The L-PRF block is a combination of bone substitute with L-PRF. The use of a L-PRF block in bone augmentation therapies could enhance and improve bone regeneration.

The primary objective of this study is to evaluate if the use of autologous leukocytes and platelet rich fibrin accelerate and promotes bone regeneration in the sinus in comparison with the standard sinus lift procedure procedure.

This is a randomized controlled clinical trial. A total of 24 patients, needing sinus lift with lateral window technique (L), will be enrolled. All patients have to fulfil all of the inclusion and none of the exclusion criteria. Written informed consent will be obtained prior to any examination carried out for study purposes. Randomization will be performed using sealed, sequentially numbered, opaque envelopes containing treatment allocation.

Under local anaesthesia, the required L will be performed. Once the blood extraction is done the surgery can start following the normal procedure for the lateral approach of sinus floor elevation. Once the preparation of the sinus floor elevation is done the randomization envelopes will be open and the selected treatment will be applied. For the test group the sub-sinus cavity will be filled with L-PRF block and the window will be closed with L-PRF membranes. For the control group the sub-sinus cavity will be filled with only DBBM and the window will be closed with a collagen membrane. Afterwards suturing will be conducted and a CBCT will be taken for control and observation.

After 6 months the subjects return for a check-up of the healing process. A CBCT will be taken to assess the bone regeneration. Implant surgery will be discussed.

With a crestal incision the implant site will be exposed. The drilling will be performed according to implant protocol and the implant will be placed. Follow-up will be till 5 year.

Inclusion Criteria:

• Males and females ≥ 18 years of age.
• Ability to understand the nature of the proposed surgical procedure and sign an informed consent form.
• ASA I and ASA II.
• In need of an implant in the posterior region of the maxilla,
• RBH of <4 mm or RBH >4 mm but no transcrestal approach possible (due to anatomy).
• Healthy oral mucosa and no active periodontal disease.
• Edentulous sites consisting of native, non-augmented bone.

Exclusion Criteria:

• General contraindications for implant placement and/or surgical treatment.
• Acute infection or residual lesions in the edentulous sites.
• Acute maxillary sinus pathosis.
• Ongoing inflammatory and/or autoimmune diseases of the oral cavity.
• Patients with poor oral hygiene who are not amenable to improvement.
• Immunosuppressants, corticosteroids, or bisphosphonate
• History of malignancy, radiotherapy, or chemotherapy for malignancy within the past five years.
• Smoker > 10 cigarettes.
• Uncontrolled insulin-dependent diabetes.
• Pregnant or lactating women.
• Alcohol and drug abuse.