Synthesis of 3D porous ceramic scaffolds obtained by the sol-gel method with surface morphology modified by hollow spheres for bone tissue engineering applications

In the present work, we modified the surface morphology of 3D porous ceramic scaffolds by incorporating strontium phosphate (SrP) hollow nano-/microspheres with potential application as delivery system for the local release of therapeutic substances. SrP hollow spheres were synthesized by a template-free hydrothermal method. The influence of the reaction temperature, time and concentration of reactants on precipitates' morphology and size were investigated. To obtain a larger number of open hollow spheres, a new methodology was developed consisting of applying a second hydrothermal treatment to spheres by heating them at 120 °C for 24 h. The X-ray diffraction (XRD) analysis indicated that spheres consisted of a main magnesium-substituted strontium phosphate phase ((Sr3(PO4)2). The scanning electron microscopy (SEM) micrographs confirmed that spheres had hollow interiors (∼350 nm size) and an average diameter of 850 nm. Spheres had a specific surface area of 30.5 m2/g, a mesoporous shell with an average pore size of 3.8 nm, and a pore volume of 0.14 cm/g. These characteristics make them promising candidates for drug, cell and protein delivery. For the attachment of spheres to scaffolds’ surface, ceramic structures were immersed in an ethanol solution containing 0.1 g of hollow spheres and kept at 37 °C for 4 h. The scaffolds with incorporated spheres were bioactive after being immersed in simulated body fluid (SBF) for 7 days and spheres were still adhered to their surface after 14 daysThis work is part of the project PID2020-116693RB-C21 funded by MCIN/AEI/10.13039/501100011033 Spain. Grant CIAICO/2021/157 funded by Generalitat Valenciana Spain

Implant Stability of Biological Hydroxyapatites Used in Dentistry

The aim of the present study was to monitor implant stability after sinus floor elevation with two biomaterials during the first six months of healing by resonance frequency analysis (RFA), and how physico-chemical properties affect the implant stability quotient (ISQ) at the placement and healing sites. Bilateral maxillary sinus augmentation was performed in 10 patients in a split-mouth design using a bobine HA (BBM) as a control and porcine HA (PBM). Six months after sinus lifting, 60 implants were placed in the posterior maxilla. The ISQ was recorded on the day of surgery from RFA at T1 (baseline), T2 (three months), and T3 (six months). Statistically significant differences were found in the ISQ values during the evaluation period. The ISQ (baseline) was 63.8 ± 2.97 for BBM and 62.6 ± 2.11 for PBM. The ISQ (T2) was ~73.5 ± 4.21 and 67 ± 4.99, respectively. The ISQ (T3) was ~74.65 ± 2.93 and 72.9 ± 2.63, respectively. All of the used HAs provide osseointegration and statistical increases in the ISQ at baseline, T2 and T3 (follow-up), respectively. The BBM, sintered at high temperature with high crystallinity and low porosity, presented higher stability, which demonstrates that variations in the physico-chemical properties of a bone substitute material clearly influence implant stability.Odontologí

Comparison of Two Xenograft Materials Used in Sinus Lift Procedures: Material Characterization and In Vivo Behavior

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Abstract: Detailed information about graft material characteristic is crucial to evaluate their clinical outcomes. The present study evaluates the physico-chemical characteristics of two xenografts manufactured on an industrial scale deproteinized at different temperatures (non-sintered and sintered) in accordance with a protocol previously used in sinus lift procedures. It compares how the physico-chemical properties influence the material’s performance in vivo by a histomorphometric study in retrieved bone biopsies following maxillary sinus augmentation in 10 clinical cases. An X-ray diffraction analysis revealed the typical structure of hydroxyapatite (HA) for both materials. Both xenografts were porous and exhibited intraparticle pores. Strong differences were observed in terms of porosity, crystallinity, and calcium/phosphate. Histomorphometric measurements on the bone biopsies showed statistically significant differences. The physic-chemical assessment of both xenografts, made in accordance with the protocol developed on an industrial scale, confirmed that these products present excellent biocompatibilitity, with similar characteristics to natural bone. The sintered HA xenografts exhibited greater osteoconductivity, but were not completely resorbable (30.80 ± 0.88% residual material). The non-sintered HA xenografts induced about 25.92 ± 1.61% of new bone and a high level of degradation after six months of implantation. Differences in the physico-chemical characteristics found between the two HA xenografts determined a different behavior for this material.Odontologí

Bioeutectic® ceramics for biomedical application obtained by laser floating zone method. In vivo evaluation

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license.In this study, the Bioeutectic® blocks were inserted into the critical size defects of eight rabbits, using both tibiae, and the physical and chemical nature of the remodeled interface between the Bioeutectic® implants and the surrounding bone were performed at four and 15 months. The results showed a new fully mineralized bone growing in direct contact with the implants. The ionic exchange, taking place at the implant interface with the body fluids was essential in the process of the implant integration through a dissolution-precipitation-transformation mechanism. The study found the interface biologically and chemically active over the 15 months implantation period. The osteoblastic cells migrated towards the interface and colonized the surface at the contact areas with the bone. The new developed apatite structure of porous morphology mimics natural bone. © 2014 by the authors.The authors wish to acknowledge funding from the European Community at the 7th Framework Program EU No. 314630-UV Marking and Generalitat Valenciana (GVA) within the Project ACOMP/2009/173.Peer Reviewe

SEM-EDX Study of the Degradation Process of Two Xenograft Materials Used in Sinus Lift Procedures

Some studies have demonstrated that in vivo degradation processes are influenced by the material’s physico-chemical properties. The present study compares two hydroxyapatites manufactured on an industrial scale, deproteinized at low and high temperatures, and how physico-chemical properties can influence the mineral degradation process of material performance in bone biopsies retrieved six months after maxillary sinus augmentation. Residual biomaterial particles were examined by field scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) to determine the composition and degree of degradation of the bone graft substitute material. According to the EDX analysis, the Ca/P ratio significantly lowered in the residual biomaterial (1.08 ± 0.32) compared to the initial composition (2.22 ± 0.08) for the low-temperature sintered group, which also presented high porosity, low crystallinity, low density, a large surface area, poor stability, and a high resorption rate compared to the high-temperature sintered material. This demonstrates that variations in the physico-chemical properties of bone substitute material clearly influence the degradation process. Further studies are needed to determine whether the resorption of deproteinized bone particles proceeds slowly enough to allow sufficient time for bone maturation to occur.Odontologí

Titanium Surface Analysis after Instrumentation with Different Burs Simulating the Implantoplasty Technique: A Pilot In Vitro Experimental Study

Background: The present pilot in vitro study evaluated, physically and biologically, the effects produced by the wear of the titanium surface using different drill models. (2) Methods: Titanium disks were subjected to wear using four different burs and accordingly divided into the following test groups (n = 12 disks per group): Tungsten Burs (TB group), Tungsten Carbide Burs (TCB group), Coarse-Grained Diamond Burs (CGB group), and Fine-Grained Diamond Burs (FGB group). As a control group (CON group), titanium disks with a smooth surface (machined) were used. The samples were subjected to atomic force microscopy (AFM), profilometry analysis, scanning electron microscopy (SEM), and cell viability and adhesion assessments. (3) Results: The values of the measured roughness parameters showed statistical differences among the five groups (p = 0.0035 for Ra and p = 0.0010 for Rz). All test groups showed an important difference statistically (p = 0.0032) to the CON group for the cell viability and adhesion analysis. The data of cell absorbance at 570 nm were 0.4122 0.05 for the CON group, 0.1354 0.02 for the TB group, 0.123 0.01 for the TCB group, 0.1414 0.02 for the CGB group, and 0.1216 0.03 for the FGB group. Additionally, the cell count showed the following adherence percentages: 57.6 4.6% for the CON group, 22.9 3.3% for the TB group, 23.4 2.9% for the TCB group, 22.5 3.1% for the CGB group, and 23.7 3.3% for the FGB group. However, no statistical differences were found among the four test groups analyzed (p = 0.3916). (4) Conclusions: The results showed that the changes produced on the surface by the four different bur models altered the topography characteristics and affected the cell viability and adhesion in comparison with the control groupThe author Sergio Alexandre Gehrke was funded by a post-doctoral grant nº 2021/PER/00020 from the Ministerio de Universidades under the program “Ayudas para la recualificación del sistema universitario español de la Universidad Miguel Hernandez” modalidad “Margarita Salas para la formación de jóvenes doctores”. The funders had no role in the study design, data collection and analysis, decision to publish, nor preparation of the manuscript. The authors thank M.A. Duhagon for kindly providing the cells for this experiment

Effect of Sr, Mg and Fe substitution on thephysico-chemical and biological properties ofSi Ca P multilayer scaffolds

tIn this work, a new combination of ceramic materials is proposed for bone tissue engi-neering applications. Multilayer scaffolds consisting of a core composed mainly of calciumpyrophosphate and external coatings of silica and calcium doped with Fe3+, Sr2+and Mg2+were prepared. To study the influence of the arrangement of dopant ions in the externalcoatings, two different scaffolds were developed: scaffolds 3J consisting of a single exter-nal coating with 9 mol% of Fe3+, Sr2+and Mg2+ions; and scaffolds 3S comprising threeexternal coatings, each containing 3 mol% of Fe3+, Sr2+and Mg2+ions. Scaffolds were physico-chemically characterized and evaluated for in vitro bioactivity and cellular response in thepresence of MG-63 cells. The results showed that the core scaffold displayed no in vitro bioac-tivity or good cellular response, but served as a support for the external coatings given itsmechanical resistance. The cell viability of scaffolds 3J and 3S increased more than 100%in relation to the core, and also improved cell proliferation and adhesion resulting in adense layer of cells that covered the scaffolds’ entire surface. The arrangement of ions inthe external coatings did not influence the cellular response, but determined the bioactivityrate

Novel Resorbable and Osteoconductive Calcium Silicophosphate Scaffold Induced Bone Formation

This aim of this research was to develop a novel ceramic scaffold to evaluate the response of bone after ceramic implantation in New Zealand (NZ) rabbits. Ceramics were prepared by the polymer replication method and inserted into NZ rabbits. Macroporous scaffolds with interconnected round-shaped pores (0.5–1.5 mm = were prepared). The scaffold acted as a physical support where cells with osteoblastic capability were found to migrate, develop processes, and newly immature and mature bone tissue colonized on the surface (initially) and in the material’s interior. The new ceramic induced about 62.18% ± 2.28% of new bone and almost complete degradation after six healing months. An elemental analysis showed that the gradual diffusion of Ca and Si ions from scaffolds into newly formed bone formed part of the biomaterial’s resorption process. Histological and radiological studies demonstrated that this porous ceramic scaffold showed biocompatibility and excellent osteointegration and osteoinductive capacity, with no interposition of fibrous tissue between the implanted material and the hematopoietic bone marrow interphase, nor any immune response after six months of implantation. No histological changes were observed in the various organs studied (para-aortic lymph nodes, liver, kidney and lung) as a result of degradation products being released.Part of this work has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO) contract grant number: MAT2013-48426-C2-1-R and MAT2013-48426-C2-2-R. We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI

Novel Resorbable and Osteoconductive Calcium Silicophosphate Scaffold Induced Bone Formation

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).Abstract: This aim of this research was to develop a novel ceramic scaffold to evaluate the response of bone after ceramic implantation in New Zealand (NZ) rabbits. Ceramics were prepared by the polymer replication method and inserted into NZ rabbits. Macroporous scaffolds with interconnected round-shaped pores (0.5–1.5 mm = were prepared). The scaffold acted as a physical support where cells with osteoblastic capability were found to migrate, develop processes, and newly immature and mature bone tissue colonized on the surface (initially) and in the material’s interior. The new ceramic induced about 62.18% ± 2.28% of new bone and almost complete degradation after six healing months. An elemental analysis showed that the gradual diffusion of Ca and Si ions from scaffolds into newly formed bone formed part of the biomaterial’s resorption process. Histological and radiological studies demonstrated that this porous ceramic scaffold showed biocompatibility and excellent osteointegration and osteoinductive capacity, with no interposition of fibrous tissue between the implanted material and the hematopoietic bone marrow interphase, nor any immune response after six months of implantation. No histological changes were observed in the various organs studied (para-aortic lymph nodes, liver, kidney and lung) as a result of degradation products being released.Odontologí

Comparative analysis of the mechanical limits of resistance in implant/abutment set of a new implant design: An in vitro study

Objective: The aim of the present in vitro study was to evaluate the resistance on quasi-static forces and in the fatigue mechanical cycling of a new implant design compared to two other conventional implant designs. Materials and methods: Eighty-eight implants with their respective abutments were tested and distributed into four groups (n = 22 per group): Morse taper connection implant (MT group), conventional external hexagon implant (EH con group), new Collo implant of external hexagon with the smooth portion out of the bone insertion (EH out group), and new Collo implant of external hexagon with the implant platform inserted to the bone level (EH bl group). All the sets were subjected to quasi-static loading in a universal testing machine, and we measured the maximum resistance force supported by each sample. Another 12 samples from each group were submitted to the cyclic fatigue test at 4 intensities of forces (n = 3 per force): 80%, 60%, 40%, and 20%. The number of cycles supported by each sample at each force intensity was evaluated. Results: The three groups of implants with external hexagon connection had similar maximum strength values of the sets (p > 0.05). Meanwhile, samples from the MT group showed the highest resistance values in comparison to the other three groups (p < 0.05). In the fatigue test, the Collo out group supported a smaller number of cycles that led to the fracture than the other 3 groups proposed at loads of 80%, 60%, and 40%, and only at the load value of 20% all groups had the same performance. Conclusions: Within the limitations of the present in vitro study, the results showed that the new Collo implant performs better when installed at bone level.Part of this work was supported by Ministry of Science and Innovation—Grant PID2020-116693RB-C21 funded by MCIN/AEI/ 10.13039/501100011033. The author Sergio Alexandre Gehrke was funded by post-doctoral grant n˚ 2021/PER/00020 from the Ministerio de Universidades under the program "Ayudas para la recualificacio´n del sistema universitario español de la Universidad Miguel Hernandez" modalida