Perspectivas atuais da engenharia de tecidos da articulação temporomandibular / Perspectivas Actuales de la Ingeniería de Tejidos para la Articulación Temporomandibular / Current Perspectives of Tissue Engineering for the Temporomandibular Joint

Introdução: As limitações das terapias atuais para doenças degenerativas da articulação temporomandibular (ATM) levaram ao aumento do interesse em estratégias regenerativas. A engenharia de tecidos (ET), combinando células-tronco, arcabouços e fatores de crescimento, pode fornecer uma substituição biológica funcional e permanente das estruturas da ATM, além de prevenir o avanço de doenças degenerativas. Objetivo: Este artigo descreve as perspectivas atuais da ET das estruturas da ATM em modelos animais. Metodologia: As abordagens da ET foram categorizadas de acordo com as estruturas primárias da ATM: 1) o disco articular, 2) o côndilo mandibular e 3) a fossa glenóide e eminência articular. Resultados: As áreas com a maior quantidade de estudos são o côndilo mandibular e disco articular, em estudos que abordam o uso de arcabouços tridimensionais, de origem sintética e/ou natural, podendo ou não estar associados a células tronco (diferenciadas ou não) e a fatores de crescimento. Conclusão: A ET da ATM ainda é uma área relativamente nova, em desenvolvimento e em constante avanço. Os avanços tecnológicos desenvolvidos nessa área têm o potencial de auxiliar no desenvolvimento de terapias mais eficientes e menos invasivos... (AU)

Introducción: Las limitaciones de las terapias actuales para las enfermedades degenerativas de la articulación temporomandibular (ATM) han llevado a un mayor interés en las estrategias regenerativas. La ingeniería de tejidos, que combina células, andamios y factores de crecimiento, puede proporcionar un reemplazo biológico funcional y permanente de las estructuras de la ATM, además de prevenir el avance de enfermedades degenerativas. Objetivo: Este artículo describe las perspectivas actuales de la ingeniería de tecidos de las estructuras de la ATM en modelos animales. Metodología: Los enfoques de ingeniería de tejidos se clasificaron según las estructuras primarias de la ATM: 1) el disco articular, 2) el cóndilo mandibular y 3) la fosa glenoidea y la eminencia articular. Resultados: Las áreas con mayor número de estudios son el cóndilo mandibular y el disco articular, en estudios que abordan el uso de estructuras tridimensionales, de origen sintético y/o natural, que pueden o no estar asociadas a células (diferenciadas o no) y con factores de crecimiento. Conclusión: La ingeniería de tejidos de la ATM es todavía un área relativamente nueva, en desarrollo y en constante avance. Los avances tecnológicos desarrollados en esta área tienen el potencial de ayudar en el desarrollo de terapias más eficientes y menos invasivas... (AU)

Introduction: The limitations of current therapies for degenerative diseases of the temporomandibular joint (TMJ) have led to increased interest in regenerative strategies. Tissue engineering (TE), combining stem cells, scaffolds, and growth factors, can provide a functional and permanent biological replacement of TMJ structures, in addition to preventing the advancement of degenerative diseases. Aim: This article describes current TE perspectives of TMJ structures in animal models. Methods: TE approaches were categorized according to the primary TMJ structures: 1) the articular disc, 2) the mandibular condyle, and 3) the glenoid fossa and articular eminence. Results: The areas with the greatest number of studies are the mandibular condyle and articular disc, in studies that address the use of three-dimensional scaffolds, of synthetic and/ or natural origin, which may or may not be associated with stem cells (differentiated or not) and with growth factors. Conclusion: TE of the TMJ is still a relatively new, developing, and constantly advancing area. The technological advances developed in this area have the potential to assist in the development of more efficient and less invasive therapies... (AU)

Preventive and therapeutic effects of relaxin on bisphosphonate related osteonecrosis of the jaw: an experimental study in rats / Efeitos preventivos e terapêuticos da relaxina na osteonecrose da mandíbula relacionada a bisfosfonatos: um estudo experimental em ratos

Objective: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a challenging complication of chronic bisphosphonate (BP) use. The hormone relaxin is able to induce the multistep differentiation process of human osteoclastogenesis, exhibits antifibrotic and anti-inflammatory actions, and promotes vasodilatation, wound healing, and angiogenesis. The present study aimed to evaluate the effects of relaxin in the prevention and management of BRONJ. Material and Methods: Thirty-six male Sprague Dawley rats were randomly divided into four groups. Rats in group 1 (n = 10) received relaxin and BP simultaneously for 12 weeks. Rats in group 2 (n = 10) received injections of BP for 12 weeks, followed by relaxin for another 12 weeks. Rats in group 3 (n = 10) received only BP injections, and those in group 4 (control, n = 6) received only saline. Necrosis and inflammation in the rats' mandibles were evaluated as indicators of BRONJ. Results: Necrosis and inflammation were not detected in group 1 (BP + relaxin). In group 3 (BP only), incidence rates of necrosis and inflammation were 90% and 60%, respectively. Conclusions: Our findings suggest that relaxin may be potently effective in preventing BRONJ and have some benefit in the treatment of existing BRONJ (AU)

Objetivo: A osteonecrose da mandíbula relacionada ao bisfosfonato (BRONJ) é uma desafiadora complicação do uso crônico de bisfosfonato (BP). O hormônio relaxina é capaz de induzir o processo múltiplo de diferenciação da osteoclastogênese humana, exibe ações anti-fibróticas e anti-inflamatórias e promove vasodilatação, cicatrização de feridas e angiogênese. O presente estudo teve como objetivo avaliar os efeitos da relaxina na prevenção e tratamento do BRONJ. Material e Métodos: Trinta e seis ratos Sprague Dawley machos foram divididos aleatoriamente em quatro grupos. Os ratos do grupo 1 (n = 10) receberam relaxina e BP simultaneamente por 12 semanas. Os ratos do grupo 2 (n = 10) receberam injeções de BP por 12 semanas, seguidos de relaxina por mais 12 semanas. Os ratos do grupo 3 (n = 10) receberam apenas injeções de BP e os do grupo 4 (controle, n = 6) receberam apenas solução salina. Necrose e inflamação nas mandíbulas dos ratos foram avaliadas como indicadores de BRONJ. Resultados: Necrose e inflamação não foram detectadas no grupo 1 (BP + relaxina). No grupo 3 (somente BP), as taxas de incidência de necrose e inflamação foram de 90% e 60%, respectivamente. Conclusões: Nossos resultados sugerem que a relaxina pode ser potentemente eficaz na prevenção do BRONJ e ter algum benefício no tratamento do BRONJ existente.(AU)

The effect of natural products in animal models of temporomandibular disorders

Abstract Treatment of temporomandibular disorders (TMD) is a challenge for health care professionals. Therefore, new approaches have been investigated, such as the use of natural products. Objective This systematic review aims to summarize the natural products used in treatment of experimental models of TMD. Methodology A systematic search was performed in the databases Medline, Web of Science, Scopus, Embase, SciELO, LILACS, and Scholar Google databases in January 2020, dating from their inception. Pre-clinical studies with natural products for intervention in experimental TMD were included. Two reviewers independently selected the studies, extracted the data, and evaluated the risk of bias. Results 17 records were selected, and 17 different natural products were found, including three lectins, three plants or algae extracts, three sulfated polysaccharides, three cocoa preparations, and five isolated compounds. Concerning the risk of bias, most studies lacked on randomization and blinding. Nociception induced by phlogistic agents was evaluated in most articles, and in five studies it was associated with analysis of inflammatory parameters. In order to investigate the mechanism of action of the natural products used, eight studies evaluated expression of neural or glial molecular markers. Conclusions 16 of 17 natural products found in this review presented positive results, showing their potential for treatment of TMD. However, the lack of methodological clarity can influence these results.

High Mobility Group Box 1 and Heat Shock Protein-70 Expression Post (-)-Epigallocatechin-3-Gallate in East Java Green Tea Methanolic Extract Administration During Orthodontic Tooth Movement in Wistar Rats

Abstract Objective: To investigate the expression of High Mobility Group Box 1 (HMGB1) and Heat Shock Protein-70 (HSP-70) during orthodontic tooth movement (OTM) after (-)- Epigallocatechin-3-Gallate (EGCG) in East Java Green Tea (Camelia Sinensis) Methanolic Extract (GTME) administration in vivo. Material and Methods: 28 Wistar rats (Rattus Novergicus) was used and divided into 4 groups accordingly: K- without EGCG and OTM; K+ with OTM, without EGCG for 14 days; T1with OTM for 14 days and EGCG for 7 days; treatment group 2 (T2) with OTM and EGCG for 14 days. OTM animal model was achieved through the installation of the OTM device by means of NiTi close coil spring with 10g force placed between the first incisor and first maxillary molars. The samples were terminated on Day 14. The pre-maxillary was isolated for the immunohistochemical examination. Analysis of Variance (ANOVA) then continued with Tukey Honest Significant Difference (HSD) (p<0.05) was performed to analyze the data. Results: The highest HMGB1 and HSP-70 expression were found in the K+ group pressure side, meanwhile the lowest HMGB1 and HSP-70 expression were found in K- group tension side in the alveolar bone. There was a significant decrease of HMGB1 and HSP-70 expression in T2 compared to T1 and K+ with significant between groups (p<0.05; p=0.0001). Conclusion: The decreased expression of HMGB1 and HSP-70 in alveolar bone of OTM wistar rats due to post administration of GTME that consisted EGCG.

Effect of the Application of Chlorella Vulgaris Ointment to the Number of Fibroblast Cells as an Indicator of Wound Healing in the Soft Tissue of Pig Ears

Abstract Objective: To analyze the clinical and histological condition of Chlorella vulgaris ointment extract smearing on wound healing. Material and Methods: The sample consisted of 9 pigs by making 4 incisions on the pig's right ear measuring 2cm x 1cm and applying Chlorella vulgaris ointment in 3 concentrations namely 5%, 10%, 15% and without ointment application as the control group. Furthermore, the observation of the clinical condition of wounds divided into 4 time periods (day 1, 3, 7 and 14). After completing clinical observations based on time period, the skin of the pig's ear was taken by cutting in the area that had been made injured. Skin tissue extraction carried out under inhalation and local anesthesia. The tissue pieces are then processed in the anatomical pathology laboratory to become 36 slide preparations. The clinical trial assessment was done using parameters of wound moisture, color of wound and scab wound. Whereas for histological examination was done by looking at the number of fibroblast cells in the CX31 light microscope with 40x magnification. ANOVA and Kruskal Wallis tests were used. Results: In the clinical observation conditions there were significant differences between the treatment group and the control group as well as the number of fibroblast cells there were significant differences between the 3 concentrations of Chlorella vulgaris extract ointment and the per time period control group. Conclusion: Chlorella vulgaris extract ointment containing 15% extract gives the best results in accelerating the wound healing process in the pig's ear seen from wound healing and increased number of fibroblast cells.

Oral implant osseointegration model in C57Bl/6 mice: microtomographic, histological, histomorphometric and molecular characterization

Abstract Despite the successful clinical application of titanium (Ti) as a biomaterial, the exact cellular and molecular mechanisms responsible for Ti osseointegration remains unclear, especially because of the limited methodological tools available in this field. Objective: In this study, we present a microscopic and molecular characterization of an oral implant osseointegration model using C57Bl/6 mice. Material and Methods: Forty-eight male wild-type mice received a Ti implant on the edentulous alveolar crest and the peri-implant sites were evaluated through microscopic (μCT, histological and birefringence) and molecular (RealTimePCRarray) analysis in different points in time after surgery (3, 7, 14 and 21 days). Results: The early stages of osseointegration were marked by an increased expression of growth factors and MSC markers. Subsequently, a provisional granulation tissue was formed, with high expression of VEGFb and earlier osteogenic markers (BMPs, ALP and Runx2). The immune/inflammatory phase was evidenced by an increased density of inflammatory cells, and high expression of cytokines (TNF, IL6, IL1) chemokines (CXCL3, CCL2, CCL5 and CXC3CL1) and chemokine receptors (CCR2 and CCR5). Also, iNOS expression remained low, while ARG1 was upregulated, indicating predominance of a M2-type response. At later points in time, the bone matrix density and volume were increased, in agreement with a high expression of Col1a1 and Col21a2. The remodelling process was marked by peaks of MMPs, RANKL and OPG expression at 14 days, and an increased density of osteoclasts. At 21 days, intimate Ti/bone contact was observed, with expression of final osteoblast differentiation markers (PHEX, SOST), as well as red spectrum collagen fibers. Conclusions: This study demonstrated a unique molecular view of oral osseointegration kinetics in C57Bl/6 mice, evidencing potential elements responsible for orchestrating cell migration, proliferation, ECM deposition and maturation, angiogenesis, bone formation and remodeling at the bone-implant interface in parallel with a novel microscopic analysis.

Pulp analysis of teeth submitted to different types of forces: a histological study in rats

Abstract Objective: The purpose of this study was to histologically evaluate pulp and dentin under induced tooth movement (ITM) with different types of forces. Material and Methods: The maxillary right first molars of rats were submitted to movement with continuous (CF), continuous interrupted (CIF) and intermittent (IF) forces during 5, 7 and 9 days with nickel-titanium (NiTi) closed-coil springs exerting 50cN force magnitude. The groups were histologically evaluated as for cellularity pattern, presence of dystrophic, hemodynamic alterations in the pulp as well dentin alterations. The main observed alterations were related to hemodynamic pulp characteristics, such as presence of thrombosis, vascular congestion and hemorrhages. The hemodynamic alterations were statistically evaluated by Shapiro-Wilk normality test and analysis of variance by the Kruskall-Wallis test. Results: There was no significant differences observed between groups in the different types of applied forces and duration of ITM (vascular congestion, p=1.000; hemorrhage, p=0.305; thrombosis, p=1.000). Conclusions: Pulp tissue alterations resulting from ITM were limited to hemodynamic events, without progressing to irreversible degeneration, regardless of the type of force applied.

Efeito de diferentes doses de dexametasona sobre o reparo alveolar em ratos / Effect of different doses of dexamethasone on alveolar repair in rats

Objetivo: O objetivo deste trabalho foi avaliar o efeito de diferentes doses pré-operatórias de dexametasona sobre o processo de reparo alveolar. Métodos: Sessenta ratos foram randomicamente divididos em 4 grupos de 15 animais cada que receberam dose única préoperatória de dexametasona equivalente a doses humanas de 4mg (grupo 4mg), 8mg (grupo 8mg), 12mg (grupo 12mg) e soro fisiológico 0,9% (grupo controle). Em seguida os animais foram anestesiados e tiveram seus primeiros molares inferiores esquerdos (M1) extraídos. Os animais foram sacrificados aos 3, 7, e 40 dias e os alvéolos dentários dissecados e reduzidos. O alvéolo do M1 foi radiografado para mensuração da densidade radiográfica e em seguida descalcificado para obtenção de cortes histológicos em parafina para análise histomorfológica e estereométrica. Os dados quantitativos foram submetidos à análise estatística em um nível de significância de 5%. Resultados: As características histomorfológicas do processo de reparo alveolar foram similares entre os 4 grupos. Os grupos controle e 12mg mostraram diferenças quanto à densidade radiográfica e percentual de matriz conjuntiva aos 3 dias e no percentual de tecido ósseo aos 7 dias. Este último ocorrendo também entre grupo controle e 8mg (p<0,05). Conclusão: Nenhuma das doses testadas impediu o reparo dos alvéolos com tecido ósseo neoformado aos 40 dias. Entretanto, a dose equivalente a 12mg diminuiu a quantidade de tecido conjuntivo e matriz osteóide nas fases iniciais do reparo. (AU)

Objective: The objective of this study was to evaluate the effect of different preoperative doses of dexamethasone on the alveolar repair process. Methods: Sixty rats were randomly divided into 4 groups of 15 animals receiving a single pre-operative dose of dexamethasone equivalent to 4 mg (group 4mg), 8mg (group 8mg), 12mg (group 12mg) and saline 0.9 % (group control). Then the animals were anesthetized and had their first left lower molars (M1) extracted. The animals were euthanized at 3, 7, and 40 days and then the alveolus was dissected and reduced. The alveolus of M1 was radiographed for radiographic density measurement and then decalcified to obtain histological sections in paraffin for histomorphological and stereometric analysis. The quantitative data were submitted to statistical analysis at a significance level of 5%. Results: The histomorphologic characteristics of the alveolar repair process were similar among the 4 groups. However, the control and 12mg groups showed differences in radiographic density, and percentage of conjunctive matrix at 3 days and percentage of bone tissue at 7 days. The latter occurring also among control group and 8mg (p <0.05). Conclusion: None of the used doses prevented the socket healing with newly formed bone at 40 days. However, the dosis equivalent to 12mg decreased the quantity of connective tissue and osteoid matrix at the late period of repair. (AU)

Efeitos à distância de feridas cirúrgicas em mucosa oral sobre populações granulocíticas na medula óssea em modelo murino / Remote effects of surgical oral mucosa wounds on populations granulocytes in the bone marrow in a murine model

Neste trabalho procuramos determinar os efeitos à distância de um ferimento cirúrgico único na cavidade bucal (localizado no palato duro, de extensão 3 mm) sobre a medula óssea em camundongos C57BL/6. Para isto, quantificamos células totais, eosinófilos, neutrófilos e fagócitos mononucleares, tanto na medula óssea recém-coletada, como na medula óssea cultivada em presença de diferentes citocinas. As citocinas foram utilizadas para revelar defeitos sutis que não são detectáveis no exame da medula óssea recém-coletada. Na medula óssea recém-coletada, foi encontrado um aumento modesto, mas significativo, nos números de neutrófilos. Em culturas incubadas com Interleucina (IL)-3, foi observada uma redução significativa dos números de células totais, neutrófilos e fagócitos mononucleares. Em culturas incubadas com Fator Estimulante de Colônias de Granulócitos (G-CSF), foram observados efeitos negativos semelhantes aos encontrados com IL-3, com supressão de células totais, neutrófilos e fagócitos mononucleares. Em culturas incubadas com Fator Estimulante de Colônias de Granulócitos e Macrófagos (GM-CSF), foi observada redução significativa somente sobre o número de neutrófilos. O mesmo ocorreu na presença de Fator Estimulante de Colônias de Macrófagos (M-CSF). Utilizamos também rhG-CSF (Filgrastim®), que tem atividade em cultura de células murinas, sendo observado efeito negativo apenas sobre neutrófilos, em contraste com o observado na presença de G-CSF murino. O efeito positivo sobre o número de neutrófilos na medula óssea recém-coletada poderia ser explicado pela exposição a microrganismos da microbiota bucal no local da lesão, causando bacteremia. Para testar esta hipótese, adotamos uma estratégia de desinfecção local (Clorhexidina a 0,2% e 0,04%) antes da realização do corte, e avaliamos a repercussão deste tratamento sobre as diferentes respostas anteriormente caracterizadas. O tratamento com Clorhexidina a 0,2% eliminou os efeitos observados anteriormente sobre os números de células totais, neutrófilos e fagócitos mononucleares. Em contrapartida, após o tratamento com Clorhexidina a 0,04% alguns dos efeitos anteriormente encontrados, quanto aos números de neutrófilos e de fagócitos mononucleares, persistiram. Procuramos também avaliar se o bloqueio da resposta de glicocorticóides endógenos ao trauma cirúrgico, pelo uso de Mifepristone (RU486), antagonista do receptor de glicocorticóides, poderia modificar os efeitos da ferida na cavidade bucal sobre a medula óssea. Não houve evidência de bloqueio específico dos efeitos do trauma com o uso de RU486, comparativamente aos controles que receberam veículo. Em experimentos-piloto, avaliamos os efeitos do trauma cirúrgico, induzido em camundongos BP-2 segundo os protocolos utilizados anteriormente em camundongos C57BL/6, obtendo evidência de respostas importantes entre cepas no padrão de resposta da medula óssea. Dentro das limitações do presente estudo, podemos concluir que o trauma cirúrgico bucal atinge a medula óssea à distância, demonstrando efeitos positivos 24h após o trauma e negativos quando utilizamos citocinas. Além disso, a presença de bactérias bucais é responsável pela depressão da resposta da medula. (AU)

In this study, we aimed to identify, using C57BL/6 mice, long-distance effects of a single, surgical oral wound of 3 mm extension in the hard palate, on the bone marrow. To do so, we enumerated total cells as well as eosinophil, neutrophil and mononuclear phagocytes, from recently harvested bone marrow, and from cultured bone marrow following different cytokine stimuli. Cytokines were used to reveal subtle effects on the recently harvest bone marrow. In recently harvested bone marrow, a small but significant increase was found in neutrophil numbers. In cultures exposed to interleukin (IL)-3 there were decreased total cell, neutrophil and mononuclear phagocyte numbers. In cultures exposed to granulocyte-colony stimulating factor (G-CSF), reduced total cell, neutrophil and mononuclear phagocyte numbers were observed resembling those in IL-3-exposed cultures. In cultures exposed to granulocytemacrophage-colony stimulating factor (GM-CSF), significant reduction was fund only in neutrophil numbers. The occurred when macrophage-colony stimulating factor (M-CSF) was used. We also used recombinant human G-CSF (rhG-CSF, Filgrastim®), which acts on murine cells, observing reduction in neutrophil numbers, unlike observations of murine G-CSF. The increase in neutrophil numbers in the fresh bone marrow might be induced by exposure of wounded surfaces to oral microorganisms and possibly by bacteremia. To test this hypothesis, the hard palate was disinfected with clorhexidine (CHX) 0.2% or 0.04%, prior to wounding. The treatment with CHX 0.2% abolished the cytokine effects in the total cell, neutrophil and mononuclear phagocyte numbers. By contrast, after treatment with CHX 0.04%, cytokine effects on the neutrophil and mononuclear phagocyte numbers persisted. We also sought to evaluate whether the effect of oral wounding on bone marrow was dependent on endogenous glucocorticoids. Blockade of the glucocorticoid antagonist receptor with mefipristone (RU486) provided results comparable to those of control group given vehicle only, thus ruling out this hypothesis. In pilot experiments, we also evaluated the effects of surgical trauma in BP-2 mice, using the protocol previously used for C57BL/6 mice, and found significant differences in the bone marrow responses between these two strains. Briefly, our limited experimental evidence shows that oral surgical trauma can influence the bone marrow at distance over a 24h postoperative period, and inducing positive or negative effects on various leukocyte lineages, before and after culture with cytokines. Available evidence points to oral bacteria as involved in these long-distance effects on bone-marrow. (AU)

Repair of bone defects using adipose-derived stem cells combined with alpha-tricalcium phosphate and gelatin sponge scaffolds in a rat model

Abstract Objectives This study aimed to evaluate the potential of adipose-derived stem cells (ASCs) combined with a modified α-tricalcium phosphate (α-TCP) or gelatin sponge (GS) scaffolds for bone healing in a rat model. Material and Methods Bone defects were surgically created in the femur of adult SHR rats and filled with the scaffolds, empty or combined with ASCs. The results were analyzed by histology and histomorphometry on days seven, 14, 30, and 60. Results Significantly increased bone repair was observed on days seven and 60 in animals treated with α-TCP/ASCs, and on day 14 in the group treated with GS/ASCs, when compared with the groups treated with the biomaterials alone. Intense fibroplasia was observed in the group treated with GS alone, on days 14 and 30. Conclusions Our results showed that the use of ASCs combined with α-TCP or GS scaffolds resulted in increased bone repair. The higher efficacy of the α-TCP scaffold suggests osteoconductive property that results in a biological support to the cells, whereas the GS scaffold functions just as a carrier. These results confirm the potential of ASCs in accelerating bone repair in in vivo experimental rat models. These results suggest a new alternative for treating bone defects.

Evaluation of an experimental rat model for comparative studies of bleaching agents

ABSTRACT Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. Conclusion The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents.

Brazilian minipig as a large-animal model for basic research and stem cell-based tissue engineering. Characterization and in vitro differentiation of bone marrow-derived mesenchymal stem cells

Stem cell-based regenerative medicine is one of the most intensively researched medical issues. Pre-clinical studies in a large-animal model, especially in swine or miniature pigs, are highly relevant to human applications. Mesenchymal stem cells (MSCs) have been isolated and expanded from different sources. Objective: This study aimed at isolating and characterizing, for the first time, bone marrow-derived MSCs (BM-MSCs) from a Brazilian minipig (BR1). Also, this aimed to validate a new large-animal model for stem cell-based tissue engineering. Material and Methods: Bone marrow (BM) was aspirated from the posterior iliac crest of twelve adult male BR1 under general anesthesia. MSCs were selected by plastic-adherence as originally described by Friedenstein. Cell morphology, surface marker expression, and cellular differentiation were examined. The immunophenotypic profile was determined by flow cytometry. The differentiation potential was assessed by cytological staining and by RT-PCR. Results: MSCs were present in all minipig BM samples. These cells showed fibroblastic morphology and were positive for the surface markers CD90 (88.6%), CD29 (89.8%), CD44 (86.9%) and negative for CD34 (1.61%), CD45 (1.83%), CD14 (1.77%) and MHC-II (2.69%). MSCs were differentiated into adipocytes, osteoblasts, and chondroblasts as demonstrated by the presence of lipidic-rich vacuoles, the mineralized extracellular matrix, and the great presence of glycosaminoglycans, respectively. The higher gene expression of adipocyte fatty-acid binding protein (AP2), alkaline phosphatase (ALP) and collagen type 2 (COLII) also confirmed the trilineage differentiation (p<0.001, p<0.001, p=0.031; respectively). Conclusions: The isolation, cultivation, and differentiation of BM-MSCs from BR1 makes this animal eligible as a useful large-animal model for stem cell-based studies in Brazil. .

Experimental study on penetration of dental implants into the maxillary sinus in different depths

The exposing of dental implant into the maxillary sinus combined with membrane perforation might increase risks of implant failure and sinus complications. Objective: The purpose of this study was to investigate the effects of the dental implant penetration into the maxillary sinus cavity in different depths on osseointegration and sinus health in a dog model. Material and Methods: Sixteen titanium implants were placed in the bilateral maxillary molar areas of eight adult mongrel dogs, which were randomly divided into four groups according to the different penetrating extents of implants into the sinus cavities (group A: 0 mm; group B: 1 mm; group C: 2 mm; group D: 3 mm). The block biopsies were harvested five months after surgery and evaluated by radiographic observation and histological analysis. Results: No signs of inflammatory reactions were observed in any maxillary sinus of the eight dogs. The tips of the implants with penetrating depth of 1 mm and 2 mm were found to be fully covered with newly formed membrane and partially with new bone. The tips of the implants with penetrating depth over 3 mm were exposed in the sinus cavity and showed no membrane or bone coverage. No significant differences were found among groups regarding implant stability, bone-to-implant contact (BIC) and bone area in the implant threads (BA). Conclusions: Despite the protrusion extents, penetration of dental implant into the maxillary sinus with membrane perforation does not compromise the sinus health and the implant osseointegration in canine. .

Análise da utilização do osteoscafTM como substituto ósseo em cirurgia de levantamento de seio maxilar / Use of OsteoScaf™ in maxillary sinus augmentation

Procedimentos de levantamento do seio maxilar têm sido realizados para aumentar o volume ósseo e promover a estabilidade do implante, na região posterior de maxilas severamente atrofiadas. Ao longo dos anos, resultados de vários estudos demonstraram que alguns substitutos ósseos podem suportar implantes em função, após o levantamento de seio maxilar, igual ou melhor quando utilizado o osso autógeno. Neste estudo, foi avaliado o comportamento de um substituto ósseo completamente biodegradável (OsteoScaf™) no modelo experimental de levantamento de seio maxilar em coelhos. Além disso, ele foi comparado com o osso autógeno e outros dois substitutos ósseos, não totalmente biodegradáveis, disponíveis comercialmente (Bio-Oss® e BoneCeramic®). Avaliação clínica, tomografia computadorizada por feixe cônico, microtomografia computadorizada, análises microscópicas e análise molecular, através da técnica de PCR, foram realizadas após 2, 4 e 8 semanas de cirurgia. O levantamento de seio maxilar utilizando o osso autógeno demonstrou maior reabsorção, ao longo do tempo, comparado aos substitutos ósseos, os quais revelaram maior neoformação óssea após 8, 4 e 2 semanas, respectivamente. O grupo Bio-Oss® apresentou maior neoformação óssea, ao longo do tempo, quando comparado aos grupos Osteoscaf™ e BoneCeramic®, os quais foram qualitativamente emelhantes. O grupo BoneCeramic® mostrou uma resposta celular de células gigantes até 8 semanas. Concluiu-se que os substitutos ósseos, neste estudo, obtiveram melhor desempenho do que o osso autógeno, e o OsteoScaf™ demonstrou maior reabsorção do que os outros grupos, em todos períodos.

Maxillary sinus augmentation procedures have been applied to increase bone volume and to promote stability of implants in the severely atrophied posterior maxilla. Over the years, the outcomes of several studies have demonstrated that some bone substitutes can support implants in function after sinus augmentation as well as, or better than those with autogenous bone. Our experimental model evaluated the behavior of a fully biodegradable bone substitute (OsteoScaf™) in a rabbit sinus lift procedure. We compared this with autogenous bone and other two available non-biodegradable bone substitutes (Bio-Oss® and BoneCeramic®). Clinical evaluation, Cone Beam Computed Tomography, Microcomputed Tomography, microscopic and molecular evaluation were used for data analysis at 2, 4 and 8 weeks after sinus augmentation. Autogenous bone was more resorbed over time than the other materials. All bone substitutes showed more bone formation at 8, 4 and 2 weeks, respectively. Bio-Oss® showed more bone formation/timepoint than Osteoscaf™ and Boneceramic®, which were similar. Boneceramic® showed a florid giant cell response up to 8 weeks. We concluded that the bone graft materials all performed better than autogenous bone and OsteoScaf™ showed comparative bone growth yet greater degradation than the other two materials.

Eficácia na remoção da necrose óssea térmica: realizada por implantes osseointegráveis com câmaras coletoras / Removal effectiveness of thermal osteonecrosis: performed by osseointegrated implants with collecting chambers

Durante a confecção do alvéolo, promove-se o aumento da temperatura da broca devido à fricção, aquecendo o tecido ósseo adjacente e seus componentes celulares, podendo provocar a Necrose Óssea Térmica. A necrose óssea térmica deteriora a porção orgânica do tecido ósseo (tanto matriz óssea como as células), bem como as células diferenciadas e indiferenciadas presentes na circulação sanguínea e medula óssea local. Alguns trabalhos demonstraram que o aquecimento ósseo acima de 47oC por 1 minuto provoca tal fenômeno. Atualmente existem variações na técnica de perfuração com objetivo de diminuir o grau de aquecimento e aumentar as taxas de sucesso dos tratamentos reabilitadores. Sabemos que nem todos os profissionais são cautelosos em utilizar materiais de qualidade e que mesmo os materiais com qualidade, após repetido uso, perdem a eficácia. Seria ideal que o implante osseointegrável gerenciasse a remoção destas áreas de necrose óssea térmica, independentemente da execução correta da técnica de perfuração e da qualidade das brocas. Com isso, garantiríamos que o tecido ósseo poderia se reparar ao redor dos implantes da melhor maneira possível. Neste trabalho avaliamos a eficácia de 3 modelos de implante com câmaras coletoras funcionais diferentes, em tecido ósseo de minipig. O implante com câmara coletora interna demonstrou-se 37,22% mais eficaz que o implante com câmaras externas e 3 arestas cortantes, quando os alvéolos eram confeccionados sem irrigação e com brocas desgastadas. O implante com câmaras coletoras externas e 4 arestas também demonstrou-se eficaz, porém manteve 83,75% das células viáveis enquanto que no grupo com câmaras internas este resultado foi de 91,39%.

The manufacture of the alveolus can increase the temperature of the drill due to friction heating the adjacent bone tissue and its cellular components, this phenomenon is known by thermal osteonecrosis. The thermal osteonecrosis deteriorates the organic portion of bone (bone matrix and cells), as well as undifferentiated and differentiated cells circulating in the blood and bone marrow. Some studies have demonstrated that bone heating above 47oC for 1 minute causes this phenomenon. Currently there are variations in drilling technique aiming to reduce the heating degree and increase the success rates of rehabilitation treatments. We know that not all professionals are cautious of using quality materials and even the materials with quality after repeated use, lose their effectiveness. Would be ideal that implants manages and removes these areas with thermal osteonecrosis, regardless of the technique of implementing the drilling and the quality of drills. With this, we ensure that bone tissue could possibly repair around implants in the best way. In this study we evaluated the efficacy of 3 implant models with different functional collecting chambers in minipigs bone tissue. The implant with internal collection chamber proved to be 37.22% more effective than the implant with external chambers and three sharp edges, when the alveolus were manufactured without irrigation and uncut drills. The implant with external collecting chambers and four sharp edges also showed an effective but 83.75% of the cells remained viable while in the group with internal chambers this result was 91.39%.

Eficácia na remoção da necrose óssea térmica: realizada por implantes osseointegráveis com câmaras coletoras / Removal effectiveness of thermal osteonecrosis: performed by osseointegrated implants with collecting chambers

Durante a confecção do alvéolo, promove-se o aumento da temperatura da broca devido à fricção, aquecendo o tecido ósseo adjacente e seus componentes celulares, podendo provocar a Necrose Óssea Térmica. A necrose óssea térmica deteriora a porção orgânica do tecido ósseo (tanto matriz óssea como as células), bem como as células diferenciadas e indiferenciadas presentes na circulação sanguínea e medula óssea local. Alguns trabalhos demonstraram que o aquecimento ósseo acima de 47oC por 1 minuto provoca tal fenômeno. Atualmente existem variações na técnica de perfuração com objetivo de diminuir o grau de aquecimento e aumentar as taxas de sucesso dos tratamentos reabilitadores. Sabemos que nem todos os profissionais são cautelosos em utilizar materiais de qualidade e que mesmo os materiais com qualidade, após repetido uso, perdem a eficácia. Seria ideal que o implante osseointegrável gerenciasse a remoção destas áreas de necrose óssea térmica, independentemente da execução correta da técnica de perfuração e da qualidade das brocas. Com isso, garantiríamos que o tecido ósseo poderia se reparar ao redor dos implantes da melhor maneira possível. Neste trabalho avaliamos a eficácia de 3 modelos de implante com câmaras coletoras funcionais diferentes, em tecido ósseo de minipig. O implante com câmara coletora interna demonstrou-se 37,22% mais eficaz que o implante com câmaras externas e 3 arestas cortantes, quando os alvéolos eram confeccionados sem irrigação e com brocas desgastadas. O implante com câmaras coletoras externas e 4 arestas também demonstrou-se eficaz, porém manteve 83,75% das células viáveis enquanto que no grupo com câmaras internas este resultado foi de 91,39%.

The manufacture of the alveolus can increase the temperature of the drill due to friction heating the adjacent bone tissue and its cellular components, this phenomenon is known by thermal osteonecrosis. The thermal osteonecrosis deteriorates the organic portion of bone (bone matrix and cells), as well as undifferentiated and differentiated cells circulating in the blood and bone marrow. Some studies have demonstrated that bone heating above 47oC for 1 minute causes this phenomenon. Currently there are variations in drilling technique aiming to reduce the heating degree and increase the success rates of rehabilitation treatments. We know that not all professionals are cautious of using quality materials and even the materials with quality after repeated use, lose their effectiveness. Would be ideal that implants manages and removes these areas with thermal osteonecrosis, regardless of the technique of implementing the drilling and the quality of drills. With this, we ensure that bone tissue could possibly repair around implants in the best way. In this study we evaluated the efficacy of 3 implant models with different functional collecting chambers in minipigs bone tissue. The implant with internal collection chamber proved to be 37.22% more effective than the implant with external chambers and three sharp edges, when the alveolus were manufactured without irrigation and uncut drills. The implant with external collecting chambers and four sharp edges also showed an effective but 83.75% of the cells remained viable while in the group with internal chambers this result was 91.39%.

Análise da utilização do osteoscafTM como substituto ósseo em cirurgia de levantamento de seio maxilar / Use of OsteoScaf™ in maxillary sinus augmentation

Procedimentos de levantamento do seio maxilar têm sido realizados para aumentar o volume ósseo e promover a estabilidade do implante, na região posterior de maxilas severamente atrofiadas. Ao longo dos anos, resultados de vários estudos demonstraram que alguns substitutos ósseos podem suportar implantes em função, após o levantamento de seio maxilar, igual ou melhor quando utilizado o osso autógeno. Neste estudo, foi avaliado o comportamento de um substituto ósseo completamente biodegradável (OsteoScaf™) no modelo experimental de levantamento de seio maxilar em coelhos. Além disso, ele foi comparado com o osso autógeno e outros dois substitutos ósseos, não totalmente biodegradáveis, disponíveis comercialmente (Bio-Oss® e BoneCeramic®). Avaliação clínica, tomografia computadorizada por feixe cônico, microtomografia computadorizada, análises microscópicas e análise molecular, através da técnica de PCR, foram realizadas após 2, 4 e 8 semanas de cirurgia. O levantamento de seio maxilar utilizando o osso autógeno demonstrou maior reabsorção, ao longo do tempo, comparado aos substitutos ósseos, os quais revelaram maior neoformação óssea após 8, 4 e 2 semanas, respectivamente. O grupo Bio-Oss® apresentou maior neoformação óssea, ao longo do tempo, quando comparado aos grupos Osteoscaf™ e BoneCeramic®, os quais foram qualitativamente emelhantes. O grupo BoneCeramic® mostrou uma resposta celular de células gigantes até 8 semanas. Concluiu-se que os substitutos ósseos, neste estudo, obtiveram melhor desempenho do que o osso autógeno, e o OsteoScaf™ demonstrou maior reabsorção do que os outros grupos, em todos períodos.

Maxillary sinus augmentation procedures have been applied to increase bone volume and to promote stability of implants in the severely atrophied posterior maxilla. Over the years, the outcomes of several studies have demonstrated that some bone substitutes can support implants in function after sinus augmentation as well as, or better than those with autogenous bone. Our experimental model evaluated the behavior of a fully biodegradable bone substitute (OsteoScaf™) in a rabbit sinus lift procedure. We compared this with autogenous bone and other two available non-biodegradable bone substitutes (Bio-Oss® and BoneCeramic®). Clinical evaluation, Cone Beam Computed Tomography, Microcomputed Tomography, microscopic and molecular evaluation were used for data analysis at 2, 4 and 8 weeks after sinus augmentation. Autogenous bone was more resorbed over time than the other materials. All bone substitutes showed more bone formation at 8, 4 and 2 weeks, respectively. Bio-Oss® showed more bone formation/timepoint than Osteoscaf™ and Boneceramic®, which were similar. Boneceramic® showed a florid giant cell response up to 8 weeks. We concluded that the bone graft materials all performed better than autogenous bone and OsteoScaf™ showed comparative bone growth yet greater degradation than the other two materials.

Biocompatibilidade e tempo de presa do clinker do cimento Portland cinza, com ou sem sulfato de cálcio

Objetivo: avaliar a biocompatibilidade do clinker do cimento Portland cinza, sem e com 2% e 5% de sulfato de cálcio. Métodos: vinte e quatro ratos receberam implantes no tecido subcutâneo, de tubos de polietileno preenchidos com o pó do clinker do cimento Portland cinza, sem ou com 2% e 5% de sulfato de cálcio. Após 15, 30 e 60 dias da implantação, os animais foram mortos e os espécimes preparados para a análise microscópica.Os tempos de presa de cada material foram avaliados de acordo com as especificações n° C266-08 da ASTM. Os dados foram analisados pelos testes ANOVA e de Tukey, para o tempo de presa; e pelo de Kruskal-Wallise de Dunn para a biocompatibilidade, com nível de significância de 5%. Resultados: histologicamente, não se constatou diferença estatística entre os materiais. Conclusão:o clinker sem sulfato de cálcio apresentou tempo de presa inicial de 5 min. e final de 55 min., seguido pelo clinker com 2% de sulfato de cálcio (8-95 min.) e pelo clinker com 5% de sulfato de cálcio (10-110 min.)

Primary stability of orthodontic miniscrews inserted into femurs of osteopenic rats

Aim: To test the hypothesis that bone quality may affect the stability of anchorage devices implanted in a rat model. Methods: Twenty male Wistar rats were divided into 2 groups: Group 1 (rats treated with FK506) and Group 2(rats treated with saline solution vehicle). The immunosuppressant tacrolimus was used with the intention of causing a condition of osteopenia in Group 1. A total of 20 orthodontic mini-implants were used. One mini-implant was inserted in the right femur of each rat. After sacrificing the animals, blocks of bone tissue containing the mini-implants were removed for mechanical pull-out tests to be performed in a universal test machine at a crosshead speed of 0.5 mm/s. The maximum insertion force values and pull-out test were recorded and submitted the nonparametric analyses including the Kruskal-Wallis test and Mann-Whitney tests (p<0.05). The test for Pearson’s correlation was used to verify the correlation between bone mineral density and the pull-out test. The dose of FK506 was 2 mg/kg/day. Densitometric analysis was performed to observe the effect of FK506 on the bone mineral density. Results: The mean insertion force values were similar in both groups, with no statistically significant difference between them (P > 0.05). The mean pull-out force values were higher in Group 2 than in Group 1, with statistically significant difference between the groups (P < 0.05). Conclusions: Bone quality may affect the stability of mini-implants. Orthodontic mini-implants did not present good primary stability in a rat model with osteopenia.

Commercial swine model: an alternative for direct pulp capping studies / Modelo de suíno comercial: uma alternativa para estudos de capeamento pulpar direto

Purpose: To test the use of commercial swine as an in vivo model for studying pulp healing in response to direct capping agents. Methods: Six swine sus scrofa domesticus (Landrace X Large White) were used in the experiment. Under anesthesia, class V cavities were prepared with a pulp exposure, which was directly capped with hard-setting calcium hydroxide (Dycal®, Dentsply, Petrópolis, Rio de Janeiro, Brazil). Restorations were performed with resin-modified glass ionomer cement (Vitremer® 3M Espe St Paul, MN, USA). After 7 or 70 days (n = 6), the animals were died; the teeth were extracted, formalin-fixed and prepared for histological evaluation. The biological response was categorized using the following criteria: inflammatory response, soft tissue organization, reactionary and, reparative dentin formations. Results: After seven days pulp in most specimens inflammatory response was present and after 70 days reparative dentin was formed at the pulp exposure area in almost all the animals. These responses were similar to those previously reported in human in similar periods of evaluation. In addition, the swine model showed another advantages: easy handling and economical feasibility compared to other animal models. Conclusion: The commercial swine model seems to be an adequate animal model to test pulp biocompatibility.

Objetivo: O objetivo do estufo foi analisar o uso de suínos industriais como modelo para a avaliação da resposta pulpar a procedimentos de capeamento direto. Metodologia: Em 6 suínos sus scrofa domesticus foram realizados preparos cavitários classe V até expor o tecido pulpar. Após a hemorragia ter sido controlada, o local exposto foi capeado com cimento de hidróxido de cálcio (Dycal®, Dentsply, Petrópolis, Rio de Janeiro, Brasil) e na sequência os dentes foram restaurados com cimento de ionômero de vidro (Vitremer® 3M Espe St Paul, MN, USA). As respostas teciduais foram analisadas após 7 (n = 6) e 70 (n = 6) dias. Os animais foram abatidos, os dentes extraídos e, posteriormente, processados para análise morfológica descritiva quanto aos seguintes critérios: resposta inflamatória, organização do tecido pulpar, dentina reacional e reparativa. Resultados: Após 7 dias observou-se a presença de infiltrado inflamatório e decorridos 70 dias, dentina reparativa foi formada na área de exposição em quase todos os espécimes, sendo estes achados similares aos achados previamente reportados em capeamentos realizados em humanos. Além disso, o modelo demonstrou outras vantagens, tais como a viabilidade econômica (baixo custo comparado a outros modelos animais) e facilidade de manuseio. Conclusão: O uso de suínos de raças comerciais pode ser considerado como alternativa para os testes de biocompatibilidade dentino-pulpar.