How long does a dental bone graft heal on? How long for the hole to close up and the pain stop?

You would have been given after care procedure for your bone graft, if you did not, here it is and it also answers your question:

Recovery

After your dental bone graft, avoid hard or chewy foods until the area is cleared by your doctor. Because you need to avoid putting pressure on the area until the healing is well underway, you may not be able to wear dentures for a few weeks after the procedure. Avoid brushing the area until the incision has healed, and then brush lightly without pressure.

If you smoke, stop. Cigarette smoking slows the healing of wounds throughout the body and complicates dental procedures. People who smoke have a higher risk of bone graft failure.

It takes 6 to 12 months for your dental bone graft to heal completely. It may take more than one bone graft to build the bone up as much as necessary for the dentist to place an implant. Your dentist will see you for follow-up appointments to check on the healing of the bone graft site and perform x-rays to check on the status of the bone in the area. Sometimes, even if you do everything right, the bone graft fails. If your bone graft fails, the dentist will remove it and try again after the area has healed.

After Care for Dental Bone Graft | eHow.com