Bone-implant Contact Research Articles

Comparative Evaluation of Bone–Implant Contact in Various Surface-Treated Dental Implants Using High-Resolution Micro-CT in Rabbits’ Bone

This study evaluated the bone-to-implant contact (BIC) of various surface-treated dental implants using high-resolution micro-CT in rabbit bone, focusing on the effects of different treatments on osseointegration and implant stability before and after bone demineralization. Six male New Zealand White rabbits were used. Four implant types were tested: machined surface with anodizing, only etching, sandblasting with Al2O3 + etching, and sandblasting with TiO2 + etching. Implants were scanned with high-resolution micro-CT before and after demineralization. Parameters like implant volume, surface area, and BIC were determined using specific software tools. During demineralization, the BIC changed about 6% for machined surface with anodizing, 5% for only etching, 4% for sandblasting with Al2O3 + etching, and 10% for sandblasting with TiO2 + etching. Demineralization reduced BIC percentages, notably in the machined surface with anodizing and sandblasting with TiO2 + etching groups. Etching and sandblasting combined with etching showed higher initial BIC compared to anodizing alone. Demineralization negatively impacted the BIC across all treatments. This study underscores the importance of surface modification in implant integration, especially in compromised bone. Further research with larger sample sizes and advanced techniques is recommended.

Does an Osteoporosis-like Condition Jeopardize the Osseointegration Process around Dental Implants Placed in Animal Models? A Systematic Review.

Knowing that osteoporosis is a metabolic disease that could decrease dental implant success and survival, the purpose of this review was to gather information on the characteristics of implant osseointegration in animal models of induced osteoporosis. By pointing out the role of some factors that could improve the success rate in these situations, this study aimed to enhance the knowledge about this process that can be further translated to clinical designs. A systematic search in PubMed/Medline, Lilacs, Cochrane Library, Scopus and Web of Science was conducted to identify information between 2002 and 2023 regarding osseointegration of dental implants in animal models of induced osteoporosis. The following search strategy was utilized and adjusted to each database: (((dental implant) AND (Osseointegration)) AND (osteoporosis)) AND/OR (osteoporosis treatment). The inclusion criteria were animal studies in English, involving the placement of an osseointegrated implant in osteoporotic bone, and evaluating bone to implant contact (BIC) %. Exclusion criteria were studies in humans, in vitro studies, procedures involving any kind of bone graft and studies evaluating medication related osteonecrosis of the jaw. A standardized data extraction form was used to record data for each study, covering article title, date, authors, number of animals, purpose of study, type of analysis used by authors, follow-up, type of implant, test and control groups, intervention and conclusions. The risk of bias of the included studies was assessed using the Systematic Review Centre for Laboratory animal Experimentation (SYRCLE) Risk of Bias tool.20 Results: A total of 204 articles were found for evaluation and selection. All of the 43 selected studies evaluated the bone-implant contact (BIC) %. Other parameters such as bone to implant mechanical interface, bone area (BA) and bone volume (BV) ratio were also evaluated in some of the studies. There was a tendency for compromised results of implant osseointegration in the presence of osteoporosis. Modification of the implant surface, systemic and local use of anti-resorptive drugs and other substances, showed benefits for the implant success in osteoporotic sites. Still, no consensus among studies on the superiority of systemic medications in improving the process of peri-implant bone repair, was observed. Although it is possible to improve the osseointegration of implants in osteoporotic bone, either by using systemic or local factors, the metabolic bone syndrome caused by osteoporosis can jeopardize the osseointegration of dental implants.

Nonlinear Finite Element Analysis of Bone–Implant Contact in Three Short Dental Implant Models with Varying Osseointegration Percentages

Objectives: Dental implants have become a cornerstone of restorative dentistry, providing a long-lasting method for tooth replacement. The degree of osseointegration has a significant effect on biomechanical stability at the bone–implant contact (BIC), determining the continued efficacy of these implants. However, the exact consequences of changing osseointegration levels on different implant designs, especially in bones with variable densities, are not well known. Methods: This study used 3D finite element analysis (FEA) to look at the biomechanical performance of three short dental implants: BioMet 3iT3, Straumann® Standard Plus Short-Regular Neck (SPS-RN), and Straumann® Standard Plus Short-Wide Neck (SPS-WN). This paper tested the implants at four stages of osseointegration: 25%, 50%, 75%, and 100% in both high-density (bone type III) and low-density (bone type IV) cancellous bone. It also created and examined realistic CAD models under static occlusal loading conditions to assess stress distribution and major strains at the bone–implant contact. Results: The study discovered that as osseointegration increases, von Mises stress and principal strains go down significantly for all implant types. The SPS-WN implant had the lowest strain values, especially for bone with low density. These reductions demonstrate increased mechanical stability as the bone–implant interface becomes more capable of dispersing mechanical stresses, minimizing the potential for localized deformation and bone resorption. Conclusions: The results highlight the importance of achieving optimum osseointegration to reduce mechanical stress and increase the lifespan of dental implants. The SPS-WN type implant performed better in biomechanical tests than the others, especially when bone conditions were not ideal. This makes it a great choice for clinical applications that need long-term implant success.

Evaluation of biocompatibility and osseointegration of multi-component TiAl6V4 titanium alloy implants.

This study aimed to investigate the biocompatibility and osseointegration of novel titanium (Ti) implants with a perforated part with high surface roughness (Ra >4 μm) and a smooth solid part (test group), as compared to smooth solid Ti implants (control group; Ra < 0.8 μm). Test and control implants were implanted in rabbit femurs. After 4 and 15 weeks, host tissue reaction and quality of tissue formed were evaluated with histopathology, while micro-CT scans were used to quantitatively assess bone-implant contact (BIC), surrounding bone formation, and bone ingrowth. After 4 and 15 weeks, minimal host reaction was found in the test group. Histopathological analysis showed new bone formation around the implants in both the test and control groups after 4 weeks. Furthermore, additional bone growth was often observed within the holes of the test implants. After 15 weeks, the test implants showed high bone ingrowth and the presence of mature bone in direct contact with the implant surface, whereas, bone ingrowth was poorer for the control group with 30% of the control implants, showing larger gaps at the bone-implant interface. Quantitative micro-CT analysis revealed comparable BIC and bone formation in both groups at 4 weeks, but higher BIC and more bone formation in the test group than in the control group after 15 weeks. No significant differences were observed in any of the analyses. In conclusion, partially perforated, high-roughness Ti implants showed excellent osseointegration and minimal host reaction, indicating their potential for orthopedic applications in bone repair and regeneration.

Adoptive transfer of immunomodulatory macrophages reduces the pro-inflammatory microenvironment and increases bone formation on titanium implants

Macrophages play a central role in orchestrating the inflammatory response to implanted biomaterials and are sensitive to changes in the chemical and physical characteristics of the implant. Macrophages respond to biological, chemical, and physical cues by polarizing into pro-inflammatory (M1) or anti-inflammatory (M2) states. We previously showed that rough-hydrophilic titanium (Ti) implants skew macrophage polarization towards an anti-inflammatory phenotype and increase mesenchymal stem cell (MSC) recruitment and bone formation around the implant. In the present study, we aimed to investigate whether the adoptive transfer of macrophages in different polarization states would alter the inflammatory microenvironment and improve biomaterial integration in macrophage-competent and macrophage-ablated mice. We found that ablating macrophages increased the presence of neutrophils, reduced T cells and MSCs, and compromised the healing and biomaterial integration process. These effects could not be rescued with adoptive transfer of naïve or polarized macrophages. Adoptive transfer of M1 macrophages into macrophage-competent mice increased inflammatory cells and inflammatory microenvironment, resulting in decreased bone-to-implant contact. Adoptive transfer of M2 macrophages into macrophage-competent mice reduced the pro-inflammatory environment in the peri‑implant tissue and increased bone-to-implant contact. Taken together, our results show the importance of macrophages in controlling and modulating the inflammatory process in response to implanted biomaterials and suggest they can be used to improve outcomes following biomaterial implantation. Statement of significanceMacrophages are central in orchestrating the inflammatory response to implanted biomaterials and are sensitive to biomaterial chemical and physical characteristics. Our study shows that a deficiency of macrophages results in prolonged inflammation and abolishes bone-biomaterial integration. Adoptive transfer of immunomodulatory macrophages into macrophage-competent mice reduced the inflammatory environment and increased bone-implant contact.

Hyperbranched Poly-l-Lysine Modified Titanium Surface With Enhanced Osseointegration, Bacteriostasis, and Anti-Inflammatory Properties for Implant Application: AnExperimental InVivo Study.

This study aimed to explore multiple effects of hyperbranched poly-l-lysine (HBPL) titanium (Ti) surfaces on osseointegration, bacteriostasis, and anti-inflammation across three different animal models. Ti surfaces were covalently modified with HBPL, with uncoated surfaces as controls. Characterization included scanning electron microscopy (SEM) and surface chemistry and elemental analysis (EDX). Ti and Ti-HBPL implants were placed in conventional canine edentulous sites, post-operative infection canine edentulous sites, and diabetic rat tibias. Implants from canine edentulous models were analyzed using micro-CT and histomorphometry to assess osseointegration at 8 weeks. Post-operative infection beagles were used to evaluate antibacterial efficacy through clinical parameters and bacterial cultures at 1 week. In diabetic rats, micro-CT and histomorphometry were performed at 8 weeks. HBPL was uniformly grafted on Ti-HBPL surfaces. Ti-HBPL surfaces showed higher bone volume/total volume (BV/TV, p < 0.001), bone-implant contact (BIC%, p < 0.001), and trabecular number (Tb.N, p < 0.01) in beagles. Besides, it displayed higher BIC% (p < 0.001) and bone area fraction occupancy (BAFO%, p < 0.01) in hard tissue sections. In an infected model, Ti-HBPL surfaces exhibited lower bleeding on probing (BOP, p < 0.001), and plaque index (DI, p < 0.01), with reduced bacterial colony formation (p < 0.001) compared to the control group. In diabetic rats, Ti-HBPL surfaces showed an increase in BV/TV (p < 0.01) and Tb.N (p < 0.001), downregulated TNF-α and IL-1β (p < 0.01), and upregulated IL-10 (p < 0.01) and osteocalcin (OCN) expression (p < 0.01). HBPL-Ti surfaces demonstrated enhanced osseointegration, bacteriostasis, and anti-inflammatory effects invivo.

Biocompatibility and dimensional stability through the use of 3D-printed scaffolds made by polycaprolactone and bioglass-7: An in vitro and in vivo study.

This experiment aimed to observe the differences in biological properties by producing BGS-7 + PCL scaffolds with different weight fractions of BGS-7 through 3D printing and to confirm whether using the scaffold for vertical bone augmentation is effective. Cube-shaped bioglass (BGS-7) and polycaprolactone (PCL) scaffolds with different weight fractions (PCL alone, PCL with 15% and 30% BGS-7) are produced using 3D printing. The surface hydroxyapatite (HA) apposition, the pH change, proliferation and attachment assays, and various gene expression levels are assessed. After a 7-mm implant was inserted 3 mm into the rabbit calvaria, vertical bone augmentation is performed around the implant and inside the scaffold in four ways: scaffold only, scaffold+bone graft, bone graft only, and no graft. Sacrifice is performed at 6, 12, and 24 weeks, and the various parameters are compared radiographically and histologically. HA apposition, cell proliferation, cell attachment, and expression of osteogenic genes increase as the proportion of BGS-7 increase. In the in vivo test, a higher bone-implant contact ratio, bone volume ratio, bone mineral density, and new bone area are observed when the scaffold and bone grafts were used together. The 3D-printed scaffold, a mixture of BGS-7 and PCL, exhibit higher biological compatibility as the proportion of BGS-7 increase. Additionally, the use of scaffold is effective for vertical bone augmentation.

The Biocompatibility and the Effect of Titanium and PEKK on the Osseointegration of Customized Facial Implants.

The purpose of this study was to investigate the optimization of computer-aided design/computer-aided manufacturing (CAD/CAM) patient-specific implants for mandibular facial bone defects and compare the biocompatibility and osseointegration of machined titanium (Ma), Sandblasted/Large-grit/Acid-etched (SLA) titanium, and polyetherketoneketone (PEKK) facial implants. We hypothesized that the facial implants made of SLA titanium had superior osseointegration when applied to the gonial angle defect and prevented the senile atrophy of the bone. Histologic findings of the soft-tissue reaction, hard-tissue reaction, and bone-implant contact (BIC (%) of 24 Ma, SLA, and PEKK facial implants at 8 and 12 weeks were investigated. There was no statistical difference in the soft tissue reaction. Bone was formed below the periosteum in all facial implants at 12 weeks and the BIC values were significantly different at both 8 and 12 weeks (p < 0.05). Ma, SLA, and PEKK facial implants are biocompatible with osseointegration properties. SLA can enhance osseointegration and provoke minimal soft tissue reactions, making them the most suitable choice. They provide an excellent environment for bone regeneration and, over the long term, may prevent atrophy caused by an aging mandible. The bone formation between the lateral surface of the facial implant and periosteum may assist in osseointegration and stabilization.

The current role of CT in total knee arthroplasty.

Advanced 3D imaging and CT-based navigation have emerged as valuable tools to use in total knee arthroplasty (TKA), for both preoperative planning and the intraoperative execution of different philosophies of alignment. Preoperative planning using CT-based 3D imaging enables more accurate prediction of the size of components, enhancing surgical workflow and optimizing the precision of the positioning of components. Surgeons can assess alignment, osteophytes, and arthritic changes better. These scans provide improved insights into the patellofemoral joint and facilitate tibial sizing and the evaluation of implant-bone contact area in cementless TKA. Preoperative CT imaging is also required for the development of patient-specific instrumentation cutting guides, aiming to reduce intraoperative blood loss and improve the surgical technique in complex cases. Intraoperative CT-based navigation and haptic guidance facilitates precise execution of the preoperative plan, aiming for optimal positioning of the components and accurate alignment, as determined by the surgeon's philosophy. It also helps reduce iatrogenic injury to the periarticular soft-tissue structures with subsequent reduction in the local and systemic inflammatory response, enhancing early outcomes. Despite the increased costs and radiation exposure associated with CT-based navigation, these many benefits have facilitated the adoption of imaged based robotic surgery into routine practice. Further research on ultra-low-dose CT scans and exploration of the possible translation of the use of 3D imaging into improved clinical outcomes are required to justify its broader implementation.

Correlation between Implant Surface Roughness and Implant Stability: A Systematic Review.

The aim of this study was to find in the literature data on the relationship between implant surface roughness and implant stability achieved, from the time of placement to three months afterward, to help us to know what type of surface roughness is more favorable to guarantee implant stability and osseointegration. A systematic review was conducted in accordance with the PRISMA 2020 (Preferred Reporting Items for Systematic Review and Meta-analysis) statement, and the protocol was registered on the Open Science Framework. The specific inclusion and exclusion criteria were selected using the PICOS framework. The databases Medline (PubMed), Scopus, the Web of Science and The Cochrane Library were searched up to October 2023. The selection of studies and data extraction were conducted by two independent reviewers. The review included a total of 11 studies. A total of 1331 dental implant placements were identified. Two of the eleven selected studies were on humans in vivo, eight were on animals in vivo, and one was on animals in vitro. A statistically significant correlation between surface roughness and implant stability as measured by resonance frequency analysis (RFA) was not identified in ten of the eleven selected studies. It appears that there is no correlation between primary stability and the degree of implant roughness. However, there appears to be a correlation between the roughness of the implant and the degree of osseointegration, as indicated by bone-implant contact values. This correlation is more closely related to secondary stability. The great methodological variability makes it difficult to compare data and draw conclusions, so it would be desirable to agree on a common methodology to help draw appropriate conclusions from published studies.

Osseointegrative and antimicrobial properties of graphene oxide nano coated dental implants: A systematic review.

Osseointegration stands as a pivotal concept within the realm of dental implants, signifying the intricate process through which a dental implant integrates with the adjoining bone tissue. Graphene oxide (GO) has been shown to promote osseointegration, the process by which the implant fuses with the surrounding bone. The objective of this study was to assess the osseointegrative and antimicrobial properties of GO nano coated dental implants. A systematic search was conducted using electronic databases (e.g., PubMed, Scopus, Web of Science) to identify relevant studies published. Inclusion criteria encompassed studies that evaluated the effects of GO nano coating on osseointegrative and antimicrobial characteristics of dental implants. Studies not written in English and published before 2012 were excluded. The initial search yielded a total of 127 potential studies, of which six met the inclusion criteria and five were included in the review. These studies provided data on GO nano coated dental implants and their osseointegrative and antimicrobial properties. All the included studies showed moderate risk of bias. None of the studies provided information related to sample size calculation or sampling technique. The findings from the included studies demonstrated that GO nano coating had a positive impact on osseointegrative properties of dental implants. Enhanced bone-implant contact and increased bone density were observed in animals and humans receiving GO nano coated implants. Furthermore, the antimicrobial properties of GO nano coating were found to inhibit bacterial colonization and biofilm formation on the implant surface, reducing the risk of implant-associated infections. The findings indicate that GO nano coating holds promise in enhancing the success rate and longevity of dental implants. However, more studies with larger sample sizes, are needed to further strengthen the evidence and determine the long-term effects of GO nano coated dental implants.

Effects of electrical stimulation with alternating fields on the osseointegration of titanium implants in the rabbit tibia - a pilot study.

Introduction: Electrical stimulation has been used as a promising approach in bone repair for several decades. However, the therapeutic use is hampered by inconsistent results due to a lack of standardized application protocols. Recently, electrical stimulation has been considered for the improvement of the osseointegration of dental and endoprosthetic implants. Methods: In a pilot study, the suitability of a specifically developed device for electrical stimulation in situ was assessed. Here, the impact of alternating electric fields on implant osseointegration was tested in a gap model using New Zealand White Rabbits. Stimulation parameters were transmitted to the device via a radio transceiver, thus allowing for real-time monitoring and, if required, variations of stimulation parameters. The effect of electrical stimulation on implant osseointegration was quantified by the bone-implant contact (BIC) assessed by histomorphometric (2D) and µCT (3D) analysis. Results: Direct stimulation with an alternating electric potential of 150mV and 20Hz for three times a day (45min per unit) resulted in improved osseointegration of the triangular titanium implants in the tibiae of the rabbits. The ratio of bone area in histomorphometry (2D analysis) and bone volume (3D analysis) around the implant were significantly increased after stimulation compared to the untreated controls at sacrifice 84days after implantation. Conclusion: The developed experimental design of an electrical stimulation system, which was directly located in the defect zone of rabbit tibiae, provided feedback regarding the integrity of the stimulation device throughout an experiment and would allow variations in the stimulation parameters in future studies. Within this study, electrical stimulation resulted in enhanced implant osseointegration. However, direct electrical stimulation of bone tissue requires the definition of dose-response curves and optimal duration of treatment, which should be the subject of subsequent studies.

Osteoproductivity of Injectable Bone Grafts with and without Ostrich Eggshell Membrane Protein in Rabbit Femur.

The aim of this study was to evaluate the biocompatibility and effectiveness in terms of osseointegration of dental implants composed of novel injectable bone grafts with and without ostrich eggshell particles and membrane protein in rabbit femur. Sixteen adult male New Zealand rabbits were used in this study. A bone defect was created in each animal's right and left femur, and a dental implant was placed adjacent to the defect. Two graft materials were prepared, one containing the membrane protein and the other not. In two groups, the defects were filled with these materials. In the negative control group (NC, (n:8)), the defects were left empty. A commercial product of biphasic calcium sulfate was used as a positive control material (PC, n = 8). The graft groups were defined as the group with the membrane protein (MP+, (n:8)), and without the membrane protein (MP-, n:8). The animals were euthanized at the 12th week after surgery. The samples were investigated using histology, histomorphometry, and micro-computed tomography. Data were statistically analyzed using one-way ANOVA and Tukey's tests (p = 0.05). Both the PC and MP+ groups had similar newly formed bone areas, and the mean values of these groups were significantly (p < 0.05) higher than those of the MP- and NC groups. The PC group had the highest amount of unresorbed material, while the MP- group had the lowest amount of unresorbed material. The bone-implant contact (BIC) scores of the PC and MP+ groups were significantly higher (p < 0.05) than that of the NC group. The connective tissue area of the PC group was the lowest, which was significantly lower than the other groups (p < 0.05). The grafts produced are highly biocompatible and also showed osteoproductivity. Their cost-effectiveness and osteoproductive activity require further investigation.

Therapeutic Efficacy of an Erythromycin-Loaded Coaxial Nanofiber Coating in a Rat Model of S. aureus-Induced Periprosthetic Joint Infection.

Implant surface nanofiber (NF) coatings represent an alternative way to prevent/treat periprosthetic joint infection (PJI) via local drug release. We developed and characterized a coaxial erythromycin (EM)-doped PLGA/PCL-PVA NF coating. The purpose of this study was to determine the efficacy of EM-NF coatings (EM0, no EM, EM100 (100 mg/mL), and EM1000 (1000 mg/mL) wt/wt) in a rat PJI model. A strong bond of the EM-NF coating to the surface of titanium (Ti) pins was confirmed by in vitro mechanical testing. Micro-computed tomography (mCT) analysis showed that both EM100 and EM1000 NF effectively reduced periprosthetic osteolysis compared to EM0 at 8 and 16 weeks after implantation. Histology showed that EM100 and EM1000 coatings effectively controlled infection and enhanced periprosthetic new bone formation. The bone implant contact (BIC) of EM100 (35.08%) was higher than negative controls and EM0 (3.43% and 0%, respectively). The bone area fraction occupancy (BAFO) of EM100 (0.63 mm2) was greater than controls and EM0 (0.390 mm2 and 0.0 mm2, respectively). The BAFO of EM100 was higher than that of EM1000 (0.3 mm2). These findings may provide a basis for a new implant surface fabrication strategy aimed at reducing the risks of defective osseointegration and PJI.

Automated design of bone-preserving, insertable, and shape-matching patient-specific acetabular components.

Effective treatment of large acetabular defects remains among the most challenging aspects of revision total hip arthroplasty (THA), due to the deficiency of healthy bone stock and degradation of the support columns. Generic uncemented components, which are favored in primary THA, are often unsuitable in revision cases, where the bone-implant contact may be insufficient for fixation, without significant reaming of the limited residual bone. This study presents a computational design strategy for automatically generating patient-specific implants that simultaneously maximize the bone-implant contact area, and minimize bone reaming while ensuring insertability. These components can be manufactured using the same additive manufacturing methods as porous components and may reduce cost and operating-time, compared to existing patient-specific systems. This study compares the performance of implants generated via the proposed method to optimally fitted hemispherical implants, in terms of the achievable bone-implant contact surface, and the volume of reamed bone. Computer-simulated results based on the reconstruction of a set of 15 severe pelvic defects (Paprosky 2A-3B) suggest that the patient-specific components increase bone-implant contact by 63% (median: 63%; SD: 44%; 95% CI: 52.3%-74.0%; RMSD: 42%), and reduce the volume of reamed bone stock by 97% (median: 98%; SD: 4%; 95% CI: 95.9%-97.4%; RMSD: 3.7%).

Effect of depression and the antidepressant fluoxetine on osseointegration-A pre-clinical invivo experimental study.

The aim of this study was to explore the effect of depression and selective serotonin reuptake inhibitors on implant osseointegration and bone healing. Forty-eight 6- to 8-week-old SPF Sprague-Dawley male rats were randomly divided into four groups: the Control group, the Fluoxetine group, the Depression group and the De&Flu group. The rats in the Depression group and the De&Flu group were subjected to a depression modelling process, and the rats in the Control group and the Fluoxetine group were raised normally. Then, a titanium implant was placed in the right tibia of each rat. In the Fluoxetine group and De&Flu group, fluoxetine was injected subcutaneously daily, while subcutaneously injecting physiological saline in the Control group and Depression group. Collecting serum from the rats used for ELISA. The surgical area was cut for microcomputed tomography and histology observation. After 12 weeks, bone mineral density was lower in the De&Flu group than in the Control group, Depression group and Fluoxetine group. Bone mineral density was also lower in the Depression group and the Fluoxetine group than in the Control group. The percentage of bone-implant contact (BIC%) in De&Flu rats was lower than in the Control, Depression and Fluoxetine groups. The BIC% in the Depression group and the Fluoxetine group was lower than in the Control group. Depression and fluoxetine negatively affect bone density and implant osseointegration independently, and this damaging effect is exacerbated when both factors are present. The mechanism may be related to the dysregulation of the hypothalamic-pituitary-adrenal axis and inflammation in the body.

Mesoscale characterization of osseointegration around an additively manufactured genistein-coated implant

Given the hierarchical nature of bone and bone interfaces, osseointegration, namely the formation of a direct bone-implant contact, is best evaluated using a multiscale approach. However, a trade-off exists between field of view and spatial resolution, making it challenging to image large volumes with high resolution. In this study, we combine established electron microscopy techniques to probe bone-implant interfaces at the microscale and nanoscale with plasma focused ion beam-scanning electron microscopy (PFIB-SEM) tomography to evaluate osseointegration at the mesoscale. This characterization workflow is demonstrated for bone response to an additively manufactured Ti-6Al-4V implant which combines engineered porosity to facilitate bone ingrowth and surface functionalization via genistein, a phytoestrogen, to counteract bone loss in osteoporosis. SEM demonstrated new bone formation at the implant site, including in the internal implant pores. At the nanoscale, scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy confirmed the gradual nature of the bone-implant interface. By leveraging mesoscale analysis with PFIB-SEM tomography that captures large volumes of bone-implant interface with nearly nanoscale resolution, the presence of mineral ellipsoids varying in size and orientation was revealed. In addition, a well-developed lacuno-canalicular network and mineralization fronts directed both towards the implant and away from it were highlighted.

Cortico-cancellous osseointegration into additively manufactured titanium implants using a load-bearing femoral ovine model.

Introduction: Titanium-based implants can be used to fill voids in bone reconstruction surgery. Through additive manufacturing (AM), it is possible to produce titanium implants with osteoconductive properties such as high porosity and low stiffness. AM facilitates a level of design flexibility and personalization that is not feasible with traditional techniques. Methods: In this study, osseointegration into titanium alloy (Ti-6Al-4V) lattices was investigated for 12weeks post-implantation using a novel bicortical load-bearing ovine model. The objective was to assess the safety and efficacy of AM-fabricated implants using two lattice structures of contrasting stiffness spanning the full width of the femoral condyle. Results: This was achieved by evaluating implant osseointegration and bone-implant contact properties by histomorphometry, scoring local implant tissue responses via histopathology, and micro-computed tomography reconstruction. Discussion: We found that Ti-6Al-4V implants facilitated widespread and extensive osseointegration, with bone maturation ongoing at the conclusion of the trial period. Following the implantation period, no adverse clinical indications that could be directly ascribed to the presence of the implanted device were identified, as determined by macroscopic and microscopic observation.

A Comparative Evaluation of Stress Distribution Around Different Widths of Implant and Bony Interface in Function During Axial and Non-axial Loading: A Finite Element Analysis.

The study employed three-dimensional (3D) finite element analysis (FEA) and examined how implant diameters affect stress distribution across the implant-bone contact and how stress transmission through this interface changes during axial and non-axial loading. A 3D mandibular model was created using cone beam CT of a patient with implants inserted into the first mandible molar. Nobel Biocare implants (Nobel Biocare, Switzerland) with specific dimensions of 3.5 mm, 4.3 mm, 5.0 mm, and 6.0 mm were chosen. Models were created in CATIAV5R19 (Dassault Systemes, France) from threaded titanium implant dimensions. Implants were finite element-modeled utilizing ANSYS Workbench v11.0 (Ansys, Inc, Pennsylvania, USA). The analysis involved applying 100 N axial, 50 N buccolingual, and 50 N mesiodistal loads. In a lower first molar bone segment, the implant top surface was loaded in 100 N axial, 50 N buccolingual, and 50 N mesiodistal orientations. The cortical bone proximal to the implant neck had the most von Mises stress, regardless of model or stress scenario. In Model I cortical bone, maximal stress was centered at the implant neck. Most stress was on lingual bone plates, lesser on buccal, and least on mesial and distal. Less than half of the implant stress was transmitted to the cortical bone. The stress transferred from the implant to the cortical bone in Model II was less than half of the implant stress. The same was true for Models III and IV. In Model I cancellous bone, stress was concentrated in the implant's coronal half and minimal in the apical half. The stress patterns under axial loading were distributed favorably. Therefore, it can be inferred that an augmentation in the diameter of the implant enhances the even distribution of stress at the interface between the bone and the implant by offering a larger surface area for the dispersion of stress. Furthermore, it was determined that applying force along an implant's axis was a beneficial loading direction and did not negatively impact its lifespan.

Sclerostin antibody enhances implant osseointegration in bone with Col1a1 mutation

We evaluated the potential of sclerostin antibody (SclAb) therapy to enhance osseointegration of dental and orthopaedic implants in a mouse model (Brtl/+) mimicking moderate to severe Osteogenesis Imperfecta (OI). To address the challenges in achieving stable implant integration in compromised bone conditions, our aim was to determine the effectiveness of sclerostin antibody (SclAb) at improving bone-to-implant contact and implant fixation strength. Utilizing a combination of micro-computed tomography, mechanical push-in testing, immunohistochemistry, and Western blot analysis, we observed that SclAb treatment significantly enhances bone volume fraction (BV/TV) and bone-implant contact (BIC) in Brtl/+ mice, suggesting a normalization of bone structure toward WT levels. Despite variations in implant survival rates between the maxilla and tibia, SclAb treatment consistently improved implant stability and resistance to mechanical forces, highlighting its potential to overcome the inherent challenges of OI in dental and orthopaedic implant integration. These results suggest that SclAb could be a valuable therapeutic approach for enhancing implant success in compromised bone conditions.