What is the most likely anatomic cause of the clinical findings at No. 8 and No. 9?

Question

Quizplus · Accepted Answer

The prominent V-shaped curvature of the CEJ and the narrower lingual surfaces of the maxillary central incisors make proximal access from the lingual approach easier than from the facial. The prominent curvature of the CEJ incisally on the mesial surface of No. 8 and No. 9 contributes to the inability to fully explore and identify calculus and contributes to the inability to adapt scaling instruments, thereby leaving or partially removing calculus. Residual calculus and incomplete plaque removal contribute to the clinical findings and tissue changes at No. 8 and No. 9, which include papillary and marginal erythema and edema and increased bleeding on probing.

What Is the Most Likely Anatomic Cause of the Clinical