@Mounir Mallek: I’m not sure what you mean by removing Bone without damaging Live tissues. Clearly bone is a live tissue. So, are you talking about accessing the apex without damaging adjacent teeth and roots? If that’s the question then the answer is really studying the preoperative CBCT and radiograph and looking at bony eminences on the alveolar bone and looking at the CEJ and the placement of entry of the root into the alveolar process. The rest is having perceptual ability and knowing your anatomy.
The second question is I usually prescribe some anti-swelling medications and for pain they need mostly NSAIDs. Antibiotics are recommended if a patient is immune compromised or vital structures were exposed (sinus, etc.) Otherwise, most healthy people don’t need antibiotic coverage and heal normally. But I do prescribe Chlorohexidine oral rinse for 5 days post op.

@Mounir Mallek: that’s the whole surgery course I teach at our school and is hard to answer in a comment. But the key is the handpiece, water port, and then the motion. Most importantly to not torque and heat up the bone. This way it has a chance to regenerate once the source of infection is addressed through a proper apico and retrofilling procedure. My favorite bur for this is the Lindaman Bur and a surgical round #6. I’m a minimalist whenever possible. 🙂