Comprehensive Guide to Occlusal Radiographic Imaging and Clinical Application and Technique

An occlusal image is a specific type of intraoral radiograph used in dental practice.
Frequency of Use: These are relatively rare and not used as frequently as other intraoral images مانند bitewings or periapical (PA) radiographs.
Characteristic: It serves as a cross between an OPG (orthopantomogram) and a standard intraoral radiograph.
Sensor Selection:
- Size 4 sensor: Often preferred to capture the broadest area.
- Size 2 sensor: May be used for pediatric patients or individuals with limited tolerance.
- Choice is dependent on the patient's age and their capacity for compliance.

Occlusal images are essential diagnostic tools for specific circumstances where localizing structures is a priority:

Localization of Objects:
- Locating misplaced or unerupted teeth.
- Identifying and locating foreign bodies within the jaw or soft tissues.
Evaluation of Trauma and Development:
- Evaluating root fragments following dental trauma.
- Identifying supernumerary (extra) teeth.
- Monitoring unerupted or impacted teeth (e.g., impacted premolars).
Pathological Assessment:
- Evaluating the extent of cysts or other disease aspects in the maxillary or mandibular regions.
- While larger lesions might require an OPG, occlusal views offer a specific localized perspective.

Despite their utility in localization and viewing hard tissue structures, occlusal images have significant diagnostic limitations:

Caries Diagnosis: These images do not provide the fine detail required for accurate caries detection; clinicians must rely on bitewing or periapical radiographs for this purpose.
Periodontal Disease: Occlusal films are considered "lousy" for evaluating periodontal bone loss.
Periapical Lesions: If a periapical lesion is suspected, a standard periapical (PA) film is the mandatory diagnostic tool rather than an occlusal film.

Definition: A mesiodens is the most common type of supernumerary tooth.
Location: It is located in the midline (mesio-middle; dens-tooth) of the maxilla.
Presentation:
- Generally presents around the time of the emergence of maxillary central and lateral incisors.
- Often appears conical in shape.
Clinical Impact:
- Mesiodens can prevent the normal eruption process of the central or lateral incisors.
- Because teeth typically present in pairs, the failure of one central incisor to erupt while the other has emerged should prompt a search for a mesiodens.
Radiographic Appearance: Often visible in a mixed dentition scenario where permanent teeth have not yet fully erupted and show open apices.

Proper angulation of the central X-ray beam (collimator) is critical for capturing the intended anatomical area.

Vertical Angulation: Approximately $-55^\circ$ .
Patient Positioning: The patient bites down on the sensor, and their head is tilted back to allow access.
Beam Direction: The central ray is aimed through the patient's midline (midsagittal plane) to ensure an even spread of tissue is captured.
Mental Visualization: The clinician should follow the straight line of the beam with their eye or finger to ensure it encompasses the target teeth.

Vertical Angulation: Approximately $+65^\circ$ .
Area of Interest: Specifically identifies the premaxilla and the anterior third of the maxilla.
Patient Safety: A thyroid collar should be used for this procedure due to the placement and angulation of the collimator.
Midsagittal Plane: The beam must be directed through the midsagittal plane.
Common Errors: Placing the collimator too high will miss the anterior teeth and focus on the nasal/mid-facial structures, creating a messy image that is difficult to interpret.

Patient Positioning: Requires the patient to tilt their head significantly far back.
Clinical Difficulty: This procedure is often difficult for patients to tolerate in a clinical setting compared to a preclinic mannequin, as it may trigger a gag reflex.
Primary Use: Viewing hard tissue structures and identifying radiolucencies or restorations, though not for specific caries diagnosis.

Emergence Patterns: Clinicians must be familiar with eruption and emergence dates to identify delays caused by obstructions like supernumerary teeth.
Root Development: In young children (e.g., around the time of central incisor emergence), roots may only show approximately $⅔$ emergence on a radiograph.
Growth Studies: Occlusal imaging is frequently used in growth studies, such as those conducted by Dr. Liu.

Sensor Inadequacy: Using a sensor that is too small (e.g., a size 2 plate in an adult for trauma) can lead to the loss of critical information, such as the view of the root apices (APC).
Corrective Actions: If an occlusal image fails to provide the necessary detail or misses the area of interest, the clinician should prescribe:
- A Periapical (PA) radiograph.
- An OPG (orthopantomogram), provided the patient can tolerate it.

Reference Textbook: "Oral Radiology: Principles and Interpretation" by Pharaoh and White.
Students are encouraged to read the specific chapter on occlusal imaging available on the Canvas course page.