 19-2 Equipment Preparation for Bite-Wing Images

1. Set the exposure factors (kilovoltage, milliamperage, and time) on the x-ray unit according to the recommendations of the receptor manufacturer.

2. If a beam alignment device is used with the bite-wing technique, open the sterilized package containing the device, and assemble the device on a covered work area.

3. If a bite-wing tab is used, attach the tab to the white side of the film, or the correct side of the receptor.

Exposure Sequence for Receptor Placements

When using the bite-wing technique, an exposure sequence, or definite order for receptor placements and exposure, must be followed. The dental radiographer must have an established exposure routine to prevent errors and make efficient use of time. Working without an exposure sequence may result in omitting an area or exposing an area twice.

As discussed in Chapter 16, a complete mouth radiographic series (CMRS) is an intraoral series of dental images that shows all the tooth-bearing areas of the maxilla and the mandible. The CMRS may consist of periapical images alone, anterior and posterior vertical bite-wings, or a combination of periapical and bite-wing images. Bite-wing exposures are used only for areas where teeth have interproximal contact with other teeth.

The number of bite-wing images necessary for a patient is based on the curvature of the arch and the number of teeth present in the posterior areas. The curvature of the arch often differs between the premolar and molar areas (Figure 19-13). If the curvature of the arch differs, it is impossible to open all the posterior contact areas on one bite-wing image. Consequently, two bite-wing receptors are typically exposed on each side of the arch. Because the curvature of the arch differs in most adult patients, a total of 4 bite-wings are exposed: 1 right premolar, 1 right molar, 1 left premolar, and 1 left molar.

FIGURE 19-13 Note the difference in the curvature of the arch in premolar and molar areas.

When posterior teeth are missing (e.g., in patients in whom the premolars have been extracted as part of orthodontic treatment), one bite-wing exposure on each side of the arch (instead of two) may be sufficient to cover the number of teeth present.

In the patient who requires both periapical and bite-wing exposures, the following exposure sequence is recommended:

1. First, expose all anterior periapical receptors (see Chapters 17 and 18).

2. Follow with posterior periapical receptors (see Chapters 17 and 18 ).

3. Finish with bite-wing exposures.

The sequence ends with bite-wing exposures because these receptors are relatively easy for the patient to tolerate. It is unwise to end the examination with difficult exposures (e.g., painful placements or placements that elicit the gag reflex).

In the patient who requires bite-wings only, the following exposure sequence is recommended for each side of the mouth:

1. Expose the premolar bite-wing first. (This receptor is easier for the patient to tolerate and is less likely to evoke the gag reflex.)

2. Expose the molar bite-wing last.

Bitewing Receptor Placement

When exposing bite-wings, each exposure has a prescribed placement. Receptor placement, or the specific area where the receptor must be positioned before exposure, is dictated by the teeth and surrounding structures that must be included on the resulting bite-wing image. The specific placements described in this chapter are for a four-receptor posterior bite-wing series using size 2 receptors and bite-wing tabs. Variations in placement, receptor size, or total number of exposures may be recommended by other reference sources or individual practitioners (Box 19-1).

BOX 19-1 Guidelines for Bite-Wing Receptor Placement

1. When using film, the white side of the film always faces the tooth. The identification dot on the film has no significance in bite-wing film placement.

2. In posterior bite-wing series, receptors are placed horizontally or vertically.

3. When positioning the receptor, always center the receptor over the area to be examined (as defined in the prescribed placements).

4. When positioning the receptor, ask the patient to “slowly bite” on the bite-wing tab or on the bite-block of the beam alignment device.

Bite-Wing Receptor Placements

Receptor placements for the four posterior bite-wing exposures include the following:

• Right and left premolar exposures (Procedure 19-3)

PROCEDURE 19-3 Premolar Bite-Wing Exposure with Bite Tab (Figure 19-14)

FIGURE 19-14 The premolar bite-wing. A, Receptor placement. B, Resultant image.

1. Set vertical angulation at +10 degrees (Figure 19-15).

FIGURE 19-15 Vertical angulation is set at +10 degrees.

2. To set the horizontal angulation, stand in front of the patient. Examine the posterior curvature of the arch. To better visualize the curvature of the arch, place your index finger along the premolar area. Align the open end of the position-indicating device (PID) parallel to your index finger and the curvature of the arch in the premolar area, and direct the central ray through the contact areas (Figure 19-16).

FIGURE 19-16 A, To better visualize the curvature of the arch, place the index finger along the premolar area. B, Correct horizontal angulation of the premolar area.

3. Make certain that the PID is positioned far enough forward to cover both maxillary and mandibular canines and is positioned evenly over the mandibular and maxillary arches to avoid a cone-cut. The middle of the PID should be directed at the level of the occlusal plane (Figure 19-17). After the vertical angulation, horizontal angulation, and PID position have been established, the PID should not be adjusted, and the receptor should be placed without moving the PID.

FIGURE 19-17 The middle of the position-indicating device (PID) should be directed at the level of the occlusal plane.

4. Fold the bite-wing tab in half, and crease it. Insert the receptor into the patient’s mouth, and place the lower half of the receptor between the patient’s tongue and teeth. Place the biting surface of the tab on the occlusal surfaces of mandibular teeth. Center the receptor on the mandibular second premolar; the front edge of the receptor should be aligned with the midline of the mandibular canine. Using your index finger, hold the bite-wing tab against the buccal surfaces of the premolars (Figure 19-18). Hold the tab in place during steps 5 and 6.

FIGURE 19-18 A, Crease the middle of the bite-wing tab before placing the receptor in the patient’s mouth. B, Place the biting area of the tab on the occlusal surfaces of teeth while holding the tab against the buccal surfaces of premolars. The front edge of the receptor should be aligned with the middle of the mandibular canine.

5. Make certain that the patient’s occlusal plane is parallel to the floor. If necessary, ask the patient to lower the chin (Figure 19-19).

FIGURE 19-19 The patient’s occlusal plane must be parallel to the floor.

6. To check for cone-cut, stand directly behind the tubehead and look along the side of the PID. No portion of the receptor should be visible; the receptor should be covered by the opening of the PID (Figure 19-20). If the receptor is not visible, ask the patient to “slowly close” while you still hold the bite-wing tab. If any portion of the receptor is visible, a cone-cut will result. In such cases, the PID must be adjusted to cover the receptor. After the PID has been positioned properly, ask the patient to “slowly close” while holding the bite-wing tab.

FIGURE 19-20 A, To check for cone-cuts, stand behind the tubehead and look along the side of the position-indicating device (PID). B, No portion of the receptor should be visible. C, A cone-cut results when any portion of the receptor is visible.

7. Expose the receptor.

• Right and left molar exposures (Procedure 19-4)

PROCEDURE 19-4 Molar Bite-Wing Exposure with Bite Tab (Figure 19-21)

FIGURE 19-21 The molar bite-wing. A, Receptor placement. B, Resultant image.

1. Set the vertical angulation at +10 degrees (see Figure 19-15).

2. To set the horizontal angulation, stand in front of the patient. Examine the posterior curvature of the arch. To better visualize the curvature of the arch, place your index finger along the molar area. Align the open end of the position-indicating device (PID) parallel to your index finger and the curvature of the arch in the molar area, and direct the central ray through the contact areas (Figure 19-22).

FIGURE 19-22 A, To better visualize the curvature of the arch, place the index finger along the molar area. B, Correct horizontal angulation of the molar area.

3. Make certain that the PID is positioned far enough forward to cover both maxillary and mandibular second premolars and is positioned evenly over the mandibular and maxillary arches to avoid a cone-cut. The middle of the PID should be directed at the level of the occlusal plane (see Figure 19-17). After the vertical angulation, horizontal angulation, and PID position have been established, the PID should not be adjusted, and the receptor should be placed without moving the PID.

4. Fold the bite-wing tab in half, and crease it. Insert the receptor into the patient’s mouth, and place the lower half of the receptor between the patient’s tongue and teeth. Place the biting surface of the tab on the occlusal surfaces of mandibular teeth. Center the receptor on the mandibular second molar; the front edge of the receptor should be aligned with the midline of the mandibular second premolar. Using your index finger, hold the bite-wing tab against the buccal surfaces of the molars (Figure 19-23). Hold the tab in place during steps 5 and 6.

FIGURE 19-23 Place the biting area of the tab on the occlusal surfaces of teeth while holding the tab against the buccal surfaces of premolars. The front edge of the receptor should be aligned with the middle of the mandibular second premolar.

5. Make certain that the patient’s occlusal plane is parallel to the floor. If necessary, ask the patient to lower the chin (see Figure 19-19).

6. To check for cone-cut, stand directly behind the tubehead and look along the side of the PID. No portion of the receptor should be visible; the receptor should be covered by the opening of the PID (Figure 19-24). If the receptor is not visible, instruct the patient to “slowly close” while you still hold the bite-wing tab. If any portion of the receptor is visible, a cone-cut will result. In such cases, the PID must be adjusted to cover the receptor. After the PID has been positioned properly, instruct the patient to “slowly close” while you still hold the bite-wing tab.

FIGURE 19-24 A, To check for cone-cuts, stand behind the tubehead and look along the side of the position-indicating device (PID). B, No portion of the receptor should be visible.

7. Expose the receptor.

8. An example of a charting note to document four bite-wing exposures is given below:

Charting Bite-Wing Exposures

It is important to note that in the procedures for premolar and molar bite-wing exposures, it is recommended that the receptor be placed into the patient’s mouth after both vertical and horizontal angulations have been set.

Vertical Bite-Wings

A vertical bite-wing image can be used to examine the level of alveolar bone in the mouth. This bite-wing is placed with the long portion of the receptor in an up-and-down, or vertical, direction (Figure 19-25). Vertical bite-wings images are often used as post-treatment or follow-up images for patients with bone loss due to periodontal disease.

FIGURE 19-25 A vertical bite-wing image can be used to evaluate the level of supporting bone. (From Haring JI, Lind LJ: Radiographic interpretation for the dental hygienist, Philadelphia, 1993, Saunders.)

A modified CMRS may be performed using vertical bite-wing images. A total of 7 projections (3 anterior and 4 posterior) are used to cover the incisor, canine, premolar, and molar areas. Size 2 receptors may be used for all exposures, or a combination of size 1 (anterior teeth) and size 2 (posterior teeth) may be used. For projections in the anterior regions, a longer bite-wing tab is often necessary for the patient to be able to close completely. The patient should be instructed to bite on the tab in an end-to-end occlusal relationship (Figure 19-26).

FIGURE 19-26 Anterior interproximal area. A, Center the receptor vertically at midline, and stabilize the patient by having him or her gently close on the tab at the incisal edges of teeth. Teeth meet the tab in the end-to-end position. Suggested vertical angulation is + 10 degrees toward the center of the receptor; horizontally, the x-ray beam is directed through the interproximal spaces. B, Bite-wing image of the right canine area. (Redrawn from DeLyre WR, Johnson ON: Essentials of dental radiography for dental assistants and hygienists, ed 4, Norwalk, CT, 1990, Appleton & Lange.)

Bite-Wing Technique Modifications

Modifications in the bite-wing technique may be used to accommodate variations in anatomic conditions. Such modifications may be necessary in patients who have edentulous spaces or bony growths.

Edentulous Spaces

As described in Chapter 16, an edentulous space is an area where teeth are no longer present. An edentulous space may cause problems in bite-wing receptor placement, and a modification in technique is necessary. A cotton roll must be placed in the area of the missing tooth (or teeth) to support the bite-wing tab or the beam alignment device. When the patient closes, opposing teeth occlude on the cotton roll and support the bite-wing tab or the beam alignment device. Failure to support the bite-wing tab or the beam alignment device results in a tipped occlusal plane on the resulting image.

Bony Growths

As described in Chapter 17, a torus (plural, tori) is a bony growth in the oral cavity. Mandibular tori are bony growths along the lingual aspect (tongue side) of the mandible. When using the bite-wing technique, mandibular tori may cause problems in receptor placement, and a modification in technique is therefore necessary.

The receptor must be placed between the tori and the tongue (not on the tori) and then exposed. With large tori, the receptor is pushed away from teeth. As a result, the patient bites on the very end of the bite-wing tab to stabilize the receptor, thus making it difficult for the dental radiographer to achieve correct placement. In such cases, a bite-wing beam alignment device is recommended.

Helpful Hints

In using the bite-wing technique:

DO set all exposure factors (kilovoltage, milliamperage, time) before placing any receptors in the mouth.

DO ask patients to remove all intraoral objects and eyeglasses before placing any receptors in the patient’s mouth.

DO use a definite order (exposure sequence) when exposing receptors to avoid errors and to make efficient use of time.

DO explain to the patient the imaging procedures to be performed.

DO instruct patients on how to close on the bite-wing tab and remain still during the exposure; make certain that the patient remains closed on the bite-wing tab during the exposure.

DO set the vertical angulation at +10 degrees.

DO direct the central ray through the contact areas of the teeth, and align the opening of the PID parallel with the curvature of the arch.

DO set vertical and horizontal angulations before placing the receptor into the patient’s mouth.

DO check for cone-cuts before exposing the receptor.

DO use the word please; say, “Open, please.”

DO use praise; tell cooperative patients how much they are helping you.

DO NOT bend or crimp a film packet; excessive film bending causes distortion of the image.

DO NOT use words such as hurt. Instead, inform patients that the procedure will be “momentarily uncomfortable.”

DO NOT make comments such as “Oops.” Patients will lose confidence in your abilities when they hear such comments.

DO NOT pick up a receptor if you drop it. Leave it on the floor; it has now become contaminated. Instead, remove it and dispose of it when you clean the treatment area.

DO NOT allow patients to dictate how you should perform your duties. The dental radiographer must always remain in control of the procedures.

DO NOT begin with the molar bite-wing exposure; molar placements may cause patients to gag. Instead, always begin with the premolar bite-wing.

DO NOT position a receptor on top of a torus (tori). Instead, always position the receptor between the torus and the tongue.

Summary

• A bite-wing image includes crowns of maxillary and mandibular teeth, interproximal areas, and areas of crestal bone on the same image. Bite-wings are useful for examining the interproximal surfaces of teeth, detecting caries, and examining crestal bone levels between teeth.

• The patient bites on the wing to stabilize the bite-wing receptor.

• The bite-wing receptor is placed parallel to the crowns of both maxillary and mandibular teeth; the receptor is stabilized when the patient bites on the tab or the beam alignment device; and the central ray of the x-ray beam is directed through contacts by using a +10-degree vertical angulation.

• A beam alignment device (Rinn XCP bite-wing device with collimator is recommended) or a bite-wing tab may be used to stabilize the receptor.

• Three sizes of receptors (0, 2, and 3) can be used in the bite-wing technique; in the adult patient, a size 2 receptor is recommended.

• With correct horizontal angulation (side-to-side positioning of the PID), the central ray is directed through the contact areas of teeth; contact areas on the image appear “opened.” Incorrect horizontal angulation results in overlapped (“unopened”) contacts.

• A vertical angulation (up-and-down positioning of the PID) of +10 degrees is recommended for bite-wings exposed with a tab to compensate for the slight bend of the upper portion of the receptor and the slight tilt of maxillary teeth.

• Five basic rules are followed in the bite-wing technique: (1) The receptor must cover the prescribed area of interest, (2) the receptor must be positioned parallel to the crowns of maxillary and mandibular teeth and stabilized by the tab or the beam alignment device, (3) the vertical angulation must be directed at +10 degrees for receptors using bite tabs, (4) the central ray must be directed through the contact areas between teeth for receptors using bite tabs, and (5) the x-ray beam must be centered over the receptor to ensure that all areas are exposed.

• Before receptor exposure using the bite-wing technique, the dental radiographer must complete infection control procedures, prepare treatment area and supplies, seat the patient, explain the procedures to the patient, make chair and headrest adjustments, place the lead apron on the patient, have the patient remove intraoral objects and eyeglasses, set exposure factors, and if using a beam alignment device, assemble the device over a covered work surface.

• When exposing bite-wing images only, the radiographer should always begin with premolar bite-wing exposures (easier for patients to tolerate and gagging less likely). Premolar exposures are followed by molar exposures.

• Premolar and molar bite-wing exposures have prescribed receptor placements (see Figures 19-16B, and 19-22B).

• Vertical bite-wing images can be used to examine the level of alveolar bone and are placed with the long portion of the receptor in a vertical direction. Vertical bite-wing images are often used as post-treatment exposures in the case of patients with bone loss due to periodontal disease.

• Modifications in the bite-wing technique may be necessary when a patient has edentulous spaces or bony growths.

Bibliography

ADA Council on Scientific Affairs. An update on radiographic practices: information and recommendations. J Am Dent Assoc. 2001;132:234.

Frommer, HH, Savage-Stabulas, JJ, Intraoral technique: The paralleling method. Radiology for the dental professional, ed 9, St. Louis, Mosby, 2011.

Johnson, ON, Thomson, EM, The bite-wing examination. Essentials of dental radiography for dental assistants and hygienists, ed 8, Upper Saddle River, Pearson Education, 2007.

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Miles, DA, Van Dis, ML, Razmus, TF. Intraoral radiographic techniques. In: Basic principles of oral and maxillofacial radiology. Philadelphia: Saunders; 1992.

White, SC, Pharoah, MJ, Intraoral radiographic examinations. Oral radiology: principles and interpretation, ed 6, St. Louis, Mosby, 2009.

Quiz Questions

Fill in the Blank

1. What does the term bite-wing refer to?

_____________________________________________

2. What size receptor is recommended for use with the bite-wing technique in the adult patient?

_____________________________________________

3. What size receptor is recommended for use with the bite-wing technique in the pediatric patient with primary dentition?

_____________________________________________

4. How is the patient’s head positioned before exposing a bite-wing receptor?

_____________________________________________

5. What condition is detected by the primary use of bite-wing images?

_____________________________________________

6. What size receptor is used to include all of the posterior teeth in one bite-wing exposure?

_____________________________________________

7. What type of angulation is determined by the up-and-down movement of the position-indicating device (PID)?

_____________________________________________

8. What type of angulation is determined by the side-to-side movement of the PID?

_____________________________________________

9. When the central ray of the x-ray is not directed through the contact areas of teeth, what is seen on the resulting image?

_____________________________________________

10. When does a cone-cut result?

_____________________________________________

Multiple Choice

________ 11. Which of the following describes the primary use of the bite-wing radiograph image?

a. examination of the apical areas of teeth

b. examination of the apical and interproximal areas of teeth

c. examination of the interproximal areas of teeth

d. examination of the pulp chambers of teeth

________ 12. Which of the following is the correct vertical angulation used with the bite-wing technique and the bite tab?

a.−10 degrees

b. −20 degrees

c. +10 degrees

d. +15 degrees

________ 13. Which of the following describes the relationship of the receptor to maxillary and mandibular teeth in the bite-wing technique?

a. The receptor and teeth are parallel to each other.

b. The receptor and teeth are at right angles to each other.

c. The receptor and teeth are perpendicular to each other.

d. The receptor and teeth intersect each other.

________ 14. Which of the following about receptor placement is correct?

a. Anterior bite-wings may be placed horizontally.

b. Anterior bite-wings may be placed vertically.

c. Posterior bite-wings may be placed horizontally.

d. Posterior bite-wings may be placed vertically.

1) a, b, and c

2) b, c, and d

3) b and c

4) a and d

________ 15. Which of the following about the exposure sequence for a CMRS that includes periapical and bite-wing exposures is incorrect?

a. anterior periapicals are always exposed first.

b. posterior periapicals are exposed after anterior periapicals.

c. bite-wings are exposed last.

d. none of the above.

Essay

16. State the basic principles of the bite-wing technique.

17. Describe the two ways to stabilize the receptor in the bite-wing technique.

18. State the basic rules of the bite-wing technique.

19. Discuss patient and equipment preparations necessary before using the bite-wing technique.

20. Discuss the exposure sequence for a CMRS that includes both periapical and bite-wing exposures.

21. Describe premolar and molar bite-wing placements.

22. Explain the modifications in the bite-wing technique that are used for patients with edentulous spaces or bony growths.

23. Describe why a +10-degree vertical angulation is used with the bite-wing technique and a bite tab.