What action best achieves a smooth, flush margin after finishing?

• A. Leave margins rough to save time.
• B. Polishing only the occlusal surface.
• C. Extend margins onto the gingiva.
• D. Ensure margins are smooth and flush with surrounding tooth structure.

Answer: (D)

Achieving a smooth, flush margin is essential for a good marginal seal and proper adaptation of the restoration. When margins are smooth and flush with the surrounding tooth structure, the interface between the tooth and amalgam is continuous, reducing gaps where bacteria can penetrate and where plaque can accumulate. This helps prevent microleakage, sensitivity, recurrent decay, and periodontal irritation, and it supports the longevity of the restoration. Extending margins onto the gingiva creates inflammation and compromises access and fit, so that option is detrimental. Polishing the occlusal surface alone neglects the critical finishing of the margins themselves, leaving irregularities that can harbor plaque or cause leakage. Leaving margins rough just to save time directly undermines the seal. Therefore, the best action is to finish and polish so that margins are smooth and flush with the surrounding tooth structure.