Sequential osseointegration of a novel implant system based on 3D printing in comparison with conventional titanium implants

Biomechanical and histomorphometric evaluation of biodegradable mini-implants for orthodontic anchorage in the mandible of beagle dogs

OBJECTIVE

To evaluate the effectiveness of a mini-implant composed of unsintered hydroxyapatite, poly (L-lactic acid) and poly(lactic-co-glycolic acid) (u-HA/PLLA/PLGA) composites as an anchorage device under consistent orthodontic force (OF) loading in vivo.

METHODS

An mandible model in beagle dogs was introduced. 144 mini-implants were implanted in both sides of the mandibles. The mini-implants in the experimental group (left side) were loaded at the magnitude of 200 g to simulate the OF. At 2, 4 and 6 months after implantation, tissue specimens were taken from the implanted sites and biomechanical, histological and histomorphometrical analysis were performed.

RESULTS

Mini-implants in the group with the highest PLLA ratio showed a 27% non-fracture rate after 4 months and 20.83% after 6 months in beagle dogs, and the non-fractured mini-implants could maintain the tensile force of 200 g, while mini-implants in the other two groups were all fractured. Histomorphological analysis showed that there was no significant relationship between Bone Volume over Total Volume (BV/TV) and the implantation time among the most of the groups. The level of Bone-Implant Contact ratio (BIC) in Medium and Low ratio group were decreased gradually from 2 to 6 months.

CONCLUSIONS

This study showed the biodegradable mini-implant could work as an alternative to the titanium alloy mini-implant by adjusting the proportion of its ingredients.

CLINICAL RELEVANCE

Degradable mini-implants for orthodontic anchorage lie in their potential to revolutionize orthodontic treatments by offering a biodegradable alternative that minimizes the need for secondary surgeries for removal, thereby enhancing patient comfort and reducing overall treatment time.

Histomorphometric Analysis of Osseointegrated Intraosseous Dental Implants Using Undecalcified Specimens: A Scoping Review

Bone histology and histomorphometry are reliable diagnostic tools for the assessment of the bone-implant interface, material safety and biocompatibility, and tissue response. They allow for the qualitative and quantitative analysis of undecalcified bone specimens. This scoping review aims to identify the most common staining techniques, study models for in vivo experiments, and histomorphometric parameters used for quantitative bone evaluation of osseointegrated dental implants in the last decade. The Web of Science, PubMed, and Scopus databases were searched on 1 July 2024 for relevant articles in English, published in the last ten years, and the data were exported to an MS Excel spreadsheet. A total of 115 studies met the eligibility criteria and were included in the present review. The results indicate that the most common study models are dogs, rabbits, and pigs. Some of the most frequently used methods for the assessment of the bone-implant interface are the Toluidine blue, Stevenel's blue with Van Gieson, and Levai-Laczko stainings. The results from this study demonstrate that the most commonly used histomorphometric parameters in implant dentistry are the bone-to-implant contact (BIC), bone area fraction occupancy (BAFO), bone area (BA), and bone density (BD). This review presents the recent trends in histomorphometric analysis of dental implants and identifies some research gaps that necessitate further research.

Impact of Implant Surface and Smoking on Peri-Implant Human Bone: What we Learned from The Last 20 Years?

The present review summarizes the findings from human histological studies conducted over the past 20 years at the University of Guarulhos, Brazil, examining the impact of various implant surface topographies and smoking on peri-implant bone response. Seven different implant surfaces were evaluated in 90 partially or completely edentulous individuals using a total of 123 micro-implants. Histometric parameters, including bone-implant contact (BIC%), bone area within the threads (BA%), and bone density (BD), were assessed after an 8-week healing period. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were also performed. Results showed that treated surfaces, regardless of the treatment type, consistently demonstrated better histometric outcomes compared to machined surfaces. Anodized surfaces and those subjected to airborne particle abrasion, followed by acid etching, exhibited higher BIC% values than machined surfaces in smoker patients. Smoking reduced BIC% around anodized implants. The presence of inflammatory cells was observed adjacent to the peri-implant soft tissue on some treated surfaces. In conclusion, implant surface topography significantly influences early bone response under unloaded conditions, with treated surfaces promoting better human bone tissue response than machined surfaces. However, smoking negatively impacts peri-implant bone healing, emphasizing the importance of smoking cessation for optimal osseointegration.

Immediate Loading Full-Arch 3D-Printed Implant-Supported Fixed Rehabilitation: A Case Report with 24-Month Follow-Up

Implant-supported immediate loading full-arch rehabilitation has been documented in the literature. More recently, computed surgical guides have frequently been used since they facilitate planning and performing surgical treatment without the need to raise a flap, thus reducing trauma and morbidity. This case report describes an immediate full-arch, fixed rehabilitation with full loading placed on four commercially available 3D-printed implants, with a 24-month follow-up. The implants were placed with the help of a digitally planned 3D-printed surgical guide. The provisional fixed prosthesis installed immediately was replaced after 3 months. At the time, the soft and hard tissue around the implants appeared stable, without signs of inflammation. The same situation was observed at the 24-month follow-up. Three-dimensional-printed implants seem to be a promising choice in this case. However, further clinical studies with longer follow-up periods are necessary to confirm their efficacy.

Titanium: A systematic review of the relationship between crystallographic profile and cell adhesion

Dental implant surface properties such as roughness, wettability, and porosity ensure cell interaction and tissue integration. The clinical performance of dental implants depends on the crystallographic texture and protein and cell bonds to the substrates, where grain size, orientation, and inclination are parameters responsible for favoring osteoblast adhesion and limiting bacterial adhesion. The lack of consensus on the best crystallographic plan for cell adhesion prompted this systematic review, which aims to answer the following question: "What is the influence of the crystallographic plane on titanium surfaces on cell adhesion?" by evaluating the literature on the crystallographic characteristics of titanium and how these dictate topographical parameters and influence the cell adhesion of devices made from this material. It followed the Preferred Reporting Standards for Systematic Reviews and Meta-Analyses (PRISMA 2020) registered with the Open Science Framework (OSF) (osf.io/xq6kv). The search strategy was based on the PICOS method. It chose in vitro articles that analyzed crystallographic structure correlated with cell adhesion and investigated the microstructure and its effects on cell culture, different crystal orientation distributions, and the influence of crystallinity. The search strategies were applied to the different electronic databases: PubMed, Scopus, Science Direct, Embase, and Google Scholar, and the articles found were attached to the Rayyan digital platform and assessed blindly. The Joanna Bringgs Institute (JBI) tool assessed the risk of bias. A total of 248 articles were found. After removing duplicates, 192 were analyzed by title and abstract. Of these, 18 were selected for detailed reading in their entirety, 9 of which met the eligibility criteria. The included studies presented a low risk of bias. The role of the crystallographic orientation of the exposed faces in a multicrystalline material is little discussed in the scientific literature and its impact is recognized as dictating the topographical characteristics of the material that facilitate cell adhesion.

Digital Implant-Supported Restoration Planning Placed in Autologous Graft Using Titanium Implants Produced by Additive Manufacturing

This clinical report presents a technique to reconstruct extensively resected mandibles using a combination of autologous bone grafts and additive manufacturing techniques. Mandibular defects, often arising from trauma, tumors, or congenital anomalies, can severely impact both function and aesthetics. Conventional reconstruction methods have their limitations, often resulting in suboptimal outcomes. In these reports, we detail clinical cases where patients with different mandibular defects underwent reconstructive surgery. In each instance, autologous grafts were harvested to ensure the restoration of native bone tissue, while advanced virtual planning techniques were employed for precise graft design and dental implant placement. The patients experienced substantial improvements in masticatory function, speech, and facial aesthetics. Utilizing autologous grafts minimized the risk of rejection and complications associated with foreign materials. The integration of virtual planning precision allowed customized solutions, reducing surgical duration and optimizing implant positioning. These 2 cases underscores the potential of combining autologous grafts with virtual planning precision and dental implants produced by additive manufacturing for mandible reconstruction.

Additive Manufacturing Titanium Dental Implants Placed in Sinuses Grafted with 70HA:30-TCP: A One-Year Retrospective Study for Evaluation of Survival Rate

The present short-term retrospective study evaluated the implant survival rate and peri-implant bone loss around additive-manufactured titanium implants placed in sinuses grafted with Plenum Osshp (Plenum Bioengenharia, Jundia, SP, Brazil) (70HA:30β-TCP) material. A total of 39 implants were inserted after 23 sinus floor elevation procedures in 16 consecutive patients. Prosthetic rehabilitation included fixed partial prostheses (three units), single crowns (eleven units), and fixed full arches (three units). Clinical and radiographic parameters of implant-supported restorations were evaluated after at least one year of occlusal loading. The implant-crown success criteria included the absence of pain, suppuration, and clinical mobility, an average distance between the implant shoulder and the first visible bone contact (DIB) < 1.0 mm from the initial surgery, and the absence of prosthetic complications at the implant-abutment interface. The overall cumulative implant survival rate was 97.43%. No prosthetic complications at the implant-abutment interface were reported. After one year, the mean DIB was 0.23 mm ± 0.14. Within the limits of this retrospective study, it can be concluded that 70 HA:30 β-TCP allowed stable and reliable bone support to maintain healthy conditions around titanium dental implants produced by additive manufacturing.

Pioneering nanomedicine in orthopedic treatment care: a review of current research and practices

A developing use of nanotechnology in medicine involves using nanoparticles to administer drugs, genes, biologicals, or other materials to targeted cell types, such as cancer cells. In healthcare, nanotechnology has brought about revolutionary changes in the treatment of various medical and surgical conditions, including in orthopedic. Its clinical applications in surgery range from developing surgical instruments and suture materials to enhancing imaging techniques, targeted drug delivery, visualization methods, and wound healing procedures. Notably, nanotechnology plays a significant role in preventing, diagnosing, and treating orthopedic disorders, which is crucial for patients' functional rehabilitation. The integration of nanotechnology improves standards of patient care, fuels research endeavors, facilitates clinical trials, and eventually improves the patient's quality of life. Looking ahead, nanotechnology holds promise for achieving sustained success in numerous surgical disciplines, including orthopedic surgery, in the years to come. This review aims to focus on the application of nanotechnology in orthopedic surgery, highlighting the recent development and future perspective to bridge the bridge for clinical translation.

The bone morphogenetic protein 2 analogue L51P enhances spinal fusion in combination with BMP2 in an in vivo rat tail model

Bone morphogenic protein 2 (BMP2) is known to induce osteogenesis and is applied clinically to enhance spinal fusion despite adverse effects. BMP2 needs to be used in high doses to be effective due to the presence of BMP2 inhibitors. L51P is a BMP2 analogue that acts by inhibition of BMP2 inhibitors. Here, we hypothesized that mixtures of BMP2 and L51P could achieve better spinal fusion outcomes regarding ossification. To test whether mixtures of both cytokines are sufficient to improve ossification, 45 elderly Wistar rats (of which 21 were males) were assigned to seven experimental groups, all which received spinal fusion surgery, including discectomy at the caudal 4-5 level using an external fixator and a porous β-tricalcium phosphate (βTCP) carrier. These βTCP carriers were coated with varying concentrations of BMP2 and L51P. X-rays were taken immediately after surgery and again six and twelve weeks post-operatively. Histological sections and µCT were analyzed after twelve weeks. Spinal fusion was assessed using X-ray, µCT and histology according to the Bridwell scale by voxel-based quantification and a semi-quantitative histological score, respectively. The results were congruent across modalities and revealed high ossification for high-dose BMP2 (10 µg), while PBS induced no ossification. Low-dose BMP2 (1 µg) or 10 µg L51P alone did not induce relevant bone formation. However, all combinations of low-dose BMP2 with L51P (1 µg + 1/5/10 µg) were able to induce similar ossificationas high-dose BMP2. These results are of high clinical relevance, as they indicate L51P is sufficient to increase the efficacy of BMP2 and thus lower the required dose for spinal fusion. STATEMENT OF SIGNIFICANCE: Spinal fusion surgery is frequently applied to treat spinal pathologies. Bone Morphogenic Protein-2 (BMP2) has been approved by the U .S. Food and Drug Administration (FDA-) and by the "Conformité Européenne" (CE)-label. However, its application is expensive and high concentrations cause side-effects. This research targets the improvement of the efficacy of BMP2 in spinal fusion surgery.