In dental radiography, the SLOB rule is used to determine the buccal-lingual position of objects. What does SLOB stand for?

The SLOB rule (also called Clark's rule or the tube shift technique) helps determine the buccal-lingual position of objects in the jaw: When the X-ray tube is shifted horizontally, an object that moves in the SAME direction as the tube shift is LINGUAL; an object that moves in the OPPOSITE direction is BUCCAL. 'SLOB: Same Lingual Opposite Buccal.' This is critical in endodontics for locating the MB2 canal of maxillary first molars, identifying impacted teeth, detecting supernumerary teeth, and locating foreign bodies or root canal instruments. The tube shift technique requires two radiographs taken at different horizontal angulations.