Radiographic Interpretation and Common Errors

RADIOSGRAPHIC INTERPRETATION AND COMMON ERRORS

Acknowledgment

  • Institution: Charles Sturt University
  • Course: Bachelor of Oral Health (Therapy and Hygiene) DOH104
  • Cultural Acknowledgment: We pay our respect to all First Nations elders both past and present from the lands where Charles Sturt students reside. In particular, we acknowledge the Wiradjuri, Ngunawal, Gundungarra, and Biripai peoples of Australia, who are the traditional custodians of the land where Charles Sturt campuses are located.

Copyright Notice

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Common Errors in Radiographic Interpretation

  • Consequences of Errors:
    • Incorrect interpretation and diagnosis.
    • Unnecessary ionising radiation exposure.
    • Need for repeat radiographs.
    • Waste of time and financial resources.
  • Impact of Errors: Errors can lead to significant obstacles in diagnosis and patient care.

Types of Errors

  • Errors in radiographic interpretation can be categorized as:
    • Technique Errors
    • Exposure Errors
    • Processing Errors
    • Film Handling Errors
    • With the widespread use of digital photography, Exposure, Processing, and Film Handling errors have been minimized and are not a primary focus of today’s lecture.

Technique Errors

  • Categories of Technique Errors:
    • Patient Preparation: Poor preparation leading to diagnostic challenges.
    • Film Placement: Incorrect positioning can significantly affect the quality of the radiograph.
    • Projection Errors: Errors related to the beam direction and angulation.

Patient Preparation Errors

  • Common Issues:
    • Radiopaque objects superimposed on the image.
    • Solution: Remove objects before radiography, if possible.
    • Blurred images due to motion.
    • Solution: Minimize movement during exposure.

Exposure Errors

  • Common Exposure Errors:
    • Double Exposure: Occurs when the same film is exposed more than once without being processed in between.
    • Film Orientation Issues: Misalignment of the film can lead to diagnostic errors.
    • Density Errors: Issues with film density lead to images that are either too dark or too light.
    • Bent Films: Caused by improper handling, results in artifacts on the image.

Density Issues in Radiography

  • Definitions:
    • Increased Density:
    • This occurs when the phosphor plate is overexposed (e.g., using a molar setting for an anterior radiograph).
    • Decreased Density:
    • Occurs when the phosphor plate is underexposed or not exposed at all, as a result of decreased radiographic exposure time (e.g., using an anterior time setting for a molar radiograph) leading to an overall whiter image.

Film Placement Errors

  • Common Problems:
    • Errors due to incorrect vertical or horizontal dimensions.
    • Beam centering errors can lead to issues such as overlapping proximal surfaces or “cone cuts.”
  • Vertical Dimension Errors:
    • Elongated Images: Result from insufficient vertical angulation.
    • Foreshortened Images: Result from excessive vertical angulation. Frequently occur during bisecting angle technique, but can also occur during bitewing radiography.

Correct Techniques for Imaging

  • Bisecting Angle Technique:
    • If executed correctly: No projection errors should occur.
    • The central beam should be aimed perpendicular to the bisecting line of the tooth-receptor angle to maintain proportional relationships (Tooth length = Image length).
  • Upper Jaw Adjustments:
    • Adjust the angle if insufficient downward beam tilting occurs: Correct by increasing positive angulation.
  • Lower Jaw Adjustments:
    • Insufficient upward beam tilt: Correct by increasing negative angulation.

Foreshortening and Elongation Correction

  • Foreshortening:
    • Correct by decreasing positive angulation for upper jaw and negative angulation for lower jaw.
  • Elongation:
    • Resulting from excessive angles, adjustments include increasing positive or negative angulation accordingly.

Common Radiographic Findings

  • Radiographs serve as a diagnostic aid used in conjunction with clinical findings to help detect:
    • Caries/failed restorations.
    • Bone loss.
    • Calculus.
    • Periapical pathology.
    • Missing or extra teeth.
    • Impacted teeth.
    • Cysts, bony lesions, tumours.
    • TMJ issues, sinus problems.
    • Other dental anomalies.

Radiographic Structures to Assess

  • Important Structures:
    • Teeth.
    • Bone.
    • PDL space (Periodontal Ligament space).
    • TMJ (Temporomandibular Joint).
    • Other relevant anatomical features.

Dental Anomalies

  • Examples of dental anomalies visible on radiographs:
    • Presence of extra teeth or absence may be noted.
    • Novel findings such as ectopic eruption can be diagnosed through radiographs.

Classification of Radiographic Findings (ICCMS)

  • Radiographic analysis of caries includes:
    • Stages of Decay:
    1. Radiolucency in the outer half of enamel (initial stage).
    2. Radiolucency in the inner half of enamel, potentially reaching the enamel-dentin junction.
    3. Radiolucency limited to the outer third of dentin (moderate stage).
    4. Radiolucency reaching the middle third of dentin.
    5. Radiolucency reaching the inner third of dentin, cavitated.
    6. Radiolucency extending into the pulp, clinically cavitated.

Radiographic Interpretation Activities

  • Activity 1: Identify the teeth shown using FDI notation, and determine which have restorations and which require them.
  • Activity 2: Identify the carious teeth and devise a treatment plan for each carious lesion.
  • Activity 3: Assess what can be observed in a particular periapical radiograph.
  • Activity 4: Identify the teeth and surfaces where calculus is visible.
  • Activity 5: Research incidence of non-syndromic tooth agenesis.
  • Activity 6: Explore radiographic findings in specific cases.

References

  • Various empirical studies and online resources that provide supplemental information regarding radiographic interpretation, including:
    • White, S.C., & Pharoah, M.J. (2009). Oral radiology principles and interpretation (6th ed.). Philadelphia, PA: Mosby.
    • Relevant articles on dental diagnostics and tooth development.