Establishment of a new pull-out strength testing method to quantify early osseointegration-An experimental pilot study.

OBJECTIVES: The animal study aims to evaluate a new experimental model for measuring sole the influence of the surface characteristics independent from implant macro-design on the level of osseointegration by registering the pull-out strength needed for removal of experimental devices with different surfaces from artificial defects. MATERIAL AND METHODS: Seventy-two test bodies (36 with the FRIADENT(®) plus surface, 36 with the P15/HAp biofunctionalized surface) were inserted in six adult domestic pigs with artificial calvarial defects. The experimental devices were designed to fit in the defects leaving a gap between the test body and the local bone. After 21 days of healing, the animals were sacrificed and the test bodies were pulled out with a standardised reproducible pull-out device measuring the pull-out strength. The pull-out strength for both groups was compared. RESULTS: Twenty-one days after insertion a mean force of 412 ± 142 N for the P15/HAp group and 183 ± 105 N for the FRIADENT(®) plus group was measured for the removal of the specimens from the calvarial bone. The difference between the groups was statistically significant (p < 0.0001). CONCLUSION: The experimental set-up seems to be a suitable method when measuring the impact of implant surfaces on the early stage of osseointegration.

Biofunctionalization of the implant surface with different concentrations of a synthetic peptide (P-15).

OBJECTIVE: This study aimed at identifying the ideal concentration of a biofunctional surface coating of dental implants with a synthetic peptide (P-15). In a previous study, P-15 was shown to enhance osseointegration parameters. MATERIAL AND METHODS: Implants (modified ANKYLOS(®) A8; FRIADENT Plus(®) surface) with five different concentrations (0-400 µg/ml) of a P-15 coating as well as uncoated controls were inserted in the frontal bone of 45 adult domestic pigs. The histomorphometric and microradiographic findings for the coated implants were compared to those for the uncoated ones after 7, 14, and 30 days. RESULTS: No significant differences were observed comparing the peri-implant bone density between the coated and uncoated implants The bone-to-implant contact, as the primary histological parameter for osseointegration, showed high rates for all surfaces investigated (between 73.3 ± 17.9% for the control and 81.9 ± 15.2% for P15 20 µg/ml after 30 days). CONCLUSIONS: No significant benefit on osseointegration of a biofunctional P-15 coating of dental implants could be displayed in the present study.

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.

Effects of fluvastatin on biliary lipids in subjects with an elevated cholesterol saturation index.

OBJECTIVE: 3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors have been suggested as agents to reduce the biliary cholesterol saturation index (CSI) in duodenal bile and therefore might be supportive in primary or secondary prevention of gallstones. However, the efficiency of the therapy seems to depend on both the HMG-CoA reductase inhibitor used and the study population selected. METHODS: We therefore investigated the effect of a high-dose application of fluvastatin on biliary lipid composition in 21 subjects exhibiting mild hypercholesterolaemia and a history of current gallstones or cholecystectomy due to gallstone disease. Subjects were treated either with 40 mg fluvastatin twice per day over a 3-month period (n = 14) or with placebo (n = 7). Bile samples were aspirated during endoscopy after intravenous ceruletid stimulation before and after therapy. RESULTS: Both groups were comparable in CSI (mean +/- SD) at baseline (1.78 +/- 0.2 placebo vs. 1.97 +/- 0.4 verum). CSI significantly decreased in the verum group to 1.45 +/- 0.4 (P = 0.003) mainly due to increased phospholipid levels, whereas no difference was observed in the placebo group (1.85 +/- 0.7, n.s.). In addition, the verum group exhibited a significant reduction of hydrophobic deoxycholic acid, which has been reported to induce cholesterol crystal precipitation, and an increase of hydrophilic cholic acid. CONCLUSION: Fluvastatin might decrease the risk of cholesterol gallstone formation in patients with elevated biliary CSI during long-term treatment by reduction of biliary cholesterol saturation and percentage change in deoxycholic acid content.