Microbiological analysis of bacterial sealing of internal conical implants with different taper angles

Abstract The present study evaluated the effect of the taper angle of different internal conical connection implants and cyclic loading on the implant-abutment bacterial seal. A total of 96 implant-abutment sets were divided into eight groups. Four groups of different taper degrees with cyclic mechanical loading of 500,000 cycles per sample, with a 120-N load at 2 Hz before analysis [16DC (16-degree, cycled), 11.5DC (11.5-degree, cycled), 3DC (3- degree, cycled) and 4DC (4- degree, cycled)] were compared to four control groups without cyclic loading [16D (16-degree), 11.5D (11.5-degree), 3D (3-degree), and 4D (4-degree)]. Microbiological analysis was performed by immersing all samples in a suspension containing Escherichia coli and incubating them at 37°C. After 14 days, the presence of bacterial seals was evaluated. Fisher-Freeman-Halton exact tests and binomial tests were performed (5% significance level). The groups showed significant differences in bacterial seal, and mechanical load cycling improved the bacterial seal in the 3DC group. In all other groups, no significant differences in bacterial seal were found between cycled and uncycled samples. To conclude, the internal conical connection with a 3-degree taper angle showed better results than the other connection with different angles when subjected to load cycling. However, none of the angles tested were fully effective in sealing the implant-abutment interface.

Evaluation of the dosimetry and centralization of scout-view function in CBCT

Abstract This study evaluated the centralization of the region of interest (ROI) in acquisition of the CBCT images, when the freely positionable scout-view (SV) function is applied. Additionally, the dosimetry of the acquired images was assessed in the SV function alone as well as in complete tomographic image in two different fields of view (FOV) (50x50 and 78x150mm). A three-location device was created to accommodate the dosimeters and the specimens, in the right, middle and left location during image acquisition. For dose assessment, thermoluminescent dosimeters were irradiated within the FOV and analyzed in a portable reader. For ROI evaluation, three specimens of gutta-percha stick were placed on the same device and the CT scans were acquired (CBCT OP 300 Maxio device, 90kV, 13mA, 85 µm voxel size, FOV of 50X50mm), with and without the SV, in three positions (3-9, 1-7 and 5-11 o'clock), simulating different regions of the mouth. Two image evaluations were performed, an objective and subjective. There was a slight percentage increase (1.36% to 1.40%) of the radiation dose with the use of SV. The distances were significantly greater in the images acquired without SV (p < 0.05). Every image obtained with SV was classified as being at the FOV's center. In conclusion, the results demonstrated that SVs function is effective to centralize the ROI in the FOV, increasing the scan precision and avoiding repetitions due to positioning errors.

Resumo Este estudo avaliou a centralização da região de interesse (ROI) na aquisição das imagens de TCFC, quando a função scout-view (SV) posicionável livremente é aplicada. Adicionalmente, a dosimetria das imagens adquiridas foi avaliada isoladamente na presença da função SV, bem como após aquisição de imagem tomográfica completa em dois diferentes campos de visão (FOV) (50x50 e 78x150mm). Um dispositivo de três localizações foi criado para acomodar os dosímetros e os espécimes, na localização direita, central e esquerda, durante a aquisição das imagens. Para avaliação da dose, dosímetros termoluminescentes foram irradiados dentro dos campos de visão e analisados em leitor portátil. Para avaliação da ROI, três espécimes de guta percha foram colocados no mesmo aparelho e as tomografias foram adquiridas (CBCT OP 300 Maxio, 90kV, 13mA, 85 μm tamanho de voxel, FOV de 50X50mm), com e sem a SV, em três posições (3-9, 1-7 e 5-11 horas), simulando diferentes regiões da boca. Foram realizadas duas avaliações de imagem, uma objetiva e outra subjetiva. Houve um leve aumento percentual (1,36% para 1,40%) da dose de radiação com o uso de SV. As distâncias foram significativamente maiores nas imagens adquiridas sem SV (p < 0,05). Todas as imagens obtidas com SV foram classificadas como sendo do centro do FOV. Em conclusão, os resultados do presente estudo demonstraram que a função scout view é eficaz para centralizar a ROI no FOV, aumentando a precisão do escaneamento e evitando repetições devido a erros de posicionamento.

Titanium dioxide nanotubes added to glass ionomer cements affect S. mutans viability and mechanisms of virulence

Abstract This in vitro study evaluated the impact of TiO2 nanotubes (n-TiO2) incorporated into glass ionomer cement (GIC) on Streptococcus mutans (S. mutans) characteristics at cellular and molecular levels. n-TiO2, synthesized by the alkaline method (20 nm in size), was added to Ketac Molar EasyMix® at 0%, 3%, 5%, and 7% by weight. S. mutans strains were cultured on GIC disks with addition or not of n-TiO2 for 1, 3, and 7 days and the following parameters were assessed: inhibition halo (mm) (n=3/group); cell viability (live/dead) (n=5/group); cell morphology (SEM) (n=3/group); and gene expression by real-time PCR (vicR, covR, gtfB, gtfC, and gtfD) (n=6/group). The data were analyzed by the Kruskal-Wallis test, repeated-measures ANOVA or two-way ANOVA, and Tukey's and Dunn's post-hoc tests (α=0.05). The agar diffusion test showed a higher antibacterial property for 5% n-TiO2 compared with 3% and 7% (p<0.05) with no effect of time (1, 3, and 7 days). The cell number was significantly affected by all n-TiO2 groups, while viability was mostly affected by 3% and 5% n-TiO2, which also affected cell morphology and organization. Real-time PCR demonstrated that n-TiO2 reduced the expression of covR when compared with GIC with no n-TiO2 (p<0.05), with no effect of time, except for 3% n-TiO2 on vicR expression. Within-group and between-group analyses revealed n-TiO2 did not affect mRNA levels of gtfB, gtfC, and gtfD (p>0.05). Incorporation of n-TiO2 at 3% and 5% potentially affected S. mutans viability and the expression of key genes for bacterial survival and growth, improving the anticariogenic properties of GIC.

Preliminary findings on the possible role of B-lymphocyte stimulator (BLyS) on diabetes-related periodontitis

Abstract The possible role of B-cell growth and differentiation-related cytokines on the pathogenesis of diabetes-related periodontitis has not been addressed so far. The aim of this study was to evaluate the effects of diabetes mellitus (DM) on the gene expression of proliferation-inducing ligand (APRIL) and B-lymphocyte stimulator (BLyS), two major cytokines associated to survival, differentiation and maturation of B cells in biopsies from gingival tissue with periodontitis. Gingival biopsies were obtained from subjects with periodontitis (n = 17), with periodontitis and DM (n = 19) as well as from periodontally and systemically healthy controls (n = 10). Gene expressions for APRIL, BLyS, RANKL, OPG, TRAP and DC-STAMP were evaluated using qPCR. The expressions APRIL, BLyS, RANKL, OPG, TRAP and DC-STAMP were all higher in both periodontitis groups when compared to the control group (p < 0.05). Furthermore, the expressions of BLyS, TRAP and RANKL were significantly higher in the subjects with periodontitis and DM when compared to those with periodontitis alone (p < 0.05). The mRNA levels of BLyS correlated positively with RANKL in the subjects with periodontitis and DM (p < 0.05). BLyS is overexpressed in periodontitis tissues of subjects with type 2 DM, suggesting a possible role of this cytokine on the pathogenesis DM-related periodontitis.

Mechanical and histological evaluation of a titanium device for orthodontic anchorage, placed with or without cyanoacrylate adhesive

ABSTRACT Objective: The objective of the present study was to perform a histological evaluation of a titanium mini-implant for orthodontic anchorage. Shear strength and fracture patterns that occurred immediately, 30 and 60 days after insertion with or without N-2-butyl-cyanoacrylate adhesive were evaluated. Methods: Ninety-six mini-implants (Arrow, Peclab, Brazil) were placed in the tibia of 9 male rabbits, with or without an adhesive (Vetbond™, 3M, USA). Histological evaluation was done by optical light microscope. Shear strength testing was performed, followed by fracture analysis with visual inspection. Results: Close contact between the newly formed bone and the device was evidenced in the group without adhesive, whereas gaps in the group with adhesive were found. Tukey test showed similar values in both groups at the immediate time point (20.70 N without adhesive and 24.69 N with adhesive), and higher values for the non-adhesive group, after 30 and 60 days (43.98 N and 78.55 N, respectively). The values for the adhesive group were similar for the immediate time point (24.69 N), 30 days (18.23 N) and 60 days (31.98 N). The fractures were adhesive for both groups at the immediate time point. The fractures were cohesive in bone for the non-adhesive group after 30 and 60 days. Conclusions: The mini-implants showed close bone contact and required higher shear strength for removal at 30 and 60 days for the non-adhesive group. Further studies are needed to assess the proper way to remove the orthodontic anchorage without cohesive fractures in bone.

RESUMO Objetivos: este estudo teve como objetivo realizar uma avaliação histológica de um mini-implante para ancoragem em Ortodontia. Avaliou-se, também, a carga de cisalhamento e o padrão de fratura imediatamente e após 30 e 60 dias da sua inserção, com ou sem o uso do adesivo N-butil-2-cianoacrilato. Métodos: noventa e seis mini-implantes (Arrow, Peclab, Brasil) foram instalados na tíbia de nove coelhos machos, com ou sem adesivo (Vetbond™, 3M, EUA). A avaliação histológica foi realizada com uso de microscópico de luz óptica. Realizou-se o teste de resistência ao cisalhamento, seguido pela análise da fratura, por meio de inspeção visual. Resultados: um contato íntimo entre o novo osso formado e o dispositivo foi evidenciado no grupo sem adesivo, enquanto espaços foram encontrados no grupo com adesivo. O teste de Tukey mostrou valores semelhantes em ambos os grupos no tempo imediato (20,70 N sem adesivo e 24,69 N com adesivo), e valores maiores para o grupo sem adesivo após 30 e 60 dias (43,98 N e 78,55 N, respectivamente). Os valores para o grupo com adesivo foram semelhantes para os tempos imediato (24,69 N), 30 dias (18,23 N) e 60 dias (31,98 N). As fraturas foram adesivas para ambos os grupos, no tempo imediato. As fraturas foram coesivas no osso para os grupos sem adesivo, após 30 e 60 dias. Conclusões: os mini-implantes mostraram um contato íntimo com o osso e requereram alta carga de cisalhamento para sua remoção após 30 e 60 dias nos grupos sem adesivo. Estudos adicionais são necessários para avaliar um método para remoção do dispositivo ortodôntico sem fratura coesiva no osso.

Clinical outcomes of peri-implantitis treated with bone substitute and resorbable membrane: a literature review with a systematic approach / Desfechos clínicos do tratamento da peri-implantite com substituto ósseo e membrana reabsorvível: revisão da literatura com abordagem sistemática

ABSTRACT Objective: The objective of this review was to evaluate the outcomes of the treatment of peri-implant defects, using Guided Bone Regeneration. Methods: A literature search was performed based on the PICO methodology in the PubMed/Medline, SciELO, Lilacs electronic databases, CAPES periodicals and the Cochrane Library. We included studies using bovine mineral matrix, associated to a collagen membrane for the treatment of peri-implantitis by Guided Bone Regeneration. Results: Of 1,163 studies, 10 were included in this review after applying the evaluation criteria. A total of 269 implants were treated in 260 patients. The follow-up period ranged from 6 to 48 months. The studies evaluated outcome in terms of reduction in probing depth, gain of clinical attachment and healing of the bony defect. Due to the heterogeneity of the studies, it was not possible to perform meta-analysis. Conclusion: Treatment of peri-implant lesions with Guided Bone Regeneration is a viable modality of treatment, providing reduction in bleeding on probing, as well as gain of clinical attachment. Complete filling of the defect is, however, an unpredictable result.

RESUMO Objetivo: O objetivo desta revisão sistemática foi avaliar os desfechos do tratamento dos defeitos peri-implantares, por meio da técnica da Regeneração Óssea Guiada. Métodos: Uma pesquisa bibliográfica, baseada na metodologia PICO, foi realizada nas bases de dados eletrônica PubMed/Medline, SciELO, Lilacs periódicos Capes e Cochrane Library. Foram incluídos estudos que utilizaram matriz mineral bovina, associado a uma membrana de colágeno para o tratamento da peri-implantite por Regeneração Óssea Guiada. Resultados: De 1.163 estudos, 10 foram incluídos nesta revisão, após aplicação dos critérios de avaliação. Um total de 269 implantes foram tratados em 260 pacientes. O período de acompanhamento variou de 6 a 48 meses. Os estudos avaliados reportaram redução média da profundidade de sondagem, ganho de inserção clínica e preenchimento ósseo do defeito. Devido à heterogeneidade dos estudos não foi possível realizar metanálise. Conclusão: O tratamento das lesões peri-implantares, com a técnica da Regeneração Óssea Guiada é uma modalidade viável de tratamento, proporcionando redução do sangramento à sondagem, bem como o ganho de inserção clínica. Porém, o completo preenchimento do defeito, é um resultado imprevisível.

Presence of Cells in Fresh-Frozen Allogeneic Bone Grafts from Different Tissue Banks

Bone replacement materials have been widely used to reconstruct atrophic jawbones. Based on previous reports demonstrating the presence of viable cells in bone blocks even after processing by musculoskeletal tissue banks for orthopedic use, the aim of this study was to evaluate the presence of cells in bone blocks from three Brazilian tissue banks for maxillary reconstructions. All samples were processed by the respective tissue banks, according to the guidelines of the Brazilian National Sanitary Surveillance Agency. Three samples were removed from each block for subsequent histological processing and stained using hematoxylin & eosin. Further evaluation included section staining by the Feulgen method and ultrastructural analysis using scanning electron microscopy (SEM). Light microscopy images from all bone samples showed presence of osteocyte-like cells in all groups and intense Feulgen staining, demonstrating presence of DNA in bone even after tissue processing. The ultrastructural analysis showed red blood cells in lacunae within the bone tissue. In conclusion, despite bone tissue processing by the musculoskeletal tissue banks, cells may be found within the bone used for allogeneic grafts.

Resumo Substitutos ósseos têm sido amplamente utilizados para reconstrução de ossos maxilares atróficos. Uma vez que relatos anteriores demonstram a existência de células viáveis em blocos ósseos após processamento pelos bancos de tecidos músculo-esqueléticos para uso ortopédico, o objetivo deste trabalho foi avaliar a presença de células provenientes de três bancos de tecidos músculo-esqueléticos do Brasil. Todas as amostras foram processadas pelos respectivos bancos seguindo as normas da Agência Nacional de Vigilância Sanitária brasileira. Foi realizada a retirada de 3 amostras de cada bloco, que foram destinadas para processamento histológico e subsequente coloração por hematoxilina e eosina e Feugen e análise ultra-estrutural através de microscopia eletrônica de varredura (MEV). As imagens de microscopia de luz de todos os fragmentos de enxertos ósseos mostraram presença de células do tipo osteócito em todos os grupos avaliados, bem como intensa coloração por Feulgen, demonstrando a presença de DNA nos ossos mesmo após o processamento realizado. As análises ultraestruturais evidenciaram a presença de hemácias nas lacunas do tecido ósseo. Conclui-se que mesmo após os processamentos realizados pelos bancos de tecidos músculo-esqueléticos é possível encontrar células nos ossos utilizados para enxertia alógena.

Caries experience and salivary aspects in individuals with fragile X syndrome

Abstract Fragile X syndrome (FXS) is the most common cause of hereditary mental retardation, but studies on the oral health condition of these patients are rare. The aim of this study was to determine the experience of dental caries in individuals with FXS, by examining the saliva profile, oral hygiene, socioeconomic characteristics and use of controlled drugs in these patients. Dental health was estimated using the decayed, missing and filled teeth index (DMF-T) and sialometry, and the pH value and buffering capacity of the saliva, colony forming units of S. mutans (CFU/mL), visible biofilm index, and socioeconomic status were all examined. The sample, comprising 23 individuals, had an average age of 17.3 ± 5.6 years, a DMF-T index of 5.5, a diminished salivary flow (78.3%), and a low (73.9%) saliva buffering capacity. Most (52.2%) individuals presented with a high abundance (CFU/mL) of S. mutans. The experience of caries was correlated with salivary parameters, poor oral hygiene, lower socioeconomic status and an increased count of S. mutans in saliva.

In vitro evaluation of gingival fibroblasts proliferation and smear layer formation in pre-conditioned root surfaces / Avaliação in vitro do comportamento biológico de fibroblastos gengivais em superfícies radiculares pré-condicionadas

ABSTRACT Objective: The objective of the present study was to evaluate, in vitro, fibroblastic proliferation on chemically conditioned root surfaces. Methods: Forty single-rooted human teeth, were cut into fragments and divided into four groups (n=20): GI (control) - scaling and root planing (SRP); GII - SRP + conditioning with 10% citric acid; GIII - SRP + conditioning with 24% EDTA gel and GIV - SRP + conditioning with 50 mg/ml of tetracycline hydrochloride. The fibroblasts were placed on these surfaces and cell proliferation evaluated using Trypan Blue stain. Smayer layer formation was analyzed using Scanning Electron Microscopy. Results: The results revealed that the chemical conditioners used were incapable of effectively removing the smear layer. However, when compared to the other groups, GIII showed the best results regarding removal of the smear layer (p<0.05). GI demonstrated the greatest cell proliferation at all studied time intervals compared to the chemically treated groups (p<0.05). Conclusion: The results of the present study reveal that all demineralizing agents evaluated presented lower cell proliferation levels when compared to the control group. In addition none of the chemical conditioners used removed the smear layer completely.

RESUMO Objetivo: Avaliar in vitro a proliferação de fibroblastos em superfícies radiculares, previamente condicionadas quimicamente. Métodos: Para este estudo, 40 dentes unirradiculares humanos hígidos, extraídos por acometimento periodontal irreversível, foram seccionados em fragmentos radiculares e divididos em 04 grupos (20 espécimes/grupo) de acordo com a aplicação do condicionamento ácido: GI (controle) - apenas submetidos à raspagem e alisamento radicular (RAR); GII - RAR + condicionamento com ácido cítrico a 10%; GIII- RAR + condicionamento com gel de EDTA a 24%, ph 7,0; e GIV- RAR + condicionamento com 50mg/ml de cloridrato de tetraciclina. Adicionalmente, as células foram plaqueadas sobre estas superfícies e foi avaliada a proliferação celular por meio do corante vital azul de Trypan. Para a análise da morfologia ultraestrutural foi utilizado Microscopia Eletrônica de Varredura (MEV). Resultados: Os resultados demonstraram que em relação à proliferação celular, os condicionadores químicos utilizados não foram capazes de remover efetivamente a smear layer. Entretanto, no grupo tratado com EDTA (GIII) foi observado uma maior remoção (P<0,05) na quantidade de smear layer quando comparado aos demais grupos. No grupo controle (GI) pode-se observar uma maior proliferação celular em todos os tempos (24h, 48h, 72h) quando comparado aos demais grupos que sofreram tratamento químico (P<0,05). Conclusão: Considerando os agentes desmineralizantes avaliados, a maior remoção de smear layer e proliferação celular foram alcançados com o gel de EDTA a 24%, quando comparado ao grupo condicionado com cloridrato de tetraciclina 50 mg/ml, após 72 horas de cultivo celular.

Influence of aesthetic coating on the load-deflection ratio of nickel­titanium archwires

Aim: To assess the influence of aesthetic surface coating on load-deflection ratios in nickel-titanium (NiTi) orthodontic wires compared with uncoated wires.Methods: NiTi wires (0.016") from four different manufacturers (Morelli, Sorocaba, SP, Brazil; TP, La Porte, IN, USA; Eurodonto, Curitiba, PR, Brazil; Ortho Organizers, San Marcos, CA, USA) were divided into eight groups, according to presence or absence of coating: group 1, Morelli coated wire; group 2, Morelli uncoated; group 3, TP coated; group 4, TP uncoated; group 5, Eurodonto coated; group 6, Eurodonto uncoated; group 7, Ortho Organizers coated; group 8, Ortho Organizers uncoated. To determine the load-deflection ratio, a three-point bending test was performed in a AGS-X 250 KN (Shimadzu) universal testing machine.Results: The results showed that aesthetic coatings did not influence load-deflection ratio in NiTi orthodontic wires at 1-mm and 2-mm activation. However, comparison across the four tested brands revealed that Eurodonto coated wires exhibited the greatest force levels at 1-mm, 2-mm, and 3-mm deflection. At 3-mm deflection, Ortho Organizers coated wires exhibited lower force levels than all other tested brands, except for TP wires.Conclusions: We conclude that the load-deflection ratio of NiTi wires was not influenced significantly by aesthetic coatings, especially at lower activations (AU)

Evaluation of cutting ability and plastic deformation of reciprocating files

Abstract This in vitro study evaluated the cutting ability of reciprocating files and the deformations caused by their multiple use. Five Reciproc® R25 files were divided into five groups for 10 simulated root canal preparations each. The resin blocks were weighed and photographed (12.5X and 20X) before and after preparation. The canals were prepared according to the manufacturer’s instructions. Enlargement of the root canals was evaluated by comparison of pre- and post-preparation images using a computer software. The preoperative and postoperative weight differences determined the cutting ability of repeatedly used instruments. The data were analyzed using Lilliefors and Friedman statistical tests. The cutting ability and enlargement of the canals gradually decreased after each use, with significant differences observed at the 8th and 9th repetitions, respectively. There was no evidence of file deformation. The cutting ability and enlargement of the simulated canals gradually decreased when a reciprocating file was used up to 10 times.

Cytotoxicity analysis of electrostatically applied epoxy coating onto CO-CR alloy / Análise da citotoxidade de pintura epóxi na aplicação eletrostática sobre liga de CO-CR

Objective: To investigate the biological effect of a new method to camouflage the cobalt-chromium (CoCr) metal structure of an RPD, onto which an electrostatic paint was applied.Methods: In vitro cytotoxicity of epoxy Politherm NOBAC30C (Weg Industries SA, Santa Catarina, Brazil) in combination with polished CoCr was tested by placing it in contact with cultured human fibroblasts and comparing it with polystyrene (control surface). The cells were cultured in the presence of the test surfaces for 24, 48, 72, 94 and 120 hours. The number of viable and non-viable cells was established by manual counting. The Tukey test was used to statistically analyze cell counts between the groups.Results: The results showed that cell proliferation was similar between the groups (p =0.2174). It was observed that at 24, 48 and 72 h, there was no significant increase in cell proliferation in all groups. From 96 to 120 h, an increase in cell proliferation was observed in all groups, with no significant difference between them (p>0.05).Conclusion: The epoxy paint studied showed no cytotoxicity in vitro.

Objetivos: Analisar, biologicamente, a possibilidade do uso de pintura por aplicação eletrostática.Métodos: Por meio de testes in vitro de citotoxicidade, comparando o comportamento da tinta epóxi Politherm 30 Nobac C (Weg Indústrias S.A, Santa Catarina, Brasil) com CoCr polido e poliestireno em contato com cultura de fibroblastos humanos. Esse teste foi realizado através de contagem de células viáveis e não viáveis em tempos de 24, 48, 72, 94 e 120 horas. Para a contagem de células viáveis foi aplicada a Análise Estatística de Tukey.Resultados: Os resultados obtidos na presente pesquisa mostraram que o comportamento de crescimento celular foi estatisticamente semelhante entre grupos (p=0,2174). Observou-se que nos tempos de 24, 48 e 72 horas, não houve aumento estatisticamente significante da proliferação celular, mantendo-se o padrão para todos os grupos estudados. A partir de 96 e 120 h observamos um aumento da proliferação celular para todos os grupos estudados, sem diferenças entre os mesmos também (p>0,05). Para os resultados de células inviáveis, aplicou-se a Análise não Paramétrica de Kruskal Wallis e o teste de Dunn, devido à baixa taxa de morte celular, sem diferença estatisticamente entre os grupos (p>0,05).Conclusão: Conclui-se, portanto, que a pintura Epóxi estudada não apresentou citotoxicidade para os testes realizados in vitro.

In vitro evaluation of the effects of risedronate associated with cobalamin on osteoblastic cells / Avaliação in vitro dos efeitos do risedronato associado à cobalamina sobre células osteoblásticas

To evaluate the action of risedronate and cobalamin, and effects when associated, when administered osteoblastic cells.

Avaliar a ação do risedronato e da cobalamina, e seus efeitos quando associados, em células osteoblásticas

Potencial osteoindutor de blocos de osso alógeno humano in vitro / Osteoinductive potential ot allogeneic human bone blacks in vitro

O enxerto alógeno apresenta diversas vantagens em relação ao enxerto autógeno, porém sua utilização é relativamente recente e cercada de incertezas em relação ao seu comportamento biológico/imunológico e eficácia como biomaterial. Alguns autores consideram-no estritamente osteocondutor, enquanto outros acreditam que ele pode ser osteoindutor. O objetivo deste trabalho foi estudar o potencial osteoindutor do osso alógeno analisando os efeitos dos extratos proteicos provenientes de blocos de aloenxerto sobre células pré-osteoblásticas humanas. As proteínas extraídas dos blocos ósseos foram incubadas em culturas de células pré-osteoblásticas, a fim de verificar o potencial de indução de proliferação celular. Foram utilizados os métodos do RT-qPCR, Vermelho de Alizarina e Von Kossa para avaliar o metabolismo das células ósseas e a formação de nódulos minerais contendo cálcio e fosfato, respectivamente. Também foi pesquisado se havia nos blocos ósseos a proteína morfogenética BMP-2. Foi possível observar, nos grupos experimentais, aumento na proliferação celular, do metabolismo das células ósseas e da produção de nódulos de cálcio e fosfato, em relação ao grupo controle. Foi possível detectar a presença de BMP-2 em seis dos nove blocos ósseos. Conclui-se que os blocos de aloenxerto mineralizado possuem proteínas com potencial osteoindutor quando testado seu comportamento in vitro em células osteoblásticas

The allogenic bone has several comparative advantages in relation to autograft bone, but its use is relatively recent and surrounded by uncertainties regarding the bioloqical/immunological behavior and effectiveness as a biomaterial. Some authors consider the material strictly osteoconductive, while others bel ieve that the materia I ca n a Iso possess osteoi nd uctive activitv Thus, we evaluated the osteoinductive potential of allograft bone by analyzing the effects of protein extracts from allograft blocks using human pre-osteoblastic cells. The protein extract from allograft block was incubated in cultures of pre-osteoblast cells in order to verify the cell proliferation potential. Moreover, it was employed the RT-qPCR, Alizarin and Von Kossa staining to evaluate the bone metabolism, as well as, the potential induction of calcium and phosphate nodule formation. Finally, it was quantified the morphogenetic protein BMP-2. It was possible to observe in the experimental group, an increase in the cell proliferation and cellular metabolism, as well as, a significant increase in the formation of nodules of calcium and phosphate in comparison to control group. It was possible to detect amounts of BMP-2 in six of nine total samples tested. It was possible to conclude that the mineralized allografts blocks have in vitro osteoinductive activity on osteoblastic cells

In Vitro Microbiological Analysis of Bacterial Seal at the Implant-Abutment Interface Using Two Morse Taper Implant Models

The objective of this study was to evaluate the bacterial seal at the implant-abutment interface using two morse taper implant models, by means of an in vitro microbiological analysis. For that were used 15 implants with mini-abutments tightened by friction, no screws (Group 1); and 30 implants with screw-tightened abutments, of which 15 received 20 N.cm of closing torque (Group 2) and the other 15 received 30 N.cm (Group 3). Microbiological analysis was carried out using colonies of Escherichia coli transported directly from a culture dish to the prosthetic component. Friction implants (Group 1) were activated by tapping and a torque wrench was used for screw-tightened implants (Groups 2 and 3). Each abutment/implant set was immersed in test tubes containing 5 mL of brain-heart infusion broth and incubated at 37 °C for 14 days, observed daily for the presence of contamination. A statistically significant difference was observed regarding the number of contaminated implants. There was greater contamination in Group 2 implants (p<0.05), with no statistically significant difference between the other groups (Group 1 = 20% and Group 3 = 0%). It was concluded that there was no significant difference in in vitro bacterial sealing between implants with mini-abutments tightened by friction without screws and implants with screw-tightened abutments with 30 N.cm of closing torque. The difference in closing torque altered the in vitro sealing ability of the tested abutments, with a greater contamination for components that received a closing torque of 20 N.cm.

O objetivo deste estudo foi avaliar comparativamente, por meio de análise microbiológica in vitro, a capacidade de selamento bacteriano de dois modelos de implante de encaixe morse. Foram utilizados 15 implantes com travamento de seus respectivos mini-pilares por fricção, sem auxílio de parafuso (Grupo 1) e 30 implantes com travamento de seus respectivos mini-pilares sólidos reforçado pela presença de parafuso, sendo que 15 destes implantes receberam torque de inserção de 20 N.cm (Grupo 2) e o restante 30 N.cm (Grupo 3). A análise microbiológica foi realizada utilizando colônias de Escherichia coli transportadas diretamente da placa de cultivo para o componente protético. Os implantes friccionais (Grupo 1) foram ativados por meio do dispositivo bate conexão e para os aparafusados foi usada a chave de torque (Grupos 2 e 3). Cada conjunto de pilar/implante foi imerso em tubos de ensaio contendo 5 mL de caldo BHI (Brain-Heart Infusion) e incubados a 37 °C durante 14 dias com verificação diária de presença de contaminação. Foi observada diferença estatisticamente significante, com relação ao número de implantes contaminados. Para os implantes do Grupo 2, houve maior contaminação (60%, p<0,05), não sendo observada diferença significativa entre os outros grupos (Grupo 1 = 20% e Grupo 3 = 0%). Conclui-se neste estudo que não houve diferença estatística significante quanto ao selamento bacteriano in vitro entre os Grupos 1 e 3. A diferença de torque de inserção alterou a capacidade de selamento in vitro dos pilares testados, sendo observada uma maior contaminação para os componentes que receberam o torque de 20 N.cm.

Use of 0.25% and 0.025% peracetic acid as disinfectant agent for chemically activated acrylic resin: an in vitro study / Uso do ácido peracético a 0.25% e a 0.025% como agente desinfetante de resina acrílica ativada quimicamente: estudo in vitro

Objective: This in vitro study evaluated the disinfection action of peracetic acid on chemically activated acrylic resin. Methods: Sixty chemically activated acrylic resin specimens were contaminated with Candida albicans (30) and Bacillus subtilis (30) for 15 minutes. Next, specimens were divided into Control Group (Group 0) and Test Group (T) for each studied microorganism. The antimicrobial effect of Proxitane® Alfa (Thech Desinfecção, São Paulo, Brazil), containing 0.25% and 0.025% concentrations of peracetic acid was verified after 1, 3, 5 and 10 minutes of exposure. The specimens were transferred to saline solution for 5 minutes, homogenized and aliquots of 100µL were plated on BHI and Sabouraud Dextrose agar. After incubation at 37ºC/24h, the number of CFU/mL recovered from each specimen was obtained. Results: The 0.025 % peracetic acid was effective against B. subtilis only after 10 minutes and against C. albicans after 3 minutes of exposure. At 0.25% concentration, the solution showed fungicidal and bactericidal efficacy after 1 minute of exposure. Conclusion: The 0.25% peracetic acid was shown to be efficient for disinfection of chemically activated acrylic resins.

Objetivo: Avaliar in vitro a ação desinfetante do ácido peracético sobre resina acrílica quimicamente ativada. Métodos: Sessenta corpos de prova em resina acrílica quimicamente ativada foram contaminados em suspensão de Candida albicans (n=30) e Bacillus subtilis (n=30) por 15 minutos. A seguir, os corpos de prova foram divididos em grupo Controle (Grupo 0), com 6 espécimes e Grupo teste composto por 24 espécimes para cada microrganismo estudado. Proxitane® Alfa (Thech Desinfecção, São Paulo, Brasil) ácido peracético foi testado nas concentrações de 0,25% e 0.025%, após 1, 3, 5 e 10 minutos de exposição. Após, cada corpo de prova foi transferido para solução fisiológica por 5 minutos, homogeneizados e alíquotas de 100 µL foram semeadas em duplicata, em BHI e Sabouraud Dextrose ágar. Após incubação a 37ºC / 24 horas, determinou-se o número de UFC/ml recuperado de cada espécime.Resultados: Na concentração de 0,025%, o ácido peracético mostrou efeito frente a Bacillus subtilis apenas após 10 minutos e para Candida albicans, após 3 minutos. Na concentração de 0,25%, a solução mostrou efeito fungicida e bactericida após apenas 1 minuto de exposição.Conclusão: O ácido peracético a 0,25% demonstrou-se eficaz na desinfecção de resina acrílica quimicamente ativada.

FGF-2, TGFâ-1, PDGF-A and respective receptors expression in pleomorphic adenoma myoepithelial cells: an in vivo and in vitro study

Myoepithelial cells have an important role in salivary gland tumor development, contributing to a low grade of aggressiveness of these tumors. Normal myoepithelial cells are known by their suppressor function presenting increased expression of extracellular matrix genes and protease inhibitors. The importance of stromal cells and growth factors during tumor initiation and progression has been highlighted by recent literature. Many tumors result from the alteration of paracrine growth factors pathways. Growth factors mediate a wide variety of biological processes such as development, tissue repair and tumorigenesis, and also contribute to cellular proliferation and transformation in neoplastic cells. OBJECTIVES: This study evaluated the expression of fibroblast growth factor-2 (FGF-2), transforming growth factor â-1 (TGFâ-1), platelet-derived growth factor-A (PDGF-A) and their respective receptors (FGFR-1, FGFR-2, TGFâR-II and PDGFR-á) in myoepithelial cells from pleomorphic adenomas (PA) by in vivo and in vitro experiments. MATERIAL AND METHODS: Serial sections were obtained from paraffin-embedded PA samples obtained from the school's files. Myoepithelial cells were obtained from explants of PA tumors provided by surgery from different donors. Immunohistochemistry, cell culture and immunofluorescence assays were used to evaluate growth factor expression. RESULTS: The present findings demonstrated that myoepithelial cells from PA were mainly positive to FGF-2 and FGFR-1 by immunohistochemistry and immunofluorescence. PDGF-A and PDGFR-á had moderate expression by immunohistochemistry and presented punctated deposits throughout cytoplasm of myoepithelial cells. FGFR-2, TGFâ-1 and TGFâR-II were negative in all samples. CONCLUSIONS: These data suggested that FGF-2 compared to the other studied growth factors has an important role in PA benign myoepithelial cells, probably contributing to proliferation of ...

Dentin matrix protein 1 (DMP1) expression in developing human teeth

Dentin matrix protein 1 (DMP1) is an acidic phosphoprotein that plays an important role in mineralized tissue formation by initiation of nucleation and modulation of mineral phase morphology. The purpose of the present study was to examine the immunoexpression of DMP1 in tooth germs of 7 human fetuses at different gestational ages (14, 16, 19, 20, 21, 23 and 24 weeks) comparing with completed tooth formation erupted teeth. The results showed the presence of DMP1 in the dental lamina, as well as in the cells of the external epithelium, stellate reticulum and stratum intermedium of the enamel organ. However, in the internal dental epithelium, cervical loop region and dental papilla some cells have not labeled for DMP1. In the crown stage, DMP1 was expressed in the ameloblast and odontoblast layer, as well as in the dentinal tubules of coronal dentin near the odontoblast area. Erupted teeth with complete tooth formation exhibited immunolabeling for DMP1 only in the dentinal tubules mainly close to the dental pulp. No staining was observed in the enamel, predentin or dental pulp matrix. DMP1 is present in all developing dental structures (dental lamina, enamel organ, dental papilla) presenting few immunoexpression variations, with no staining in mineralized enamel and dentin.

A proteína da matriz dentinária 1 (DMP1) é uma fosfoproteína ácida que tem sido relacionada diretamente ao processo de mineralização dos tecidos em formação sendo iniciadora do processo de nucleação e modulação da fase mineral. O objetivo desse trabalho foi avaliar a imunoexpressão da DMP1 em germes dentários em diferentes fases da odontogênese, obtidos de 7 fetos humanos em diversos estágios gestacionais (14, 16, 19, 20, 21, 23 e 24 semanas), comparando-se com dentes com rizogênese completa. Os resultados mostraram que a DMP1 esteve expressa na lâmina dentária, bem como, nas células do epitélio externo, retículo estrelado e estrato intermediário do órgão do esmalte. Diferentemente, no epitélio interno do órgão do esmalte, alça cervical e papila dentária algumas células não apresentaram a DMP1. Nas fases de coroa, os ameloblastos e odontoblastos apresentaram marcação positiva para a DMP1, bem como os túbulos dentinários da dentina coronária próximos à região odontoblástica. Os dentes com rizogênese completa exibiram marcação para a DMP1 apenas nos túbulos dentinários principalmente próximos à polpa dentária. Nenhuma marcação foi observada na matriz de esmalte ou pré-dentina, nem na polpa dentária. Concluímos que a DMP1 está presente em todas as fases da odontogênese, tanto na lâmina dentária, órgão do esmalte, bem como na papila dentária, com pequenas variações de nuances de expressão, estando ausente na dentina e esmalte mineralizados.