DEN 130 1 H - Dental Radiology- 41

Intraoral Imaging Notes

Chapter 41

Introduction

  • Quality Dental Images: Every dental assistant can produce quality dental images, characterized by:

    • Lack of distortion.

    • Correct density and contrast suitable for detecting dental diseases.

  • Steps for Creation: Proper adherence to steps in image receptor placement, exposure, and processing is crucial for image creation.

  • Diversified Patient Pool: Patients will have varied sizes, physical and mental abilities, dentition types, and personalities. Modifications in technique might be needed for:

    • High and narrow palate.

    • Sensitive gag reflex.

Full-Mouth Survey (FMX)

  • Importance of Images: A complete dental examination requires dental images, with the full-mouth survey being the preferred method.

  • Components of FMX: An intraoral full-mouth survey contains:

    • Periapical images.

    • Bitewing images.

  • Image Count for Adults: For average adults, a typical FMX consists of:

    • 18 to 20 images.

    • Generally, 14 periapical views and 4 to 6 bitewing views.

    • Note: Number may vary based on dentist preference and number of teeth present, particularly in the anterior region.

The Bitewing Image

  • Purpose of Bitewing View: This view displays upper and lower teeth in occlusion and is utilized to detect:

    • Interproximal decay.

    • Periodontal disease.

    • Recurrent decay under restorations.

    • The fit of metallic fillings or crowns.

The Periapical Image

  • Scope of Periapical View: Shows the entire tooth from the occlusal surface or incisal edge, extending about 2-3 mm beyond the apex to include periapical bone.

  • Use in Diagnosis: Periapical images are used for:

    • Diagnosing conditions affecting the tooth, root, and bone, including tooth formation and eruption.

    • Essential in endodontics and oral surgery procedures.

Intraoral Imaging Techniques

  • Basic Techniques:

    • There are two basic techniques for obtaining periapical images:

    • The paralleling technique.

    • The bisecting technique.

  • Recommendations: The American Academy of Oral and Maxillofacial Radiology and the American Association of Dental Schools advocate for the paralleling technique due to:

    • Accuracy of images.

    • Lower radiation exposure to patients.

  • Situational Use of Bisecting Technique: Usage may be required for patients with specific anatomical considerations such as:

    • Shallow mouth.

    • Shallow palate.

    • Presence of tori.

The Paralleling Technique: Five Basic Rules

  1. Image Receptor Placement: Ensure the receptor covers the correct teeth.

  2. Image Receptor Position: Should be parallel to the long axis of the tooth.

  3. Receptor Distance: The holder should place the receptor away from the teeth towards the middle of the mouth.

  4. Vertical Angulation: Direct the central ray of the x-ray beam perpendicular to both the receptor and the long axis of the tooth.

  5. Horizontal Angulation: Ensure the central ray of the beam is directed through the contact areas between teeth.

  6. Central Ray Positioning: The x-ray beam must be centered on the receptor to ensure full exposure.

Patient Preparation

  • Seated Procedure: Ensure the patient is seated after room preparation and adherence to infection control protocols.

Exposure Sequence for Image Receptor Placement

  • Planning the Sequence: Establishing an exposure sequence minimizes errors such as omitting areas or re-exposing the same area.

  • Digital Imaging Advantage: Direct digital imaging displays the most recently exposed image on the computer screen, simplifying this task.

Anterior Exposure Sequence

  • Start with Anterior Teeth: Begin exposure with anterior teeth (canines and incisors) because:

    • Smaller size of anterior receptor (#1) is more tolerable.

    • Anterior holder is more easily adapted by patients.

    • Lower likelihood of triggering gag reflex.

  • Recommended Sequence Using Rinn XCP Instruments:

    • Start with the maxillary right canine (tooth 6).

    • Proceed with maxillary anterior teeth until maxillary left canine (tooth 11) is reached.

    • Move to mandibular arch, starting at mandibular left canine (tooth 22), finishing with mandibular right canine (tooth 27).

Posterior Exposure Sequence

  1. Order of Views: Begin with premolar views before molar views due to:

    • Greater patient tolerance for premolar placements.

    • Reduced chances of eliciting gag reflex during premolar exposure.

    • Total placements comprise eight posterior images: four for the maxillary and four for the mandibular.

  2. Specific Steps for Maxillary Right Quadrant:

    • Assemble posterior XCP for this area.

    • First expose the premolar view (teeth 4 and 5), then molar view (teeth 1, 2, and 3).

  3. Continue to Mandibular Left Quadrant:

    • Expose premolar view (teeth 20 and 21) first, followed by molar view (teeth 17, 18, and 19).

  4. Complete the Sequence:

    • Move to the maxillary left quadrant, reassemble XCP, and expose premolar (teeth 12 and 13) first, then molar (teeth 14, 15, and 16).

    • Finish with mandibular right quadrant, beginning with premolar (teeth 28 and 29) and concluding with molar (teeth 30, 31, and 32).

Guidelines for Film Placement

  • Film Orientation:

    • The white side of the film faces teeth.

    • Anterior films are vertical; posterior films are horizontal.

  • Identification Dot: Place the dot in the slot of the holder.

  • Positioning: The film holder should be away from the teeth towards the mouth’s center, centered over the areas to be examined and parallel to the long axes of the teeth.

Bisecting Technique

  • Concept: Bisection of the angle technique is based on geometrically dividing a triangle, opposing the paralleling technique where the receptor is parallel to the tooth.

  • Angle Formation: The angle between the tooth's long axis and the receptor is bisected, directing the x-ray beam perpendicularly to this bisecting line.

  • Limitation: This technique may cause dimensional distortion in the resultant image.

Image Receptor Holders for Bisecting Technique

  • Common Holders: :

    • BAI (bisecting-angle instrument; Dentsply Rinn).

    • Stabe bite-block (Dentsply Rinn).

    • EeZee-Grip holder (Dentsply Rinn, formerly Snap-A-Ray).

  • Patient Holding: Not recommended for patients to hold their own film, as it exposes their hand and fingers to radiation.

Angulation of Position Indicator Device

  • Critical Angulation: Angulation refers to aligning the x-ray beam's central ray in horizontal and vertical planes, adjusted by moving the PID accordingly.

Horizontal Angulation

  • Definition: Positioning the tubehead and directing the central ray in a horizontal plane, remains constant between techniques.

  • Correct Angulation: Ensures central ray is perpendicular to the arch curvature and through tooth contact areas.

  • Incorrect Angulation Consequences: Results in overlapped contact areas that are unusable for interproximal examination.

Vertical Angulation

  • Definition: Positioning the PID vertically, varying with techniques:

    • Paralleling: perpendicular to both the receptor and tooth long axes.

    • Bisecting: perpendicular to the imaginary bisector.

    • Bitewing: predetermined at +10 degrees to the occlusal plane.

  • Implications of Incorrect Angulation:

    • Images that are not true to tooth length appear either elongated or foreshortened.

    • Foreshortened from excessive angulation.

    • Elongated from insufficient angulation.

Image Receptor Size and Placement in Bisecting Technique

  • Receptor Position: Close to crowns, angled towards palate or mouth floor, extending beyond the incisal/occlusal edge by about 1/8 inch.

  • Commercial Holders: Film holders with alignment indicators are available.

Patient Positioning

  • Midsagittal Plane: Should be perpendicular to the floor for ideal positioning, with maxillary films requiring the head tipped back slightly.

  • Receptor Size Usage: Size #2 receptors for both anterior (vertical) and posterior (horizontal) placements.

    • For wide arches, three films suffice for maxillary anterior; for narrow arches, four #1 films may be necessary.

Beam Alignment

  • Beam Direction: Must pass through contacts of the teeth as in paralleling, with the vertical angle directed at 90 degrees to the bisecting line.

  • Angulation Issues:

    • Excessive vertical produces foreshortened images.

    • Insufficient vertical results in elongated images.

  • Centering: Beam must be centered to prevent cone-cutting.

Bitewing Technique

  • Purpose: Shows crowns and interproximal areas of teeth and crestal bone levels for caries detection and assessment.

  • Basic Principles:

    • The receptor is parallel to both upper and lower teeth crowns.

    • Stabilization through patient biting on the bitewing tab or holder.

    • Central ray directed through contacts at +10 degrees of vertical angulation.

Image Receptor Holder and Bitewing Tab

  • Stabilization: Use of a holder or tab for bitewing technique, with red being the universal color for bitewing holders from Rinn.

Angulation of Position Indicator Device in Bitewing Technique

  • Importance of PID Angulation: Correct angulation crucial for successful bitewing exposures.

Exposure for Image Receptor Placement

  1. Always Parallel Views: Bitewing images must be parallel regardless of periapical technique used.

  2. Number of Films:

    • Depends on arch curvature and posterior teeth presence.

    • Two views typically required for both sides of the arch due to curvature variance.

  3. Total Bitewing Exposures:

    • Four films generally include one right premolar, one right molar, one left premolar, and one left molar.

Learning Objectives Lesson 41.3: Occlusal Technique, Special Dental Needs, and Mounting Radiographs

  • Explain techniques for exposing occlusal radiographs and managing patients with special medical and dental needs.

  • Discuss the common imaging errors and methods for mounting radiographs.

Occlusal Technique

  • Purpose: Used for examining large jaw areas.

  • Film Size: In adults, size #4 is used; size #2 for children.

Occlusal Images

  • Applications: Used to:

    • Locate retained roots of extracted teeth.

    • Identify supernumerary or impacted teeth.

    • Find salivary stones in submandibular glands.

    • Detect fractures of the maxilla/mandible.

    • Assess cleft palate area.

    • Measure changes in both jaws' size and shape.

Basic Principles of the Occlusal Technique

  • Film Positioning: Film should face the arch with the white side exposed, positioned between maxillary and mandibular teeth occlusal surfaces and stabilized by patient's closure.

Patients with Special Medical Needs

  • Technique Modifications: Radiographic examination may require modifications based on individual needs, including:

    • Physical disabilities (vision, hearing, mobility).

    • Ensure adequate communication with caregivers or aides present.

Developmental Disabilities

  • Definition and Examples: Substantial impairment occurring before adulthood, lasting indefinitely. Examples include autism and cerebral palsy.

  • Challenges: Patients may have coordination or comprehension difficulties, and intraoral views may need alternative methods (e.g., extraoral images) due to tolerability issues.

Patients with Special Dental Needs

  • Modifications may be necessary for:

    • Edentulous patients.

    • Endodontic patients.

    • Pediatric patients.

Edentulous Patient Considerations

  • Reasons for Imaging:

    • For detecting retained root tips, identifying bone lesions and objects.

    • Assess bone health and quantity.

  • Radiographic Selection: Panoramic, periapical, or combinations should be considered

    • Instruments accommodating missing teeth positions should incorporate cotton rolls for receptor stability.

Pediatric Patient Considerations

  • Usefulness of Imaging: Essential for assessing tooth and bone conditions, caries progression, and growth evaluation.

  • Explanation for Children: Use relatable terms to explain procedures and reduce exposure factors due to their size.

Endodontic Patient Imaging

  • Challenges in Imaging: Difficulties arise from clamps, instruments, or filling materials obstructing visibility during procedures.

  • Use of EndoRay II Holder: Facilitates film positioning around clamps and instruments.

Gagging Patient Management

  • Preventive Techniques: Convey confidence to reduce gag reflex; be patient and understanding to build tolerance over time.

  • Exposure Sequencing: Anterior imaging first; follow with premolar exposures before molar; for sensitive patients, finish with maxillary molars last.

  • Placement Techniques: Minimize palate contact during maxillary posterior placements; demonstrate placement to alleviate concerns.

  • Extreme Cases: For patients with uncontrollable gag reflex, opt for extraoral radiographs.

Dental Imaging Technique Errors

  • Quality Requirements: Diagnostic radiographs must be properly placed, exposed, and processed.

  • Consequences of Errors: Incorrect techniques can produce nondiagnostic films requiring re-exposure, increasing radiation exposure.

Mounting Dental Radiographs

  • Anatomical Landmark Recognition: Recognizing landmarks is critical for proper mounting in anatomical order for diagnostic evaluations.

  • Labeling: Every mount must be labeled with patient's name, date of exposures, dentist’s name, as well as additional identifiable information.

Selecting the Mount

  • Mount Options: Available sizes and styles must fit the patient’s radiographic survey sizes, commonly available in black, gray, and clear plastic.

Methods of Mounting

  • Two Primary Methods:

    • Labial Mounting: Films are placed with raised dots facing up, facilitating viewing as if looking at the patient directly; the patient's left is on the viewer's right.

    • Lingual Mounting: Films face down, viewed as if from within the mouth, with left and right sides mirrored accordingly.

Guidelines for Mounting Radiographs

  • Procedures:

    • Handle images by edges only.

    • Label and date films before mounting.

    • Work with clean hands, applying a defined order for film mounting.

    • Use “smile” line as a guide for bitewing radiographs.

Portable Imaging

  • Innovation: FDA-approved portable battery-powered units for direct patient use, featuring internal shielding for operator safety; usage varies by state regulations.