O termo estrutura cristalina entende-se como um conjunto de átomos periodicamente distribuídos no espaço, formando uma rede. O material composto, osso, contém uma parte orgânica formada por colágeno e uma parte inorgânica formada predominantemente por cristais de hidroxiapatita, que possui fórmula molecular Ca10(PO4)6(OH)2 em sua célula unitária. A estrutura cristalina da hidroxiapatita pode indicar a qualidade de ossos trabeculares, pela identificação do tamanho de cristalito, da microdeformação e da proporção de cálcio e fósforo nos três tipos de ossos: normal, osteopênico e osteoporótico. A osteoporose é definida pelo National Institutes of Health como uma desordem esquelética caracterizada pelo comprometimento da resistência óssea e aumento do risco de fratura. Objetiva-se avaliar e caracterizar a estrutura cristalina da matriz inorgânica de ossos secos trabeculares de vértebras de colunas de cadáveres humanos normais, osteopênicos e osteoporóticos por microscopia ótica, microscopia eletrônica de varredura e espectometria de energia dispersiva e difratometria de raios-X, utilizando o método de refinamento de Rietveld, balizando os resultados com os valores de microdureza. Foram utilizados ossos secos trabeculares de vértebras L1 de colunas de nove cadáveres humanos provenientes do Serviço de Verificação de Óbito da capital. Antes da coleta do material, elas foram pré-divididas em três grupos: normal, osteopênico e osteoporótico, através de ultrassonometria de calcâneo. A caracterização dos três tipos de ossos foi feita pelas técnicas de microscopia ótica, microscopia eletrônica de varredura, microanálise por espectrometria de energia dispersiva, microdureza e difratometria de raios-X pelo método de pó com aplicação do método de Rietveld. Os resultados mostraram uma diminuição dos valores de tamanho do cristalito (de 670 para 213 nanômetros), microdureza (de 30,27 para 21,22 knoop), proporção de cálcio e fósforo (de 2,02 para 1,73), número de trabéculas e densidade óssea e um aumento nos valores de microdeformação (de 5,4 para 16,8), sugerindo uma maior desorganização e fragilidade na estrutura cristalina da hidroxiapatita em ossos osteopênicos e osteoporóticos em relação aos normais. A caracterização microestrutural dos cristais de hidroxiapatita em ossos secos trabeculares permitiu diferenciar os três tipos de ossos (normal, osteopênico e osteoporótico) e complementar a avaliação da osteoporose, com ênfase na qualidade óssea. / The term crystal structure is understood as a set of atoms periodically distributed in space, forming a lattice The composite material, bone, contains a organic part that consists of collagen and a inorganic part that consists predominantly of hydroxyapatite crystals, having molecular formula Ca10(PO4)6(OH)2 in its unit cell. The crystal structure of hydroxyapatite can indicate the trabecular bone quality, by the identification of crystallite size, microstrain and ratio of calcium and phosphorus in bones of three types: normal, osteopenic or osteoporotic. Osteoporosis is defined by the National Institutes of Health as a skeletal disorder characterized by compromised bone strength and increased risk of fracture. The objective is to evaluate and characterize the crystalline structure of the inorganic matrix of dry trabecular bones of vertebral column of normal, osteopenic and osteoporotic human cadavers by optical microscopy, scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, using the Rietveld refinement method and microhardness. Dried trabecular bone of vertebrae L1 columns of nine human cadavers from the Serviço de Verificação de Óbito of the capital were used. Before sample collection, they were pre-divided into three groups: normal, osteopenic or osteoporotic, through Quantitative ultrasound of the calcaneus. The characterization of the three types of bones were made by optical microscopy, scanning electron microscopy, microanalysis by energy dispersive spectrometry, microhardness and powder X-ray diffraction with application of the Rietveld method. The results showed a decrease of the crystallite size (from 670 to 213 nanometers), hardness (from 30,27 to 21,22 knoop), ratio of calcium and phosphorus (from 2,02 to 1,73), trabecular number and bone density and an increase in microstrain values (from 5,4 to 16,8) suggesting greater fragility and disruption in the crystalline structure of hydroxyapatite in osteopenic and osteoporotic bone compared to normal. Microstructural characterization of hydroxyapatite crystals in dry trabecular bone could differentiate the three types of bones (normal, osteopenic and osteoporotic) and supplement assessment of osteoporosis, with an emphasis on bone quality.

State-of-the-art fluorescent imaging research is strictly limited to eight fluorophore labels duringthe study of intercellular interactions among organelles. The number of excited fluorophore colorsis restricted due to overlap in the narrow spectra of visual wavelength. However, this requires aconsiderable effort of analysis to be able to tell the overlapping signals apart. Significant overlapalready occurs with the use of more than four fluorophores and is leaving researchers limited to asmall number of labels and the hard decision to prioritize between cellular labels to use. Except for the physical limitations of fluorescent labeling, the labeling itself causes behavioralabnormalities due to sample perturbation. In addition to this, the labeling dye or dye-adjacentantibodies are potentially causing phototoxicity and photobleaching thus limiting the timescale oflive cell imaging. Nontoxic imaging modalities such as transmitted-light microscopes, such asbright-field and phase contrast methods, are available but not nearly achieving images of thespecificity as when using fluorophore labeling. An approach that could increase the number of organelles simultaneously studied withfluorophore labels, while being cost-effective and nontoxic as transmitted-light microscopes wouldbe an invaluable tool in the quest to enhance knowledge of cellular studies of organelles. Here wepresent a deep learning solution, using convolutional neural networks built to predict thefluorophore labeling effect on the nucleus, from a transmitted-light input. This solution renders afluorescent channel available for another marker and would eliminate the process of labeling thenucleus with dye or dye-conjugated antibodies by instead using deep convolutional neuralnetworks. / Allra senaste forskningen inom fluorescensmikroskopi är begränsat till upp till åtta fluoroforer förstudier av intracellulära kommunikationer mellan organeller. Antalet fluorescerande färger ärbegränsade till följd av spektralt överlapp i det synliga våglängdsområdet. Överlappande signalerbehöver matematiskt bearbetas vilket innebär ökad arbetsinsats och signifikant överlappning skerredan vid användning av fler än fyra fluoroforer. Denna begräsning innebär i slutändan att forskarehar ett litet antal fluoroforer att arbeta med och behöver därmed prioritera vilka cellulära strukturersom kan märkas samtidigt. Utöver de spektrala begräsningarna med fluorescensmikroskopi, så innebär även själva färgningenav cellulära komponenter en negativ cellulär påverkan i form av avvikande beteende.Fluorescerande färgämnen och märkta antikroppar orsakar potentiellt fototoxicitet ochljusblekning, vilket begränsar tidsrymden vid studier av levande celler. Ljusfältsmikroskop sombright-field and faskontrast har inte en toxisk påverkan men producerar inte i närheten likadetaljerade bilder som fluorescensmikroskop gör. Ett tillvägagångssätt som skulle kunna öka antalet organeller som simultant kan undersökas medfluoroforer, som samtidigt är kostnadseffektiv och inte har en toxisk påverkan somljusfältsmikroskop, skulle vara ett ovärderligt verktyg för utökad kunskap vid cellulära studier avorganeller. Här presenteras en maskininlärningsmetod byggd med artificiella neuronnät för attpredicera fluorescerande infärgningen av cellkärnan i fluorescensmikroskop, med bilder frånljusfältsmikroskop. Denna lösning frigör en fluorofor som kan användas till andra organellersamtidigt som arbetet med fluorescerande infärgning av cellkärnan inte längre är nödvändigt ochersätts med ett artificiellt neuronnät.

Human bone tissue has an inherent hierarchical structure, which is integral to its material properties. It is primarily composed of a collagen fiber matrix that is mineralized with hydroxyapatite. A comprehensive understanding of bone and the linkages between structural and cellular organization is imperative to developing fundamental knowledge that can be applied to better our understanding of bone disease manifestations and its interaction with implant devices. Herein, this thesis investigated non-traditional methods for evaluating bone structure across the nano- and meso-length scales. Firstly, due to the inhomogeneous organization of collagen fibrils and mineral platelets of bone ultrastructure, a suitable methodology for the investigation of both phases needed to be generated. In this work, focused ion beam (FIB) microscopy was employed to create site-specific scanning transmission electron microscopy (STEM) lift-outs of human osteonal bone that could be visualized with correlatively with STEM and small angle X-ray scattering (SAXS). Samples were successfully characterized using both techniques, and minimal visual damage was induced during data acquisition. This work is the first to demonstrate the potential for bone to be investigated correlatively using both STEM and SAXS. Secondly, this work is the first to employ a dual-beam plasma FIB (PFIB) equipped with a scanning electron microscope (SEM), to investigate bone tissue across the mesoscale. This equipment enables large volume three-dimensional (3D) imaging at nanoscale resolution across larger mesoscale volumes. This thesis aimed to reduce ion beam-based artifacts, which presents as curtain-like features by adjusting the composition of protective capping layers. Subsequently, large volume tomograms of bone tissue were acquired, demonstrating the effectiveness of the PFIB to reveal mesoscale features including the cellular network of bone tissue. Overall, this thesis has developed methods that allow for the application of advanced microscopy techniques to enhance the understanding of bone tissue across the nanoscale and mesoscale. / Thesis / Master of Applied Science (MASc) / Bone tissue has a unique structure that perplexes both biologists and materials scientists. The hierarchical structure of bone has garnered the interest of materials scientists since the body’s skeletal strength and toughness are governed by the nanoscale (millionth of centimetres) to macroscale (centimeters) organization of bone. In this work, the intricate organization of bone is investigated using advanced electron and ion beam microscopy techniques, which achieve high-resolution imaging of bone structure. Firstly, this work developed a sample preparation workflow to correlate electron and X-ray imaging of the same bone tissue. Secondly, this work was the first to apply serial-sectioning plasma focused ion beam tomography to human bone tissue to investigate its structure at high resolution across micron-sized volumes. Here, previously unexplored methodologies to image bone are demonstrated with the hopes of applying such techniques to investigate healthy and pathological bone tissue in the future.

Yes / More than 2 million people/year suffer a bone fracture in the UK1. Reconstruction of bone defects represents a major clinical challenge and is addressed using a number of medical devices. Although medical device compositions and applications may differ widely, all attract microorganisms and represent niches for medical device associated infections. For open fractures, the risk of infection can be 55%2. These infections are often resistant to many of the currently available antibiotics and represent a huge and growing financial and healthcare burden. The aim of this study was a fundamental understanding of how the presence of host defence peptides (HDPs)3 and/or RGD can influence the outcome of cell vs. bacterial viability and proliferation. / Presented at the conference: eCM XVI - Bone and Implant Infection June 24-26, 2015, Convention Centre, Davos Platz, Switzerland.

Over the past 5 years, the use of titanium implants as temporary anchorage devices (TADs) has become an important tool in clinical orthodontic practices. The use of TADs have provided orthodontists a way of moving teeth against fixed objects rather than against the surrounding teeth, which tend to counteract desired motion. At present, viable attachment of TADs involves direct insertion through gingival tissue and piercing of the bone. Surface modifications such as sandblasted and acid-etched treatment or bone morphogenetic protein surface treatment, however, can be applied to the TADs to promote enhanced osseointegration, thereby allowing the TADs to serve as stable anchors while avoiding bone puncture. In this study, a comparison was made between sandblasted/acid-etched TADs and sandblasted/acid-etched/recombinant human bone morphogenetic protein-2 (rhBMP-2) treated TADs to determine whether rhBMP-2 promotes enhanced osseointegration. A total of 10 rats (4 controls and 6 treated with rhBMP-2) were used in the study, with 1 TAD placed on the skull of each rat. At the end of 6 weeks, the animals were euthanized by carbon dioxide asphyxiation, and bone blocks, each containing a TAD, were prepared for histological examination and biomechanical characterization. The results of this study showed that TADs treated with rhBMP-2 had greater bone formation at the bone-implant interface and an increase in total implant stability.

Bone repair is modulated by different stimuli. There is evidence that the Transforming Growth Factor-beta (TGF-¿) super-family of cytokines have significant effects on bone structure by regulating the replication and differentiation of chondrocytes, osteoblasts and osteoclasts. There is also significant evidence that interactions with extracellular matrix molecules also influence cell behaviour. This study aimed at determining the role of the TGF-¿s, Collagen type I, Fibronectin and Laminin in bone cell behaviour. To do this MG63 bone cells were used to examine cell adhesion and alignment to different micro-contact printed ECM protein patterns of different widths. The study also aimed at examining how TGF-¿1, 2 and 3 and their solvent and carrier (HCl and BSA, respectively) effected cell surface interactions, cell morphology, cell proliferation and integrin expression. Finally, this study also aimed at examining how the TGF-¿s and their solvent and carrier influenced wound closure in an in vitro wound closure model and how TGF-¿s influence ECM secretion and integrin expression. 5, 10, 25, 50 and 100¿m wide repeat gratings of Collagen type I, Fibronectin and Laminin patterns were stamp patterned onto glass slides and plated with MG63 cells at 50,000 cells per coverslip. Cells on the fibronectin pattern attached and elongated soon after seeding, but did not adhere readily to collagen and laminin and appeared more rounded until 18hrs after seeding. Cells aligned significantly well on the 50¿m and 100¿m wide fibronectin patterned coverslips with mean angles of alignment ~7.87¿ ¿ 3.06SD and 6.45¿ ¿ 5.08SD, respectively, compared to those with smaller width (p<0.001). In comparison, cells aligned less readily to the other two ECM proteins, showing optimal alignments of 9.66¿ ¿ 4.18SD and 14.36¿ ¿ 1.57SD to the 50¿m wide collagen and laminin patterns, respectively. Differences in cell length mirrored those of alignment, with cells acquiring the greatest length when showing the greatest degree of alignment. The results indicate that MG63 cells responded significantly better to 50 and 100¿m wide fibronectin patterns compared to those with smaller width (p<0.001) indicating that the cells may attach mostly via fibronectin specific integrins. Cell surface attachment was examined via a trypsinisation assay in which the time taken to trypsinise cells from the surface provided a means of assessing the strength of attachment. The results indicated that treatment with the solvent (HCl), TGF-¿1, 2 and 3 all decreased cell attachment, but this effect was significantly greater in the case of HCl and TGF-¿3 (p<0.001). However, there were significant differences in trypsinisation rates between HCl and TGF-¿3 (p<0.001). The wound healing response to the TGF-¿s and their solvent/carrier was also investigated in 300¿m ± 10-30¿m SD wide model wounds induced in fully confluent monolayers of MG63 bone cells. The results indicated that TGF-¿3 and HCl significantly enhance wound closure when compared against negative controls, TGF-¿1 and TGF-¿2 treatment (p<0.001). It was also found that TGF-¿1 and TGF-¿2 treatment significantly improved wound closure rate in comparison to the controls (p<0.001). Experiments were performed to determine if the HCl effects on wound closure were dose dependent. Cells were incubated with 20¿M, 40¿M, 80¿M and 160¿M concentrations of HCl prior to wounding and wound closure rates were recorded. Wound closure was dependent on HCl dose with the 80¿M and 160¿M concentrations inducing increases in wound closure rates that were both significantly greater than those induced by 20¿M, 40¿M and control treatments (p<0.001). However, there were significant differences in wound closure between the 80¿M and 160¿M treatment groups after 30hrs of treatment (p<0.001). The effect of different TGF-¿ isomers and their combinations on proliferation rate and cell length of human bone cells were also assessed. The results suggest that cell morphology changes were observed significantly more in cells treated with TGF-¿(2+3) and TGF-¿(1+3) (p<0.001). Any cell treated with TGF-¿1, TGF-¿(1+2) and TGF-¿(1+2+3) showed significantly less elongation compared to the control and other TGF-¿ isomers. In terms of proliferation rate, TGF-¿3 and TGF-¿(2+3) increased cell numbers more than TGF-¿1, TGF-¿2 and other combinations. TGF-¿1 and its combinations did not show significant proliferation and attachment compared to the control due to perhaps its inhibitory effect in contact with human bone cells. Immunostaining indicated that treatment with TGF-¿3 significantly promoted the secretion of collagen type I and anti-human fibronectin in addition to integrin (¿3 and ¿1) expression. Statistically TGF-¿3 and their combinations showed significant differences in number of cells stained for collagen type I, anti-human fibronectin, ¿3 and ¿1integrin. Any cell treated with TGF-¿1 or any combination with TGF-¿1 showed significantly lower cell number stained with the same proteins and integrins (p<0.001). Imaging with WSPR allowed observation of the focal contacts without the need for immunostaining. WSPR images revealed guided cells with high contrast band like structures at the border of cells distal to the edge of guidance cue to which they aligned and with less concentrically formed band like features across the cell body. It is believed that the high contrast features are associated with the formation of focal contacts on the edge of the cells distal to the edge of fibronectin patterns, which suggests that cell guidance is aided by a decrease in cell attachment along a guidance feature. The WSPR experiments also indicated that TGF-¿s influenced the distribution of focal contacts. In the case of TGF-¿1 treated cells the bright high contrast regions were intense but only arranged around the periphery of the cell. In TGF-¿2 and TGF-¿3 cells the bright contrast regions were weaker but again mostly localised around the periphery. These findings supported the earlier trypsinisation results.

No description available.

No description available.

Bone repair is modulated by different stimuli. There is evidence that the Transforming Growth Factor-beta (TGF-β) super-family of cytokines have significant effects on bone structure by regulating the replication and differentiation of chondrocytes, osteoblasts and osteoclasts. There is also significant evidence that interactions with extracellular matrix molecules also influence cell behaviour. This study aimed at determining the role of the TGF-βs, Collagen type I, Fibronectin and Laminin in bone cell behaviour. To do this MG63 bone cells were used to examine cell adhesion and alignment to different micro-contact printed ECM protein patterns of different widths. The study also aimed at examining how TGF-β1, 2 and 3 and their solvent and carrier (HCl and BSA, respectively) effected cell surface interactions, cell morphology, cell proliferation and integrin expression. Finally, this study also aimed at examining how the TGF-βs and their solvent and carrier influenced wound closure in an in vitro wound closure model and how TGF-βs influence ECM secretion and integrin expression. 5, 10, 25, 50 and 100μm wide repeat gratings of Collagen type I, Fibronectin and Laminin patterns were stamp patterned onto glass slides and plated with MG63 cells at 50,000 cells per coverslip. Cells on the fibronectin pattern attached and elongated soon after seeding, but did not adhere readily to collagen and laminin and appeared more rounded until 18hrs after seeding. Cells aligned significantly well on the 50μm and 100μm wide fibronectin patterned coverslips with mean angles of alignment ~7.87° ± 3.06SD and 6.45° ± 5.08SD, respectively, compared to those with smaller width (p<0.001). In comparison, cells aligned less readily to the other two ECM proteins, showing optimal alignments of 9.66° ± 4.18SD and 14.36° ± 1.57SD to the 50μm wide collagen and laminin patterns, respectively. Differences in cell length mirrored those of alignment, with cells acquiring the greatest length when showing the greatest degree of alignment. The results indicate that MG63 cells responded significantly better to 50 and 100μm wide fibronectin patterns compared to those with smaller width (p<0.001) indicating that the cells may attach mostly via fibronectin specific integrins. Cell surface attachment was examined via a trypsinisation assay in which the time taken to trypsinise cells from the surface provided a means of assessing the strength of attachment. The results indicated that treatment with the solvent (HCl), TGF-β1, 2 and 3 all decreased cell attachment, but this effect was significantly greater in the case of HCl and TGF-β3 (p<0.001). However, there were significant differences in trypsinisation rates between HCl and TGF-β3 (p<0.001). The wound healing response to the TGF-βs and their solvent/carrier was also investigated in 300μm ± 10-30μm SD wide model wounds induced in fully confluent monolayers of MG63 bone cells. The results indicated that TGF-β3 and HCl significantly enhance wound closure when compared against negative controls, TGF-β1 and TGF-β2 treatment (p<0.001). It was also found that TGF-β1 and TGF-β2 treatment significantly improved wound closure rate in comparison to the controls (p<0.001). Experiments were performed to determine if the HCl effects on wound closure were dose dependent. Cells were incubated with 20μM, 40μM, 80μM and 160μM concentrations of HCl prior to wounding and wound closure rates were recorded. Wound closure was dependent on HCl dose with the 80μM and 160μM concentrations inducing increases in wound closure rates that were both significantly greater than those induced by 20μM, 40μM and control treatments (p<0.001). However, there were significant differences in wound closure between the 80μM and 160μM treatment groups after 30hrs of treatment (p<0.001). The effect of different TGF-β isomers and their combinations on proliferation rate and cell length of human bone cells were also assessed. The results suggest that cell morphology changes were observed significantly more in cells treated with TGF-β(2+3) and TGF-β(1+3) (p<0.001). Any cell treated with TGF-β1, TGF-β(1+2) and TGF-β(1+2+3) showed significantly less elongation compared to the control and other TGF-β isomers. In terms of proliferation rate, TGF-β3 and TGF-β(2+3) increased cell numbers more than TGF-β1, TGF-β2 and other combinations. TGF-β1 and its combinations did not show significant proliferation and attachment compared to the control due to perhaps its inhibitory effect in contact with human bone cells. Immunostaining indicated that treatment with TGF-β3 significantly promoted the secretion of collagen type I and anti-human fibronectin in addition to integrin (α3 and β1) expression. Statistically TGF-β3 and their combinations showed significant differences in number of cells stained for collagen type I, anti-human fibronectin, α3 and β1 integrin. Any cell treated with TGF-β1 or any combination with TGF-β1 showed significantly lower cell number stained with the same proteins and integrins (p<0.001). Imaging with WSPR allowed observation of the focal contacts without the need for immunostaining. WSPR images revealed guided cells with high contrast band like structures at the border of cells distal to the edge of guidance cue to which they aligned and with less concentrically formed band like features across the cell body. It is believed that the high contrast features are associated with the formation of focal contacts on the edge of the cells distal to the edge of fibronectin patterns, which suggests that cell guidance is aided by a decrease in cell attachment along a guidance feature. The WSPR experiments also indicated that TGF-βs influenced the distribution of focal contacts. In the case of TGF-β1 treated cells the bright high contrast regions were intense but only arranged around the periphery of the cell. In TGF-β2 and TGF-β3 cells the bright contrast regions were weaker but again mostly localised around the periphery. These findings supported the earlier trypsinisation results.

O objetivo deste estudo foi a avaliação histopatológica e radiográfica da resposta pulpar e periapical de dentes de cães após pulpotomia e utilização da Proteína Morfogenética Óssea Recombinante Humana 7. Foram utilizados 60 dentes (120 raízes) de 6 cães, divididos em 8 grupos, nos períodos experimentais de 7 dias (Grupos I, II, III, IV) e 70 dias (Grupos V, VI, VII, VIII). Após a pulpotomia, o remanescente pulpar foi recoberto com os seguintes materiais: Grupos I e V - Proteína Óssea Morfogenética Recombinante Humana 7 (rHuBMP-7) associada ao Colágeno Recombinante Humano (rHuCollagen); Grupos II e VI - Colágeno Recombinante Humano (rHuCollagen); Grupos III e VII (Controle Negativo) - Hidróxido de Cálcio p.a. e soro fisiológico e Grupos IV e VIII (Controle Positivo) - Óxido de Zinco e Eugenol. Decorridos os períodos experimentais, os animais foram mortos, as peças removidas e submetidas ao processamento histológico. A avaliação histopatológica foi realizada subjetivamente em microscópio óptico. A avaliação radiográfica foi realizada considerando-se a integridade da lâmina dura, presença de áreas de rarefação óssea periapical, de reabsorções radiculares (interna e externa) e de ponte de dentina, sendo os resultados submetidos à análise estatística utilizando-se o teste exato de Fisher. Nos espécimes que apresentavam áreas de rarefação periapical, as medidas radiográficas das lesões foram comparadas entre os grupos por meio do teste de Kruskall-Wallis. Os achados histopatológicos evidenciaram que no período de 7 dias, nos Grupos I e II havia um infiltrado inflamatório severo e intensa proliferação vascular no tecido pulpar, no Grupo IV um infiltrado inflamatório moderado enquanto no Grupo III foi observado um infiltrado inflamatório leve, estando o tecido pulpar íntegro. Em todos os grupos não havia formação de ponte de dentina e a região periapical apresentava aspectos de normalidade. No período de 70 dias, nos Grupos V, VI e VIII não houve formação de ponte de dentina, o tecido pulpar apresentava áreas de necrose com presença de células inflamatórias na região periapical e reabsorção cementária e óssea. Por outro lado, no Grupo VII, foi observada presença de ponte de dentina, ausência de processo inflamatório e ausência de reabsorção dos tecidos mineralizados. Com relação aos achados radiográficos, no período de 7 dias, todos os espécimes dos Grupos I, II, III e IV apresentavam integridade da lâmina dura, ausência de rarefação óssea periapical, ausência de reabsorção radicular (interna e externa) e ausência de ponte de dentina. No período de 70 dias, nos Grupos V, VI e VIII não houve formação de ponte de dentina em nenhum espécime sendo observadas áreas de rarefação óssea periapical em 100% das raízes do Grupo VI, 60% das raízes do Grupo VIII e 40% das raízes do Grupo V, sendo as maiores lesões encontradas no Grupo VI, seguida pelos Grupos V e VIII (p<0,05). No grupo VII, foi observada presença de ponte de dentina em 60% dos casos, integridade da lâmina e ausência de rarefação óssea periapical em 100% dos casos. Pode-se concluir que a Proteína Óssea Morfogenética Recombinante Humana 7 quando associada ao Colágeno Recombinante Humano não apresentou resultados satisfatórios. / The purpose of this study was to evaluate, both histopathologically and radiographically, the pulpal and periapical response of dogs’ teeth after pulpotomy and use of recombinant human bone morphogenetic protein-7 (rHuBMP-7). For such purpose, 60 teeth (120 roots), obtained from 6 dogs, were divided in 8 groups and evaluated in two experimental periods: 7 days (Groups I, II, III, IV) and 70 days (Groups V, VI, VII, VIII). After pulpotomy, pulp remnant was covered with the following materials: Groups I and V - recombinant human bone morphogenetic protein-7 (rHuBMP-7) associated to recombinant human like collagen (rHuCollagen); Groups II and VI - recombinant human like collagen (rHuCollagen); Groups III and VII (negative control) – calcium hydroxide and sodium chloride solution; and Groups IV and VIII (positive control) – zinc oxide and eugenol. At the established experimental periods, the animals were sacrificed and the anatomic pieces were obtained and histologically processed. The histopathologic evaluation was realized subjectively in a light microscope. The radiographic evaluation was performed considering the integrity of the lamina dura, presence of areas of periapical bone rarefaction, root resorption (internal and external) and dentin bridge formation. The results were analyzed statistically using Fisher\'s exact test. In the specimens presenting periapical bone rarefaction areas, the lesions’ radiographic measurements were compared among the groups using the Kruskall-Wallis test. The histopathologic findings in the 7-day period revealed that Groups I and II presented a severe inflammatory infiltrate and intense vascular proliferation in the pulp tissue, Group IV presented a moderate inflammatory infiltrate while Group III presented a mild inflammatory infiltrate and intact pulp tissue. In all groups, there was no dentin bridge formation and the periapical region had normal appearance. In the 70-day period, Groups V, VI and VIII showed no dentin bridge formation and pulp tissue presented necrotic areas with inflammatory cells in the periapical region as well as bone and cemental resorption. On the other hand, in Group VII, there was dentin bridge formation, absence of inflammatory process and absence of resorption of mineralized tissues. Regarding the radiographic findings, in the 7-day period, all specimens in Groups I, II, III and IV present intact lamina dura, absence of periapical bone rarefaction, absence of root resorption (internal and external) and absence of dentin bridge formation. In the 70-day period, Groups V, VI and VIII did not present dentin bridge formation in any specimen. Periapical bone rarefaction areas were observed in 100% of the roots in Group VI, 60% of the roots in Group VIII and 40% of the roots in Group V. The largest lesions were found in Group VI, followed by Groups V and VIII (p<0.05). In Group VII, there was dentin bridge formation in 60% of the cases, intact lamina dura and absence of periapical bone rarefaction in 100% of the cases. Based on these results, it may be concluded that recombinant human bone morphogenetic protein-7 associated to recombinant human like collagen did not present satisfactory results.