The imaginary line extended through all the central developmental grooves of the posterior teeth is called which line?

• A. Plane of occlusion
• B. BO line
• C. LO line
• D. CF line

Answer: (D)

The line described is a central groove reference line. It’s formed by imagining a line that runs along the central development grooves of the posterior teeth and extending it across the arch. This CF line serves as a practical reference for evaluating how the posterior occlusal surfaces align and how the occlusal contacts distribute forces, which is helpful when assessing or adjusting the occlusion.

The plane of occlusion is a broader concept describing the overall occlusal reference plane, not a single line through the grooves. The other names listed aren’t standard references for the central groove line, so they don’t describe this specific concept.