What does the SLOB rule stand for?

• A. Same-Lingual, Opposite-Buccal
• B. Same-Lingual, Same-Buccal
• C. Opposite-Lingual, Opposite-Buccal
• D. Opposite-Lingual, Same-Buccal

Answer: (A)

The SLOB rule is about using parallax in dental radiography to determine whether a neighboring tooth is lingual or buccal to the reference tooth. It stands for Same-Lingual, Opposite-Buccal. When you adjust the horizontal angulation of the X-ray beam, the image of the tooth on the lingual side moves in the same direction as the beam shift, while the tooth on the buccal side moves in the opposite direction. So if a tooth’s image moves with the beam shift, it’s on the lingual side; if it moves opposite, it’s buccal. This behavior is what the correct option describes, whereas other descriptions don’t match this observed parallax pattern.