A18 year old male patient,Mesial lesion in relation to 26.Mesial and distal amalgam restorations with marginal deterioration.Discoloured Palatal groove.

• 18岁男性患者，26号牙齿的牙冠中面出现缺损，中面及远中面的汞合金修复出现边缘恶化现象。上颚沟变色。