120 teeth with wedge-shaped defects at subgingival depth of 0 ~2 mm were selected and divided into 3 groups(n =40).Gingival retraction code and EXPASYL gingival retraction paste were used for gingival retraction in the 2 retraction groups,and none retraction was used in the control group.After restoration of the defects,all cases were followed up for 1 year and 2 years.The results were evaluated by modified USPHS criteria.No significant difference was detected for 1 year and 2 year successful rates between the extraction groups(P >0.05).The successful rate in extraction groups was higher than that in the control group(P <0.05).%选择楔状缺损颈部边缘位于龈下0～2 mm 内、较难充填的活髓患牙120颗，分3组（n ＝40）：I 组：排龈线排龈；II 组：排龈膏排龈；III 组：对照组，直接充填。充填后1、2年复查，以改良的 USPHS 直接临床评价系统评估疗效。修复1年及2年后实验组和对照组成功率差异均有显著性，实验组之间成功率差异无显著性。
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