What does the acronym 'SLOB' stand for in dental radiography for locating objects in three dimensions?

SLOB stands for Same Lingual, Opposite Buccal. This rule (also called Clark's rule) is used in dental radiography to determine the buccolingual position of an object (such as a root or calcified canal) using two radiographs taken with the x-ray tube shifted horizontally. If the tube shifts mesially and the object appears to move in the same direction (mesially), the object is lingual. If the object moves in the opposite direction (distally), the object is buccal. This technique is particularly useful in endodontics for identifying the position of additional canals and for determining root positions in impacted teeth.