Bone Neoformation Research Articles

Osseointegration Improvement of Co-Cr-Mo Alloy Produced by Additive Manufacturing.

Cobalt-base alloys (Co-Cr-Mo) are widely employed in dentistry and orthopedic implants due to their biocompatibility, high mechanical strength and wear resistance. The osseointegration of implants can be improved by surface modification techniques. However, complex geometries obtained by additive manufacturing (AM) limits the efficiency of mechanical-based surface modification techniques. Therefore, plasma immersion ion implantation (PIII) is the best alternative, creating nanotopography even in complex structures. In the present study, we report the osseointegration results in three conditions of the additively manufactured Co-Cr-Mo alloy: (i) as-built, (ii) after PIII, and (iii) coated with titanium (Ti) followed by PIII. The metallic samples were designed with a solid half and a porous half to observe the bone ingrowth in different surfaces. Our results revealed that all conditions presented cortical bone formation. The titanium-coated sample exhibited the best biomechanical results, which was attributed to the higher bone ingrowth percentage with almost all medullary canals filled with neoformed bone and the pores of the implant filled and surrounded by bone ingrowth. It was concluded that the metal alloys produced for AM are biocompatible and stimulate bone neoformation, especially when the Co-28Cr-6Mo alloy with a Ti-coated surface, nanostructured and anodized by PIII is used, whose technology has been shown to increase the osseointegration capacity of this implant.

LOCAL APPLICATION OF GROWTH HORMONE INDUCES INCREASED IMMUNOEXPRESSION OF IGF-I ON CRANIOFACIAL BONE DEFECTS REPAIR – A PILOT STUDY

The aim is to evaluate the local effect of different concentrations of growth hormone (GH) on the repair of craniofacial bone defects, through histological, histomorfometric, and insulin-like growth factor I (IGF-I) immunoexpression assessments. Critical defects (5 mm) were performed in 32 Wistar rats. The animals were divided into four groups: Group C (Control); Group S (Sponge-collagen); Group GH 0.08 mL; GH 0.104 mg; Group GH 0.1mL. Local applications were performed 3 times a week until the rats were euthanized at 60 days. The data were submitted to ANOVA and Tukey's test (P < 0.05). A healing process with predominance of collagen bers and bone neoformation near the edges of the defect was observed in groups C and S. Islands of bone neoformation were observed at the center and edges of the defect in groups GH 0.08 and GH 0.1. In GH 0.1, the bone was more compact, and the defect was completely closed in some specimens. Bone neoformation was signicantly higher in the GH-treated groups. All the specimens stained positive for IGF-I, and this immunoexpression was signicantly higher in Group GH 0.1. In conclusion, locally applied GH signicantly favored bone repair in rat calvaria, and a higher dose of GH increased the immunoexpression of IGF-I.

Effect of Cerium-Containing Hydroxyapatite in Bone Repair in Female Rats with Osteoporosis Induced by Ovariectomy

Osteoporosis is a public health problem, with bone loss being the main consequence. Hydroxyapatite (HA) has been largely used as a bioceramic to stimulate bone growth. In our work, a cerium-containing HA (Ce-HA) has been proposed and its effects on the antimicrobial and bone-inducing properties were investigated. The synthesis of the materials occurred by the suspension–precipitation method (SPM). The XRD (X-ray Diffraction) confirmed the crystalline phase, and the Rietveld refinement confirmed the crystallization of HA and Ce-HA in a hexagonal crystal structure in agreement with ICSD n° 26205. Characterizations by FT-IR (Fourier Transform Infrared Spectroscopy), XPS (X-ray Photoemission Spectroscopy), and FESEM-EDS (Field Emission Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) confirmed the presence of cerium (Ce3+ and Ce4+). The antibacterial activity of Has was evaluated against Staphylococcus aureus 25,923 and Escherichia coli 25,922 strains, which revealed that the material has antimicrobial properties and the cytotoxicity assay indicated that Ce-containing HA was classified as non-toxic. The effects of Ce-HA on bone repair, after application in bone defects in the tibia of female rats with osteoporosis induced by ovariectomy (OVX), were evaluated. After 15 and 30 days of implantation, the samples were analyzed by Raman, histology and X-ray microtomography. The results showed that the animals that had the induced bone defects filled with the Ce-HA materials had more expressive bone neoformation than the control group.

OSTEOGENIC POTENTIAL OF NANOSTRUCTURED CARBONATED HYDROXIAPATITE MICROSPHERES ASSOCIATED WITH MESENCHYMAL STEM CELL IN VITRO AND IN VIVO

<h3>Background</h3> Bone tissue is capable of self-healing in the event of injuries. However, situations such as the patient‘s age or size of the damage can compromise natural healing, bringing to the fore the need for interventions to treat bone injuries. Tissue engineering presents treatment alternatives involving the use of cells and associated biomaterials. In this context, studies using biomaterials claim that carbonated hydroxyapatite (CHA) is more resorbable than hydroxyapatite (HA) and has biological similarity to bone hydroxyapatite. <h3>Methods</h3> Parameters of indirect contact (cytotoxicity, proliferation, and migration) of the extract obtained from spheres of carbonated hydroxyapatite associated with murine bone marrow stem cells (BMSCs) in vitro were evaluated. Then the osteogenic potential of CHA extract in murine BMSCs in vitro was assessed by quantification of calcium matrix, alkaline phosphatase levels and gene expression Col1A1 and Bglap. Non-critical size bone defects were performed in rat femur. After 14 days of healing, bone blocks were obtained for analysis from treated animals and compared to non-treated animals by histological and histomorphometric evaluation. <h3>Results</h3> The CHA extract showed osteoinductive properties in vitro without the need to add osteogenic inducing medium. The ability to induce osteogenic differentiation in undifferentiated cells was confirmed by increased activity of alkaline phosphatase, formation of mineralized nodules and increased expression of the Col1A1 and Bglap genes after 7 and 14 days of differentiation. All groups presented bone neoformation at the injury site 14 days after the operation. Histomorphometric analysis showed no statistical difference between groups in the parameters of bone formation, biomaterial and connective tissue. <h3>Conclusion</h3> The CHA spheres have in vitro osteoinductive properties and, when loaded with murine BMSCs, have the potential for bone repair and regeneration in vivo, presenting biocompatibility and osteoconductive, making it a promising alternative for bone tissue engineering applications.

Evaluation of Guided Bone Regeneration in Critical Defects Using Bovine and Porcine Collagen Membranes: Histomorphometric and Immunohistochemical Analyses

Guided bone regeneration (GBR) is a technique used to facilitate bone regeneration, which uses a biocompatible membrane acting as a physical barrier to prevent the adjacent connective tissue from invading the bone defect. The aim of this study was to evaluate and compare the effectiveness of bovine and porcine collagenous membranes as barriers to connective tissue invasion during the repair of critical bone defects in rat calvaria, using histological, histometric, and immunohistochemical analyses. For this study, 72 rats were divided into three groups: clot group (CG), bovine collagen group (BCG), and porcine collagen group (PCG). Analyses were performed on days 7, 15, 30, and 60. The histological results showed that the PCG exhibited bone neoformation starting from day 7, and after 30 days of repair, the surgical defect was completely filled in some animals. For the BCG, there was little bone neoformation activity in the initial periods, and from day 30 onwards, there was an increase in bone neoformation, with a greater increase on day 60. The data obtained in the histometric analysis reveal that, on day 30, the neoformed bone area did not vary greatly between the PCG and the BCG, though both varied from the CG. By day 60, the PCG presented a greater area of neoformation than the BCG. These results were corroborated by the immunohistochemistry results. In view of the results obtained, it can be concluded that all membranes studied in this research promoted GBR.

FIBRINA RICA EM PLAQUETAS NO TRATAMENTO REGENERATIVO ÓSSEO PERIODONTAL: UMA REVISÃO DE ESCOPO

Concentrados plaquetários são compostos autógenos obtidos através da centrifugação em alta rotação do sangue venoso. Dentro dos tratamentos periodontais, eles têm sido aplicados por terem excelentes propriedades regenerativas e de neoformação óssea. Esta revisão teve por objetivo responder a seguinte pergunta foco: “Em procedimentos regenerativos ósseos periodontais, o uso da fibrina rica em plaquetas(PRF) sozinha ou combinada com biomateriais, comparada com biomateriais isoladamente, leva a alterações significativas na neoformação óssea, preenchimento de defeitos ósseos ou ganhos dimensionais?”. Uma revisão de escopo foi realizada de acordo com as normas PRISMA-ScR. As bases de dados Medline/pubMed, Scopus e Scielo foram pesquisadas usando termos-chaves e procurando ensaios clínicos aleatorizados realizados em pacientes com diferentes tipos de defeitos ósseos periodontais, que tenham ou não recebido tratamento periodontal, onde foi aplicado em um grupo PRF isoladamente ou em associação com biomaterial, quando comparado com biomateriais isoladamente. A busca eletrônica gerou 2.497 títulos/resumos e 5 artigos foram incluídos nesta revisão. No total, 175 voluntários foram tratados. Os defeitos ósseos de duas e três paredes foram os mais comumente relatados nos estudos. O tempo de acompanhamento variou entre 6 e 12 meses. Quando o PRF foi utilizado no tratamento de defeitos periodontais houve a uma melhora mais evidente nos parâmetros clínicos, incluindo uma diminuição na profundidade do defeito e diminuição da profundidade de sondagem e ganho de inserção. Os resultados desta revisão escopo indicaram que uso de PRF sozinha ou combinada com biomateriais em procedimentos regenerativos ósseos periodontais leva a uma melhora clinicamente relevante na neoformação óssea.

The Complexity of Joint Regeneration: How an Advanced Implant could Fail by Its In Vivo Proven Bone Component

Articular cartilage damage is a major challenge in healthcare due to the lack of long-term repair options. There are several promising regenerative implant-based approaches for the treatment, but the fixation of the implant remains a significant challenge. This study evaluated the potential for repair of an osteochondral implant produced through a novel combined bioprinting-based chondral-bone integration, with and without cells, in an equine model. Implants consisted of a melt electrowritten polycaprolactone (PCL) framework for the chondral compartment, which was firmly integrated with a bone anchor. The bone anchor was produced by extrusion-based printing of a low-temperature setting bioceramic material that had been proven to be effective for osteo-regeneration in an orthotopic, non-load bearing and non-articular site in the same species in an earlier in vivo study. Articular cartilage-derived progenitor cells were seeded into the PCL framework and cultured for 28 days in vitro in the presence of bone morphogenetic protein-9 (BMP-9), resulting in the formation of abundant extracellular matrix rich in glycosaminoglycans (GAGs) and type II collagen. The constructs were implanted in the stifle joints of Shetland ponies with cell-free scaffolds as controls. Clinical signs were monitored, and progression of healing was observed non-invasively through radiographic examinations and quantitative gait analysis. Biochemical and histological analyses 6 months after implantation revealed minimal deposition of GAGs and type II collagen in the chondral compartment of the defect site for both types of implants. Quantitative micro-computed tomography showed collapse of the bone anchor with low volume of mineralized neo-bone formation in both groups. Histology confirmed that the PCL framework within the chondral compartment was still present. It was concluded that the collapse of the osteal anchor, resulting in loss of the mechanical support of the chondral compartment, strongly affected overall outcome, precluding evaluation of the influence of BMP-9 stimulated cells on in vivo cartilage regeneration.

Interferência da disrupção circadiana sobre a homeostase óssea

Objetivo: O propósito deste trabalho foi avaliar se existe estreita relação entre o ciclo circadiano e o metabolismo ósseo. Métodos: A metodologia adotada foi a pesquisa bibliográfica de artigos científicos nas Bases de Dados Virtuais de Saúde (BVSs). Revisão Bibliográfica: buscou-se evidências científicas da interferência da disrupção circadiana sobre a homeostase óssea, e apontar possíveis mecanismos de ação dessa interferência. As anomalias do sono promovem alterações inflamatórias, hormonais e metabólicas causando prejuízo do metabolismo ósseo, levando a crer que otimizar o sono é um fator de grande importância nas situações em que a neoformação óssea é desejada, como por exemplo: fase de crescimento, cirurgias ortopédicas e ortognáticas, instalação de implantes dentários, tratamentos periodontais e outros. Conclusão: Concluiu-se que existe interferência da disrupção circadiana sobre a homeostase óssea, e os mecanismos pelos quais esta interferência ocorre podem ser: aumento da inflamação sistêmica, aumento do estresse oxidativo, alterações hormonais, diminuição da vitamina D e hipóxia.

Physical characterization of biphasic bioceramic materials with different granulation sizes and their influence on bone repair and inflammation in rat calvaria

Biphasic calcium phosphate bioceramics (BCP) consist of a mixture of hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) within the same particle. Due to their osteoconductive properties, biocompatibility and resemblance to natural bone, these materials have become a promising and suitable alternative to autologous bone grafting. First, the topography characteristics, specific surface area, and total pore volume of BCP were evaluated using scanning electron microscopy and the BET and BJH methods. Next, this study aimed to evaluate the intensity of the inflammatory process and the bone neoformation capacity of various particle sizes of BCP in the repair of critical defects in the calvaria of rats. A xenogeneic biomaterial was used in the control group. After 30, 60, and 90 days, the animals were euthanized, followed by the processing of the samples to measure the intensity of inflammatory infiltrates and the areas of bone neoformation. Our results indicate that no considerable differences were observed in the inflammatory scores in sites treated with distinct BCP grain sizes. A greater area of bone neoformation was measured in the xenogeneic group at all analysis times, with no substantial differences in bone formation between the BCP particle size in the range of 250–500 µm and 500–1000 µm.

Calcium Phosphate Modified with Silicon vs. Bovine Hydroxyapatite for Alveolar Ridge Preservation: Densitometric Evaluation, Morphological Changes and Histomorphometric Study.

After tooth extraction, the alveolar bone undergoes a physiological resorption that may compromise the future placement of the implant in its ideal position. This study evaluated bone density, morphological changes, and histomorphometric results undergone by alveolar bone after applying a new biomaterial composed of calcium phosphate modified with silicon (CAPO-Si) compared with hydroxyapatite of bovine origin (BHA). Alveolar ridge preservation (ARP) was performed in 24 alveoli, divided into a test group filled with CAPO-Si and a control group filled with BHA. Three months later, the mineral bone density obtained by the biomaterials, horizontal and vertical bone loss, the degree of alveolar corticalization, and histomorphometric results were evaluated. Both biomaterials presented similar behavior in terms of densitometric results, vertical bone loss, and degree of alveolar corticalization. Alveoli treated with CAPO-Si showed less horizontal bone loss in comparison with alveoli treated with BHA (0.99 ± 0.2 mm vs. 1.3 ± 0.3 mm), with statistically significant difference (p = 0.017). Histomorphometric results showed greater bone neoformation in the test group than the control group (23 ± 15% vs. 11 ± 7%) (p = 0.039) and less residual biomaterial (5 ± 10% vs. 17 ± 13%) (p = 0.043) with statistically significant differences. In conclusion, the ARP technique obtains better results with CAPO-Si than with BHA.

The slow release of BMP-7 at a low dose accelerates dental implant healing in an osteopenic environment.

The aim of the present study was to investigate in vivo whether bone morphogenetic protein-7 (BMP-7) was able to promote and accelerate dental implant healing at a low dose in an osteopenic environment by using a delayed drug-release system. Skeletally mature Chinese goats, having physiologically osteopenic (osteoporotic-like) facial bones, served as an animal model. Dental implants were provided with a delayed-release drug-delivery system and BMP-7 was applied at three different dosages. The implants, inserted into healed extraction sockets, were removed 1, 2 and 3 weeks after surgery. Quantification of osseointegration and formation of new bone in the peri- implant space were measured histomorphometrically. Data revealed no evidence of any adverse drug effect at or near the implantation sites. After the first postoperative week, bone neoformation was minimal; after the second week, peri-implant bone formation appeared, particularly in the groups with low dosages of BMP-7. After 3 weeks, new-bone volume was the largest in the group with the lowest (near-physiological) dosage of BMP-7, also showing the highest efficacy of BMP-7. Other dosage or release modes were found to be significantly less effective. BMP-7 was highly efficacious in promoting and accelerating bone formation in the peri-implant space in a hostile osteopenic environment if released by a slow-mode mechanism over time at near physiological activities. Therefore, biological functionalisation of dental implants by a high-power osteogenic factor may improve their healing success in hostile bony environments (osteopenia, osteoporosis, bone atrophy etc.).

Cyanoacrylate glue in socket repair: a comparative study

This study aimed to compare socket repair with Nylon 5-0 suture and closure using cyanoacrylate biological glue after tooth extraction. Twenty male Wistar rats, each weighing approximately 200 g were submitted to the extraction of the right and left first molar teeth. On the right side, the alveolus was closed with 2 ethyl-cyanoacrylate glue, whereas on the left side closure was with a single interrupted Nylon 5-0 suture (Ethilon). The animals were sacrificed after 3, 7, 15, and 30 postoperative days, and images of histological sections of the alveolus were captured for analysis. Histomorphometry was performed using Image J software to quantify bone neoformation in the alveolus. The results showed that on the seventh postoperative day the side treated with 2-ethyl-cyanoacrylate presented a delay in relation to the sutured side. However, on days 15 and 30, the difference in bone neoformation between gradually decreased until the thirtieth postoperative day, with no significant difference in bone neoformation in the last period of analysis. There was no difference between neoformation in the two sides (p = 0.902) after statistical analysis of the histomorphometric results. In conclusion, socket repair after alveolus closure with 2-ethyl-cyanoacrylate allows complete bone neoformation after tooth extraction, and there is no significant difference when compared with closure with Nylon 5-0.

Biological behavior of magnesium-substituted hydroxyapatite during bone repair.

The aim of this study was to analyze the biological behavior and osteogenic potential of magnesium (Mg) substituted hydroxyapatite (HA) microspheres, implanted in a critical bone defect, considering that this ion is of great clinical interest, since it is closely associated with homeostasis and bone mineralization. For the purpose of this study, 30 rats were used to compose three experimental groups: GI - bone defect filled with HA microspheres; GII - bone defect filled with HA microspheres replaced with Mg; GIII - empty bone defect; evaluated at biological points of 15 and 45 days. The histological results, at 15 days, showed, in all the groups, a discrete chronic inflammatory infiltrate; biomaterials intact and surrounded by connective tissue; and bone neoformation restricted to the borders. At 45 days, in the GI and GII groups, an inflammatory response of discrete granulomatous chronic type was observed, and in the GIII there was a scarce presence of mononuclear inflammatory cells; in GI and GII, the microspheres were seen to be either intact or fragmented, surrounded by fibrous connective tissue rich in blood vessels; and discrete bone neoformation near the edges and surrounding some microspheres. In GIII, the mineralization was limited to the borders and the remaining area was filled by fibrous connective tissue. It was concluded that the biomaterials were biocompatible and osteoconductive, and the percentage of Mg used as replacement ion in the HA did not favor a greater bone neoformation in relation to the HA without the metal.

Bone remodeling during alveolar repair is impaired by RANKL antagonist

Post-menopausal osteoporosis is detrimental to bone metabolism as well as alveolar repair. This osteometabolic disorder is an obstacle to the success of maxillofacial rehabilitations, since a large number of patients are carriers of the disease. Denosumab is widely used as a treatment for post menopausal osteoporosis. This drug exerts an antiabsorptive action by inhibiting RANKL, helping to reduce the bone loss caused by osteoporosis. This study aimed to evaluate the repair bone formed after the extraction of the upper incisor of estrogen-deficient rats treated with anti-RANKL monoclonal antibody. The rats (Rattus novergicus albinus, Wistar) were ovariectomized or SHAM operated (n=36). Half of the ovariectomized rats were treated with osteoprotegerin with an Fc fragment (OPG-Fc; 10mg/kg, twice a week), the other half received saline solution as control. After 30 days the rats had their right upper incisor extracted. After 60 days of extraction, the alveoli were evaluated by immunohistochemical, computerized microtomography and confocal microscopy. The OPG-Fc decreased the percentage of bone volume (BV/TV), thickness (Tb.Th) and number of alveolar trabecules (Tb.N) when compared to groups that received saline solution (p&lt;0.005). The OPG-Fc increased the separation between the trabecules (Tb.Sp) and the porosity (Po.tot) of the reparative alveolar bone (p&lt;0.005). The OPG-Fc decreased immunolabelling for RANKL and TRAP when compared to groups that received saline solution. Treatment with OPG-Fc decreased bone neoformation but preserved preexisting bone tissue. This data is supported by the mineral apposition rate, which showed higher values for OVX/OPG-Fc when compared to the OVX group.

Effect of alendronate on the femoral metaphyseal defect under carbamazepine in ovariectomized rats

BackgroundThe use of antiepileptic drugs and estrogen deficiency put forward higher requirements for bone defect regeneration. The present study investigated the effects of alendronate (ALN) on femoral bone defect in ovariectomized (OVX) rats under the influence of carbamazepine (CBZ).MethodsOne hundred female SD rats at 3 months of age were either sham-operated or OVX and divided into four groups: sham control (CON); OVX control (OVX); ovariectomized rats treated with CBZ via gavage (75 mg/kg/day; CBZ); ovariectomized rats treated with CBZ plus ALN (2 mg/kg/day; CBZ-ALN). A critical-sized femoral metaphyseal bone defect was established in all female SD rats. Animals from the CBZ and CBZ-ALN groups received drugs by gavage the day after bone defect surgery was performed. After the rats were sacrificed, the defected area located in the distal femur was harvested for evaluation by microcomputed tomography (micro-CT), hematoxylin and eosin (HE) staining, and Masson’s trichrome staining. The samples were also analyzed by biomechanics and immunohistochemical evaluation (IHC). Besides, biochemical analysis evaluates all serum samples.ResultsThe present study showed that ovariectomy changed the microstructural parameters of bone. The use of CBZ further decreased femur bone mass while treatment with ALN prevented bone loss. Compared to OVX and CBZ groups, CBZ-ALN group promoted bone neoformation and enhanced the ultimate load of the femur bone. However, the group of CBZ-ALN did not return to normal levels compared with the CON group. Besides, we noticed that CBZ-ALN group reduced tartrate-resistant acid phosphatase-5b (Tracp-5b) expression and had no significant effect on the expression of osteocalcin (OCN) and type I collagen (Col-I) in IHC compared with CBZ group. Biochemical analysis results presented that systemic delivery of CBZ showed pernicious effects on bone formation and resorption in ovariectomized rats, with the worse effects on C-terminal crosslinked telopeptide of type I collagen (CTX-1). Besides, a significant decrease in CTX-1 levels was observed in CBZ-ALN group as compared to the group of CBZ.ConclusionThese results demonstrated that ALN can effectively reverse the effects of CBZ on the microarchitectural properties of bone, and thus can have a positive effect on local bone neoformation in rats with osteoporosis.Clinical relevanceThe dose of 2 mg/kg ALN improves the negative effect of prescription of CBZ at 75 mg/kg and promotes bone neoformation of femoral bony deficits.

Bone repair assessment of critical size defects in rats treated with mineralized bovine bone (Bio-Oss®) and photobiomodulation therapy: a histomorphometric and immunohistochemical study.

This study aimed to investigate the effects of administering photobiomodulation therapy (PBM) with bovine bone matrix on critical size defects in rats. Seventy-two adult male rats (albinus, Wistar), 90days old, were used. Defect of 5mm in diameter was made in their calvaria. The animals were divided into 4 groups: C-blood clot, B-Bio-Oss®, L-PBM, B+L-Bio-Oss®+PBM. Each group has been subdivided into 07, 30, and 60days of observation. For PBM, a low GaAlAs energy of 660nm was irradiated, total energy density of 45J/cm2 . PBM was conducted in a trans-surgical form once only. For immunohistochemistry, a semi-quantitative analysis was made of expression of osteoprotegerin (OPG), nuclear kappa B-factor ligand receptor activator (RANKL), and tartrate-resistant acid phosphatase (TRAP). All histomorphometric data were statistically analyzed by ANOVA and Tukey test, significance level of 5%. The groups that showed the highest proportion of neoformation were L (0.39% ± 0.13) and C (0.37% ± 0.97), but groups B and B+L had larger defect size (C-1.75mm2± 0.40, B-3.02mm2± 0.63, L-2.45mm2± 0.53, B+L-3.23mm2± 1.01). In immunohistochemistry, groups B and B+L had higher immunostaining scores for OPG and RANKL at 60days, and TRAP immunostaining increased in all groups at 30days, but group L was the only one to present specimens with score 0. Although, at 60days, groups L and C presented the highest proportion of bone neoformation, at 30days group B+L had more than twice as much bone neoformation as group B, the choice of treatment application should depend on the aim of the treatment.

Reduced Bone Neoformation in Smoking Rat’s Calvaria Grafted with Bone Ceramic

The impact of cigarette smoke on bone grafts in implantodontics has been discussed in the scientific literature. The present study aimed to evaluate bone repair in calvaria of rats after the performance of critical bone defects and graft of bone ceramic biomaterial in animals exposed or not to cigarette smoke. Bone defects of 5mm in diameter were made in parietal bone. Each defect was filled with Bone Ceramic biomaterial. Twenty rats were used and divided into 2groups: test, consisting of 10rats exposed to cigarette smoke; and a control group, consisting of 10rats not exposed to cigarette smoke. The animals were euthanized in the 4th postoperative week and bone tissue samples were extracted to perform the histometric analysis. The test group showed less bone neoformation, with statistical significance (p&lt;0.05) when compared to the control group. We conclude that cigarette smoke had a negative influence on bone neoformation.

Caffeine Effect on Bone Metabolism in Rats: a Systematic Review

HIGHLIGHTS Nine of 472 initially identified articles were selected for qualitative evaluation. Most studies show that caffeine can interfere with bone metabolism. Caffeine can accelerate bone loss and delay bone repair. In contrast, caffeine can activate osteogenesis and bone neoformation.

Effect of S53P4 bioactive glass and low-level laser therapy on calvarial bone repair in rats submitted to zoledronic acid therapy.

ABSTRACTPurposeTo evaluate the influence of bioactive glass and photobiomodulation therapy (PBMT) in calvarial bone repair process in rats submitted to zoledronic acid therapy.MethodsTwenty-four rats were selected and treated with the dose of 0.035 mg/kg of zoledronic acid every two weeks, totalizing eight weeks, to induce osteonecrosis. After the drug therapy, surgical procedure was performed to create 5-mm diameter parietal bone defects in the calvarial region. The rats were then randomly assigned to groups according to the following treatments: AZC: control group, treated with blood clot; AZBIO: bone defect filled with bioactive glass; AZL: treated with blood clot and submitted to PBMT; and AZBIOL: treated with bioactive glass S53P4 and submitted to PBMT. Tissue samples were collected and submitted to histomorphometric analysis after 14 and 28 days.ResultsAt 14 days, bone neoformation in the AZBIO (52.15 ± 9.77) and AZBIOL (49.77 ± 13.58) groups presented higher values (p ≤ 0.001) compared to the AZC (23.35 ± 10.15) and AZL groups (23.32 ± 8.75). At 28 days, AZBIO (80.24 ± 5.41)still presented significant higher bone recovery values when compared to AZC (59.59 ± 16.92)and AZL (45.25 ± 5.41) groups (p = 0.048). In the 28-day period, the AZBIOL group didn’t show statistically significant difference with the other groups (71.79 ± 29.38).ConclusionsThe bioactive glass is an effective protocol to stimulate bone neoformation in critical defects surgically created in rats with drug induced osteonecrosis, in the studied periods of 14 and 28 days.

O uso de membrana de colágeno de pericárdio bovino na regeneração óssea: características e relato de caso

The aim of this article was to describe the use of the bovine pericardium collagen membrane and to present its physical-chemical characteristics through laboratory tests, in addition to a case report proving its clinical performance. Called native collagen membranes from the animal pericardium, this product has ideal characteristics for promoting bone neoformation in grafting procedures for volumetric augmentation. Scanning electron microscopy (SEM) tests showed the organization of collagen fibers, and tensile tests pointed an adequate resistance to the mechanisms of graft stabilization, through sutures, screws or pins. Within the limitations of this article, it was possible to conclude that the bovine pericardium collagen membrane has the appropriate characteristics for use in guided bone regeneration procedures, with efficient handling, stability, and predictability.