In periapical radiography, which vertical angulation error most commonly produces an elongated root image?

In periapical radiography, which vertical angulation error most commonly produces an elongated root image?

• A. Insufficient vertical angulation
• B. Beam perpendicular to the tooth crown
• C. Excessive vertical angulation (tilting the beam too far from the tooth apex)
• D. The receptor too close to tooth

Answer: (D)

When taking a periapical radiograph, image shape depends on how the tooth, receptor, and X-ray beam align in the vertical plane. An elongation of the root image happens when the geometry causes the projection to stretch the tooth along the image, typically from not directing the beam sufficiently toward the apex. If the receptor is placed very close to the tooth, small misalignments in vertical angulation have a larger effect on how the tooth is projected onto the film, making the root appear longer than it actually is. Other factors—like tilting the beam too far for foreshortening, or directing the beam perpendicular to the crown—lead to different distortions, not this elongation pattern.

When taking a periapical radiograph, image shape depends on how the tooth, receptor, and X-ray beam align in the vertical plane. An elongation of the root image happens when the geometry causes the projection to stretch the tooth along the image, typically from not directing the beam sufficiently toward the apex. If the receptor is placed very close to the tooth, small misalignments in vertical angulation have a larger effect on how the tooth is projected onto the film, making the root appear longer than it actually is. Other factors—like tilting the beam too far for foreshortening, or directing the beam perpendicular to the crown—lead to different distortions, not this elongation pattern.