Weinstein T, Goldman M
Oral Surg Oral Med Oral Pathol. 1977 Apr;43(4):627-30. doi: 10.1016/0030-4220(77)90119-0.
The anterior teeth of five adult monkeys were divided into two groups. In one group the pulps were removed and the teeth were left open to oral fluids. The other group had vital pulps. Five teeth were designated as controls. The pulp canals of both groups were debrided, filed, and flushed thoroughly. In the two experimental groups (vital and pulpless), the apical third of the canal was filled with Ca(OH)2. In the control group no medication was placed in the canal. The coronal access of the canals of all groups was sealed with amalgam. After 270 to 330 days, the teeth were sectioned and examined histologically. No apical bridging was observed in any group.
五只成年猴子的前牙被分为两组。一组去除牙髓，牙齿暴露于口腔液体中。另一组牙髓活力正常。指定五颗牙齿作为对照。两组的牙髓腔均进行清创、锉磨并彻底冲洗。在两个实验组（牙髓活力正常和无牙髓）中，根管的根尖三分之一用氢氧化钙填充。对照组根管内未放置药物。所有组根管的冠部入口均用汞合金封闭。270至330天后，将牙齿切片并进行组织学检查。任何一组均未观察到根尖桥接。
