Tooth discolouration can lead to intrinsic or extrinsic stains . intrinsic stains may be caused by tetracycline stain , excessive fluoride intake , pulp degeneration after tooth trauma and the presence of metallic restorative materials such as silver amalgam 外在變色是由于食物中的色素附在牙面上,形成斑漬,只要洗牙便可以清除這類斑漬。內(nèi)在變色的其中一個(gè)原因是在乳齒或恒齒的形成過(guò)程中,受到一些藥物例如四環(huán)素的影響。