This is a non-inferiority study to evaluate whether L-PRF achieves similar or perhaps better results in bone gain, compared with "the golden standard" DBBM, after trans-crestal sinus floor elevation.

This is a randomized controlled clinical trial with parallel group design. A total of 40 patients, needing transcrestal sinus lift (T), will be enrolled.

Under local anesthesia, the required T and implant placement will be performed and ISQ values will be recorded. Afterwards a CBCT will be taken for control. Randomization will be performed by computer generated random codes, using random permuted blocks with a block size of 4 to avoid uneven splits and minimization for the key prognostic factors RBH. Allocation will be concealed to the surgeons at completion of the common part of treatment, by opening an opaque envelope. At the same time an oral implant(s) will be inserted in the augmented area.

After 6 months a CBCT will be taken for control of the bone healing and the measurements of the newly formed bone. The abutment will be placed on top of the osseo-integrated implant(s) under local anesthesia. ISQ values will be recorded. Follow-up will be till 1 year.

Inclusion Criteria:

• Provision of informed consent
• Need for T and oral implant placement.
• RBH >3mm

Exclusion Criteria:

• Unlikely to be able to comply with the study procedures, as judged by the investigator
• Untreated periodontal disease
• Unfavorable plaque control
• Known or suspected current malignancy
• History of chemotherapy within 5y prior to study
• History of radiation on the head and neck region
• History of other metabolic bone diseases
• Need for systemic corticosteroids
• Current or previous use of intravenous/oral bisphosphonates
• Present alcohol and/or drug abuse
• Involvement in the planning and conduct of the study
• Psychiatric disorders which do not allow a normal treatment outcome