Orkin D A, Reddy J, Bradshaw D
J Prosthet Dent. 1987 Apr;57(4):421-4. doi: 10.1016/0022-3913(87)90006-0.
A survey was conducted of 423 crown margins that were divided into 355 subgingival margins and 68 supragingival margins. The plaque index, gingival bleeding, and recession surrounding the artificial crown were recorded and compared to the unprepared contralateral tooth. Gingival tissues tended to bleed 2.42 times more frequently with subgingival margins and have a 2.65 times higher chance of gingival recession. Crowns with supragingival margins did not differ significantly compared with the contralateral tooth, but crowns with subgingival margins had greater bleeding and recession compared with the contralateral tooth. It is recommended that supragingival margins become standard clinical procedures when feasible. A further analysis will be instituted to determine whether different crown materials affect the gingivae.
对423个牙冠边缘进行了一项调查，这些牙冠边缘被分为355个龈下边缘和68个龈上边缘。记录了人造牙冠周围的菌斑指数、牙龈出血情况和牙龈退缩情况，并与未预备的对侧牙齿进行比较。龈下边缘的牙龈组织出血频率往往是对侧牙齿的2.42倍，牙龈退缩的几率是对侧牙齿的2.65倍。龈上边缘的牙冠与对侧牙齿相比无显著差异，但龈下边缘的牙冠与对侧牙齿相比有更多的出血和退缩。建议在可行的情况下，龈上边缘成为标准临床操作。将进行进一步分析以确定不同的牙冠材料是否会影响牙龈。
