The 2mm twist drill will be taken to the desired depth and a directional guide will be placed into the site. The second site is then prepared with the same 2mm twist drill to the desired depth. How deep do you go? Generally as deep as you can up to 15mm in length. anything past 15mm might be considered overkill in this situation and I rarely use longer implants than 15mm. If I get into the inferior cortical bone, so much the better, but I try to avoid going all the way through the inferior border...