Facial and lingual proximal clearance may be less than 0.5 mm when breaking contact would require excessive removal of sound tooth structure. Which statement is true?

• A. False
• B. True
• C. Sometimes true
• D. Not applicable

Answer: (B)

Proximal clearance on the facial and lingual sides of a posterior cavity is the small gap needed to allow proper condensation and to recreate a clean contact with the adjacent tooth. While aiming for about 0.5 mm, there are times when breaking the contact would require removing a lot of sound tooth structure. In those cases, preserving tooth structure takes priority, so the clearance may be less than 0.5 mm. This approach keeps the tooth stronger while still allowing a functional restoration with careful matrix placement and carving to establish an acceptable contact. Therefore, the statement is true.