Plenty of studies to show that now most of the shears because you are nicely custom fit hole the cement shears and none gets to the tip now the biggest problem in some of the D bonding's. Are a result of just inadequate technique I find it interesting that as dentists we give great time and expertise to capturing a 3 mm sulcus on her crown prep than we do a 10 mm whole. That we can see the bottom right so a lot of it same with implants in what there's only one way you can do a post if you can get the edge into the bottom of the canal than you're not going. To be able to rinse it out either University of Alabama again to the study with faculty showing that with a manufacturers etchant and they took five different companies with. Their tip and a 10 mm canal none of the faculty or restorative faculty got the etchant to the bottom of the canal further when they rinsed it using their usual technique in her water syringe.