Rabbit Tibial Model Research Articles

A Clue to the Existence of Bonding between Bone and Implant Surface: An In Vivo Study.

We evaluated the shear bond strength of bone–implant contact, or osseointegration, in the rabbit tibia model, and compared the strength between grades 2 and 4 of commercially pure titanium (cp-Ti). A total of 13 grades 2 and 4 cp-Ti implants were used, which had an identical cylinder shape and surface topography. Field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and confocal laser microscopy were used for surface analysis. Four grades 2 and 4 cp-Ti implants were inserted into the rabbit tibiae with complete randomization. After six weeks of healing, the experimental animals were sacrificed and the implants were removed en bloc with the surrounding bone. The bone–implant interfaces were three-dimensionally imaged with micro-computed tomography. Using these images, the bone–implant contact area was measured. Counterclockwise rotation force was applied to the implants for the measurement of removal torque values. Shear bond strength was calculated from the measured bone–implant contact and removal torque data. The t-tests were used to compare the outcome measures between the groups, and statistical significance was evaluated at the 0.05 level. Surface analysis showed that grades 2 and 4 cp-Ti implants have similar topographic features. We found no significant difference in the three-dimensional bone–implant contact area between these two implants. However, grade 2 cp-Ti implants had a higher shear bond strength than grade 4 cp-Ti implants (p = 0.032). The surfaces of the grade 2 cp-Ti implants were similar to those of the grade 4 implants in terms of physical characteristics and the quantitative amount of attachment to the bone, whereas the grade 2 surfaces were stronger than the grade 4 surfaces in the bone–surface interaction, indicating osseointegration quality.

Effect of insertion angle on the stability of orthodontic mini-implants in a rabbit tibia model: A finite element analysis.

Mini-implants are an alternative to traditional methods of anchorage in orthodontic treatment. However, there are still questions concerning their application, in particular, with the insertion angle. To determine whether the angle of insertion of the mini-implant is a determining factor in their primary stability when they support orthodontic loads. A finite element model (FEM) of tibia bone, spring and mini-implant was developed. The three-dimensional model of the rabbit tibia was constructed based on tomographic slices. The angles that were analyzed were 90°, 80°, 70°, 60°, 50°, 45°, 40°, and 30°. A horizontal force of 2 N applied to the head of the mini-implants was simulated. The von Mises stresses and displacements were determined using FEM. Von Mises stresses were lower for an insertion angle of 40° followed by 90° and 70°; likewise, the displacements of the mini-implants with respect to the spring were lower for the 40° angle followed by 90° and 70°, we found a statistically significant association between the insertion angle and displacement. All mini-implants underwent a degree of angulation and displacement; however, mini-implants inserted to the bone surface at 40° tend to have better primary stability, and they can withstand loads immediately.

Copper Bead Therapy in Severe Bone Infection: A Rabbit Tibial Model.

We investigated the benefits of a local preventive therapy based on copper beads against severe bone infection using a rabbit open tibial fracture model. Cotton mesh balls soaked in a very high concentration of Staphylococcus aureus ATCC 6538 culture were inoculated in drilled holes of the tibiae of treated and control groups. The treated group was also implanted with small copper beads simultaneously, as prevention therapy. Survival rate in the treated group was 67% compared with 25% in the control group (difference 40%, for a 95% confidence interval: 40%, 93.4%). The few remaining animals in the control group had bone lesions which developed into osteomyelitis, while the tibiae of treated group had clear signs of reparatory processes. Sixty days after inoculation, signs of local-only toxicity were observed in healthy tibia of a separate non-infected control group. Drawbacks of copper toxicity were weighed against the threat of septicaemia and also against prolonged use of powerful systemic antibiotic medications in severe bone contamination. It was found that the proposed therapy prevented septicaemia and the spread of infection, and it also induced reparatory processes. The findings of this study may be relevant in antisepsis of open fractures in less appropriate medical settings (such as military camps or remote locations), as well as in severe bone infections.

Bone Immune Response to Materials, Part I: Titanium, PEEK and Copper in Comparison to Sham at 10 Days in Rabbit Tibia.

Bone anchored biomaterials have become an indispensable solution for the restoration of lost dental elements and for skeletal joint replacements. However, a thorough understanding is still lacking in terms of the biological mechanisms leading to osseointegration and its contrast, unwanted peri-implant bone loss. We have previously hypothesized on the participation of immune mechanisms in such processes, and later demonstrated enhanced bone immune activation up to 4 weeks around titanium implants. The current experimental study explored and compared in a rabbit tibia model after 10 days of healing time, the bone inflammation/immunological reaction at mRNA level towards titanium, polyether ether ketone (PEEK) and copper compared to a Sham control. Samples from the test and control sites were, after a healing period, processed for gene expression analysis (polymerase chain reaction, (qPCR)) and decalcified histology tissue analysis. All materials displayed immune activation and suppression of bone resorption, when compared to sham. The M1 (inflammatory)/M2 (reparative) -macrophage phenotype balance was correlated to the proximity and volume of bone growth at the implant vicinity, with titanium demonstrating a M2-phenotype at 10 days, whereas copper and PEEK were still dealing with a mixed M1- and M2-phenotype environment. Titanium was the only material showing adequate bone growth and proximity inside the implant threads. There was a consistent upregulation of (T-cell surface glycoprotein CD4) CD4 and downregulation of (T-cell transmembrane glycoprotein CD8) CD8, indicating a CD4-lymphocyte phenotype driven reaction around all materials at 10 days.

Quercitrin Nanocoated Implant Surfaces Reduce Osteoclast Activity In Vitro and In Vivo.

In this study, the effect on osteoclast activity in vitro and in vivo of titanium implants that were coated with quercitrin was evaluated. Titanium surfaces were covalently coated with the flavonoid quercitrin. The effect of the surfaces on osteoclastogenesis was first tested in vitro on RAW264.7 cells that were supplemented with receptor activator of nuclear factor kappa-B ligand (RANKL) to generate osteoclast-like cells by tartrate-resistant acid phosphatase (TRAP) inmunostaining after five days of culture, and by analysis of the mRNA expression levels of markers related to bone resorption after seven days of culture. A rabbit tibial model was used to evaluate the in vivo biological response to the implant surfaces after eight weeks of healing, analyzing the lactate dehydrogenase (LDH) and the alkaline phosphatase (ALP) activities in the wound fluid that were present at the implant interface and the peri-implant bone mRNA expression levels of several markers related to inflammation, bone resorption and osteoblast-osteoclast interaction. No differences between groups and control surfaces were found in the wound fluid analyses. Moreover, quercitrin implant surfaces significantly decreased the expression of osteoclast related genes in vitro (Trap, CalcR, Ctsk, H+ATPase, Mmp9) and in vivo (Ctsk, H+ATPase, Mmp9) as well as the expression of RankL in vivo. Moreover, quercitrin surfaces were not cytotoxic for the cells. Thus, quercitrin implant surfaces were biocompatible and decreased osteoclastogenesis in vitro and in vivo. This could be used to improve the performance of dental implants.

Chitosan-based sleeves loaded with silver and chlorhexidine in a percutaneous rabbit tibia model with a repeated bacterial challenge

Various strategies have been explored to prevent pin tract infections (PTI), including the use of antibacterial sleeves. However, an ideal animal model to evaluate the efficacy of antibacterial strategies is still lacking. This study aimed to construct an animal model with a consistent induction of infection after bacterial challenge. Further, the efficacy of silver and chlorhexidine loaded chitosan sleeves was evaluated to prevent PTI around a percutaneous implant. Titanium pins wrapped with sleeves were implanted in anterior lateral rabbit tibia. After 2 weeks, Staphylococcus aureus suspensions (1 × 106 CFU) were injected weekly to the exit site, and the clinical infection status was recorded. After 6 weeks, all rabbits were euthanized to evaluate the bacterial colonization microbiologically and histomorphometrically. Results showed that the implant screw bilaterally penetrated the tibia and kept the implant stable. A rod length of twice the thickness of the soft-tissue layer was necessary to maintain the percutaneous penetration of the implants. A 100% infection rate was obtained by the bacterial inoculation. Silver loaded sleeves reduced significantly the bacterial density and reduced the inflammatory symptoms of the percutaneous pin tract. However, the addition of chlorhexidine to the sleeves had no added value in terms of further reduction of bacteria and inflammation. In conclusion, a consistent animal model was designed to evaluate strategies to prevent PTI. In addition, the use of silver loaded chitosan sleeves can be pursued for further (pre-)clinical exploration for the prevention of PTI. Statement of SignificanceThis study constructed a bacterial challenged percutaneous rabbit tibia model to evaluate the potential of antibacterial strategies for the prevention of pin tract infections. The model was applied to evaluate a silver and chlorhexidine loaded membranes as an antibacterial sleeve. Our results demonstrate that the rabbit tibia model is suitable to evaluate antibacterial strategies for the prevention of pin tract infection as evidenced by the stable, bone fixed percutaneous implant and a 100% infection rate of the percutaneous pin tract. Silver loaded sleeves can lower the bacterial density of the percutaneous pin tract, but the addition of chlorhexidine to the silver-loaded sleeves does not contribute to an enhanced antibacterial effect. Such experiments are of considerable interest to those in the research community, industry, and clinicians involved the occurrence of infection of skin penetrating medical devices.

Investigating the mechanical, physiochemical and osteogenic properties in gelatin-chitosan-bioactive nanoceramic composite scaffolds for bone tissue regeneration: In vitro and in vivo

The aim of this work was to compare the efficacy of gelatin–chitosan based bone scaffolds after incorporation of three different bioactive nanoparticles such as hydroxyapatite (HAp), β‑tricalcium phosphate (β-TCP) and 58s bio active glass by evaluating its physicochemical, mechanical and osteogenic properties. Gelatin-chitosan based scaffolds made of gelatin-chitosan (GC) and GC composites containing 30 wt% HAp, β-TCP and 58s bioactive glass nanoparticles were fabricated using freeze drying technique. The porosity and compressive strength of all the prepared scaffolds were evaluated. The average pore size of all the prepared composite scaffolds was in the range between 90 and 125 μm. Most frequent pore size in GCT 30 scaffold was the highest of 120 μm whereas that for GCH 30 was the lowest of 96 μm as suggested by Hg porosimetry analysis. GCH30 scaffolds showed the highest average compressive strength of 3.45 MPa as opposed to 2.24 MPa exhibited by GCB 30, with high degree of interconnected porosity appropriate for cellular colonization. To study the effect of different bioceramic phases on MSCs differentiation, scaffolds were cell cultured for up to 14 days in osteogenic medium. GCB30 scaffold showed higher capacity to proliferate MSCs cultured onto it as compared to other composite scaffolds. Degree of differentiation of MSCs into osteoblast was higher in GCB30 scaffolds than in the GCH30 and GCT30 composite scaffold as evident from higher amount of RUNX2 and osteocalcin expression in the former up to 14 days of cell culture. Inclusion of 58s bioactive glass particles showed positive effects on cell differentiation. In coherence with the in vitro appearance, histomorphometric analysis and fluorochrome study in a rabbit tibia model showed a significantly greater amount of new bone formation in GCB30 compared to other composite scaffolds. The results demonstrated that the prepared GCB30 scaffold could be a better candidate as bone substitute material for its higher bioactivity in bone tissue regeneration.

Effect of Different Morphology of Titanium Surface on the Bone Healing in Defects Filled Only with Blood Clot: A New Animal Study Design.

Background The objective of the present histologic animal study was to analyze whether roughness of the titanium surface can influence and/or stimulate the bone growth in defects filled with the blood using a rabbit tibia model. Materials and Methods Forty sets (implant and abutment), dental implant (3.5 mm in diameter and 7 mm in length) plus healing abutment (2.5 mm in diameter), were inserted in the tibiae of 10 rabbits. Moreover, twenty titanium discs were prepared. The abutment and discs were treated by 4 different methods and divided into 4 groups: (group A) machined abutments (smooth); (group B) double acid etching treatment; (group C) treatment with blasting with particles of aluminum oxide blasted plus acid conditioning; (group D) treatment with thorough blasting with particles of titanium oxide plus acid conditioning. The discs were used to characterize the surfaces by a profilometer and scanning electronic microscopy. Results After 8 weeks, the new bone formation around the sets of the samples was analyzed qualitatively and quantitatively in relation to bone height from the base of the implant and presence of osteocytes. Group C (1.50±0.20 mm) and group D (1.62±0.18 mm) showed bone growth on the abutment with higher values compared to group A (0.94±0.30 mm) and group B (1.19±0.23 mm), with significant difference between the groups (P < 0.05). In addition, osteocyte presence was higher in groups with surface treatment related to machined (P < 0.05). Conclusions Within the limitations of the present study, it was possible to observe that there is a direct relationship between the roughness present on the titanium surface and the stimulus for bone formation, since the presence of larger amounts of osteocytes on SLA surfaces evidenced this fact. Furthermore, the increased formation of bone tissue in height demonstrates that there is an important difference between the physical and chemical methods used for surface treatment.

3D printed β-TCP bone tissue engineering scaffolds: Effects of chemistry on in vivo biological properties in a rabbit tibia model.

In this study the effects of 3D printed SiO2 and ZnO doped tricalcium phosphate (TCP) scaffolds with interconnected pores were evaluated on the in vivo bone formation and healing properties of a rabbit tibial defect model. Pure and doped TCP scaffolds were fabricated by a ceramic powder-based 3D printing technique and implanted into critical sized rabbit tibial defects for up to 4 months. In vivo bone regeneration was evaluated using chronological radiological examination, histological evaluations, SEM micrographs and fluorochrome labeling studies. Radiograph results showed that Si/Zn doped samples had slower degradation kinetics than the pure TCP samples. 3D printing of TCP scaffolds improved bone formation. The addition of dopants in the TCP scaffolds improved osteogenic capabilities when compared to the pure scaffolds. In summary, our findings indicate that addition of dopants to the TCP scaffolds enhanced bone formation and in turn leading to accelerated healing.

Inflammation-Induced Osteogenesis in a Rabbit Tibia Model.

Pathologic conditions associated with bone formation can serve as models to identify bone-promoting mediators. The inflammatory response to bacterial infections generally leads to osteolysis and impaired bone healing, but paradoxically, it can also have pro-osteogenic effects. As a potential model to investigate pro-osteogenic stimuli, this study characterizes the bone formation in an established rabbit tibia model of periprosthetic infection. Our hypothesis was that the infection with Staphylococcus aureus (S. aureus) correlates with bone formation as a response to local inflammation. Fluorochromes showed excessive subperiosteal bone formation in infected tibiae, starting the first week and continuing throughout the study period. Despite the observed cortical lysis on micro-CT after 28 days, infection resulted in a twofold higher bone volume in the proximal tibiae compared to uninfected controls. The ipsilateral fibulae, nor the contralateral fibulae or tibiae were affected by infection. Next, we sought to confine the cause of stimulated bone formation to the isolated S. aureus cell wall. In absence of virulent bacterial infection, the S. aureus cell wall extract induced bone in a more favorable way without cortical lysis. This suggests that the sterile inflammatory reaction to bacterial antigens may be harnessed for bone regenerative purposes. Future investigations in this rabbit tibia model can lead to further identification of effective stimuli for clinical application.

Trombosit Zengin Fibrin ve Rifamisinin Bir Allogreft ile Kombinasyonda Kemik Büyütme Üzerindeki Etkilerinin Tavşan Tibiasında Eşzamanlı İmplant Yerleştirmesiyle Histomorfometrik Olarak Değerlendirilmesi

Objective: To evaluate the potential of platelet-rich fibrin (PRF) and rifamycin to enhance guided bone augmentation with simultaneous high-profile dental implant placement in a rabbit tibia model. Materials and Methods : Dental implants protruding 2 mm were covered with dome-shaped stiff occlusive titanium barriers filled with demineralized freeze-dried bone allograft (DFDBA)+saline (7 rabbits), DFDBA + rifamycin (8 rabbits), or DFDB +PRF (8 rabbits). After 4 weeks, the animals were sacrificed, and undecalcified histomorphometric examination with toluidine blue staining was performed. Results: The bone-to-implant contact (BIC) was 58.43 ± 1.92% in the saline group, 68.3 ±20.37% in the rifamycin group, and 80.70±2.55% in the PRF group, and the percentage of new bone formation was 36.90 ± 0.94%, 45.26±0.60%, and 51.82±0.82%, respectively. Conclusions: Both PRF and rifamycin have potential to enhance GBA, and using DFDBA + PRF or DFDBA+rifamycin beneath a stiff occlusive titanium barrier next to a high-profile implant may enhance both BIC and new bone formation. Keywords : Guided bone augmentation, platelet-rich fibrin, rifamycin, allograft, high-profile dental implants

The integration of orthodontic miniscrews under mechanical loading: a pre-clinical study in rabbit.

Orthodontic miniscrews are an increasingly popular choice to achieve absolute anchorage. The temporary use of miniscrews and their recent introduction have limited the debate over the biological aspect of the materials to that of the surface that permeates the field of dental implants. The aim of the present study was to investigate the integration of grade 5 titanium mini-implants with machined or sand blasted acid etched surface (SAE) under mechanical load in a rabbit tibia model of implant integration. A total of 64 miniscrews (Ti6Al4V) of 1.5 mm diameter and 6.5 mm length were inserted in the proximal medial surface of each tibia in eight male rabbits aged 6 months. Each tibia received four miniscrews. A 100 g nickel-titanium coil spring (Neosentalloy) was applied between two miniscrews along the main axis while two miniscrews were left unloaded. The removal torque was measured for loaded and unloaded miniscrews after 12 weeks. Two miniscrews were harvested for histology. Removal torque was significantly higher for SAE mini-implants than for machined screws, under both loading conditions. Although no difference in bone to implant contact was observed among the groups, cortical area significantly decreased with both surfaces under loading. Our data indicate that SAE miniscrews have higher bone retention than MA miniscrews, although the effects of mechanical loading of these devices on cortical bone require further investigations.

Dexamethasone Delivery by an Implant-Mediated Drug Delivery System in the Canine Mandible.

A newly introduced implant-mediated drug delivery system (IMDDS) showed promising results in a rabbit tibia model. The aim of the present study is to evaluate whether dexamethasone administered by the IMDDS has sustained effects in the canine mandible - a different anatomic location, in a different species. IMDDS was installed at the mesial root of the second premolar site in the mandibles of six beagle dogs. After complete healing, 10 mg dexamethasone was administered through the IMDDS. The same amount of drug was administered to five control animals by intramuscular injection. The release pattern was monitored for 2 weeks by measuring plasma drug concentrations. A sustained plasma dexamethasone concentration was detected after a peak at 6 hours until the end of the observation period, despite individual variations. The concentration was lower than reported in the rabbit tibia model. In contrast, plasma concentration of the control group showed an early peak at 2 hours and decreased rapidly. Dexamethasone was effectively released from the IMDDS for a prolonged time in the canine mandible model.

Titanium implants coated with UV‐irradiated vitamin D precursor and vitamin E: in vivo performance and coating stability

This study aimed at evaluating the biological response of titanium implants coated with UV-irradiated 7-dehydrocholesterol (7-DHC) and vitamin E (VitE) invivo and analyzing the effects of aging on their stability and bioactivity invitro. Titanium surfaces were coated with 7-DHC and VitE, UV-irradiated and incubated for 48h at 23°C to allow cholecalciferol synthesis. The invivo biological response was tested using a rabbit tibia model after 8weeks of healing by analyzing the wound fluid and the mRNA levels of several markers at the bone-implant interface (N=8). The stability of the coating after storage up to 12weeks was determined using HPLC analysis, and the bioactivity of the stored modified implants was studied by an invitro study with MC3T3-E1 cells (N=6). A significant increase in gene expression levels of osteocalcin was found in the bone tissue attached to implants coated with the low dose of 7-DHC and VitE, together with a higher ALP activity in the wound fluid. Implants treated with the high dose of 7-DHC and VitE showed increased tissue necrosis and inflammation. Regarding the aging effects, coated implants were stable and bioactive up to 12weeks when stored at 4°C and avoiding oxygen, light and moisture. This study demonstrates that Ti implants coated with UV-irradiated 7-DHC and VitE promote invivo gene expression of bone formation markers and ALP activity, while they keep their osteopromotive potential invitro and composition when stored up to 12weeks at 4°C.

Bioactivity of sol–gel-derived TiO2 coating on polyetheretherketone: In vitro and in vivo studies

A polyetheretherketone (PEEK) surface was modified using a sol–gel-derived TiO2 coating in order to confer bone-bonding ability. To enhance the bonding strength of the coating layer, pretreatment with either O2 plasma or sandblasting was performed prior to sol–gel coating. Additionally, post-treatment with acid was carried out to confer apatite (calcium phosphate)-forming ability to the surface. Biomechanical and histological analyses performed using an in vivo rabbit tibia model showed that PEEK surfaces modified with sol–gel-derived TiO2 and acid post-treatment had better bone-bonding properties than uncoated PEEK surfaces. These modified surfaces also performed well in terms of their in vitro cell responses due to their modified surface chemistries and topographies. Although O2 plasma or sandblasting treatment were, for the most part, equivocal in terms of performance, we conclude that sol–gel-derived TiO2 coating followed by acid post-treatment significantly improves the bone bonding ability of PEEK surfaces, thus rendering them optimal for their use in surgical implants. Statement of SignificanceThe role of polyetheretherketone (PEEK) as an alternative biomaterial to conventional metallic implant materials has become increasingly important. However, its low bone bonding ability is yet to be resolved. This in vivo and in vitro investigation on the functionalization of PEEK surfaces highlights the utility of this material in clinical interventions that require implants, and may extend range of applications of PEEK.

3D scaffold induces efficient bone repair: in vivo studies of ultra-structural architecture at the interface

Biodegradable designer 3D scaffold bridges critical size defect and induces new bone formation as revealed by ssNMR, SEM, EDX and μ-CT in rabbit tibial model during healing. No growth factor was needed due to chemical and microstructural cues.

Bone response to collagenized xenografts of porcine origin (mp3(®) ) and a bovine bone mineral grafting (4BONE(™) XBM) grafts in tibia defects: experimental study in rabbits.

This study aimed to carry out the evaluation of bone response of new bone formation to two different xenografts (bovine and porcine) biomaterials inserted in rabbit tibiae. The study used a total of 20 male New Zealand albino rabbits. They received a total of 40 grafts in the proximal metaphyseal areas of both tibiae. Two biomaterials were evaluated: 20 porcine xenografts, as a bone granulate (OsteoBiol(®) MP3(®) ; Tecnoss srl, Giaveno, Italy), were placed in the proximal metaphyseal area of the right tibia, 20 anorganic bovine bone mineral grafting (4BONE(™) XBM, MIS Implants Inc., BARLEV, Israel) were placed in the left tibia. Following graft insertion, the animals were sacrificed in two groups of 10 animals, after 1 and 4months, respectively. For each group, biomaterials were analyzed: newly formed bone, residual graft materials and the connective tissue. Histomorphometric, EDX analysis and element mapping were performed at 1 and 4months after graft insertion. At 4months after treatment, the bone defects displayed radiological images that showed complete repair of osseous defects. Histomorphometric evaluation showed that for the porcine xenograft, the study averages for newly formed bone represented 84.23±2.9%, while bovine matrix was 79.34±2.1%. For residual graft material, the porcine biomaterial had 11.23±1.7% and the bovine graft 31.56±2.3%. Finally, the connective tissue for MP3 was 10.33±1.8%, while for the 4BONE(™) XBM we obtained 14.34±2.9%. Element analysis revealed higher percentages of Ca (54±9%) and P (35±6%) in the group B than group A and control group (P<0.05). Defects of a critical size in a rabbit tibia model can be sealed using a bovine porous biphasic calcium phosphate and MP3 material; this supports new bone formation, creates a bridge between borders, and facilitates bone ingrowth in both biomaterials. Furthermore, this study observed partial dissolution of the mineral phase of four bone graft and complete resorption of porcine MP3 biomaterial and its incorporation into the surrounding bone. Depending on clinical needs, each biomaterial could be useful in daily clinical practice.

Evaluation of Ti implants coated with Ag-containing borate bioactive glass for simultaneous eradication of infection and fracture fixation in a rabbit tibial model – ERRATUM

Evaluation of Ti implants coated with Ag-containing borate bioactive glass for simultaneous eradication of infection and fracture fixation in a rabbit tibial model – <b>ERRATUM</b>

Zn/Ag micro-galvanic couples formed on titanium and osseointegration effects in the presence of S. aureus

Titanium implants possessing simultaneous osseointegration and antibacterial ability are desirable. In this work, three types of Zn/Ag micro-galvanic couples are fabricated on titanium by plasma immersion ion implantation to investigate the osseointegration and antibacterial effects as well as the involved mechanisms. The in vitro findings disclose enhanced proliferation, osteogenic differentiation, and gene expressions of the rat bone mesenchymal stem cells (rBMSCs), as well as good antibacterial ability on all three micro-galvanic couples. Excellent antimicrobial ability is also observed in vivo and the micro-CT and histological results reveal notable osseointegration in vivo despite the presence of bacteria. The Zn/Ag micro-galvanic couple formed on Zn/Ag dual-ion co-implanted titanium shows the best osseointegration as well as good antibacterial properties in vivo obtained from a rabbit tibia model. The difference among the three Zn/Ag micro-galvanic couples can be ascribed to the contact between the Ag NPs and Zn film, which affects the corrosion process. Our results indicate that the biological behavior can be controlled by the corrosion process of the Zn/Ag micro-galvanic couples.

Suture materials affect peri-implant bone healing and implant osseointegration.

The aim of this study was to evaluate the effects of the remnants of two suture materials on osseointegration of titanium implants in a rabbit tibial model. Calibrated defects were prepared in the tibia of five Chinchilla rabbits. Filaments of nonresorbable (NR) nylon or resorbable (R) chitosan were placed at the bone to implant interface, whereas control sites had no suture material. After a healing period of 4 weeks, a pull-out test procedure was performed followed by enzymatic analyses of the wound fluid and relative quantification of mRNA levels for bone-related and cytokine markers from the peri-implant bone. A trend toward a reduced pull-out force was observed in the NR group (NR: 23.0 ± 12.8 N; R: 33.9 ± 11.3 N; control: 33.6 ± 24.0 N). Similarly, the bone resorption marker vacuolar type H+-ATPase was increased in the NR group compared with that in the control group (P = 0.041). The R group showed trends for lower alkaline phosphatase activity and osteocalcin expression and higher total protein content and RNA compared with the control group. In this submerged healing model, peri-implant bone healing was marginally affected by the two suture materials tested. However, there was a tendency toward better osseointegration and lower expression of bone resorption markers in the R group compared with the control group.