for people ages 18 years and up (full criteria)
healthy people welcome
study started
estimated completion:
Mark Ryder



Improved predictability and quality of bone healing after a tooth is removed is clinically relevant, in that, it improves our ability to achieve successful implant placement at edentulous sites. Currently, a variety of grafting materials and biologic agents are utilized clinically to improve bone healing and provide sufficient dimensions of bone to support a dental implant. Platelet rich fibrin (PRF) is one such product that can be used for this application. PRF is a concentrated blood product attained from the patient's own blood consisting of a natural bioscaffold with integrated growth factors capable of sustained release. Once processed, PRF is implanted back into the patient at the wound or defect site to encourage healing. The literature regarding PRF is currently dominated by heterogeneous applications of PRF for reparative and regenerative therapies without a consensus of its clinical efficacy and appropriate application. In this clinical study, PRF will be evaluated to ascertain its clinical efficacy in improving bone formation and alveolar dimensional stability after tooth extraction. A classic bone grafting material used for this purpose, freeze dried bone allograft (FDBA), will be incorporated with the PRF or compared directly to PRF alone. It is hypothesized that the natural scaffold and incorporated growth factors of PRF augmented with the solubility resistance of FDBA will function as an ideal bioscaffold to promote bone healing to a greater extent compared to PRF, FDBA, or blood clot alone.

Official Title

Ridge Preservation With Platelet Rich Fibrin Augmented With Freeze Dried Bone Allograft: A Comparative Clinical, Histological, and Micro-computed Tomography Study


This is a randomized controlled clinical study evaluating the efficacy of four treatment modalities for ridge preservation after extraction of a tooth in preparation for dental implant placement. After tooth extraction the alveolar crest remodels during healing with reductions in vertical and horizontal dimensions. The resulting reduced dimensions after healing of the alveolar crest may be inadequate to successfully place a dental implant to replace the missing tooth. In an attempt to minimize the reductions in dimensions and provide mature healthy bone to support the dental implant, different ridge preservation techniques (treatment of the extraction socket) have been utilized.

Forty subject from the UCSF Dental School who will be having a tooth extracted and replaced with a dental implant will be randomly assigned into the four ridge preservation treatment groups. After three months of healing bone samples from the ridge preservation site will be collected during the implant placement when bone is removed during the osteotomy preparation for the implant. Samples will be evaluated for the extent and quality of bone healing via histomorphometric and micro-CT analysis. Clinical measures of alveolar ridge dimensions will be taken before and after tooth extraction to determine extent of dimensional stability under the different treatment groups.

The four treatments modalities for ridge preservation include autologous platelet rich fibrin (PRF), PRF+freeze dried bone allograft (FDBA), FDBA, collagen barrier membrane. Subjects will be enrolled in the study from the time the socket treated to the time of implant placement (3 months). The results of this study will help to elucidate the extent and quality of bone healing using four different methods for ridge preservation in preparation for implant placement. Further, this study will advance our knowledge of PRF, an autologous sourced blood product used in dentoalveolar surgeries with proven in-vitro qualities but still requiring more extensive clinical testing to demonstrate its full clinical utility.


Alveolar Ridge Preservation FDBA PRF Blood Clot PRF+FDBA


You can join if…

Open to people ages 18 years and up

  1. Single rooted teeth requiring extraction
  2. Intact buccal and lingual plate within approximately 3-4 mm from gingival crest
  3. No clinical or radiographic signs of periapical pathology
  4. Acceptable oral hygiene

You CAN'T join if...

  1. Unable to comply with necessary scheduled visits
  2. Poor oral hygiene
  3. Failing/failed endodontic treatment with history/presence of sinus tracts
  4. Pregnant woman or patients who intend to become pregnant
  5. Tobacco use
  6. Immunosuppressed
  7. Type I or type II diabetes
  8. Patient with any blood disorder

Lead Scientist

  • Mark Ryder
    Professor, Orofacial Sciences. Authored (or co-authored) 32 research publications


in progress, not accepting new patients
Start Date
Completion Date
University of California, San Francisco
Study Type
Last Updated