Acellular dermal matrix in skin wound healing in rabbits - histological and histomorphometric analyses

OBJECTIVES: To analyze the histology and histomorphometry of healing associated with acellular dermal matrix in skin wounds in rabbits. METHODS: Twelve male rabbits were divided into two groups: the control group (CG) and the matrix group (MG). Three skin wounds with a total area of 20 × 20 mm were created on the dorsal region of each animal. Photographic records of the lesions taken over a 21-day period and use of the ImageJ program allowed calculation of the wound contraction rate. The lesions were biopsied on days 3, 14 and 21 for histomorphometric analysis to define the thicknesses of the dermis and epidermis (hematoxylin-eosin) and calculate the densities of type I and type III collagen (picrosirius). RESULTS: No significant difference in the healing rate was found between the groups (p>0.05). The MG presented greater epidermal thickness on day 3 (p<0.05) and on days 14 and 21 (p<0.001). The MG presented greater dermal thickness throughout the study period (p<0.05). The type I collagen density was higher in the MG throughout the study period (p<0.05), and the type III collagen density was higher in the MG on days 3 and 14 (p<0.05) and on day 21 (p<0.001). CONCLUSION: The use of acellular dermal matrix increased the thickness of the dermal and epidermal layers and the amount of type I and III collagen during skin wound healing and did not alter the rate of wound contraction.

Horizontal Bone Reconstruction on sites with different amounts of native bone: a retrospective study

Abstract: The lack of guidelines for bone augmentation procedures might compromise decision making in implantology. The objective of this study was to perform a retrospective study to verify the outcomes of horizontal bone reconstruction in implant dentistry with different types of materials and amounts of native bone in the recipient bed to allow for a new guideline for horizontal bone reconstruction. One hundred preoperative CT scans were retrospectively evaluated and categorized in accordance to horizontal bone defects as presence (Group P) or absence (Group A) of cancellous bone in the recipient bed. Different approaches were used to treat the edentulous ridge and the outcomes were defined either as satisfactory or unsatisfactory regarding the possibility of implant placement. The percentage distribution of the patients according to the presence or absence of cancellous bone was 92% for Group P and 8% for Group A. In Group P, 98% of the patients had satisfactory outcomes, and the use of autografts had 100% of satisfactory outcomes in this group. In Group A, 37.5% of the patients had satisfactory outcomes, and the use of autografts also yielded 100% of satisfactory outcomes. The use of allografts and xenografts in Group A had 0% and 33.3% of satisfactory outcomes, respectively. Therefore, it seems reasonable to speculate that the presence of cancellous bone might be predictive and predictable when the decision includes bone substitutes. In cases of absence of cancellous bone in the recipient bed, the use of a vitalized graft seems to be mandatory.

Implantes cerâmicos em casos estéticos: uma nova possibilidade clínica / Dental ceramic implants in aesthetic cases: a new clinical possibility

A substituição de um elemento dental por um implante em pacientes que apresentam tecido gengival delgado gera uma preocupação devido à translucidez gengival, onde a coloração acinzentada do titânio pode levar ao fracasso estético do tratamento. Desta maneira, os implantes de zircônia se diferenciam principalmente por sua coloração clara, a qual se aproxima das características de cor da raiz, e por sua biocompatibilidade, além de possibilitarem a escolha do paciente por um tratamento totalmente livre de metal. Portanto, este relato de caso clínico demonstrou uma inovação técnica por meio da utilização de um implante confeccionado em zircônia para solução de um caso clínico de alta complexibilidade estética em uma paciente jovem, com fenótipo gengival delgado e alto grau de exigência estética. O caso foi finalizado com prótese cimentada e facetas metal free confeccionadas por meio de cerâmica injetada. Após a finalização do caso, concluiu-se que, apesar da desvantagem relacionada à sensibilidade técnica, o implante confeccionado em zircônia possibilitou a solução estética deste caso clínico de fenótipo gengival delgado, sem a necessidade de utilização de enxertos gengivais.

The replacement of a dental element in patients with thin gingival tissue generates a concern due to gingival translucency, where the titanium gray coloration can lead to failure of the treatment. Thus, the zirconia implants are distinguished primarily by their coloration and their biocompatibility, in addition to enabling the selection of a totally metal-free treatment. Therefore, this clinical report, showed an innovative technique using a zirconia implant in a clinical situation with high complex esthetic needs for in a young patient with thin gingival phenotype and high level of aesthetic requirement. The clinical case was concluded with cemented prosthesis and metal-free veneers made by pressed ceramics. After the end of the case, it was concluded that, despite the disadvantage related to the technical sensitivity, the zirconia implant provided an aesthetic solution of this clinical case of thin gingival phenotype, without the need of gingival grafts.

Instalação de implante com carga imediata através de um sistema de cirurgia guiada de alta precisão (DIOnavi) / Single implant and immediate loading with a high precision guided surgical system (DIOnavi) – a case report

Os avanços na Implantodontia em busca de resultados previsíveis que possam alinhar estética e função têm levado ao desenvolvimento de sistemas virtuais de planejamento e confecção de guias computadorizados. As cirurgias sem retalho promovem maior conforto aos pacientes, além de apresentarem melhores resultados na manutenção da perda óssea. Entretanto, alguns sistemas ainda apresentam limitações, o que pode levar a diferenças entre o planejamento e o resultado final. Este trabalho teve como objetivo apresentar um caso clínico de instalação de implante com ativação imediata, através do sistema de tecnologia digital de alta precisão DIOnavi (Busan, Coreia). Através de imagens obtidas em tomografias computadorizadas e escaneamento intraoral, o planejamento foi realizado através de um software e um guia cirúrgico, obtido a partir de impressão 3D. Após a instalação do implante, foi instalado um abutment personalizado em titânio e uma coroa provisória cimentada, ambos previamente preparados. O sistema se mostrou eficiente quanto à precisão dos instrumentos e componentes, podendo ser aplicado em diversas situações clínicas, em vista das características.

Advances on implant dentistry aiming predictable results on esthetics and function has led to the development of virtual planning systems and fabrication of computerized surgical guides. Flapless procedures provide more comfort and better results regarding bone loss preservation. However, some systems still have limitations, which can result on differences when the initial and final outcomes are compared. This paper presents a clinical case of immediate implant placement and function using the high-precision digital technology system (DIOnavi, Busan Korea). By means of CBCT and intra-oral scanning, a computer program was used to idealize the surgical guide, with the digital information sent to a 3D-printing machine. After implant placement, the pre-fabricated customized titanium abutment and the cement-retained provisional crown were delivered. This system demonstrated effi ciency related to precision of surgical and prosthetic components and can be recommended for several clinical situations.

Fração mononuclear da medula óssea para reconstrução óssea em levantamento de seio maxilar / Stem cells for bone reconstruction in sinus lifting

Introdução: a demanda por procedimentos de enxertia óssea apresenta um crescimento substancial na área de reabilitação bucal. Entretanto, os pacientes dispostos a se submeter às cirurgias reconstrutivas procuram por procedimentos menos invasivos e com um pós-operatório menos mórbido. Técnicas de reconstrução óssea menos invasivas utilizam, tradicionalmente, substitutos ósseos no sentido de alcançar esses objetivos. No entanto, novos estudos voltados à engenharia tecidual apresentam as células-tronco da medula óssea, em associação a substitutos ósseos, como potencial de melhoramento das características biológicas dos materiais de enxertia. Objetivo: apresentar um caso clínico com a utilização de um concentrado do aspirado da medula óssea autógena (com isolamento da fração mononuclear da medula óssea), associado ao Bio-Oss em um procedimento de levantamento de seio maxilar. Resultados: decorridos cinco meses do procedimento de enxertia composta (Bio-Oss + concentrado de células-tronco medulares),, foram removidas biópsias ósseas durante a cirurgia de instalação dos implantes. Após processamento, as imagens histológicas apresentaram grande quantidade de tecido mineralizado vital para um pós-operatório de cinco meses. Conclusão: o uso do concentrado da fração mononuclear da medula óssea associado ao substituto ósseo xenógeno Bio-Oss em levantamento de seio maxilar parece repercutir em adequado reparo ósseo, culminando em um menor tempo de cicatrização óssea. Porém, estudos clínicos prospectivos randomizados devem ser executados...

Introduction: The demand for bone reconstruction in oral rehabilitation has been growing substantially. However, patients willing to undergo reconstructive surgery want less invasive procedures with less postoperative morbidity. Less invasive bone reconstruction techniques have used bone substitutes to achieve these objectives. Nevertheless, recent studies about tissue engineering have demonstrated that stem cells, in combination with bone grafts, may potentially improve the biological characteristics of grafting material. Objective: To describe a clinical case of sinus elevation using autologous bone marrow aspirate resulting from the isolation of a bone marrow mononuclear fraction combined with Bio-Oss. Results: Five months after the combined grafting procedure (Bio-Oss + bone marrow stem cells), bone biopsies were harvested during implant placement surgery. Histological images revealed a large amount of vital mineralized tissue for a 5-month postoperative time. Conclusion: The clinical use of bone marrow mononuclear fraction combined with Bio-Oss - a xenogeneic bone substitute - in maxillary sinus elevation seems to result in good bone repair and shorter healing time...

Adipose-derived stem cells (ADSC) in the viability of a random pattern dorsal skin flap in rats

PURPOSE: To evaluate the viability of random pattern dorsal skin flaps in rats after injection of adipose-derived stem cells (ADSC). METHODS: Thirty five adult male Wistar EPM rats (weight 250-300 g) were distributed, at random, in two groups. I- Control (flap elevation with injection of saline solution) with fifteen animals and II- Experimental (flap elevation with injection of ADSC ) with fifteen animal. The ADSC were isolated from others five adult male rats. A dorsal skin flap measuring 10x4 cm was raised and a plastic barrier was placed between the flap and its bed in both groups and the injection (cells or saline solution) were perfomed immediately after the surgery. The percentage of flap necrosis was measured on the seventh postoperative day. RESULTS: The ADSC were able to replicate in our culture conditions. We also induced their adipogenic, osteogenic and chondrogenic differentiation to verify their mesenchymal stem cells potentiality in vitro. The results were statistically significant showing that the ADSC decreased the area of necrosis (p<0.05). CONCLUSIONS: The cells demonstrated adipogenic, osteogenic and chondrogenic differentiation potential in vitro. The administration of adipose-derived stem cells was effective to increase the viability of the random random pattern dorsal skin flaps in rats. .

Terapia celular em regeneração óssea. Avaliação histomorfométrica de diferentes metodologias / Cell therapy on bone regeneration. An histomorphometric evaluation of different methodologies

Proposição: este estudo analisou a associação de diferentes metodologias de terapia celular a um enxerto ósseo xenógeno (Bio-Oss). Material e Métodos: 33 coelhos Nova Zelândia foram divididos, randomicamente, em cinco grupos experimentais (n=6) e um grupo controle (n=3). Foram criadas situações de defeitos ósseos bilaterais com o auxílio de fresas trefinas com 12 mm de diâmetro preenchidos – no grupo 1 com Bio-Oss; no grupo 2 com Bio-Oss enriquecido com medula óssea fresca; no grupo 3 com Bio-Oss enriquecido com a fração de células mononucleares da medula óssea; no grupo 4 com Bio-Oss enriquecido com células-tronco mesenquimais da medula óssea; e no grupo 5 com Bio-Oss enriquecido com células-tronco mesenquimais do tecido adiposo. Em cada animal, um dos defeitos ósseos foi recoberto com uma membrana colágena e o outro foi mantido sem recobrimento. Após oito semanas, os animais foram sacrificados, sendo seus ossos parietais fixados em formol 10% e processados para análise histomorfométrica. Resultados: no grupo-controle não existiu formação óssea. A histomorfometria demonstrou, para os lados sem recobrimento por membrana nos grupos de 1 a 5, TMV de 6,56 + 1,20%; 12,45 + 11,65%; 21,13 + 0,55; 27,9 + 5,79 e 16,67 + 5,0; respectivamente. O TMV para os lados com recobrimento pela membrana, nos grupos de 1 a 5, foi de 13,06 + 5,24%; 21,14 + 7,38%; 28,17 + 3,19; 28,24 + 6,17 e 17,21 + 7,3; respectivamente. Conclusão: a terapia celular pode maximizar os resultados regenerativos, normalmente propiciados por um biomaterial osseocondutor. O uso do concentrado de células mononucleares da medula óssea pareceu ser a metodologia com maior potencial para uso clínico.

Objective: this study investigated the combination of different cell therapy approaches in combination with a xenograft (Bio-Oss). Material and Methods: 33 New Zealand rabbits were randomly divided into five experimental groups (n=6) and one control group (n=3). Bilateral bone defects were created using 12 mm diameter trefin burs filled – in group 1, with Bio-Oss, in group 2 with Bio-Oss enriched with fresh bone marrow, in group 3 with Bio-Oss enriched with bone marrow mononuclear fraction, in group 4 with Bio-Oss enriched with bone marrow stem cells and, in group 5, with Bio-Oss enriched with adipose tissue stem cells. In each animal, one bone defect was covered by a collagen membrane and the other defect was not covered. After eight weeks, the animals were sacrificed and their parietal bone fixed in 10% formalin and processed for histomorphometric analysis. Results: in control group bone formation did not occur. Histomorphometry demonstrated, for the sides not covered by the collagen membrane, in groups 1, 2, 3, 4 and 5, a VMT of 6.56 + 1.20%; 12.45 + 11.65%; 21.13 + 0.55; 27.9 + 5.79 and 16.67 + 5.0, respectively. The sides covered by the collagen membrane demonstrated, in groups 1, 2, 3, 4 and 5, a VMT of 13.06 + 5.24%; 21.14 + 7.38%; 28.17 + 3.19; 28.24 + 6.17 and 17.21 + 7.3, respectively. Conclusion: cell therapy can maximize the regenerative results normally obtained by an osseoconductor biomaterial. The use of bone marrow mononuclear fraction concentration seems to be the methodology with higher potential for clinical use

TGF-β1 on induced osteogenic differentiation of human dermal fibroblast

PURPOSE: To evaluate the role of transforming growth factor beta 1 (TGF-β1) on the induced osteogenic differentiation of human dermal fibroblasts. METHODS: We performed four groups with cultured dermal fibroblasts according to the culture medium: CONTROL (DMEM culture medium); TGF-β1 (DMEM culture medium with 10 ng/ml of TGF-β1); OSTEOG (DMEM culture medium with 0.5 µg/ml of ascorbic acid, 10 mmol/l of β-glycerophosphate and 10 nmol/L of dexamethasone); and OSTEOG/TGF-β1 (osteogenic medium with 10 ng/ml of TGF-β1). Alkaline phosphatase (ALP) activity and the amount of osteocalcin (OC) in the supernatant, as well as the capability to form calcium phosphate deposits, were analysed for 28 days RESULTS: There were significant differences (p<0.05) between CONTROL and TGF-β1 groups in comparison with OSTEOG and OSTEOG/TGF-β1 groups in the ALP activity and OC amount. Although, both osteogenic groups had the same behavior with regard the expression curve during the experimental time, the OSTEOG/TGF-β1 group achieved significantly higher ALP and OC levels and showed no significant difference in the levels of mineralized deposits and in comparison with the levels found in the OSTEOG group. CONCLUSION: The addition of transforming growth factor beta 1 to the osteogenic culture medium increased the activity of alkaline phosphatase and the amount of osteocalcin, but TGF-β1 did not alter the presence of mineralized calcium phosphate deposits. .

Development of experimental in vitro burn model

PURPOSE: To propose an experimental burn model in NIH-3T3 cell line. METHODS: Induction of thermal injury in cultures of mouse fibroblast - NIH-3T3- cell line and determination of cell viability by MTT and imunofluorescence. RESULTS: The heating of the Petri dish increased proportionally to the temperature of the base and the time of exposure to microwave. In this in vitro burn model, using the cell line NIH-3T3 was observed drastic cellular injury with significant changes in cell viability and activity. It showed drastically modified cell morphology with altered membrane, cytoskeleton and nucleus, and low cellularity compared to the control group. CONCLUSION: The burn model in vitro using the cell line NIH-3T3 was reproductive and efficient. This burn model was possible to determine significant changes in cell activity and decreased viability, with drastic change in morphology, cell lysis and death. .

Adipose-derived stem cells (ADSC) in the viability of random skin flap in rats

PURPOSE: To evaluate the effects of the adipose-derived stem cells (ADSC) in the viability of random skin flap in rats. METHODS: Thirty five adult male Wistar rats (weight 250-300 g) were used. ADSC were isolated from adult male rats (n=5). ADSC were separated, cultured and then analyzed. A dorsal skin flap measuring 10x4 cm was raised and a plastic barrier was placed between the flap and its bed. After the surgical procedure, the animals were randomized into two groups (n=15 each group), group control and group ADSC. In all groups the procedures were performed immediately after the surgery. The percentage of flap necrosis was measured on the seventh postoperative day. RESULTS: The ADSC were able to replicate in our culture conditions. We also induced their adipogenic, osteogenic and chondrogenic differentiation, verifying their mesenchymal stem cells potentiality in vitro. The results were statistically significant showing that the ADSC decreased the area of necrosis (p<0.05). CONCLUSION: The cells demonstrated adipogenic, osteogenic and chondrogenic differentiation potential in vitro. The administration of adipose-derived stem cells was effective to increase the viability of the random skin flaps in rats. .

Keratinocyte growth factor protected cultured human keratinocytes exposed to oxidative stress / Fator de crescimento de queratinócitos protegeu queratinócitos humanos cultivados expostos ao estresse oxidativo

PURPOSE: To evaluate effects of oxidative stress and supplementation of keratinocyte growth factor (KGF) on cultivated human keratinocytes. METHODS: Oxidative stress was produced through addition of hydrogen peroxide (H2O2) to the culture medium. Cultivated human keratinocytes were divided in 4 groups: Group control (G C), Group KGF (G KGF), Group H2O2 (G H2O2), Group H2O2 and KGF (G H2O2-KGF). Each experiment was accomplished with the same lineage cultivated keratinocytes, in triplicate. Cell viability was evaluated by trypan blue exclusion assay. RESULTS: The results showed that the culture medium supplemented with KGF presented a small rate of cell viability when compared to cells only in culture medium (p<0,001). It demonstrated that only the growth factor does not have protector effects for cells in vitro. However, in front of the oxidative stress produced by addition of hydrogen peroxide to the medium, KGF showed a beneficial effect, protecting cells when compared to the group that suffered hydrogen peroxide action but had not been exposed to KGF (p<0,001). CONCLUSION: KGF determined protection to the primary human keratinocytes exposed to oxidative stress.

OBJETIVO: Avaliar os efeitos do estresse oxidativo e da suplementação do fator de crescimento de queratinócitos (KGF) em queratinócitos humanos cultivados. MÉTODOS: O estresse oxidativo foi produzido através da adição de peróxido de hidrogênio (H2O2) ao meio de cultura. Os queratinócitos humanos cultivados foram divididos em quatro grupos: grupo controle (G C), grupo KGF (G KGF), grupo H2O2 (G H2O2), grupo H2O2 e KGF (G H2O2-KGF). Cada experimento foi realizado com a mesma linhagem celular, em triplicata. A viabilidade celular foi avaliada pelo ensaio da exclusão do azul de tripan. RESULTADOS: Os resultados mostraram que o meio de cultura suplementado com o KGF apresentou menor taxa de viabilidade celular quando comparado às células do grupo controle (p<0,001). Isso mostra que somente o fator de crescimento de queratinócitos não apresentou efeito protetor às células em cultura. Entretanto, frente ao estresse oxidativo produzido pela adição do peróxido de hidrogênio ao meio de cultura, o KGF mostrou efeito benéfico, protegendo as células quando comparado ao grupo que sofreu a ação do estresse oxidativo, mas que não foi exposta ao KGF (p<0,001). CONCLUSÃO: O KGF determinou a proteção aos queratinócitos humanos primários cultivados expostos ao estresse oxidativo.