Assessment of Pyrogenic Response of Medical Devices and Biomaterials by the Monocyte Activation Test (MAT): A Systematic Review.

Pyrogens are fever-inducing substances routinely investigated in health products through tests such as the Rabbit Pyrogen Test (RPT), the Limulus Amebocyte Lysate (LAL), and the Monocyte Activation Test (MAT). However, the applications of the MAT for medical devices and biomaterials remain limited. This work aimed to overview the studies evaluating the pyrogenicity of medical devices and biomaterials using the MAT, highlighting its successes and potential challenges. An electronic search was performed by December 2023 in PubMed, Scopus, and Web of Science, identifying 321 records which resulted in ten selected studies. Data were extracted detailing the tested materials, MAT variants, interferences, and comparisons between methods. Methodological quality was assessed using the ToxRTool, and the results were synthesized descriptively. The selected studies investigated various materials, including polymers, metals, and natural compounds, employing the different biological matrices of the MAT. Results showed the MAT's versatility, with successful detection of pyrogens in most materials tested, though variability in sensitivity was noted based on the material and testing conditions. Challenges remain in optimizing protocols for different material properties, such as determining the best methods for direct contact versus eluate testing and addressing the incubation conditions. In conclusion, the MAT demonstrates significant potential as a pyrogen detection method for medical devices and biomaterials. However, continued research is essential to address existing gaps, optimize protocols, and validate the test across a broader range of materials.

Successful Management of a Tooth With an Endodontic-Periodontal Lesion Using a Bone Graft.

As periodontal and endodontic tissues have a close association, they come into close touch and have a lot of possible places for communication. In a clinical setting, this correlation promotes infection spread and results in the typical endo-perio lesion appearance. Because the two tissues are in close touch with one another, managing such lesions can be difficult. The success of treatment depends on a thorough examination and careful planning, with the sole focus on repair and regeneration. In these situations, bone graft materials with such characteristics have demonstrated encouraging outcomes. The treatment outcome along with a follow-up for a case of an endo-perio lesion with furcation involvement is shown in the accompanying case report. In treating such instances, a multidisciplinary approach is necessary, emphasizing regeneration.

One-Stage Lateral Sinus Floor Elevation Using Different Grafts: A Systematic Review of Controlled Clinical Trials.

PURPOSE: The purpose of this systematic review was to assess histological and imaging outcomes related to new bone formation around implants, inserted simultaneously with sinus augmentation, comparing different types of grafts. MATERIALS AND METHODS: Systematic Review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta- Analysis (PRISMA), and the Cochrane Handbook for Systematic Reviews of Interventions. LILACS/BVS, Medline/PubMed, Cochrane Library and Embase databases, including gray literature and manual investigation, were searched to identify clinical trials reporting human histological and imaging data of bone formation around implants, inserted into the maxillary sinus at the same moment of the elevation and augmentation procedure, using several materials. Study selection, risk of bias (Rob 2.0 or ROBINS I), quality of evidence (GRADE), and data collection were performed by two independent reviewers. RESULTS: Of the 1101 potentially eligible articles, 44 were retrieved, 12 were assessed for eligibility and 5 were included in this systematic review (4 randomized and one controlled clinical trials). As a result, 130 grafted sinuses with 179 installed implants in 103 patients, aged between 24 and 79 years and followed up from 6 to 15 months, were analyzed. The heterogeneity between studies did not allow the data to be combined for meta-analyses. All graft materials proved to be viable options for the intervention. The use of BCP was related to higher bone-to-implant contact. CONCLUSION: All the assessed grafts are viable options for the intervention addressed. The use of some material is justified to maintain the sinus volume and allow bone formation in the apical site of implants under the sinus membrane. Longer chair time and the morbidity of the donor site should be considered when choosing autogenous bone. Synthetic biphasic materials can be selected for this intervention due to superior values of %BIC when compared to DBB.

Use of Tibial Cortical Autograft for the Osteotomy Site in Medial Opening-Wedge High Tibial Osteotomy.

Background: Medial opening-wedge high tibial osteotomy (OWHTO) is a useful treatment option in patients with medial compartment osteoarthritis. Typically, the osteotomy site is filled with material such as autologous bone graft, allograft, or synthetic bone substitute. However, all these options have disadvantages. Purpose/Hypothesis: The purpose of this study was to describe tibial cortical autograft as an alternative to conventional graft options. It was hypothesized that the tibial rectangular cortical bone that is removed from the proximal medial cortical surface of the distal tibial fragment longitudinally could be a reliable option for recovery of the gap in the osteotomy area. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 520 patients with medial compartment osteoarthritis who underwent OWHTO between June 2009 and March 2019 were retrospectively analyzed. Patients were divided into 3 groups according to the graft material used to fill the osteotomy site: allograft in group A, iliac crest autograft in group B, and tibial autograft in group C. Bone union, evaluated by radiographs performed at 2 weeks, 4 weeks, 2 months, 3 months, 6 months, and 1 year postoperatively, was defined as occurring when at least 50% of the gap site was bridged with callus. Clinical assessment was performed using the International Knee Documentation Committee (IKDC) and Lysholm scores. Results: Included were 122 patients: 40 patients in group A, 42 patients in group B, and 40 patients in group C. The mean correction was 13.87°± 3.58° in group A, 12.33°± 3.92° in group B, and 14.10°± 2.99° in group C. The mean time for radiological bone union was 6.95 ± 1.40 months in group A, 4.48 ± 1.02 months in group B, and 5.07 ± 1.70 months in group C. Patients in all groups had similar IKDC and Lysholm scores at the final follow-up. Conclusion: This is the first report of this specific procedure in the literature. All clinical and radiological findings showed that use of tibial cortical autograft was an efficient method in patients undergoing OWHTO.

Improved intervertebral fusion in LLIF rabbit model with a novel titanium cage.

BACKGROUND CONTEXT: There is no established small animal approach model for the strict simulation of lateral lumbar interbody fusion (LLIF) surgery. PURPOSE: This study aims to establish a reliable LLIF rabbit model that strictly simulates the procedure and to preliminarily evaluate the differences in fusion outcomes with different graft materials. STUDY DESIGN: A controlled laboratory. METHODS: Fifty-four 4-month-old white New Zealand female and male rabbits were selected and divided into five groups: Group A (dissection group) consisted of 9 rabbits, Group B (normal approach group) consisted of 9 rabbits, Group C (autogenous iliac bone group) consisted of 12 rabbits, Group D (BMP-2 carrier material group) consisted of 12 rabbits, and Group E (allograft bone group) consisted of 12 rabbits. Based on data from Group A, a novel titanium metal fusion device was designed. Postoperatively, at the 12-week mark, manual palpation was employed to compare the interbody fusion status among Groups B, C, D, and E. Specimens from Groups C, D, and E were subjected to Micro-CT scanning to compare various parameters such as trabecular bone volume (BV), bone volume fraction (BV/TV, BVF), and bone surface area (BS). Furthermore, a tissue histopathological examination was performed to observe the structure and morphology of newly formed bone within the fusion mass as well as the remodeling of the graft in each group. RESULTS: Based on the measurements obtained from the dissection group, we designed a U-shaped interbody fusion device with dimensions of 10 mm in length, 2.5 mm in width, and 1.3 mm in height. In Group B, 9 cases exhibited intervertebral mobility. In Group C, 1 case showed nonfusion. In Group D, all cases achieved fusion. In Group E, 4 cases did not achieve fusion. Additionally, the Micro-CT results showed that the interbody fusion index scores were 4.64±0.50 in Group C, 4.33±0.65 in Group D, and 3.36±0.81 in Group E. There was no statistically significant difference in fusion index scores between Groups C and D (p=.853). Notably, Groups C and D had higher scores than Group E (p<.001). The trabecular bone volume (BV) in Groups C and D also showed no significant difference but was significantly higher than in Group E (p<.001). Furthermore, the histopathological results revealed that the specimens from Group E had less newly formed cartilage and bone compared to Groups C and D. CONCLUSIONS: This study successfully established a strict simulation of the clinical LLIF procedure in a rabbit model. Moreso, we conducted a preliminary validation indicating that the BMP-2 carrier material achieved interbody fusion outcomes similar to autogenous iliac bone. CLINICAL SIGNIFICANCE: The findings of this investigation from animal models provide a theoretical basis for the clinical use of BMP-2 to promote early spinal fusion in LLIF procedures. Importantly, the study provides a small animal model foundation for research related to LLIF surgery.

Osseointegration Potential Assessment of Bone Graft Materials Loaded with Mesenchymal Stem Cells in Peri-Implant Bone Defects.

Many studies have been exploring the use of bone graft materials (BGMs) and mesenchymal stem cells in bone defect reconstruction. However, the regeneration potential of Algipore (highly purified hydroxyapatite) and Biphasic (hydroxyapatite/beta-tricalcium phosphate) BGMs combined with bone marrow-derived mesenchymal stem cells (BMSCs) remains unclear. Therefore, we evaluated their osseointegration capacities in reconstructing peri-implant bone defects. The cellular characteristics of BMSCs and the material properties of Algipore and Biphasic were assessed in vitro. Four experimental groups-Algipore, Biphasic, Algipore+BMSCs, and Biphasic+BMSCs-were designed in a rabbit tibia peri-implant defect model. Implant stability parameters were measured. After 4 and 8 weeks of healing, all samples were evaluated using micro-CT, histological, and histomorphometric analysis. In the energy-dispersive X-ray spectroscopy experiment, the Ca/P ratio was higher for Algipore (1.67) than for Biphasic (1.44). The ISQ values continuously increased, and the PTV values gradually decreased for all groups during the healing period. Both Algipore and Biphasic BGM promoted new bone regeneration. Higher implant stability and bone volume density were observed when Algipore and Biphasic BGMs were combined with BMSCs. Biphasic BGM exhibited a faster degradation rate than Algipore BGM. Notably, after eight weeks of healing, Algipore with BSMCs showed more bone-implant contact than Biphasic alone (p < 0.05). Both Algipore and Biphasic are efficient in reconstructing peri-implant bone defects. In addition, Algipore BGM incorporation with BSMCs displayed the best performance in enhancing implant stability and osseointegration potential.

Demineralized dentin matrix promotes gingival healing in alveolar ridge preservation of premolars extracted for orthodontic reason: a split-mouth study.

Objective: The purpose of this study was to prospectively evaluate the efficacy of a demineralized dentin matrix (DDM) in decreasing the initial inflammatory response of the gingiva and facilitating the repair and regeneration of soft tissue in alveolar ridge preservation. Methods: This clinical study employed a split-mouth design. Fourteen patients with a total of forty-four sites underwent extraction and alveolar ridge preservation (ARP) procedures. A Bilaterally symmetrical extraction operation were conducted on the premolars of each patient. The experimental group received DDM as a graft material for ARP, while the control group underwent natural healing. Within the first month postoperatively, the pain condition, color, and swelling status of the extraction sites were initially assessed at different time points Subsequently, measurements were taken for buccal gingival margin height, buccal-lingual width, extraction socket contour, and the extraction socket area and healing rate were digitally measured. Additionally, Alcian Blue staining was used for histological evaluation of the content during alveolar socket healing. Results: Both groups experienced uneventful healing, with no adverse reactions observed at any of the extraction sites. The differences in VAS pain scores between the two groups postoperatively were not statistically significant. In the early stage of gingival tissue healing (3 days postoperatively), there were statistically significant differences in gingival condition and buccal gingival margin height between the two groups. In the later stage of gingival tissue healing (7, 14, and 30 days postoperatively), there were statistically significant differences in buccal-lingual width, extraction socket healing area, and healing rate between the two groups. Furthermore, the histological results from Alcian Blue staining suggested that the experimental group may play a significant role in promoting gingival tissue healing, possibly by regulating inflammatory responses when compared to the control group. Conclusion: The application of DDM in alveolar ridge preservation has been found to diminish initial gingival inflammation after tooth extraction. Additionally, it has shown the ability to accelerate early gingival soft tissue healing and preserve its anatomical contour. Clinical trial registration: chictr.org.cn, identifier ChiCTR2100050650.

Immediate dental implantation after indirect sinus elevation using osseodensification concept: a case report.

Implantation in the posterior maxilla is more challenging due to the insufficient bone height after maxillary sinus pneumatization and the low bone density. Osseodensification (OD) is considered a novel, less invasive, and more effective indirect sinus floor elevation technique. Case presentation: A 52-year-old male presented to the oral and maxillofacial surgery department with a main complaint of chewing difficulties in the right posterior area maxilla (teeth numbers: 26 and 27). A cone-beam computed tomography (CBCT) imaging showed that the residual bone height ranged between 1 and 4 mm and the width ranged between 9 and 12 mm in the area of teeth numbers 16 and 17. Intervention and outcome: The treatment plan was to extract the teeth (numbers: 16 and 17) and conduct internal sinus lifting and bone grafting using the OD burs with immediate implantation. Clinical discussion: OD is proposed as an alternative procedure to the direct (lateral window) sinus floor elevation procedure. The amount of vertical bone gain obtained by this technique in transcrestal sinus lifting can be the same as external sinus lifting in this case. Conclusion: OD can be considered a promising technique for direct sinus floor elevation, considering the amount of vertical bone gain obtained by this technique.

Corrigendum: Demineralized dentin matrix promotes gingival healing in alveolar ridge preservation of premolars extracted for orthodontic reason: a split-mouth study.

[This corrects the article DOI: 10.3389/fendo.2023.1281649.].

Techniques and graft materials for repairing peripheral nerve defects.

Peripheral nerve defects refer to damage or destruction occurring in the peripheral nervous system, typically affecting the limbs and face. The current primary approaches to address peripheral nerve defects involve the utilization of autologous nerve transplants or the transplantation of artificial material. Nevertheless, these methods possess certain limitations, such as inadequate availability of donor nerve or unsatisfactory regenerative outcomes post-transplantation. Biomaterials have been extensively studied as an alternative approach to promote the repair of peripheral neve defects. These biomaterials include both natural and synthetic materials. Natural materials consist of collagen, chitosan, and silk, while synthetic materials consist of polyurethane, polylactic acid, and polycaprolactone. Recently, several new neural repair technologies have also been developed, such as nerve regeneration bridging technology, electrical stimulation technology, and stem cell therapy technology. Overall, biomaterials and new neural repair technologies provide new methods and opportunities for repairing peripheral nerve defects. However, these methods still require further research and development to enhance their effectiveness and feasibility.

APDDM mixed with i-PRF as a graft material for bone regeneration - A case report.

Demineralized dentine matrix (DDM) has both osteoconductive and osteoinductive properties, and has porous structure which helps in cell and blood vessel penetration and the release of various growth factors from the dentinal tubules. The first human dentine autograft case was done in 2002 in Japan for maxillary sinus lifting. In this clinical report, we use a hand-operated order made stainless steel apparatus to crush the tooth and prepare the DDM chair side. Chemical treatment of DDM particulate was done for demineralization and sterilisation purpose, and used immediately as a graft material for socket preservation. Dentascan after 4 month showed remarkable bone at the site of grafting and implant was placed. The patient was restored successfully with their own DDM and implant-supported prosthesis.

Biomedical Membrane of Fish Collagen/Gellan Gum Containing Bone Graft Materials.

The development of a guided bone regeneration (GBR) membrane with non-mammalian fish collagen has the advantage of low risk for transmission of infectious diseases in tissue regeneration. In this work, a fish collagen/gellan gum and bone graft material (FC/GG-BGM) composite GBR membrane were fabricated through solution blending and casting procedures in a vacuum. The membranes were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy observation (SEM), and atomic force microscope (AFM) analyses. FT-IR results suggested that ionic interactions were formed between FC and GG both in composite powder and membranes. In vivo experiments showed that these FC/GG-BGM composite membranes could generate osteoblast minerals and promote loose bone calcification, thus accelerating bone regeneration. At 2 weeks, the defected site of rats treated with FC/GG-BGM membrane (0.377 ± 0.012 mm3) showed higher regeneration than that of rats treated with the bovine collagen membrane (0.290 ± 0.015 mm3) and control rats without membrane (0.160 ± 0.008 mm3). Compared with bovine collagen membrane, the FC/GG-BGM composite membrane displays better bone regeneration ability. Therefore, FC/GG-BGM composite membrane is suitable as a GBR membrane for bone regeneration.

Better Functional Recovery After Single-Level Compared With Two-Level Posterolateral Lumbar Fusion.

Background Multiple studies describe the outcomes of patients undergoing single-level and multilevel posterolateral lumbar fusion (PLF). However, a comparison of outcomes between single-level and two-level PLF is lacking. The aim of this prospective cohort study was to compare outcomes between single-level and two-level instrumented PLF. Methods A total of 42 patients were enrolled at nine US centers between October 2015 and June 2017. Data included radiologic outcomes, visual analog scale (VAS) Back and Leg Pain, disability per the Oswestry Disability Index (ODI), and health-related quality of life (QoL) per 36-Item Short Form Survey version 2.0 (SF-36v2) at six weeks and three, six, 12, and 24 months. Results Twelve-month and 24-month follow-ups were completed by 38 (90.5%) and 32 (76.2%) subjects, respectively. The average age was 67 years, and 54.8% were female. Twenty-six received single-level PLF, and 16 received two-level PLF. In the single-level group, there was one reoperation, two postoperative infections, and one dural tear. In the two-level group, there was one postoperative infection. The surgeon computed tomography (CT)-based evaluation of fusion rate was 67.6% (25/37) at 12-month follow-up and 94.1% (32/34) at 24-month follow-up. The third-party evaluation of fusion rate was 52.8% (19/36) at six months, 81.1% (30/37) at 12 months, and 86.5% (32/37) at 24 months. There was a tendency toward a higher fusion rate in single-level compared with two-level PLF. The ODI, SF-36v2 Mental Component Score (MCS), and VAS Back Pain and Leg Pain outcomes improved by the first follow-up visit in both the single-level and two-level groups. Improvement in the ODI was 5.86 (95% confidence interval (CI): 0.03-11.69) points greater in the single-level group compared with the two-level group. Conclusions Compared with the two-level PLF subjects, single-level PLF subjects had better functional outcomes and reported higher satisfaction with the outcome of surgery but showed similar fusion, pain, and generic health-related quality of life outcomes. Both single-level and two-level PLF subjects demonstrated high fusion rates in association with improvements in pain, functional, and quality of life outcomes, as well as high satisfaction levels.

The urgent need to achieve an optimal strategic stock of human allogeneic skin graft materials in case of a mass disaster in Poland.

A burn is a sudden injury which immediate or long-term consequences may be life-threatening for the patient. A mass disaster event may involve large numbers of severely burned patients. Patients of this type typically have a limited area of healthy, unburned skin from which an autologous split thickness skin graft could be collected. In a clinical situation of this type, it is necessary to use a particular skin substitute. Non-viable allogeneic human skin graft materials might be considered as the most suitable skin substitutes in the treatment of such patients. At present, Poland does not have a sufficient supply of human allogeneic skin graft materials to meet the needs arising from a sudden and unforeseen mass disaster. This study involved an analysis of selected mass disasters. From this an estimate was made from a verified casualty profile of the necessary minimum stock of human allogeneic skin graft materials. An insufficient amount of skin results from an inadequate number of skin donors, which in turn results from the current tissue donation system. Therefore, a proposal has been made for the organizational, legal and systemic changes required to improve the situation in Polish transplantology, with particular emphasis on skin donation. In order to achieve a strategic stock of human skin grafts, a tissue collecting transplantation team should be organized. The rights and obligations of the non-physician transplant team member should be extended. Proposals have been made for awareness campaigns (adverts, posters etc.) and educational schemes (educational video, lectures during transplant coordinator training, etc.). Finally, a proposal has been made for possible methods to deal with the logistic management of the allogeneic skin stock. The required, essential stock of human allogeneic skin in the event of a mass disaster has been estimated at 600,000 cm2.

Using a mixture of local bone dust and morselized bone as graft materials in single- and double-level ACDF.

BACKGROUND: Using a cage filled with local bone in anterior cervical discectomy and fusion (ACDF) can eliminate morbidities associated with autograft harvest from the iliac crest while achieving high fusion rates. However, there is still no consensus regarding the methods for using local bone grafts. This retrospective study was performed to compare the clinical and radiological outcomes of using a mixture of bone dust and morselized bone versus morselized bone alone in ACDF. METHODS: A retrospective study of 228 patients affected by cervical degenerative disease who had undergone single- or double-level ACDF between January 2014 and June 2018 was performed. Nanohydroxyapatite/polyamide-66 (n-HA/PA66) combined with morselized bone was used in 111 patients (group A: single-level ACDF in 51 patients and double-level ACDF in 60 patients), whereas the n-HA/PA66 cage combined with a mixture of bone dust and morselized bone was used in 117 patients (group B: single-level ACDF in 58 patients and double-level ACDF in 59 patients). The fusion rate, extent of cage subsidence, fusion segmental height (FSH), C2-7 lordosis, segmental sagittal alignment (SSA), 10-point visual analog scale (VAS) score, and Neck Disability Index (NDI) were compared between the two groups. RESULTS: The VAS score and NDI were significantly reduced after the operation in group A and group B. At the final follow-up, the fusion rate was 90.2 % (46/51) and 94.8 % (55/58) in patients treated with single-level ACDF in group A and group B, respectively (p > 0.05). In patients treated with double-level ACDF, bone fusion was achieved in 52 patients (86.7 %) in group A and 55 patients (93.2 %) in group B (p > 0.05). The fusion rate of single- and double-level ACDF was higher in patients in group B than those in group A at the 3-month, 6-month and 12-month follow-ups (p < 0.05). The extent of cage subsidence after single- and double-level ACDF was lower in patients in group B (1.5 ± 0.5 mm and 2.3 ± 0.8 mm, respectively) than in those in group A (1.8 ± 0.7 mm and 2.9 ± 1.4 mm, respectively) (p < 0.05). There was no significant difference between the two groups in the C2-7 lordosis, FSH, SSA, VAS score, or NDI before or after the operation (p > 0.05). CONCLUSIONS: Using a mixture of local bone dust and morselized bone as cage-filling materials yielded comparably good clinical outcomes as using morselized bone alone in single- and double-level ACDF. However, the mixture graft of bone dust and morselized bone was more beneficial in promoting early fusion and reducing cage subsidence.

Injectable Affinity and Remote Magnetothermal Effects of Bi-Based Alloy for Long-Term Bone Defect Repair and Analgesia.

As alternatives, metallic/nonmetallic bone graft materials play significant roles in bone defect surgery to treat external trauma or bone disease. However, to date, there are rather limited long-term implantable materials owning to in situ molding incapability of metallics and poor mechanical property of nonmetallics. Here, Bi-based low melting point alloy, with unique properties of injectability, solid-liquid phase transition, mechanical capability, and biocompatibility, present obvious long-lasting bone affinity as the excellent artificial bone-substitute. It is particularly necessary to point out that the targeted injected Bi alloy remains in its original position for up to 210 days without moving, as well as, displays good osseointegration ability to resolve repeated revision trauma caused by losing bone repair material. Additionally, with outstanding electrical and thermal conductivity, an unconventional way using Bi alloy to realize very beneficial hyperthermia analgesia via non-invasive wireless energy delivery is first proposed, which avoids adverse effects on bone remodeling inflicted by traditional drugs. The significantly decreased expression of pain sensitizing factor, such as, interleukin-6, neuropeptide substance, and transient receptor potential vanilloid 1 reveals the potential mechanism of hyperthermia analgesia. The present findings suggest the combination therapy of Bi alloy in bone repair and analgesia, which owns far-reaching clinical application value.

Alloplastic Bone Substitutes for Periodontal and Bone Regeneration in Dentistry: Current Status and Prospects.

Various bone graft products are commercially available worldwide. However, there is no clear consensus regarding the appropriate bone graft products in different clinical situations. This review is intended to summarize bone graft products, especially alloplastic bone substitutes that are available in multiple countries. It also provides dental clinicians with detailed and accurate information concerning these products. Furthermore, it discusses the prospects of alloplastic bone substitutes based on an analysis of the current market status, as well as a comparison of trends among countries. In this review, we focus on alloplastic bone substitutes approved in the United States, Japan, and Korea for use in periodontal and bone regeneration. According to the Food and Drug Administration database, 87 alloplastic bone graft products have been approved in the United States since 1996. According to the Pharmaceuticals and Medical Devices Agency database, 10 alloplastic bone graft products have been approved in Japan since 2004. According to the Ministry of Health and Welfare database, 36 alloplastic bone graft products have been approved in Korea since 1980. The approved products are mainly hydroxyapatite, ß-tricalcium phosphate, and biphasic calcium phosphate. The formulations of the products differed among countries. The development of new alloplastic bone products has been remarkable. In the near future, alloplastic bone substitutes with safety and standardized quality may be the first choice instead of autologous bone; they may offer new osteoconductive and osteoinductive products with easier handling form and an adequate resorption rate, which can be used with growth factors and/or cell transplantation. Careful selection of alloplastic bone graft products is necessary to achieve predictable outcomes according to each clinical situation.

Utility of Thermal Cross-Linking in Stabilizing Hydrogels with Beta-Tricalcium Phosphate and/or Epigallocatechin Gallate for Use in Bone Regeneration Therapy.

ß-tricalcium phosphate (ß-TCP) granules are commonly used materials in dentistry or orthopedic surgery. However, further improvements are required to raise the operability and bone-forming ability of ß-TCP granules in a clinical setting. Recently, we developed epigallocatechin gallate (EGCG)-modified gelatin sponges as a novel biomaterial for bone regeneration. However, there is no study on using the above material for preparing hydrogel incorporating ß-TCP granules. Here, we demonstrate that vacuum heating treatment induced thermal cross-linking in gelatin sponges modified with EGCG and incorporating ß-TCP granules (vhEc-GS-ß) so that the hydrogels prepared from vhEc-GS-ß showed high stability, ß-TCP granule retention, operability, and cytocompatibility. Additionally, microcomputed tomography morphometry revealed that the hydrogels from vhEc-GS-ß had significantly higher bone-forming ability than ß-TCP alone. Tartrate-resistant acid phosphatase staining demonstrated that the number of osteoclasts increased at three weeks in defects treated with the hydrogels from vhEc-GS-ß compared with that around ß-TCP alone. The overall results indicate that thermal cross-linking treatment for the preparation of sponges (precursor of hydrogels) can be a promising process to enhance the bone-forming ability. This insight should provide a basis for the development of novel materials with good operativity and bone-forming ability for bone regenerative medicine.

Maximizing the strength of calcium sulfate for structural bone grafts.

Calcium sulfate (CS) combines remarkable properties of biodegradability, biocompatibility, and osteoconductivity but its low strength limits the range of its applications in orthopaedic surgery. In this study we have addressed this limitation by optimizing the fabrication process for pure CS, and by using mechanical testing procedures which are relevant for load carrying, or structural bone grafts (flexural tests in hydrated condition). By optimizing the processing parameters (pressure during setting, CS powder to water ratio, saturated solution) we produced CS samples with the highest flexural strength ever reported in hydrated conditions. Once these optimal conditions are used, the addition of "reinforcing" inclusions in the material decreased its strength because these inclusions actually act as defects instead of reinforcements. In addition, the CS can be formed in precise shapes while maintaining optimal processing conditions and provided a strength similar to that of bone with the same dimensions. Dense and porous materials can be combined to duplicate the trabecular and cortical architecture of long bones, with only a small loss of overall strength.

Clinical and histopathological comparative study of two equine-derived bone graft: a human study.

OBJECTIVE: To compare the performance of collagenated bone graft substances with different collagen ratios after sinus floor augmentation. METHODS: The cross-sectional study was conducted at Hacettepe University, Ankara, Turkey, from September 2011 to September 2013. Sinus floor augmentation was done with two different equinederived xenografts in patients before dental implant application. Of the two randomised groups, one was treated with 100% collagenated bone mix (Group A), and the other half with 90% collagenated bone mix + 10% collagen gel (Group B).Six months after sinus augmentation, prior to dental implant surgery, a specimen was taken from the implant socket with trephine drill for histopathological evaluation of new bone, connective tissue and residual graft material at each augmented site. SPSS 19 was used for data analysis. RESULTS: Of the 19 patients, 12(63%) were females and 7(37%) were males. The overall mean age was 51.68±11,96 years (range: 24-69 years). A total of 30 sinus floor augmentations were done. New bone formation was significantly better in Group A(15 sinus floor augmentation) than in Group B (the other 15 sinus floor augmentation) (p<0.05), but there was no significant difference in connective tissue formation and residual graft materials between the groups (p>0.05). CONCLUSIONS: Collagenated bone mix was found to be a suitable graft material for sinus floor augmentation, but increased collagen ratio did not improve new bone formation over the 6-month healing process.