Platelet Rich Fibrin (PRF) Membranes in Lateral Alveolar Ridge Augmentation. A Randomized Controlled Study Comparing an Autogenous Bone Graft Covered by a Platelet Rich Fibrin (PRF) Membrane (Test Group) or an Anorganic Bovine Bone Substitute and a Resorbable Collagen Barrier Membrane (Control Group)

Tooth loss can in many cases be treated with an artificial titanium root (dental implant) and subsequent manufacture of a porcelain crown. After the tooth is lost bone resorption of the existing jaw bone often occurs making implant placement difficult. Therefore, bone augmentation is often necessary before implant placement. Six months after the bone augmentation has been performed, the implant can be inserted into the jaw bone and after additionally 6 months the final porcelain crown can be mounted.

Reconstruction of the jaw bone is often done by harvesting a bone block from the patient's own jaw. The bone block is harvested typically from the posterior part of the lower jaw, where after it is placed and fixated by screws in the part of the jaw where the bone is missing. Finally, the bone graft is covered with artificial bone substitute and a collagen membrane. Recent studies have suggested that adding platelet-rich fibrin (PRF) membranes will have an advantageously effect in reconstruction of the jaw bone and bone healing. PRF membranes are derived from a blood sample of the patient and has been introduced to accelerate soft tissue as well as bone healing. No comparative studies have been conducted in humans for the time being evaluating the effect of PRF in conjunction with bone augmentation. Therefore, the purpose of this study is to compare a control group with a test group in which the control group is treated in a standardized manner, while PRF is added to the bone graft in the test group. After 6 months of bone healing, a dental implant can be inserted in both groups using a standard technique.

For the two groups, the following is examined:

1. The final treatment outcome of the dental implant focusing on clinical outcome, radiologic outcome, aesthetic outcome, patient satisfaction.
2. Bone changes over time with a focus on volume changes. In addition, focus on soft tissue healing.
3. Bone healing assessed using bone biopsies taken in connection with the implant installation.

All included patients is missing a tooth where bone augmentation is needed before an implant can be inserted. A general study is conducted and patients are randomly assigned to a control group (20 patients) and a test group (20 patients). The control group is treated with a standard bone augmentation procedure. This is done in local anesthesia, where initially a bone graft is removed from the back of the lower jaw. The gingiva corresponding to the toothless area is loosened and the bone graft is fixed with 2 titanium screws before being covered with a artificial bone substitute and a membrane to protect the bone graft during the healing period. The test group is treated in the same way, however, a PRF-membrane is used instead of the bone substitute material and the membrane. The PRF-membrane is prepared by taking a blood sample from the arm (80 ml) as with a regular blood sample. The blood is centrifuged, which transforms the blood into a platelet-rich membrane. Thus, the membrane is produced 100% natural without any additives. However, the membranes contain growth factors that have the potential to promote mucosal and bone healing. In both groups, common penicillin (Amoxicillin / Clavulanic acid, 1000/250 mg) and painkillers (Ibuprofen, 400 mg x 4, supplemented with Panodil 1000 mg x 4) are given before surgery.

After six months, the dental implant is inserted using standard procedure in both groups. The gingiva is set aside and perpendicular to the bone grafted area, a cylindrical bone tissue biopsy (2 mm in diameter, approximately 8 mm long) is taken containing the applied bone graft and the original jaw comb (for study 3). Then the previously inserted 2 titanium screws are removed and the implant is inserted.

After another six months, the final porcelain crown is made. The implant is exposed and a healing cap is applied. After 2-3 weeks, the gum is healed, after which the final impression is made to the crown, which the patient will have installed 1-2 weeks after.

The bone augmentation procedure, the implant installation and manufacturing of the porcelain crown are characterized by minimal risks and complications. In bone augmentation, there is minimal risk of altered sensation similar to the lower lip. It is typically of a temporary nature but can be permanent in very rare cases. The implant operation, including subsequent crown manufacturing, is performed in both groups by a standardized procedure, which is also characterized by minimal risk of side effects and complications. Thus, numerous studies have shown that implant treatment is characterized by a high implant survival of approx. 95% after 10 years.

As part of the treatment, a total of 3 scans of the jaw (for study2) as well as 3 ordinary dental films are made for assessment of the jaw bone volume and as a control of the bone around the implant. This radiation dose equals approximately 60 days of background radiation in Denmark.