Radiology · single question
What rule determines the position of objects at DIFFERENT angles in a radiograph?
Show answer and explanation
Correct answer: A. SLOB Rule (Same Lingual, Opposite Buccal)
SLOB Rule (A): Same Lingual, Opposite Buccal. When the X-ray tube is shifted horizontally, objects move in relation to each other on the radiograph:
• If the tube shifts and the object moves in the SAME direction as the tube shift → the object is located LINGUAL
• If the tube shifts and the object moves in the OPPOSITE direction → the object is BUCCAL
• Also called Clark's Rule or the buccal object rule.
• Clinical applications: locating supernumerary teeth (mesiodens), determining the position of impacted canines, locating root canal curvature, finding foreign bodies.
• Example: maxillary canine localization for impaction — shift the X-ray tube; if the canine moves the same direction as the tube → palatal impaction.
• If the tube shifts and the object moves in the SAME direction as the tube shift → the object is located LINGUAL
• If the tube shifts and the object moves in the OPPOSITE direction → the object is BUCCAL
• Also called Clark's Rule or the buccal object rule.
• Clinical applications: locating supernumerary teeth (mesiodens), determining the position of impacted canines, locating root canal curvature, finding foreign bodies.
• Example: maxillary canine localization for impaction — shift the X-ray tube; if the canine moves the same direction as the tube → palatal impaction.