Biofunctionalization of titanium implants with a biomimetic active peptide (P‐15) promotes early osseointegration

Objectives: The early stages of peri‐implant bone formation play an essential role in the osseointegration and long‐term success of dental implants. By incorporating bioactive coatings, this biofunctionalization of implant surfaces may enhance the attachment of the implant to the surrounding bone and stimulate bone regeneration. Material and methods: To demonstrate faster osseointegration, the surfaces of dental implants were grit‐blasted and acid‐etched. They were then coated with hydroxyapatite (HA) and experimental implants were further coated with a biomimetic active peptide (P‐15) in one of two concentrations. These biofunctionalized samples and controls with no peptide were placed in the forehead region of 12 adult pigs. Six animals were evaluated for a period of 14 or 30 days. Results: Histomorphometric analysis demonstrated that the implants with the high concentration of P‐15 had significantly higher percentage of bone‐to‐implant contact (BIC) at 14 (P=0.018) and 30 (P=0.015) days compared with the other groups. Both concentrations of P‐15 showed increased peri‐implant bone density compared to the control group at 30 days. Conclusion: Biofunctionalization of the implant surface with a biomimetic active peptide leads to significantly increased BIC rates at 14 and 30 days and higher peri‐implant bone density at 30 days. To cite this article:
Lutz R, Srour S, Nonhoff J, Weisel T, Damien CJ, Schlegel KA. Biofunctionalization of titanium implants with a biomimetic active peptide (P‐15) promotes early osseointegration.
Clin. Oral Impl. Res. 21 , 2010; 726–734.
doi: 10.1111/j.1600‐0501.2009.01904.x     

Histological evaluation of the peri‐implant tissues of three human‐retrieved Straumann implants

The most frequently‐used histological parameters to define dental implant osseointegration include bone‐to‐implant contact and quantitative and qualitative assessments of the surrounding tissue (rate of mineralized/non‐mineralized tissue and proportion of lamellar and woven bone compared to soft tissue or bone marrow). The aim of this paper was to present the histological features of the bone tissue surrounding three well‐functioning Straumann SLA and SLActive implants placed in two patients after 12 and 60 months of loading. The percentage of osseointegration ranged from 66.4% and 71.9% for SLA surfaces, to 88.3% for the SLActive implant. Such results confirm that osseointegration occurs with high rates of bone‐to‐implant contact in humans, and that implants can be similarly clinically successful, although they show different bone‐to‐implant contact values.     

Calvarial bone regeneration by a combination of natural anorganic bovine-derived hydroxyapatite matrix coupled with a synthetic cell-binding peptide (PepGen): an experimental study in rats

Objectives: The aim of this study was to evaluate histologically the effect of natural anorganic bovine‐derived hydroxyapatite matrix (ABM) coupled with a synthetic cell‐binding peptide on the healing of critical size calvarial defects in rats. Material and methods: Sixteen 4‐month‐old rats were used in the study. A 5 mm trephine defect was created in each parietal bone of every animal. One defect was left untreated (control) while the contralateral defect was treated with a natural ABM coupled with a synthetic cell‐binding peptide (test). At 60 and 120 days post‐operatively, groups of eight animals were sacrificed and 7–10‐μm‐thick decalcified sections were produced from both test and control sides. Three sections, 100 μm apart, representing the central area of each defect were selected for the histometric analysis. Results: Histological analysis showed limited bone formation in both control and test defects at both observation periods. The control defects healed with fibrous connective tissue occupying the midportion of the defect and minimal new bone formation at the periphery. In the test defects, the major part of the defect was occupied by graft particles embedded in connective tissue. After 60 days of healing the residual defects accounted up to 94.6% of the original defect dimensions in the control specimens and 90.6% in the test specimens. The differences between test and control defects were not statistically significant (P=0.06). After 120 days of healing, the residual defects accounted up 89.9% of the original defect dimensions in the control specimens and 85% in the test specimens. The difference was not statistically significant (P=0.33). Conclusion: The ABM coupled with a synthetic cell‐binding peptide failed to substantially promote new bone formation in rat calvarial defects.     

Effect of FK‐506 (tacrolimus) therapy on bone healing of titanium implants: a histometric and biomechanical study in mice

Immunosuppressive agents have been recognized as a factor affecting bone metabolism. The aim of the present study was to evaluate the influence of FK‐506 administration on the healing of bone around titanium implants. Thirty‐two male mice were randomly allocated to two groups: the FK‐506 group (n = 16 mice), which received subcutaneous administration of FK‐506 (1 mg kg^?1 d^?1); and the control group (n = 16 mice), which received saline solution by the same route of administration. After 2 wk, one titanium implant with sandblasted/acid‐etched surface was placed in the femur. The therapy continued until the mice were killed 2 and 4 wk after surgery. The femurs with implants were evaluated by biomechanical testing and histologic analysis. The bone–implant contact (BIC) and bone volume (BV/TV) within a 100‐μm‐wide circumferential zone lateral to the implant surface were histomorphometrically analyzed. Compared with the control group, the FK‐506 group showed significantly lower BIC and BV/TV at both 2 and 4 wk. Biomechanical tests showed that FK‐506 significantly impaired the strength of bone–implant integration at both 2 and 4 wk postoperatively. Our data indicate that immunosuppressive therapy with FK‐506 negatively affects the fixation of titanium implants.