Influence of biphasic β-TCP with and without the use of collagen membranes on bone healing of surgically critical size defects. A radiological, histological, and histomorphometric study

Study of biphasic calcium phosphate (BCP) ceramics of tilapia fish bones by age

Biphasic calcium phosphate (BCP), consisting of bioceramics such as HAp + β-TCP and Ca10(PO4)6(OH)2 + Ca3(PO4)2, is a popular choice for optimizing performance due to its superior biological reabsorption and osseointegration. In this study, BCP was produced by calcining the bones of tilapia fish (Oreochromis niloticus) reared in net cages and slaughtered at an age ranging from 15 to 420 days. The bones were cleaned and dried, calcined at 900 °C for 8 h, and then subjected to high-energy grinding for 3 h to produce BCP powders. After the calcination process, the crystalline phase's hydroxyapatite (HAp) and/or beta-tricalcium phosphate (β-TCP) were present in the composition of the bioceramic. The age-dependent variation in phase composition was confirmed by complementary vibrational spectroscopy techniques, revealing characteristic peaks and bands of the bioceramic. This variation was marked by an increase in HAp phase and a decrease in β-TCP phase. Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) from 25 to 1400 °C showed the characteristic mass losses of the material, with a greater loss observed for younger fish, indicating the complete removal of organic components at temperatures above 600 °C. Comparison of the results obtained by X-Ray Diffraction (XRD) and Rietveld refinement with Raman spectroscopy showed excellent agreement. These results showed that with temperature and environment control and adequate fish feeding, it is possible to achieve the desired amounts of each phase by choosing the ideal age of the fish. This bioceramic enables precise measurement of HAp and β-TCP concentrations and Ca/P molar ratio, suitable for medical orthopedics and dentistry.

Polycaprolactone versus collagen membrane and 1‐year clinical outcomes: A randomized controlled trial

BACKGROUND

Polycaprolactone (PCL) is a synthetic aliphatic polyester widely used in biomedical applications with biodegradability in the body and promotes cell proliferation and differentiation. A newly developed bilayered PCL membrane was developed for possibly being used as a membrane in guided bone regeneration (GBR).

PURPOSE

To compare the clinical efficacy between a newly developed bilayered PCL membrane with a Cytoplast™ RTM collagen membrane for GBR with simultaneous implant placement.

MATERIALS AND METHODS

Twenty-four patients were randomized to PCL or RTM group, and a total of 24 dental implants were placed. Primary outcomes were patient mean buccal bone thickness (BBT) immediately postimplantation and at 6 months using cone-beam CT and soft tissue surface dimensional changes (STC) at crown insertion, 6 months, and 1 year after loading using intraoral scanner. Secondary outcomes included success rate, clinical parameters, healing index, implant stability, pink esthetic score, and marginal bone levels.

RESULTS

The percentage of reduced BBT at 6 months was 32.38%, 25.94%, and 23.96% in the test group and 34.42%, 14.75%, and 6.34% in the control group at the corresponding levels. The mean difference of changed BBT associated with PCL membrane, when compared to collagen membrane, at 6 months was -0.02 ± 0.18 mm (95% confidence interval [CI]: -0.40 to 0.35), 0.29 ± 0.28 mm (95% CI: -0.29 to 0.87), and 0.62 ± 0.38 mm (95% CI: -0.17 to 1.42) at 0, 2, and 4 mm from implant shoulder. Minimal loss of STC was observed in both groups up to 1 year of loading. The mean difference loss of surface dimensional change associated with PCL membrane, when compared to collagen membrane, at 1 year of loading was 0.31 ± 0.19 mm (95% CI: -0.07 to 0.70), 0.22 ± 0.26 mm (95% CI: -0.33 to 0.76), and 0.17 ± 0.30 mm (95% CI: -0.45 to 0.78) at 0, 2, and 4 mm from implant shoulder. None of these differences were statistically significant (unpaired t-test, degrees of freedom [df] = 22; p > 0.05).

CONCLUSION

Within the limits of this trial, both barrier membranes resulted in comparable outcomes for GBR with implant placement after 1 year in function. Further research is necessary with a larger sample size.

Guided Bone Regeneration Using BioGlue As a Barrier Material With and Without Biphasic Calcium Phosphate

The aim of this study was to investigate the effects of Bioglue as a mechanical barrier with or without biphasic calcium phosphate (BCP) in a rat tibia model. Sixty Sprague Dawley male rats weighing 250 ± 20 g and 10 to 12 weeks of age were studied. Unicortical defects were created on the right tibia of all rats. Subjects were randomly divided into 3 groups. BioGlue group (24 rats); BioGlue alone, Graft group (24 rats); BioGlue + BCP and Control group; unfilled and uncovered (12 rats). Animals were euthanized at 7th, 21st, and 45th days postoperatively for histological and histomorphometric analyses. BioGlue material exhibited no adverse effects until the end of observation period. Bone-healing scores did not differ statistically between Control and BioGlue group, but found to be lower in Graft group on 21st and 45th days, (P < 0.001 and P < 0.01 on the 21st day and P < 0.01 and P < 0.05 on the 45th day, respectively). New bone formation in Graft group was found to be statistically different from Control group on the 7th and 21st days (P < 0.01 and P < 0.05 respectively), whereas no statistical difference was observed between BioGlue and Control group at all times. The present analysis indicates that BioGlue functioned well as a mechanical barrier allowing new bone formation. No additional benefit of combination treatment was detected in this study design and BCP did not offer any advantage for bone regeneration, thus it can serve as only a space maintainer.

Effects of collagen/β-tricalcium phosphate bone graft to regenerate bone in critically sized rabbit calvarial defects

Bone defects remain a significant health issue and a major cause of morbidity in elderly patients. Composites based on collagen/calcium phosphate have been widely used for bone repair in clinical applications, owing to their comparability to bone extracellular matrix. This study aimed to evaluate the effects of a scaffold of collagen/calcium phosphate (COL/β-TCP) on bone formation to assess its potential use as a bone substitute to repair bone defects. Bilateral full-thickness critically sized calvarial defects (8 mm in diameter) were created in New Zealand white rabbits and treated with COL/β-TCP or COL scaffolds. One defect was also left unfilled as a control. Bone regeneration was assessed through histological evaluation using hematoxylin and eosin and Masson's trichrome staining after 4 and 8 weeks. Alizarin Red staining was also utilized to observe the mineralization process. Our findings indicated that COL/β-TCP implantation could better enhance bone regeneration than COL and exhibited both new bone growth and scaffold material degradation.

Histological and Histomorphometric Analyses of Two Bovine Bone Blocks Implanted in Rabbit Calvaria

This study compared the osteogenic potential of two types of bovine bone blocks. Blocks were obtained by either sintered or a nonsintered process. Calvaria were surgically exposed in 20 rabbits. In each animal, six 0.5-mm-diameter cortical microperforations were drilled with a carbide bur before grafting to promote graft irrigation. The sintered (group 1) and nonsintered (group 2) bovine bone blocks (6 mm diameter, 5 mm high) were bilaterally screwed onto calvarial bone. Blocks were previously prepared from a larger block using a trephine bur. Rabbits were sacrificed after 6 and 8 weeks for the histological and histomorphometric analyses. Samples were processed using the historesin technique. The quantitative and qualitative analyses of the newly formed bone were undertaken using light microscopy. Both groups showed modest new bone formation and remodeling. At the 8-week follow-up, the sintered group displayed significantly lower bone resorption (average of 10% in group 1 and 25% in group 2) and neo-formation (12.86 ± 1.52%) compared to the nonsintered group (16.10 ± 1.29%) at both follow-ups (p < 0.05). One limitation of the present animal model is that the study demonstrates that variations in the physico-chemical properties of the bone substitute material clearly influence the in vivo behavior.

Intraosteal Behavior of Porous Scaffolds: The mCT Raw-Data Analysis as a Tool for Better Understanding

The aim of the study is to determine the existing correlation between high-resolution 3D imaging technique obtained through Micro Computed Tomography (mCT) and histological-histomorphometric images to determine in vivo bone osteogenic behavior of bioceramic scaffolds. A Ca-Si-P scaffold ceramic doped and non-doped (control) with a natural demineralized bone matrix (DBM) were implanted in rabbit tibias for 1, 3, and 5 months. A progressive disorganization and disintegration of scaffolds and bone neoformation occurs, from the periphery to the center of the implants, without any differences between histomorphometric and radiological analysis. However, significant differences (p < 0.05) between DMB-doped and non-doped materials where only detected through mathematical analysis of mCT. In this way, average attenuation coefficient for DMB-doped decreased from 0.99 ± 0.23 Hounsfield Unit (HU) (3 months) to 0.86 ± 0.32 HU (5 months). Average values for non-doped decreased from 0.86 ± 0.25 HU (3 months) to 0.66 ± 0.33 HU. Combination of radiological analysis and mathematical mCT seems to provide an adequate in vivo analysis of bone-implanted biomaterials after surgery, obtaining similar results to the one provided by histomorphometric analysis. Mathematical analysis of Computed Tomography (CT) would allow the conducting of long-term duration in vivo studies, without the need for animal sacrifice, and the subsequent reduction in variability.

Demineralized Bone Matrix Coating Si-Ca-P Ceramic Does Not Improve the Osseointegration of the Scaffold

The aim of this study was to manufacture and evaluate the effect of a biphasic calcium silicophosphate (CSP) scaffold ceramic, coated with a natural demineralized bone matrix (DBM), to evaluate the efficiency of this novel ceramic material in bone regeneration. The DBM-coated CSP ceramic was made by coating a CSP scaffold with gel DBM, produced by the partial sintering of different-sized porous granules. These scaffolds were used to reconstruct defects in rabbit tibiae, where CSP scaffolds acted as the control material. Micro-CT and histological analyses were performed to evaluate new bone formation at 1, 3, and 5 months post-surgery. The present research results showed a correlation among the data obtained by micro-CT and the histomorphological results, the gradual disintegration of the biomaterial, and the presence of free scaffold fragments dispersed inside the medullary cavity occupied by hematopoietic bone marrow over the 5-month study period. No difference was found between the DBM-coated and uncoated implants. The new bone tissue inside the implants increased with implantation time. Slightly less new bone formation was observed in the DBM-coated samples, but it was not statistically significant. Both the DBM-coated and the CSP scaffolds gave excellent bone tissue responses and good osteoconductivity.

Bone regeneration using a porcine bone substitute collagen composite in vitro and in vivo

The biocharacteristics of xenogeneic grafts make them a possible substitute for autogenous bone grafts in dental bone graft procedures. This study aimed to develop a novel porcine graft with collagen capable of generating new bone in bone defects via osteoconduction over 8 weeks of healing and to compare it with a porcine graft. The porcine collagen graft was made to undergo a cell viability test (MTT) and alkaline phosphatase assay (ALP). The surgical procedure was performed in 20 male adult New Zealand white rabbits. Four calvarial critical-size defects of 6 mm in diameter were prepared in each rabbit. The upper left defect was filled with a porcine graft of 500–1000 μm, the upper right with a porcine collagen graft, the lower left with hydroxyapatite/beta-tricalcium phosphate and the lower right served as the control without any filling material. The rabbits were divided and sacrificed at 2, 4, 6 and 8 weeks after surgery. Histological and micro-CT scan results showed that the performance of the porcine collagen graft is superior for regenerating new bone. Porcine collagen graft showed cell viability and osteoblast-like cell differentiation in vitro. The results indicate that porcine collagen graft is a potential bone substitute for clinical application.

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.

The Influences of Different Ratios of Biphasic Calcium Phosphate and Collagen Augmentation on Posterior Lumbar Spinal Fusion in Rat Model

PURPOSE

To determine the influence of different ratios of hydroxyapatite (HA)/beta tricalcium phosphate (β-TCP) and collagen augmentation for posterior lumbar fusion in a rat model.

MATERIALS AND METHODS

We generated a posterior lumbar fusion model in 50 rats and divided it into five groups of equal number as follows; 1) autologous bone graft as group A, 2) 70% HA+30% β-TCP as group B, 3) 70% HA+30% β-TCP+collagen as group C, 4) 30% HA+70% β-TCP as group D, and 5) 30% HA+70% β-TCP+collagen as group E. Rats were euthanized at 12 weeks after surgery and fusion was assessed by manual palpation, quantitative analysis using microCT and histology.

RESULTS

The score of manual palpation was significantly higher in group C than group E (3.1±1.1 vs. 1.8±0.8, p=0.033). However, in terms of microCT analysis, group D showed significantly higher scores than group B (5.5±0.8 vs. 3.1±1.1, p=0.021). According to quantitative volumetric analysis, 30% HA+70% β-TCP groups (group D and E) showed significantly reduced fusion mass at 12 weeks after surgery (123±14.2, 117±46.3 vs. 151±27.3, p=0.008, 0.003, respectively). Collagen augmentation groups revealed superior results in terms of both microCT score and histologic grade.

CONCLUSION

A 7:3 HA/β-TCP ratio with collagen augmentation rather than a 3:7 HA/β-TCP ratio could be a more favorable graft substitute for lumbar spinal fusion. There was positive role of collagen as an adjunct for spinal bone fusion process.

Morphological and Structural Study of a Novel Porous Nurse's A Ceramic with Osteoconductive Properties for Tissue Engineering

The characterization process of a new porous Nurse’s A ceramic and the physico chemical nature of the remodeled interface between the implant and the surrounding bone were studied after in vivo implantation. Scaffolds were prepared by a solid-state reaction and implanted in New Zealand rabbits. Animals were sacrificed on days 15, 30, and 60. The porous biomaterial displayed biocompatible, bioresorbable, and osteoconductive capacity. The degradation processes of implants also encouraged osseous tissue ingrowths into the material’s pores, and drastically changed the macro- and microstructure of the implants. After 60 healing days, the resorption rates were 52.62% ± 1.12% for the ceramic and 47.38% ± 1.24% for the residual biomaterial. The elemental analysis showed a gradual diffusion of the Ca and Si ions from the materials into the newly forming bone during the biomaterial’s resorption process. The energy dispersive spectroscopy (EDS) analysis of the residual ceramic revealed some particle categories with different mean Ca/P ratios according to size, and indicated various resorption process stages. Since osteoconductive capacity was indicated for this material and bone ingrowth was possible, it could be applied to progressively substitute an implant.

Bone neoformation of a novel porous resorbable Si-Ca-P-based ceramic with osteoconductive properties: physical and mechanical characterization, histological and histomorphometric study

OBJECTIVE

The aims of the present work were to study a new porous Nurse's A ceramic (Si-Ca-P-based material) bone substitute and examine its mechanical properties in vitro and the biocompatibility, osteoconductivity and resorption process in vivo.

MATERIALS AND METHOD

Porous ceramic scaffolds were prepared by solid-state reaction and implanted in critical-sized defect created in 15 NZ rabbits. Strength values were determined by the diametrical compression of disk test. Weibull analyses were performed following the European Standard for technical ceramics EN-843-5: 1996, considering 90% of confidence intervals. Results were correlated with scanning microscope observations of fracture surfaces. Implanted scaffolds were characterized by histological and histomorphometric point of view.

RESULTS

The parameters of the Weibull distribution of strength, determined by diametrical compression of disks, were modulus m = 13, and characteristic strength σ₀  = 0.60 MPa (90% confidence limit: m = 7.2-17.6, σ₀  = 0.570-0.578). Porous calcium silicophosphate scaffolds showed significantly more bone formation in the pores and in the periphery of the implant than the control group. Histomorphometric analysis revealed that the ceramic scaffold (62.23 ± 0.34*) produced higher values of bone-to-implant contact (BIC) percentages (higher quality, closer contact); moreover, defect closure was significative in relation with control group.

CONCLUSIONS

The porous calcium silicophosphate ceramic is biocompatible, partially resorbable and osteoinductive material. This rabbit study provides radiological and histological evidences confirming the suitablity of this new material for bone tissue regeneration on critical defects.

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

OBJECTIVES

This study aimed to carry out the evaluation of bone response of new bone formation to two different xenografts (bovine and porcine) biomaterials inserted in rabbit tibiae.

MATERIALS AND METHODS

The study used a total of 20 male New Zealand albino rabbits. They received a total of 40 grafts in the proximal metaphyseal areas of both tibiae. Two biomaterials were evaluated: 20 porcine xenografts, as a bone granulate (OsteoBiol(®) MP3(®) ; Tecnoss srl, Giaveno, Italy), were placed in the proximal metaphyseal area of the right tibia, 20 anorganic bovine bone mineral grafting (4BONE(™) XBM, MIS Implants Inc., BARLEV, Israel) were placed in the left tibia. Following graft insertion, the animals were sacrificed in two groups of 10 animals, after 1 and 4 months, respectively. For each group, biomaterials were analyzed: newly formed bone, residual graft materials and the connective tissue. Histomorphometric, EDX analysis and element mapping were performed at 1 and 4 months after graft insertion.

RESULTS

At 4 months after treatment, the bone defects displayed radiological images that showed complete repair of osseous defects. Histomorphometric evaluation showed that for the porcine xenograft, the study averages for newly formed bone represented 84.23 ± 2.9%, while bovine matrix was 79.34 ± 2.1%. For residual graft material, the porcine biomaterial had 11.23 ± 1.7% and the bovine graft 31.56 ± 2.3%. Finally, the connective tissue for MP3 was 10.33 ± 1.8%, while for the 4BONE(™) XBM we obtained 14.34 ± 2.9%. Element analysis revealed higher percentages of Ca (54 ± 9%) and P (35 ± 6%) in the group B than group A and control group (P < 0.05).

CONCLUSIONS

Defects of a critical size in a rabbit tibia model can be sealed using a bovine porous biphasic calcium phosphate and MP3 material; this supports new bone formation, creates a bridge between borders, and facilitates bone ingrowth in both biomaterials. Furthermore, this study observed partial dissolution of the mineral phase of four bone graft and complete resorption of porcine MP3 biomaterial and its incorporation into the surrounding bone. Depending on clinical needs, each biomaterial could be useful in daily clinical practice.

A Novel Porcine Graft for Regeneration of Bone Defects

Bone regeneration procedures require alternative graft biomaterials to those for autogenous bone. Therefore, we developed a novel porcine graft using particle sizes of 250–500 μm and 500–1000 μm in rabbit calvarial bone defects and compared the graft properties with those of commercial hydroxyapatite (HA)/beta-tricalcium phosphate (β-TCP) over eight weeks. Surgery was performed in 20 adult male New Zealand white rabbits. During a standardized surgical procedure, four calvarial critical-size defects of 5 mm diameter and 3 mm depth were prepared. The defects were filled with HA/β-TCP, 250–500 μm or 500–1000 μm porcine graft, and control defects were not filled. The animals were grouped for sacrifice at 1, 2, 4, and 8 weeks post-surgery. Subsequently, sample blocks were prepared for micro-computed tomography (micro-CT) scanning and histological sectioning. Similar bone formations were observed in all three treatment groups, although the 250–500 μm porcine graft performed slightly better. Rabbit calvarial bone tissue positively responded to porcine grafts and commercial HA/β-TCP, structural analyses showed similar crystallinity and porosity of the porcine and HA/β-TCP grafts, which facilitated bone formation through osteoconduction. These porcine grafts can be considered as graft substitutes, although further development is required for clinical applications.

Enhanced bone regeneration with a novel synthetic bone substitute in combination with a new natural cross-linked collagen membrane: radiographic and histomorphometric study

OBJECTIVES

4Bone is a fully synthetic bioactive bone substitute composed of 60% hydroxyapatite (HA) and 40% beta-tricalcium phosphate (ß-TCP). This study aimed to investigate the effect of resorbable collagen membranes (RCM) on critical size defects in rabbit tibiae filled with this novel biphasic calcium phosphate at 15, 30, 45, and 60 days by radiological and histomorphometric analysis.

MATERIAL AND METHODS

Three critical size defects of 6 mm diameter were created in both tibiae of 20 New Zealand rabbits and divided into three groups according to the filling material: Group A (4Bone), Group B (4Bone plus RCM), and Group C (unfilled control group). At each of the four study periods, five rabbits were sacrificed. Anteroposterior and lateral radiographs were taken. Samples were processed for observation under light microscopy.

RESULTS

At the end of treatment, radiological analysis found that cortical defect closure was greater in Group B than Group A, and radiopacity was clearly lower and more heterogeneous in Group A cortical defects than in Group B. There was no cortical defect closure in Group C. Histomorphometric evaluation showed significant differences in newly formed bone and cortical closure in Group B compared with Groups A and C, with the presence of higher density newly formed bone in cortical and medullar zones.

CONCLUSIONS

Biphasic calcium phosphate functioned well as a scaffolding material allowing bone ingrowth and mineralization. The addition of absorbable collagen membranes enhanced bone gain compared with non-membrane-treated sites. This rabbit study provides radiological and histological evidence confirming the suitability of this new material for guided tissue regeneration of critical defects.

Bone regenerative medicine: classic options, novel strategies, and future directions

This review analyzes the literature of bone grafts and introduces tissue engineering as a strategy in this field of orthopedic surgery. We evaluated articles concerning bone grafts; analyzed characteristics, advantages, and limitations of the grafts; and provided explanations about bone-tissue engineering technologies. Many bone grafting materials are available to enhance bone healing and regeneration, from bone autografts to graft substitutes; they can be used alone or in combination. Autografts are the gold standard for this purpose, since they provide osteogenic cells, osteoinductive growth factors, and an osteoconductive scaffold, all essential for new bone growth. Autografts carry the limitations of morbidity at the harvesting site and limited availability. Allografts and xenografts carry the risk of disease transmission and rejection. Tissue engineering is a new and developing option that had been introduced to reduce limitations of bone grafts and improve the healing processes of the bone fractures and defects. The combined use of scaffolds, healing promoting factors, together with gene therapy, and, more recently, three-dimensional printing of tissue-engineered constructs may open new insights in the near future.

Bone regenerative medicine: classic options, novel strategies, and future directions

This review analyzes the literature of bone grafts and introduces tissue engineering as a strategy in this field of orthopedic surgery. We evaluated articles concerning bone grafts; analyzed characteristics, advantages, and limitations of the grafts; and provided explanations about bone-tissue engineering technologies. Many bone grafting materials are available to enhance bone healing and regeneration, from bone autografts to graft substitutes; they can be used alone or in combination. Autografts are the gold standard for this purpose, since they provide osteogenic cells, osteoinductive growth factors, and an osteoconductive scaffold, all essential for new bone growth. Autografts carry the limitations of morbidity at the harvesting site and limited availability. Allografts and xenografts carry the risk of disease transmission and rejection. Tissue engineering is a new and developing option that had been introduced to reduce limitations of bone grafts and improve the healing processes of the bone fractures and defects. The combined use of scaffolds, healing promoting factors, together with gene therapy, and, more recently, three-dimensional printing of tissue-engineered constructs may open new insights in the near future.