comparing immediate functionally loaded implants and immediate non functionally loaded implants in the posterior mandibular region on bases of bone density and bone loss evaluated by cone-beam computed tomography (CBCT).

Patients are more demanding after the revolution in immediate implant dentistry which reduces implant procedure nowadays according to literature and research. In response to patients' demands not only implants are immediately placed but also immediately loaded within 72 hours reducing the time for prosthetic loading and also improving bone formation according to some studies. The debate in modern implant dentistry is whether to immediately load the implants in functional occlusion or non-functional occlusion and which will improve the osseointegration and reduce crestal bone loss.

Implants of the BioInfinity system were placed in 16 subjects divided into two groups.

Group (A): 8 patients with missing posterior mandibular teeth whom will be rehabilitated with immediate functionally loaded implants.

Group (B): 8 patients with missing posterior mandibular teeth in whom immediate non-functionally loaded implants were used.

The two groups were evaluated at baseline, immediately after implant placement and 4 months postoperative to evaluate crestal bone level and quantitative radiographic bone density using CBCT.

Inclusion Criteria:

• Adult patients aged (20-40) years old.
• Missing Posterior tooth or teeth indicated for implant placement.
• Residual alveolar ridge at least 10 mm high and at least 4 mm wide.

Exclusion Criteria:

• Systemic diseases that will contraindicate the surgery.
• Poor Oral Hygiene.
• The patient refuses to undergo the surgery.
• Parafunctional habits.