EPA-coated titanium implants promote osteoconduction in white New Zealand rabbits

Micro/nanostructured calcium phytate coating on titanium fabricated by chemical conversion deposition for biomedical application

A bioactive micro/nanostructured calcium phytate coating was successfully prepared on titanium surfaces by chemical conversion deposition, mainly through hydrothermal treatment of a mixed solution of phytic acid and saturated calcium hydroxide solution. Ultraviolet radiation was carried out to improve the adhesion of the coating to the titanium substrate. Pure titanium with a sandblasted/acid-etched surface was used as the control group. The topography and chemical composition of the modified surfaces were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), and static water contact angle measurement. A pull-off test was performed to measure the coating-to-substrate adhesion strength. Bovine serum albumin was used as a model to study the protein adsorption effect. Cells were cultured on titanium surfaces for 7 days in osteogenic differentiation medium, then the osteoblast compatibility in vitro were explored by alkaline phosphatase and alizarin red staining. After 1, 2, 4 and 8 wks of immediate implantation of titanium implants into the mandibles of New Zealand white rabbits, biological effects in vivo were researched by microcomputed tomography analysis and histological evaluation. The results indicated that the roughness and hydrophilicity of the modified surfaces with micro/nanostructure remarkably increased compared to those of the control group. The pull-off test showed the average adhesion strength at the coating-substrate interface to be higher than 13.56 ± 1.71 MPa. In addition, approximately 4.41 mg/L calcium ion was released from the calcium phytate micro/nano coatings to the local environment after 48 h of immersion. More importantly, the micro/nanostructure titanium substrates significantly promoted cellular differentiation in vitro and in vivo. After 8 wks, the bone implant contact ratio (BIC, %) of the modified implants was higher than that of the control group, at 94.09 ± 0.55% and 86.18 ± 1.99% (p < 0.05). Overall, this study provided new insights into the factors promoting early osseointegration of titanium alloys, which had great potential not only for dental implants but also for various other biomaterial applications.

Effect of Laser Therapy on the Osseointegration of Immediately Loaded Dental Implants in Patients under Vitamin C, Omega-3 and Calcium Therapy

BACKGROUND:

The use of laser therapy in the biostimulation of bone repair has been growing steadily.

AIM:

This study aimed to evaluate the radio-densitometric effect of low-intensity laser therapy on the osseointegration of immediately loaded dental implants in patients under vitamin C, omega-3 and calcium therapy.

PATIENTS AND METHODS:

A single implant was placed in the mandibular first molar region of twenty patients which were equally divided into two groups. In the non-laser group, the healing phase was left to progress spontaneously without any intervention, while in the laser group it was augmented with low-level laser therapy of wavelength 904 nm in contact mode, continuous wave, 20 mW output power and exposure time 30 sec with a dose 4.7 J/cm². Patients in both groups were given vitamin C, calcium and omega-3 starting one month preoperatively. Postoperative digital panoramas were taken immediately after surgery, 1.5 months and 6 months postoperatively. Changes in bone density along the bone-implant interface at the mesial, distal and apical sides were assessed using the Digora software.

RESULTS:

Independent student t-test was used to compare means of variables between the laser and the non-laser group while repeated measures ANOVA was used to compare bone densities at different times for the same group. Significant increased differences were observed at the mesial, distal and apical sides surrounding the implants of both groups per time. However, the rate of increase was significantly higher in the laser group. The mean difference at the mesial side after 6 months was 21.99 ± 5.48 in the laser group and 14.21 ± 4.95 in the non-laser group, while it read 21.74 ± 3.56 in the laser group and 10.78 ± 3.90 in non-laser group at the distal side and was 18.90 ± 5.91 in the laser group and 10.39 ± 3.49 in non-laser group at the apical side. Significance was recorded at P = 0.004, P = 0.0001, and 0.001 at the mesial, distal and apical sides respectively.

CONCLUSION:

The low-intensity laser irradiation significantly promoted bone healing and speeded up the osseointegration process emphasising the laser’s biostimulatory effect.

A novel nano-copper-bearing stainless steel with reduced Cu(2+) release only inducing transient foreign body reaction via affecting the activity of NF-κB and Caspase 3

Foreign body reaction induced by biomaterials is a serious problem in clinical applications. Although 317L-Cu stainless steel (317L-Cu SS) is a new type of implant material with antibacterial ability and osteogenic property, the foreign body reaction level still needs to be assessed due to its Cu(2+) releasing property. For this purpose, two macrophage cell lines were selected to detect cellular proliferation, apoptosis, mobility, and the secretions of inflammatory cytokines with the influence of 317L-Cu SS. Our results indicated that 317L-Cu SS had no obvious effect on the proliferation and apoptosis of macrophages; however, it significantly increased cellular migration and TNF-α secretion. Then, C57 mice were used to assess foreign body reaction induced by 317L-Cu SS. We observed significantly enhanced recruitment of inflammatory cells (primarily macrophages) with increased TNF-α secretion and apoptosis level in tissues around the materials in the early stage of implantation. With tissue healing, both inflammation and apoptosis significantly decreased. Further, we discovered that NF-κB pathway and Caspase 3 played important roles in 317L-Cu SS induced inflammation and apoptosis. We concluded that 317L-Cu SS could briefly promote the inflammation and apoptosis of surrounding tissues by regulating the activity of NF-κB pathway and Caspase 3. All these discoveries demonstrated that 317L-Cu SS has a great potential for clinical application.