A Minimally Invasive Surgical Procedure to Harvest Palate Periosteum as a Source of Mesenchymal Stromal/Stem Cells for Bone Tissue Engineering.

The aim of this study is to validate a minimally invasive surgical procedure to harvest palate periosteum as a source of tissue for mesenchymal stromal/stem cells. We performed a standardized procedure to harvest the palate periosteum in ten subjects, which consisted of a 3 mm disposable punch and a Molt periosteal elevator to harvest a small full-thickness fragment of soft tissue at the hard palate area, between the upper bicuspids, 3 to 4 mm apical to the cement enamel junction. The one-third inner portion was fragmented, and following standard cell culture procedures, the adherent cells were cultured for three passages, after obtaining 70-90% confluence. Cell morphology analysis, flow cytometry analysis, and viability and osteogenic differentiation assays were performed. In all 10 cases, uneventful healing was observed, with no need for analgesic intake. The evaluation of cell morphology showed elongated spindle-shaped cells distributed in woven patterns. A high viability range was verified as well as an immunophenotype compatible with mesenchymal stem cell lineage. The differentiation assay showed the potential of the cells to differentiate into the osteogenic lineage. These results demonstrate that the minimally invasive proposed surgical technique is capable of supplying enough periosteum source tissue for stem cell culture and bone tissue engineering.

In Vivo Evaluation of Collagen and Chitosan Scaffold, Associated or Not with Stem Cells, in Bone Repair.

Natural polymers are increasingly being used in tissue engineering due to their ability to mimic the extracellular matrix and to act as a scaffold for cell growth, as well as their possible combination with other osteogenic factors, such as mesenchymal stem cells (MSCs) derived from dental pulp, in an attempt to enhance bone regeneration during the healing of a bone defect. Therefore, the aim of this study was to analyze the repair of mandibular defects filled with a new collagen/chitosan scaffold, seeded or not with MSCs derived from dental pulp. Twenty-eight rats were submitted to surgery for creation of a defect in the right mandibular ramus and divided into the following groups: G1 (control group; mandibular defect with clot); G2 (defect filled with dental pulp mesenchymal stem cells-DPSCs); G3 (defect filled with collagen/chitosan scaffold); and G4 (collagen/chitosan scaffold seeded with DPSCs). The analysis of the scaffold microstructure showed a homogenous material with an adequate percentage of porosity. Macroscopic and radiological examination of the defect area after 6 weeks post-surgery revealed the absence of complete repair, as well as absence of signs of infection, which could indicate rejection of the implants. Histomorphometric analysis of the mandibular defect area showed that bone formation occurred in a centripetal fashion, starting from the borders and progressing towards the center of the defect in all groups. Lower bone formation was observed in G1 when compared to the other groups and G2 exhibited greater osteoregenerative capacity, followed by G4 and G3. In conclusion, the scaffold used showed osteoconductivity, no foreign body reaction, malleability and ease of manipulation, but did not obtain promising results for association with DPSCs.

Conditioned Media from Human Pulp Stem Cell Cultures Improve Bone Regeneration in Rat Calvarial Critical-Size Defects.

The aim of this study was to test whether lyophilized conditioned media from human dental pulp mesenchymal stem cell cultures promote the healing of critical-size defects created in the calvaria of rats. Prior to the surgical procedure, the medium in which dental pulp stem cells were cultured was frozen and lyophilized. After general anesthesia, an 8 mm diameter bone defect was created in the calvaria of twenty-four rats. The defects were filled with the following materials: xenograft alone (G1) or xenograft associated with lyophilized conditioned medium (G2). After 14 or 42 days, the animals were euthanized, and the specimens processed for histologic and immunohistochemical analysis. Bone formation at the center of the defect was observed only in the G2 at 42 days. At both timepoints, increased staining for VEGF, a marker for angiogenesis, was observed in G2. Consistent with this, at 14 days, G2 also had a higher number of blood vessels detected by immunostaining with an anti-CD34 antibody. In conclusion, conditioned media from human dental pulp mesenchymal stem cell cultures had a positive effect on the regenerative process in rat critical-size bone defects. Both the formation of bone and enhancement of vascularization were stimulated by the conditioned media.

Adult mesenchymal stem cells and their possibilities for Dentistry: what to expect?

INTRODUCTION: Stem cells obtained from the pulp of human deciduous teeth are highly proliferative and plastic multipotent cells, which makes them a relevant model of stem cells, applied in several biomedical areas, with different purposes. OBJECTIVE: Based on a brief review of the literature, the present work intends to present from conceptual aspects about stem cells, classifications, potential (in vitro and in vivo) applications in dental practice, cell culture, cryopreservation and its importance, ethical and regulatory aspects, as well as the role of the dental surgeon as the endorser responsible for the entire clinical stage that involves the process of collecting stem cells obtained from dental pulps for cryopreservation, with a view to using them under appropriate conditions, in accordance with scientifically proven and justified good laboratory and clinical practices.

Mesenchymal Stem Cells from Human Exfoliated Deciduous Teeth and the Orbicularis Oris Muscle: How Do They Behave When Exposed to a Proinflammatory Stimulus?

Mesenchymal stem cells (MSCs) have been studied as a promising type of stem cell for use in cell therapies because of their ability to regulate the immune response. Although they are classically isolated from the bone marrow, many studies have sought to isolate MSCs from noninvasive sources. The objective of this study was to evaluate how MSCs isolated from the dental pulp of human exfoliated deciduous teeth (SHED) and fragments of the orbicularis oris muscle (OOMDSCs) behave when treated with an inflammatory IFN-γ stimulus, specifically regarding their proliferative, osteogenic, and immunomodulatory potentials. The results demonstrated that the proliferation of SHED and OOMDSCs was inhibited by the addition of IFN-γ to their culture medium and that treatment with IFN-γ at higher concentrations resulted in a greater inhibition of the proliferation of these cells than treatment with IFN-γ at lower concentrations. SHED and OOMDSCs maintained their osteogenic differentiation potential after stimulation with IFN-γ. Additionally, SHED and OOMDSCs have been shown to have low immunogenicity because they lack expression of HLA-DR and costimulatory molecules such as CD40, CD80, and CD86 before and after IFN-γ treatment. Last, SHED and OOMDSCs expressed the immunoregulatory molecule HLA-G, and the expression of this antigen increased after IFN-γ treatment. In particular, an increase in intracellular HLA-G expression was observed. The results obtained suggest that SHED and OOMDSCs lack immunogenicity and have immunomodulatory properties that are enhanced when they undergo inflammatory stimulation with IFN-γ, which opens new perspectives for the therapeutic use of these cells.

Human levator veli palatini muscle: a novel source of mesenchymal stromal cells for use in the rehabilitation of patients with congenital craniofacial malformations.

BACKGROUND: Bone reconstruction in congenital craniofacial differences, which affect about 2-3% of newborns, has long been the focus of intensive research in the field of bone tissue engineering. The possibility of using mesenchymal stromal cells in regenerative medicine protocols has opened a new field of investigation aimed at finding optimal sources of multipotent cells that can be isolated via non-invasive procedures. In this study, we analyzed whether levator veli palatini muscle fragments, which can be readily obtained in non-invasive manner during palatoplasty in cleft palate patients, represent a novel source of MSCs with osteogenic potential. METHODS: We obtained levator veli palatini muscle fragments (3-5 mm3), during surgical repair of cleft palate in 5 unrelated patients. Mesenchymal stromal cells were isolated from the muscle using a pre-plating technique and other standard practices. The multipotent nature of the isolated stromal cells was demonstrated via flow cytometry analysis and by induction along osteogenic, adipogenic, and chondrogenic differentiation pathways. To demonstrate the osteogenic potential of these cells in vivo, they were used to reconstruct a critical-sized full-thickness calvarial defect model in immunocompetent rats. RESULTS: Flow cytometry analysis showed that the isolated stromal cells were positive for mesenchymal stem cell antigens (CD29, CD44, CD73, CD90, and CD105) and negative for hematopoietic (CD34 and CD45) or endothelial cell markers (CD31). The cells successfully underwent osteogenic, chondrogenic, and adipogenic cell differentiation under appropriate cell culture conditions. Calvarial defects treated with CellCeram™ scaffolds seeded with the isolated levator veli palatini muscle cells showed greater bone healing compared to defects treated with acellular scaffolds. CONCLUSION: Cells derived from levator veli palatini muscle have phenotypic characteristics similar to other mesenchymal stromal cells, both in vitro and in vivo. Our findings suggest that these cells may have clinical relevance in the surgical rehabilitation of patients with cleft palate and other craniofacial anomalies characterized by significant bone deficit.

Is There a Noninvasive Source of MSCs Isolated with GMP Methods with Better Osteogenic Potential?

BACKGROUND: A new trend in the treatment for alveolar clefts in patients with cleft lip and palate involves the use of bone tissue engineering strategies to reduce or eliminate the morbidity associated with autologous bone grafting. The use of mesenchymal stem cells-autologous cells obtained from tissues such as bone marrow and fat-combined with various biomaterials has been proposed as a viable option for use in cleft patients. However, invasive procedures are necessary to obtain the mesenchymal stem cells from these two sources. To eliminate donor site morbidity, noninvasive stem cell sources such as the umbilical cord, orbicularis oris muscle, and deciduous dental pulp have been studied for use in alveolar cleft bone tissue engineering. In this study, we evaluate the osteogenic potential of these various stem cell types. METHODS: Ten cellular strains obtained from each different source (umbilical cord, orbicularis oris muscle, or deciduous dental pulp) were induced to osteogenic differentiation in vitro, and the bone matrix deposition of each primary culture was quantified. To evaluate whether greater osteogenic potential of the established mesenchymal stem cell strains was associated with an increase in the expression profile of neural crest genes, real-time qPCR was performed on the following genes: SRY-box 9, SRY-box 10, nerve growth factor receptor, transcription factor AP-2 alpha, and paired box 3. RESULTS: The mesenchymal stem cells obtained from deciduous dental pulp and orbicularis oris muscle demonstrated increased osteogenic potential with significantly more extracellular bone matrix deposition when compared to primary cultures obtained from the umbilical cord after twenty-one days in culture (p = 0.007 and p = 0.005, respectively). The paired box 3 gene was more highly expressed in the MSCs obtained from deciduous dental pulp and orbicularis oris muscle than in those obtained from the umbilical cord. CONCLUSION: These results suggest that deciduous dental pulp and orbicularis oris muscle stem cells demonstrate superior osteogenic differentiation potential relative to umbilical cord-derived stem cells and that this increased potential is related to their neural crest origins. Based on these observations, and the distinct translational advantage of incorporating stem cells from noninvasive tissue sources into tissue engineering protocols, greater study of these specific cell lines in the setting of alveolar cleft repair is indicated.

Adult mesenchymal stem cells and their possibilities for Dentistry: what to expect?

ABSTRACT Introduction: Stem cells obtained from the pulp of human deciduous teeth are highly proliferative and plastic multipotent cells, which makes them a relevant model of stem cells, applied in several biomedical areas, with different purposes. Objective: Based on a brief review of the literature, the present work intends to present from conceptual aspects about stem cells, classifications, potential (in vitro and in vivo) applications in dental practice, cell culture, cryopreservation and its importance, ethical and regulatory aspects, as well as the role of the dental surgeon as the endorser responsible for the entire clinical stage that involves the process of collecting stem cells obtained from dental pulps for cryopreservation, with a view to using them under appropriate conditions, in accordance with scientifically proven and justified good laboratory and clinical practices.

RESUMO Introdução: As células-tronco obtidas a partir da polpa de dentes decíduos humanos são células multipotentes altamente proliferativas e plásticas, o que as torna um modelo relevante de células-tronco, aplicado em diversas áreas biomédicas, com diferentes propósitos. Objetivo: A partir de uma breve revisão da literatura, o presente trabalho pretende apresentar desde aspectos conceituais acerca das células-tronco, classificações, potenciais aplicações (in vitro e in vivo) na prática odontológica, cultivo celular, criopreservação e sua importância, aspectos éticos e regulatórios, bem como o papel do cirurgião-dentista como homologador responsável por toda a etapa clínica que envolve o processo de coleta das células-tronco obtidas a partir de polpas dentais para criopreservação, com vistas ao uso em condições adequadas, em acordo com as boas práticas laboratoriais e clínicas cientificamente comprovadas e justificadas.

Existe associação entre o ângulo formado pelo terço inferior das paredes medial e lateral do seio maxilar e o risco de perfuração da membrana? Um estudo transversal / Is there association between the angle of medial and lateral maxillary sinus walls at the inferior third and the risk of membrane perforation? A cross-sectional study

Objetivo: avaliar a prevalência das medidas dos ângulos formados entre a parede medial e lateral do seio maxilar em seu terço inferior, e verificar a correlação entre os ângulos medidos e sua localização anatômica específica em áreas de dentes posteriores. Material e métodos: foram selecionados 64 cortes parasagitais em 25 exames tomográficos de uma amostra de pacientes uni ou bilateralmente desdentados, registrados para atendimento na Clínica de Implantologia Oral da Universidade do Grande Rio entre 1998 e 2004. Depois, os cortes foram digitalizados por um único operador, com cobertura transparente e em resolução 4.800 dpi. Os ângulos dos assoalhos dos seios maxilares (θ) foram medidos traçando-se linhas retas tangenciais às paredes medial e lateral, e separando sua distribuição por sítios posteriores (primeiros pré-molares, segundo pré-molares, primeiro molares e segundos molares), proporcionando três grupos: grupo 1 (θ ≤ 30º); grupo 2 (30º≤ θ ≤ 60º) e grupo 3 (> 60º). O teste qui-quadrado foi usado para avaliar a prevalência dos ângulos medidos e sua correlação com a localização anatômica, e o teste Anova para avaliar a correlação entre as médias dos ângulos mensurados e a localização anatômica. Resultados: os ângulos obtusos (grupo3) prevaleceram significativamente em 65,6% dos cortes parassagitais avaliados (p<0,01)...

A influência do biotipo periodontal na estética peri-implantar / The influence of periodontal biotype on peri-implant dental aesthetics

A preocupação com a estética é cada vez maior na terapia com implantes osseointegrados e a criação de uma margem gengival harmônica, uma completa formação de papila interdental e o biotipo periodontal têm aparecido como fatores primordiais para a obtenção de um resultado estético de excelência. O objetivo do trabalho foi apresentar uma revisão da literatura mostrando os fatores de risco envolvidos na estética peri-implantar e observar a possível relação entre esses fatores e o biotipo periodontal. A influência que o biotipo periodontal exerce sobre os tecidos peri-implantares parece ser bem controversa entre os autores, porém, de acordo com a literatura, a qualidade do biotipo periodontal pode ditar a estratégia de planejamento para a instalação de implantes na região anterior da maxila, podendo ter relação principalmente com a manutenção da papila interdental, com o tecido ósseo subjacente e com a estabilidade da margem gengival livre.

Nowadays, esthetics has been one of the main issues on dental implant therapy. Creation of a harmonious gingival margin, with complete formation of interdental papilla and periodontal biotype has emerged as key factors for achieving excellent results. The aim of this paper was to present a literature review showing the risk factors involved in peri-implant aesthetics and the possible relationship between these factors and periodontal biotypes. The influence of periodontal biotype on peri-implant tissues appeared quite controversial among authors but, according to the literature, the quality of periodontal biotype can dictate the treatment strategy for implant placement in the anterior maxillary region, being related to the maintenance of the interdental papillae, the underlying bone tissue, and to the stability of the free gingival margin

Implantes curtos: uma opção para regiões atróficas e fatores que influenciam os seus índices de sucesso / Short implants: an option for atrophic regions and factors influencing their success rates - a literature review

As perdas dentárias podem gerar vários problemas, sendo a atrofia óssea uma das mais frequentes, dificultando posteriormente a reabilitação oral. O uso de próteses removíveis e longos períodos de edentulismo podem agravar o quadro de atrofia. Devido à teoria de que o implante deveria ser o mais longo possível, procedimentos cirúrgicos para suprir esse déficit de volume ósseo horizontal/vertical foram amplamente estudados como: enxertos em blocos inlays/onlays, distração osteogênica (DOA), enxertos em seio maxilar, regeneração óssea guiada (ROG) e lateralização do nervo alveolar inferior (LNAI). Porém, alto custo biológico, morbidade e literatura não conclusiva levaram a busca por alternativas. Vários estudos vêm demonstrando que os implantes curtos podem apresentar índices de sucesso comparáveis aos dos implantes mais longos. Desta forma, o objetivo deste trabalho foi fazer uma revisão da literatura científica a respeito dos implantes curtos abordando as modificações em sua macro e microgeometria, o desenvolvimento de novas técnicas cirúrgicas e os conhecimentos de biomecânica, entre outros fatores que aumentaram as taxas de sucesso e sobrevivência dessa modalidade de tratamento.

Tooth loss can cause several problems, being bone atrophy one of the most frequent, compromising subsequent oral rehabilitation procedures. The use of removable partial dentures and long periods of tooth loss may worsen this scenario. Due to the theory that the implant should be as long as possible for adequate stability, surgical procedures to address bone deficits in horizontal/vertical dimensions have been widely studied, such as grafts block inlays/onlays, distraction osteogenesis (DOA), maxillary sinus grafts, guided-bone regeneration (GBR), and inferior alveolar nerve lateralization (IANL). However, the high biological cost, morbidity and inconclusive literature prompt the search for alternatives. Several studies have shown that short implants may have success rates comparable to those in longer implants. Thus, the objective of this study is to review the scientific literature addressing the changes in its macro and micro-geometry, the development of new surgical techniques, and knowledge in biomechanics, as well as and other factors that increase the success and survival rates in this treatment modality.

Enxertos ósseos xenógenos utilizados na Implantodontia Oral / Xenogenic bone grafts used in oral Implantology

O comportamento in vivo dos biomateriais é dependente de suas características físico-químicas. O presente trabalho teve como objetivo realizar uma revisão de literatura sobre os biomateriais utilizados emenxertos ósseos, enfatizando a hidroxiapatita de origem bovina absorvível (Bio-Oss) e as suas principais características fisico-químicas

Revisão da histoanatomia dos tecidos peri-implantares: implicações funcionais estéticas / Literature review of the periimplant tissues: functional and aesthetics implications

Buscou-se levantar informações na literatura sobre a hístoanatomia dos tecidos peri-implantares, fazendo analogias desses tecidos com os tecidos periodontais, como também verificando as possíveis influências de alguns procedimentos na reabilitação com implantes sobre os tecidos peri-implantares. Constatou-se a existência de semelhanças e diferenças entre ambos os tecidos, tanto em termos estruturais quanto em suas respostas à presença de biofilme, à aplicação de cargas funcionais e para funcionais, como também aos tipos de mucosa (queratinizada e não queratinizada). Alguns fatores ligados à característica do implante utilizado, tais como a textura de superfície e o projeto do implante, bem como seu posicionamento tridimensional, parecem ter influência sobre a homeostasia dos tecidos peri-implantares, enquanto a instalação imediata do implante e a imediata aplicação de carga parece não ter influência sobre esses tecidos; porém, ainda não há um consenso na literatura sobre isso, o que demanda a realização de mais estudos clínicos longitudinais devidamente controlados.

Considerações anatômicas relacionadas à cirurgia do seio maxilar / Anatomic considerations regarding maxillary sinus surgery

A importância clínica e anatômica do seio maxilar em relação à cirurgia para instalação de implantes é considerada neste trabalho, através de uma revisão de literatura. Os aspectos ditos relevantes pelos diversos autores, citados para o planejamento e execução doacesso à cavidade do seio maxilar de maneira previsível e segura são também enfocados.