Reconstruction of parietal bone defects with adiposederived mesenchymal stem cells. Experimental study.

PURPOSE: This study assessed the regeneration potential of mesenchymal stem cells (MSC) from adipose tissue associated with platelet-rich plasma (PRP) in bone regeneration. METHODS: Thirty Wistar rats (Rattus norvegicus albinos) were divided into five groups (according to the grafting material and time to euthanasia): (1) autograft - 14 days (control), (2) autograft - 28 days (control), (3) MSC + PRP - 14 days, (4) MSC + PRP + papaverine - 14 days and (5) MSC + PRP + papaverine - 28 days. After euthanasia, the graft was removed and histological slides were prepared. They were assessed by a blinded pathologist using a previously published histological scale as parameter. RESULTS: There was some degree of neoformed bone trabeculae (NBT) in 93.3% of the samples, as well as osteoblastic activity (OA). The autograft groups (14 and 28 days) had higher levels in the formation of bone trabeculae. Nonparametric data were analyzed using the Wilcoxon-Mann-Whitney test and proved not to be statistically significant at p < 0.05. CONCLUSIONS: Experimental parietal bone reconstruction, combining MSC, PRP and papaverine presented regeneration in all groups with no significant difference among them.

Reconstruction of parietal bone defects with adiposederived mesenchymal stem cells. Experimental study

Abstract Purpose: This study assessed the regeneration potential of mesenchymal stem cells (MSC) from adipose tissue associated with platelet-rich plasma (PRP) in bone regeneration. Methods: Thirty Wistar rats (Rattus norvegicus albinos) were divided into five groups (according to the grafting material and time to euthanasia): (1) autograft - 14 days (control), (2) autograft - 28 days (control), (3) MSC + PRP - 14 days, (4) MSC + PRP + papaverine - 14 days and (5) MSC + PRP + papaverine - 28 days. After euthanasia, the graft was removed and histological slides were prepared. They were assessed by a blinded pathologist using a previously published histological scale as parameter. Results: There was some degree of neoformed bone trabeculae (NBT) in 93.3% of the samples, as well as osteoblastic activity (OA). The autograft groups (14 and 28 days) had higher levels in the formation of bone trabeculae. Nonparametric data were analyzed using the Wilcoxon-Mann-Whitney test and proved not to be statistically significant at p < 0.05. Conclusions: Experimental parietal bone reconstruction, combining MSC, PRP and papaverine presented regeneration in all groups with no significant difference among them.

Hydrolytic degradation and in vivo resorption of poly-l-lactic acid-chitosan biomedical devices in the parietal bones of Wistar rats.

OBJECTIVES: This study sought to describe events related to the degradation/resorption of a device composed of polylactic acid (PLA) after implantation into Wistar rats. METHODS: Five-millimeter-diameter PLA rigid scaffolds and flexible analogs were elaborated, bioactivated through culture with osteoblasts, and implanted into the parietal bones of adult Wistar rats after 15 days. After 3 months, the samples were recovered and analyzed via optical microscopy (histochemical techniques) and scanning electron microscopy. This research was approved by the animal ethics review committee of Universidad of Valle in Cali, Colombia, according to the endorsement of the ethics committee CEAS 001-016. RESULTS: Initially, there was surface erosion and fragmentation of the device, inducing an inflammatory response compatible with the foreign body reaction, in addition to the presence of a pseudocapsule and a mixed inflammatory infiltrate that was responsible for phagocytosis of the material. Regeneration of the defect via the apposition of new bone occurred simultaneously with resorption of the material. CONCLUSIONS: The results illustrated that the degradation/resorption of PLA occurs in a centripetal pattern.

Photobiomodulation of mesenchymal stem cells encapsulated in an injectable rhBMP4-loaded hydrogel directs hard tissue bioengineering.

Photobiomodulation (PBM) therapy displays relevant properties for tissue healing and regeneration, which may be of interest for the tissue engineering field. Here, we show that PBM is able to improve cell survival and to interact with recombinant human Bone Morphogenetic Protein 4 (rhBMP4) to direct and accelerate odonto/osteogenic differentiation of dental derived mesenchymal stem cells (MSCs). MSCs were encapsulated in an injectable and thermo-responsive cell carrier (Pluronic® F-127) loaded with rhBMP4 and then photoactivated. PBM improved MSCs self-renewal and survival upon encapsulation in the Pluronic® F-127. In the presence of rhBMP4, cell odonto/osteogenic differentiation was premature and markedly improved in the photoactivated MSCs. An in vivo calvarial critical sized defect model demonstrated significant increase in bone formation after PBM treatment. Finally, a balance in the reactive oxygen species levels may be related to the favorable results of PBM and rhBMP4 association. PBM may act in synergism with rhBMP4 and is a promise candidate to direct and accelerate hard tissue bioengineering.

Reconstrução de calota craniana com prótese customizada de PMMA após craniectomias descompressivas / Skull reconstruction with PMMA customized prostheses after decompressive craniectomies

Introdução: A craniectomia descompressiva é uma cirurgia indicada no tratamento da hipertensão intracraniana em situações graves de traumas cranioencefálicos. Esta cirurgia confere uma aparência bizarra ao paciente, como se "parte da cabeça" houvesse sido retirada. Após a regressão do edema cerebral e quando o paciente reunir boas condições clínicas, a reconstrução craniana está indicada. A reconstrução da calota craniana poderá ser realizada com osso autólogo ou com materiais aloplásticos. Este estudo objetiva apresentar a experiência do autor com reconstruções de calota craniana utilizando próteses customizadas de PMMA. Métodos: Foram selecionados 14 pacientes submetidos à craniectomia descompressiva que, após serem liberados clinicamente pela Neurocirurgia, realizaram a reconstrução da calota craniana com próteses de PMMA customizadas por prototipagem entre os anos de 2014 e 2015 e com, no mínimo, 6 meses de pós-operatório. Sinais e sintomas de síndrome do Trefinado, tomografia computadorizada e aparência estética dos pacientes foram analisadas no pré e no 6º mês pós-operatório. Resultados: Todos os pacientes apresentaram melhora sintomatológica, melhora estética e expansão cerebral após a cirurgia. Conclusão: A reconstrução da calota craniana com prótese customizada de PMMA promoveu a melhora dos sinais e sintomas e da aparência estética de todos os 14 pacientes operados. A utilização de protótipos para customizar próteses cranianas facilitou a técnica operatória e possibilitou a recuperação de um contorno craniano muito próximo da normalidade.

Introduction: Decompressive craniectomy is indicated for the treatment of intracranial hypertension in cases of serious traumatic brain injury. This surgery results in a bizarre appearance, as if "part of the head" had been. After regression of cerebral edema and when the patient is in good clinical condition, the reconstruction of the skull is indicated. Reconstruction of the skull can be performed with autologous bone or with alloplastic materials. This study sought to present the experience of the author with skull reconstructions using custom PMMA prostheses. Methods: In between 2014 and 2015, fourteen patients with previous (longer than 6 months) decompressive craniectomies were selected after Neurosurgery medical clearance and underwent skull reconstruction with customized PMMA prototyped prostheses. Signs and symptoms of syndrome of the trephined, computed tomography, and aesthetic appearance of the patients were analyzed preoperatively and at 6 months after reconstruction. Results: All patients presented with improved symptomatology, aesthetic improvement and expansion of the brain after surgery. Conclusion: Reconstruction of the skull with customized prototyped PMMA prostheses improved the signs and symptoms and the aesthetic appearance in all 14 patients of this series. The use of prototypes to customize cranial prostheses facilitates the operative technique and enables patients to develop a nearly normal cranial contour.

A New, Single-Stage, Distraction-Mediated, Cranial Vault Expansion Technique for the Multisuture Deformity.

Multisuture craniosynostosis with a mild cloverleaf deformity is rare but associated with high morbidity and mortality. Conventional treatment to alleviate intracranial hypertension in a young infant involves multisuturectomy and relies on passive correction of the deformity followed by additional staged reconstruction later in infancy. Early regional craniectomy and rigid reconstruction have been described, but the cranial bone has limited stability to tolerate plate fixation and extensive dissection of the bone-dura interface may devascularize the cranial bone flap and limit its durability. The authors report an interesting technique to treat a mild form of cloverleaf skull deformity using early, nondevascularizing osteotomies followed by application of semiburied cranial distractors in multiple planes to increase intracranial volume and treat the deformity, and its attendant volumetric constriction, in a single stage.

Assessment of bone healing in rabbit calvaria grafted with three different biomaterials.

This study evaluated the bone regeneration process in rabbit calvaria induced by three types of biomaterials: two xenogenous, consisting of deproteinized bovine bone, while the other was alloplastic, based on biphasic calcium phosphate. Five New Zealand white rabbits weighing between 2,900 and 3,500 g were submitted to four standard 8 mm-diameter perforations at the parietal bone. Three perforations were filled with three grafts and biomaterials, two of them received bovine Bio-Oss® and Endobon® Xenograft Granules, and the other consisted of fully alloplastic Straumann® Bone Ceramic. The fourth remaining cavity was used as control with coagulum. After eight weeks, the animals were sacrificed, and the samples were prepared for morphometric and qualitative analysis. The cavities filled with alloplastic biomaterials showed higher percentages of newly formed bone (p<0.05), while the cavities with xenogenous biomaterials showed higher amount of residual graft (p<0.05). Although the results showed greater bone formation with Straumann® Bone Ceramic, further studies are required to prove which is the more effective biomaterial for bone induction process.

Utilization of ethyl cyanoacrylate and 2-octyl cyanoacrylate adhesives for autogenous bone graft fixation: histomorphometric study in rats.

The present study analyzes the repair process of autogenous bone graft in a block fixed with ethyl cyanoacrylate and 2-octyl cyanoacrylate adhesives in rat calvaria. Forty-eight rats, divided into 3 groups, received round osteotomies at the right parietal bone for the attainment of autogenous bone graft fragment, which was fixed at the opposite side to the donor site with ethyl cyanoacrylate (ethyl group) and 2-octyl cyanoacrylate (octyl group) adhesives. In the control group, bone fragment was only juxtaposed at the parietal bone surface without any fixation material. The animals were euthanized after 10 and 60 postoperative days. The calvariae were processed in a laboratory for the attainment of slides stained through the hematoxylin and eosin technique for histological and histometric analysis. The qualitative analysis showed a discrete inflammatory infiltrate in the control group and moderate inflammatory infiltrate in the ethyl and octyl groups at the 10-day period, which remained at the 60-day period, mainly in the octyl group. The bone fragment remained bonded to the recipient site through the adhesive, but graft incorporation was not observed in any of the specimens. Resorption was higher in the octyl group followed by the ethyl and control groups, both at the 10- and 60-day periods, but with no statistical significance (P < .05). Although promoting graft fixation and its maintenance at the recipient site, both studied adhesives did not allow the graft incorporation, producing a localized and discrete inflammatory reaction, which persisted at 60 days, being more intense in the octyl cyanoacrylate group.

Calvarial autogenous bone graft for maxillary ridge and sinus reconstruction for rehabilitation with dental implants.

Autogenous bone grafting is the gold-standard technique for bone augmentation procedures prior to implant placement. If the amount of available intraoral donor bone is insufficient, it is necessary to harvest bone graft from extraoral sites, such as calvaria. Although this technique is well established, only a few case reports show the histological analysis of the grafted bone at the moment of implant placement. This article reports the case of a 48-year-old female patient with a critical atrophic maxillary ridge reconstructed using autogenous calvarial bone graft prior to implant placement, with clinical and histological evaluation. Bone was collected under general anesthesia from the parietal bone. The outer cortical originated the bone blocks, and the medullar bone layer between was collected to be used in the sinus augmentation procedure, together with 5 of the bone blocks triturated. Six months after bone augmentation, 8 implants were placed in the grafted area and 2 biopsies were retrieved (anterior and the posterior regions), allowing the visualization of the bone-remodeling process in the grafted areas. The patient had a stable recovery. Our results showed that although necrotic bone could still be seen in the outer layer of the grafted area, the interface between this necrotic bone and the already remodeled bone was consistent with biocompatibility. Two-year radiographic evaluation showed success of the grafts and the implants in supporting an esthetic and functionally stable prosthesis. Summarizing, calvarial bone grafts are a viable alternative for the attainment of adequate bone volume prior to implant placement.

Block bone graft fixation (onlay): a modification of the surgical technique.

Several reconstructive methods of the alveolar ridge have been reported to make possible future rehabilitations with implants. Many of these methods come from studies done in animals, mainly rats. With this clinical practice based on scientific evidence, any experimental procedure that can be undertaken in real life is fundamental. Thus, any research that emulates as closely as possible those techniques used in humans are important. This study describes the modification of the technique for block bone graft fixation (onlay) in rats using the "lag screw"-type technique, normally used in clinical procedures for grafts in humans. The conclusion was that the execution of the described procedures minimizes interference of blood flow in the area because of the maintenance of the muscle insertion in the buckle aspect of the most anterior region of the mandible, providing better stability to the graft and better contact interface of the graft and receptor bed.

Repair of critical-size bone defects using bone marrow stromal cells: a histomorphometric study in rabbit calvaria. Part I: use of fresh bone marrow or bone marrow mononuclear fraction.

OBJECTIVES: The aim of this study was to compare the bone healing observed after the use of (1) a scaffold enriched with fresh bone marrow, (2) a scaffold enriched with bone marrow mononuclear fraction, and (3) a scaffold alone. MATERIAL AND METHODS: Twenty one rabbits were randomly divided into three groups of six animals and 1 group of 3 animals. Bilateral 12-mm diameter defects were created in the animals' parietal bones. In Control Group, the defects were filled with a xenograft alone (n = 6); in Group 1, with a xenograft enriched with fresh bone marrow (n = 6); in Group 2, with a xenograft enriched with bone marrow mononuclear fraction (n = 6) and in Unfilled Group, nothing was grafted (n = 3). In Groups 1, 2, and Control, one of the calvarial defects was randomly covered with a barrier membrane. The rabbits were sacrificed 8 weeks after surgery, and their parietal bones were harvested and analyzed histomorphometrically. RESULTS: The histomorphometric analysis showed no difference between Group 1 and the Control Group regarding non-vital mineralized tissue area, but Group 2 showed a statistically significant higher percentage than the Control Group (P < 0.05) for both situations, with membrane (21.24 ± 3.78% and 13.52 ± 3.00%, respectively) and without membrane (20.91 ± 2.01% and 13.08 ± 1.72%, respectively). Group 2 showed the highest percentage of vital mineralized tissue area, followed by Group 1 and the Control Group (P < 0.05) for both situations, with membrane (28.17 ± 3.19%; 21.14 ± 7.38% and 13.06 ± 5.24%, respectively) and without membrane (21.13 ± 0.55%; 12.45 ± 6.34% and 6.56 ± 1.20%, respectively). Group 2 showed the lowest percentage of non-mineralized tissue area, followed by Group 1 and Control Group (P < 0.05) for both situations, with membrane (50.59 ± 6.64%; 58.75 ± 7.14% and 73.41 ± 6.87%, respectively) and without membrane (57.97 ± 1.91%; 71.74 ± 6.63% and 80.37 ± 2.67%, respectively). The sides in which the defects were covered with the barrier membrane showed better bone healing compared with the uncovered sides, in all groups (intragroup comparison, P < 0.05). The Unfilled Group specimens showed no bone formation. CONCLUSIONS: Both methods using bone marrow stromal cells contributed to enhancing bone healing, especially that using the bone marrow mononuclear fraction. The use of a barrier membrane seemed to have a synergistic effect.

Modification of xenogeneic graft materials for improved release of P-15 peptides in a calvarium defect model.

Particulate bone augmentation is an established clinical alternative to regenerate bone. However, in regions of poor bone quality or previously infected sites, the clinical outcomes are more inconsistent. For that purpose, peptides have been added to particulate materials in an attempt to render them with antibacterial properties or to improve their osseoconductivity. For instance, competence-stimulating peptide (CSP) has been studied to decrease the division rate of Streptococcus mutans. Also, the addition of a specific short amino acid sequence peptide derived from type I collagen (P-15) to the bone substitutes has been introduced in an attempt to increase its osseoconductivity. The present study hypothesized that xenogeneic graft materials with and without CSP would present improved host-to-biomaterial response when used in combination with P-15. Particulate graft materials with and without P-15, OsteoGraf with CSP and OsteoGraf, were implanted in an 8-mm rabbit calvarial defect for 4 weeks, and thereafter, histological and histomorphometrical evaluation was performed. The results showed that both OsteoGraf and CSP groups with the addition of P-15 induced bone growth towards the center of the defect. Furthermore, the addition of CSP to Osteograf showed a tendency to increase its osteoconductivity when combined with P-15. The results of the current study suggested that P-15 had some impact on osteogenesis; however, the effect differed between different bone substitute materials. Further investigation is necessary to clarify its effectiveness when used in combination with bone substitutes.

Effects of cigarette smoke inhalation and coffee consumption on bone formation and osseous integration of hydroxyapatite implant.

The present study aims to assess the effects of cigarette smoke inhalation and/or coffee consumption on bone formation and osseous integration of a dense hydroxyapatite (DHA) implant in rats. For this study, 20 male rats were divided into four groups (n = 5): CT (control) group, CE (coffee) group, CI (cigarette) group and CC (coffee + cigarette) group. During 16 weeks, animals in the CI group were exposed to cigarette smoke inhalation equivalent to 6 cigarettes per day; specimens in the CE group drank coffee as liquid diet; and rats in the CC group were submitted to both substances. In the 6th week a 5 mm slit in the parietal bone and a 4 mm slit in the tibia were performed on the left side: the former was left open while the latter received a DHA implant. As soon as surgeries were finished, the animals returned to their original protocols and after 10 weeks of exposure they were euthanised (ethically sacrificed) and the mentioned bones collected for histological processing. Data showed that exposure to cigarette smoke inhalation and coffee consumption did not interfere in weight gain and that solid and liquid diet consumption was satisfactory. Rats in the CC group showed a decrease in bone neoformation around the tibial DHA implant (31.8 ± 2.8) as well as in bone formation in the parietal slit (28.6 ± 2.2). On their own, cigarette smoke inhalation or coffee consumption also led to diminished bone neoformation around the implant and delayed the bone repair process in relation to the CT group. However, reduction in the bone repair process was accentuated with exposure to both cigarette smoke inhalation and coffee consumption in this study.

Effects of cigarette smoke inhalation and coffee consumption on bone formation and osseous integration of hydroxyapatite implant / Os efeitos do cigarro e do consumo de café sobre a formação óssea e a integração óssea de implantes de hidroxiapatita

The present study aims to assess the effects of cigarette smoke inhalation and/or coffee consumption on bone formation and osseous integration of a dense hydroxyapatite (DHA) implant in rats. For this study, 20 male rats were divided into four groups (n = 5): CT (control) group, CE (coffee) group, CI (cigarette) group and CC (coffee + cigarette) group. During 16 weeks, animals in the CI group were exposed to cigarette smoke inhalation equivalent to 6 cigarettes per day; specimens in the CE group drank coffee as liquid diet; and rats in the CC group were submitted to both substances. In the 6th week a 5 mm slit in the parietal bone and a 4 mm slit in the tibia were performed on the left side: the former was left open while the latter received a DHA implant. As soon as surgeries were finished, the animals returned to their original protocols and after 10 weeks of exposure they were euthanised (ethically sacrificed) and the mentioned bones collected for histological processing. Data showed that exposure to cigarette smoke inhalation and coffee consumption did not interfere in weight gain and that solid and liquid diet consumption was satisfactory. Rats in the CC group showed a decrease in bone neoformation around the tibial DHA implant (31.8 ± 2.8) as well as in bone formation in the parietal slit (28.6 ± 2.2). On their own, cigarette smoke inhalation or coffee consumption also led to diminished bone neoformation around the implant and delayed the bone repair process in relation to the CT group. However, reduction in the bone repair process was accentuated with exposure to both cigarette smoke inhalation and coffee consumption in this study.

O presente estudo teve como objetivo avaliar os efeitos do tabagismo e do consumo de café, isolada ou concomitantemente, sobre a formação óssea e a osseointegração de implantes hidroxiapatita densa. Foram utilizados 20 ratos machos, divididos em quatro grupos (n = 5): grupo CT (controle); grupo CA (café); grupo CI (cigarro), e grupo CC (cigarro + café). Durante 16 semanas, os animais do grupo CI foram expostos à fumaça de seis cigarros/dia; os animais do grupo CA consumiram café como dieta líquida, e os animais do grupo CC, ambas as substâncias. Após seis semanas de exposição, uma falha óssea de 5 mm foi produzida no osso parietal esquerdo e de 4 mm, na tíbia esquerda dos animais. A falha do parietal foi mantida aberta, enquanto na tíbia corpos cerâmicos de hidroxiapatita densa (HAD) foram implantados em cavidade produzida cirurgicamente. Após as cirurgias, os animais retornaram aos protocolos experimentais e, ao término de dez semanas, foram eutanasiados, sendo as tíbias e os parietais coletados para processamento histológico. A exposição à fumaça do cigarro e o consumo de café não interferiram no ganho de peso dos animais, e os consumos de dieta líquida e sólida foram satisfatórios entre os grupos. Os animais do grupo CC apresentaram menor volume de osso neoformado ao redor do implante de HAD na tíbia (31,8 ± 2,8) e menor osteogênese na falha produzida no osso parietal (28,6 ± 2,2). O café e o cigarro consumidos isoladamente provocam a diminuição do volume de osso ao redor do implante e o atraso no processo de reparação óssea. Observou-se que o consumo de café associado à exposição à fumaça do cigarro reduziu de forma acentuada o processo de reparação óssea, no presente estudo.

Exploring anorganic bovine bone granules as osteoblast carriers for bone bioengineering: a study in rat critical-size calvarial defects.

It is known that current trends on bone bioengineering seek ideal scaffolds and explore innovative methods to restore tissue function. In this way, the objective of this study was to evaluate the behavior of anorganic bovine bone as osteoblast carrier in critical-size calvarial defects. MC3T3-E1 osteoblast cells (1x10(5) cells/well) were cultured on granules of anorganic bovine bone in 24-well plates and after 24 h these granules were implanted into rat critical-size calvarial defects (group Biomaterial + Cells). In addition, other groups were established with different fillings of the defect: Blood Clot (negative control); Autogenous Bone (positive control); Biomaterial (only granules) and Cells (only MC3T3-E1 cells). After 30 days, the animals were euthanized and the calvaria were technically processed in order to allow histological and morphometric analysis. It was possible to detect blood vessels, connective tissue and newly formed bone in all groups. Particularly in the Biomaterial + Cells group, it was possible to observe a profile of biological events between the positive control group (autogenous bone) and the group in which only anorganic bovine granules were implanted. Altogether, the results of the present study showed that granules of anorganic bovine bone can be used as carrier to osteoblasts and that adding growth factors at the moment of implantation should maximize these results.

Simultaneous fronto-orbital advancement and dynamic posterior cranial vault expansion in Apert syndrome.

Craniosynostosis in Apert syndrome is routinely treated by wide frontal and bilateral supraorbital reshaping and posterior cranial decompression. Dynamic cranial vault expansion has proved to be useful in craniofacial surgery, and its use has extended to syndromic patients. Although a controversy remains between conventional osteotomy and application of the spring-mediated technique in surgical treatment of craniosynostosis, there have been several positive clinical reports on expansion techniques for nonsyndromic and syndromic craniosynostosis. Simultaneous fronto-orbital advancement and posterior cranial vault expansion have been applied successfully to 2 patients of Apert syndrome, without intraoperative complications or postoperative morbidity and improving final cranial shape.

Exploring anorganic bovine bone granules as osteoblast carriers for bone bioengineering: a study in rat critical-size calvarial defects

It is known that current trends on bone bioengineering seek ideal scaffolds and explore innovative methods to restore tissue function. In this way, the objective of this study was to evaluate the behavior of anorganic bovine bone as osteoblast carrier in critical-size calvarial defects. MC3T3-E1 osteoblast cells (1x10(5) cells/well) were cultured on granules of anorganic bovine bone in 24-well plates and after 24 h these granules were implanted into rat critical-size calvarial defects (group Biomaterial + Cells). In addition, other groups were established with different fillings of the defect: Blood Clot (negative control); Autogenous Bone (positive control); Biomaterial (only granules) and Cells (only MC3T3-E1 cells). After 30 days, the animals were euthanized and the calvaria were technically processed in order to allow histological and morphometric analysis. It was possible to detect blood vessels, connective tissue and newly formed bone in all groups. Particularly in the Biomaterial + Cells group, it was possible to observe a profile of biological events between the positive control group (autogenous bone) and the group in which only anorganic bovine granules were implanted. Altogether, the results of the present study showed that granules of anorganic bovine bone can be used as carrier to osteoblasts and that adding growth factors at the moment of implantation should maximize these results.

Sabe-se que uma das atuais tendências na bioengenharia óssea é procurar um carreador ideal e explorar métodos inovadores para restaurar a função do tecido. Desta forma, nosso objetivo foi avaliar o comportamento do osso bovino inorgânico como carreador de osteoblastos em defeitos ósseos de tamanho crítico em calvária de ratos. Osteoblastos da linhagem MC3T3-E1 (1x10(5) células/poço) foram cultivadas em grânulos de osso bovino inorgânico sob placas de 24 poços e após 24 h esses grânulos foram implantados em defeitos ósseos de tamanho crítico em calvária de ratos. Além deste grupo experimental (Biomaterial + Células), foram estabelecidos outros grupos com diferentes preenchimentos do defeito crítico: coágulo sanguíneo (controle negativo); osso autógeno (controle positivo); Biomaterial (apenas grânulos) e Células (apenas células MC3T3-E1). Após 30 dias, os animais foram eutanasiados e as calvárias foram processadas histotecnicamente, a fim de permitir a análise histológica e morfometria. Nossos resultados mostraram que em todos os grupos avaliados foi possível detectar vasos sanguíneos, tecido conjuntivo e osso neoformado. Em especial para o grupo tratado com Biomaterial + Células, foi possível observar um perfil de eventos biológicos intermediário ao grupo controle positivo (osso autógeno) e o grupo de biomaterial (apenas grânulos inorgânico bovino). Ao todo, nossos resultados mostraram que os grânulos de osso bovino inorgânico podem ser usados como carreador de osteoblastos e que a adição de fatores de crescimento no momento em que ocorre o implante deve maximizar os resultados.

Osteointegration of autogenous bone graft associated with osteoblastic cells under treatment with caffeine.

PURPOSE: The present study investigated osteointegration of autogenous bone (AB) from calvaria graft associated with osteoblastic cells (OC) in bone defects in rats subjected to daily administration of caffeine. MATERIALS AND METHODS: Male rats received daily intraperitoneal injection of 1.5% caffeine (0.2 mL/100 g body weight) or saline solution for 30 days. Then they were anesthetized, submitted to the extraction of the upper right incisor, and implanted with AB only and AB + OC. The animals were killed on 7th, 21st, and 42nd days after surgery, and their maxilla were processed for obtaining semiserial sections (5 µm) stained with hematoxylin and eosin. Through image analysis system, the bone volume and the quality of graft in adjacent areas were estimated. RESULTS: The results showed that in caffeine treatment, the AB + OC graft showed no foreign body and acute inflammatory reactions inside the defect when compared to AB. The histometric results revealed that the association AB + OC produced significant increase (10%-15%) in bone volume in later experimental period (42 days) when compared with saline solution group (P ≤ 0.01). CONCLUSIONS: It was concluded that the association of AB from calvaria + OC demonstrated progressive osteointegration and accelerated the repair of bone defects in animals treated with daily caffeine.

Histomorphometric evaluation of calcium phosphate bone grafts on bone repair.

UNLABELLED: Because of its biocompatibility and osteoconductive properties, calcium-phosphate cement has been used as bone surrogate. OBJECTIVE: The purpose of this study was to do a histomorphometric comparison of bone regeneration using hydroxyapatite biphasic ceramic, calcium-phosphate cement and autogenous bone graft. STUDY DESIGN: Prospective and laboratorial experiment. MATERIALS AND METHODS: Two 5mm in diameter cavities (left and right--test and control) were made in the parietal bone of 72 rats. The GI, GII, GIII and GIV test cavities were filled with calcium-phosphate cement, biphasic ceramic hydroxyapatite, autogenous bone graft and blood. The animals were killed at 30, 60 and 90 days and the specimens underwent histomorphometric analysis. RESULTS: The results showed that autogenous bone graft treated defects had significantly more new bone at 30 days compared to other test groups. Within 60 and 90 days, bone formation was more significant in the test groups GI, GII and GIII; GI and GII encompassed larger areas. Throughout the evaluation periods, GII tests showed more bone formation when compared to GI. CONCLUSIONS: Biomaterials depicted a significantly increase in bone content, when compared to autogenous bone graft, concerning bone regeneration.

Histomorphometric evaluation of calcium phosphate bone grafts on bone repair / Avaliação histomorfométrica de enxertos ósseos de cimento fosfato de cálcio no processo de reparo ósseo

Because of its biocompatibility and osteoconductive properties, calcium-phosphate cement has been used as bone surrogate. OBJECTIVE: The purpose of this study was to do a histomorphometric comparison of bone regeneration using hydroxyapatite biphasic ceramic, calcium-phosphate cement and autogenous bone graft. STUDY DESIGN: Prospective and laboratorial experiment. MATERIALS AND METHODS: Two 5mm in diameter cavities (left and right - test and control) were made in the parietal bone of 72 rats. The GI, GII, GIII and GIV test cavities were filled with calcium-phosphate cement, biphasic ceramic hydroxyapatite, autogenous bone graft and blood. The animals were killed at 30, 60 and 90 days and the specimens underwent histomorphometric analysis. RESULTS: The results showed that autogenous bone graft treated defects had significantly more new bone at 30 days compared to other test groups. Within 60 and 90 days, bone formation was more significant in the test groups GI, GII and GIII; GI and GII encompassed larger areas. Throughout the evaluation periods, GII tests showed more bone formation when compared to GI. CONCLUSIONS: Biomaterials depicted a significantly increase in bone content, when compared to autogenous bone graft, concerning bone regeneration.

Os materiais de fosfato de cálcio, pelas características de biocompatibilidade e osteocondução, estão sendo estudados como substitutos ósseos. OBJETIVO: Comparar histomorfometricamente o reparo ósseo promovido pela cerâmica bifásica de hidroxiapatita, cimento fosfato de cálcio e enxerto ósseo autógeno. FORMA DE ESTUDO: Prospectivo e experimental em laboratório. MATERIAL E MÉTODO: Foram criadas duas cavidades (esquerda e direita - teste e controle) de 5mm de diâmetro nos ossos parietais de 72 ratos Wistar. As cavidades testes GI, GII, GIII e GIV foram preenchidas com cimento fosfato de cálcio, cerâmica bifásica de hidroxiapatita, enxerto ósseo autógeno e coágulo sanguíneo. Os animais foram sacrificados aos 30, 60 e 90 dias e os espécimes avaliados histomorfometricamente. RESULTADOS: Os resultados mostraram maior formação óssea no período de 30 dias para o GIII quando comparado aos outros grupos testes. Nos períodos de 60 e 90 dias, a neoformação óssea foi mais acentuada nos grupos testes GI, GII e GIII, alcançando maiores áreas em GI e GII. Em todos os períodos de avaliação, as cavidades testes GII apresentaram maiores áreas frente às GI. CONCLUSÃO: Os biomateriais foram superiores ao enxerto autógeno no reparo ósseo.