A Clinical and Histologic Evaluation of Implant Integration in the Posterior Maxilla After Sinus Floor Augmentation with Autogenous Bone, Bovine Hydroxyapatite, or a 20:80 Mixture

Purpose: This study was designed to clinically and histologically evaluate the integration of titanium implants in different grafting materials used for maxillary sinus augmentation procedures. Materials and Methods: A total of 21 patients and 36 maxillary sinuses were augmented with (1) autogenous particulated bone from the mandibular ramus, (2) bovine hydroxyapatite (BH) with membrane coverage, or (3) an 80/20 mixture of BH and autogenous bone. The grafts were allowed to heal for 6 to 9 months prior to placement of microimplants for histology and standard implants for prosthetic rehabilitation. After another 6 months of healing, when abutments were connected, the microimplants were retrieved for histologic and morphometric analyses. The outcome of the standard implants was clinically evaluated after 1 year of loading. Results: The mean bone-implant contact was 34.6 ± 9.5%, 54.3 ± 33.1%, and 31.6 ± 19.1% for autogenous bone, mixture of 20% autogenous bone/80% BH, and 100% BH, respectively. The corresponding values for the bone area parameter were 37.7 ± 31.3%, 39.9 ± 8%, and 41.7 ± 26.6%. The BH area was found to be 12.3 ± 8.5% and 11.8 ± 3.6% for 20% autogenous bone/80% BH and 100% BH, respectively. There were no statistically significant differences for any parameter between any of the groups. After 1 year of loading, 6 of the 33 implants placed in autogenous bone grafts, 2 of the 35 implants placed in the BH/autogenous bone mixture, and 2 of 43 implants placed in BH were lost. There were no statistically significant differences between any of the groups. Discussion: The histomorphometric analysis showed no differences between the 3 groups, indicating that autogenous bone graft can be substituted with bovine hydroxyapatite to 80% or 100% when used for maxillary sinus floor augmentation. The effect of adding autogenous bone remains unclear but may allow for a reduction of the healing time. Conclusion: The results from this clinical and histologic study indicate that similar short-term results can be expected when using autogenous bone, BH, or a mixture of them for maxillary sinus floor augmentation and delayed placement of dental implants.