63颗前牙金属烤瓷冠粘戴后基牙游离龈变色的临床观察

目的：了解前牙金属烤瓷冠粘戴后基牙游离龈变色的特点。方法：肉眼观察６３颗前牙在修复前后游离龈的色泽变化。结果：修复前１２颗死髓变色基牙游离龈轻度变色。修复后，２３颗活髓基牙游离龈轻度变色，其中包括９颗用瓷肩台形式金属烤瓷冠修复的基牙、４颗游离龈重度变色；１１颗死髓基牙游离龈轻度变色，２５颗游离龈重度变色，１２颗死髓变色基牙均为重度变色。结论：由于游离龈的光透过性及金属基底冠对牙根的阻光作用，基牙游离龈变色是一种不可避免的可逆光学现象。死髓变色基牙游离龈变色较重，瓷肩台形式的金属烤瓷冠有助于减轻这种游离龈变色。

CLINIC OBSERVATION ON DISCOLORATION IN FREE GINGIVA OF 63 ANTERIOR ABUTMENTS AFTER CEMENTING OF PORCELAIN FUSED TO METAL CROWN

Objective:To study the discoloration of anterior abutment free gigniva after cementing of porcelain fused to metal crown.Methods:63 anterior abutment free gingiva were observed with naked eye before and after restoration.Results:Before restoration,only 12 non vital darkened abutments showed slight gingival discoloration.After restoration,23 vital abutments appeared slight gingival discoloration,including 9 vital abutments restored by porcelain fused to metal crown with full circular procelain shoulder and 4 vital abutments appeared severe gingival discoloration;11 non vital abutments appeared slight gingival discoloration,25 appeared severe gingival discoloration;12 non vital darkened abutments all appeared severe discoloration.Conclusion:This phenomenon is of reversible and inevitable optical nature because of the light transmission of the free gingiva and the existence of metal base crown which blocks the lights from the internal tooth structure and darkens the root.Non vital darkened abutment has more severe gingival discoloration.Porcelain fused to metal crown with full circular porcelain shoulder helps to reduce this phenomenon.