Métodos alternativos para determinação da potência de veneno e antiveneno botrópico: aplicações e perspectivas para o controle da qualidade / Alternative methods for potency evaluation for Bothrops venom and antivenom: applications and perspectives for quality control

Introdução: Acidentes com animais peçonhentos são classificados como doenças tropicais negligenciadas e são atualmente a mais frequente causa de intoxicação em humanos no Brasil. O único tratamento disponível é a rápida administração de antivenenos específicos e de qualidade garantida. Para assegurar a eficácia e a segurança desses produtos, são realizados ensaios de determinação da potência in vivo para veneno e antiveneno, desde as etapas de produção até sua liberação final. Apesar dos diversos estudos sobre métodos   alternativos ao ensaio murino, nenhum método foi efetivamente validado. Objetivo: Compilar os métodos alternativos desenvolvidos para os antivenenos botrópicos, avaliando sua disponibilidade, perspectivas e aplicações em laboratórios de produção e controle da qualidade. Método: Foi realizada uma busca nas bases PubMed, BVS e Scopus entre novembro de 2021 e junho de 2022. Foram identificados 89 trabalhos, dos quais 31 foram selecionados de acordo com os critérios de elegibilidade. Resultados: Nos métodos alternativos identificados, observamos a preferência de 42,80% dos estudos por metodologias que utilizem linhagens celulares como método alternativo aos ensaios murinos, sendo que a maioria destes trabalhos 58,30% optou pela linhagem celular Vero. Conclusões: Pela diversidade das toxinas encontradas em cada gênero de serpentes, entende-se que é de extrema importância que o ensaio de potência dos antivenenos tenha como base a avaliação e a quantificação precisa da inibição da atividade biológica dos venenos. Ensaios de citotoxicidade são amplamente utilizados e têm acumulado evidências de sua adequação como importante ferramenta alternativa ao ensaio murino para o controle da qualidade de veneno e antiveneno antibotrópico.

Introduction: Accidents with venomous animals are classified as neglected tropical diseases and are currently the most frequent cause of intoxication in humans in Brazil. The only available treatment is the rapid administration of specific, quality-assured antivenoms. To ensure the efficacy and safety of these products, in vivo potency determination tests for venom and antivenom are performed during the production stages, until final release. Despite several studies on alternative methods to the murine assay, no method has been effectively validated. Objective: To compile alternative methods developed for Bothrops antivenoms, assessing the availability of the methods and the prospects and applications in Bothrops venom and antivenom production and quality control laboratories. Method: A search was conducted in PubMed, BVS, and Scopus databases between November 2021 and June 2022. 89 articles were identified, of which 31 were selected according to the eligibility criteria. Results: We observed in the alternative methods identified a preference of 42.80% of the studies for methodologies that use cell lines as an alternative method to the murine assays, and most of these works (58.30%) opted for a VERO cell line. Conclusions: Due to the diversity of toxins found in each genus of snakes, it is understood that the potency assay for antivenoms should be based on the evaluation and precise quantification of the inhibition of biological activity of venoms. Cytotoxicity assays are widely used and have been accumulating evidence of their suitability as an important alternative tool to the murine assay for quality control for Bothrops venom and antivenom.

Peri-implant health after supportive mucositis therapy is associated with increased levels of FGF-2

Abstract This study aimed to analyze Fibroblast Growth Factor-2 (FGF-2) levels in the peri-implant crevicular fluid throughout supportive mucositis therapy. Twenty-six participants with Branemark protocol prosthesis were divided into two groups: the control group, characterized by healthy peri-implants, and the mucositis group, presenting a diagnosis of peri-implant mucositis. All participants underwent clinical examination, radiographic analysis, prosthesis removal, and non-invasive peri-implant therapy (mechanical debridement associated with chlorhexidine 0.12%) during a period of 36 days divided into three intervals. Peri-implant crevicular fluid samples were collected at each interval in order to analyze FGF-2 levels by immuno-enzymatic assay. The control and mucositis groups showed difference in keratinized mucosa. The smaller the range of keratinized mucosa the higher susceptibility of peri-implant mucositis. Throughout the treatment intervals, participants were diagnosed in different groups indicating whether or not the non-invasive therapy was able to treat peri-implant mucositis. There was a significant difference of FGF-2 levels between groups, with the higher FGF-2 levels in the control group (p=0.01). After supportive therapy, the mucositis group showed significantly increased FGF-2 levels (p<0.01) compared to initial levels. After 36 days of supportive therapy, there was a reduction of peri-implant mucositis from 70% to 23%. Clinical and laboratory outcomes showed a clear correlation since FGF-2 levels increased after 36 days. It was concluded that the therapy protocol was effective and promoted a regenerative reaction and FGF-2 can be considered a future target for peri-implant mucositis understanding.

Resumo Este estudo teve como objetivo analisar os níveis de FGF-2 no fluido crevicular peri-implantar durante a terapia de suporte da mucosite. Vinte e seis participantes com prótese protocolo Branemark foram divididos em dois grupos: o grupo controle, caracterizado por saúde peri-implanter, e o grupo mucosite, apresentando diagnóstico de mucosite peri-implantar. Todos os participantes foram submetidos a exame clínico, análise radiográfica, retirada da prótese e terapia não invasiva peri-implantar (debridamento mecânico associado à clorexidina 0,12%) durante um período de 36 dias, dividido em três intervalos. Amostras de fluido crevicular peri-implantar foram coletadas em cada intervalo para análise dos níveis de FGF-2, por ensaio imunoenzimático. Os grupos controle e mucosite não apresentaram diferença nos parâmetros clínicos, exceto para mucosa queratinizada. Ao longo dos intervalos de tratamento, os participantes foram diagnosticados em diferentes grupos, indicando se a terapia não invasiva era ou não capaz de tratar a mucosite peri-implantar. Houve diferença significativa dos níveis de FGF-2 entre os grupos, sendo os níveis de FGF-2 maiores no grupo controle (p = 0.01). Após a terapia de suporte, o grupo com mucosite apresentou níveis de FGF-2 significativamente aumentados (p <0.01) em comparação aos níveis iniciais. Após 36 dias de terapia de suporte, houve redução da mucosite peri-implantar de 70% para 23%. Os resultados clínicos e laboratoriais mostraram uma correlação clara, uma vez que os níveis de FGF-2 aumentaram após 36 dias. O protocolo de terapia foi eficaz e promoveu uma reação regenerativa. O FGF-2 pode ser considerado um alvo futuro para o tratamento da mucosite peri-implantar.

Empreender para inovar: oportunidades para atuação na ciência / Entrepreneurship to innovate: opportunities for action in science

Empreender para inovar abre novas possibilidades de aplicação dos conhecimentos adquiridos na academia para o desenvolvimento econômico e social no país. Para isso, é importante que todos os atores do ecossistema relacionados com a Tríplice Hélice da Inovação se integrem para a criação de um ambiente de inovação com mecanismos que auxiliem e acelerem o desenvolvimento sustentável do Brasil. O presente comentário pretende divulgar políticas e iniciativas relevantes dos setores públicos e privados para sua interlocução com vistas a fomentar o empreendedorismo e a inovação; bem como contribuir para a ampliação do conhecimento acerca das oportunidades para a atuação de cientistas nesse contexto.

Entrepreneurship to innovate opens new possibilities for applying knowledge acquired in academia for economic and social development in the country. For this, it is important that all actors in the ecosystem related to the Triple Helix of Innovation integrate to create an innovation environment with mechanisms that help and accelerate the sustainable development of Brazil. This commentary intends to disseminate relevant policies and initiatives from the public and private sectors for their dialogue with a view to fostering entrepreneurship and innovation; as well as contributing to the expansion of knowledge about the opportunities for the work of scientists in this context.

Thiourethane-functionalized fillers: biological properties and degradation resistance

Abstract This study determined the effect of thiourethane-functionalized fillers (TU) on the antimicrobial properties, cytotoxicity, degree of conversion (DC), water sorption (Wsp) and solubility (Wsl) of experimental composites. TU-modified fillers were added at different ratios in experimental composites: 0 (Control-TU0), 25% (TU25), 50% (TU50), 75% (TU75) and 100wt% (TU100). The antimicrobial properties were detected through the exhaustion test and counting of Streptococus mutans colonies for biofilm formation. Cytotoxicity to human gingival fibroblasts was evaluated in three different parameters: XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide), NRU (Neutral Red Uptake assay) and CVDE (Crystal Violet Dye Exclusion test)) at the same cells. ELISA was used to measure the IL-6 and b-FGF biomarkers. DC was determined by Fourier-transformed infrared spectroscopy, while Wsp and Wsl by mass variations. Inhibitory capacity of biofilm formation was not observed for any material. All groups presented at least 70% of cell survival within the observed periods (24h and 7 days). Positive control (toxic) had high IL-6 values and low b-FGF values. No significant variations in DC, Wsp, and Wsl were observed among the experimental groups. The use of thiourethane did not present antimicrobial and cytotoxic activity and the tested materials presented equivalent properties to those conventionally used in dentistry.

In vitro and in vivo biocompatibility of reoss® in powder and putty configurations

Article This study evaluated comparatively two configurations (powder and putty) of a composite biomaterial based on PLGA (Poly(lactide-co-glycolide)/nanoescale hydroxyapatite (ReOss®, Intra-Lock International) through microscopic morphology, in vitro cytotoxicity, biocompatibility and in vivo response as a bone substitute. SEM and EDS characterized the biomaterials before/after grafting. Cytocompatibility was assessed with murine pre-osteoblasts. Osteoconductivity and biocompatibility were evaluated in White New Zealand rabbits. Both configurations were implanted in the calvaria of eighteen animals in non-critical size defects, with blood clot as the control group. After 30, 60 and 90 days, the animals were euthanized and the fragments containing the biomaterials and controls were harvested. Bone blocks were embedded in paraffin (n=15) aiming at histological and histomorphometric analysis, and in resin (n=3) aiming at SEM and EDS. Before implantation, the putty configuration showed both a porous and a fibrous morphological phase. Powder revealed porous particles with variable granulometry. EDS showed calcium, carbon, and oxygen in putty configuration, while powder also showed phosphorus. After implantation EDS revealed calcium, carbon, and oxygen in both configurations. The materials were considered cytotoxic by the XTT test. Histological analysis showed new bone formation and no inflammatory reaction at implant sites. However, the histomorphometric analysis indicated that the amount of newly formed bone was not statistically different between experimental groups. Although both materials presented in vitro cytotoxicity, they were biocompatible and osteoconductive. The configuration of ReOss® affected morphological characteristics and the in vitro cytocompatibility but did not impact on the in vivo biological response, as measured by the present model.

Resumo Este estudo avaliou comparativamente duas configurações (pó e massa) de um biomaterial composto com base de PLGA (Poli(láctico-co-glicólico)/hidroxiapatita em nanoescala (ReOss®, Intra-Lock International) através da morfologia microscópica, citotoxicidade in vitro, biocompatibilidade e resposta in vivo como substituto ósseo. MEV e EDS caracterizaram os biomateriais antes/após o enxerto. A citocompatibilidade foi avaliada em pré-osteoblastos murinos. A osteocondutividade e a biocompatibilidade foram avaliadas em coelhos Branco da Nova Zelândia. Ambas as configurações foram implantadas na calvária de dezoito animais em defeitos não-críticos, com coágulo sanguíneo como grupo controle. Após 30, 60 e 90 dias, os animais foram eutanasiados e os fragmentos contendo os biomateriais e controles coletados. Blocos ósseos foram embebidos em parafina (n=15) destinados às análises histológica e histomorfométrica, e em resina (n=3) destinadas à MEV e EDS. Antes da implantação, a configuração massa mostrou ambas fases morfológicas porosa e fibrosa. O pó revelou partículas porosas com granulometria variável. EDS mostrou cálcio, carbono e oxigênio na configuração massa, enquanto o pó mostrou também fósforo. Após a implantação a EDS revelou cálcio, carbono e oxigênio em ambas configurações. Os materiais foram considerados citotóxicos pelo teste XTT. A análise histológica mostrou nova formação óssea e nenhuma reação inflamatória nos sítios de implante. Entretanto, a análise histomorfométrica indicou que a quantidade de osso neoformado não foi estatisticamente diferente entre os grupos experimentais. Embora ambos os materiais tenham apresentado citotoxicidade in vitro, foram biocompatíveis e osteocondutores. A configuração do ReOss® afetou as características morfológicas e a citocompatibilidade in vitro, porém não impactou a resposta biológica in vivo, como medido pelo presente modelo.

Comparison of primary human gingival fibroblasts from an older and a young donor on the evaluation of cytotoxicity of denture adhesives

Abstract Denture adhesives (DA) improve the retention and stability of ill-fitting dentures, especially for older adults. These materials should be biocompatible, i.e., they cannot cause undesired biological responses and be non-cytotoxic to oral tissues. However, in vitro testing of DA biocompatibility employing primary cell culture may possibly be affected by other factors, such as the donor age. Objective To compare the cytotoxicity of three different denture adhesives when assessed in primary gingival fibroblasts from a young donor or from an older donor, as well as the release of the basic fibroblast growth factor (bFGF), and the inflammatory response marker interleukin-6 (IL-6). Material and Methods Gingival fibroblasts isolated from a 30- and a 62-year-old donor were assayed for proliferation (1-7 days) and sensitivity to latex (positive control). Fibroblasts were indirectly exposed to Corega Ultra (cream), Corega powder and Fixodent Original for a 24 h period and assayed by XTT and Crystal Violet tests. The release of IL-6 and bFGF by exposed cells was determined by ELISA. Results While cells from the young donor presented higher cell growth after 7 days, the sensitivity to increasing concentrations of latex extracts was very similar between young and older cells. Both XTT and CVDE detected no difference between the DA and the control group. All materials induced higher levels of IL-6 and bFGF compared to control. Cells from the older donor exposed to Corega Ultra released lower levels of cytokine and growth factor. Conclusions All materials were considered non-cytotoxic, but affected cytokine and growth factor release. The biological differences found between fibroblasts from both donors could be due to individual or age-related factors. The authors suggest the use of cells from older donors on studies of dental products aimed at older patients, to better simulate their physiological response.

Salivary protein polymorphisms and risk of dental caries: a systematic review

Abstract Dental caries is an oral pathology associated with both lifestyle and genetic factors. The caries process can be influenced by salivary composition, which includes ions and proteins. Studies have described associations between salivary protein polymorphisms and dental caries experience, while others have shown no association with salivary proteins genetic variability. The aim of this study is to assess the influence of salivary protein polymorphisms on the risk of dental caries by means of a systematic review of the current literature. An electronic search was performed in PubMed, Scopus, and Virtual Health Library. The following search terms were used: “dental caries susceptibility,” “dental caries,” “polymorphism, genetics,” “saliva,” “proteins,” and “peptides.” Related MeSH headings and free terms were included. The inclusion criteria comprised clinical investigations of subjects with and without caries. After application of these eligibility criteria, the selected articles were qualified by assessing their methodological quality. Initially, 338 articles were identified from the electronic databases after exclusion of duplicates. Exclusion criteria eliminated 322 articles, and 16 remained for evaluation. Eleven articles found a consistent association between salivary protein polymorphisms and risk of dental caries, for proteins related to antimicrobial activity (beta defensin 1 and lysozyme-like protein), pH control (carbonic anhydrase VI), and bacterial colonization/adhesion (lactotransferrin, mucin, and proline-rich protein Db). This systematic review demonstrated an association between genetic polymorphisms and risk of dental caries for most of the salivary proteins.

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

ABSTRACT Objective The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA) microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA). Material and Methods The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group) (n=5/period/group). After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance. Results The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA, p<0.05) indicating greater biosorption. An increase in the RANKL/OPG ratio was observed in the CHA group on the 7th day. Conclusion CHA spheres were osteoconductive and presented earlier biosorption, inducing early increases in the levels of proteins involved in resorption.

Effect of time of extraction on the biocompatibility of endodontic sealers with primary human fibroblasts

The aim of this work was to evaluate the effects of different times of extraction on the cytotoxicity of six representatives of different root canal sealer groups-Real Seal SE, AH Plus, GuttaFlow, Sealapex, Roth 801, and ThermaSeal Plus-with human gingival fibroblasts. The materials were prepared according to manufacturers' specifications, and were incubated in culture medium (DMEM) at 37ºC for 1, 7, 14, 21, and 28 days, with daily washing, to simulate periodontal ligament clearance. Human fibroblasts were exposed to the final extracts at 24 hours, and cell viability was determined by MTT assay, with exposure to unconditioned DMEM as a negative control. Statistical analysis comparing cytotoxicities at each exposure time was performed by ANOVA with Scheffé adjustment for multiple comparisons at a 95% confidence level. Results indicated that GuttaFlow was significantly less cytotoxic than all other sealers (p < 0.05) at 1 day of extraction. After 7 days of extraction, cell viability for GuttaFlow was significantly increased as compared with that of all groups except sealer AH Plus. At day 14, cytotoxicity of Sealapex was significantly higher than that of all other sealers (p < 0.05). At days 21 and 28, there were no significant differences in cytotoxicity among sealer groups. All materials presented some level of cytotoxicity to fibroblasts, while GuttaFlow was the least cytotoxic sealer tested. However, the cytotoxicity of all materials seemed to decrease similarly in a time-dependent manner.

Citocompatibilidade do cimento reparador ceramicrete em cultura primária de osteoblastos humanos / Cytocompatibility of the ceramicrete repair cement in primary culture of human osteoblasts

Ainda são muito raras as informações sobre a resposta de osteoblastos humanos ao Ceramicrete (CC), um material proposto para ser usado como cimento reparador que apresenta características bastante promissoras. Assim, o objetivo do presente estudo foi verificar o grau de citocompatibilidade do CC em culturas primárias de osteoblastos humanos. Para isso, foi utilizado um modelo experimental baseado na quantidade de material usado em uma retro-obturação, criando condições mais próximas a situação clínica real. Retrocavidades obturadas com CC foram colocados em poços de cultura contendo meio de cultura (α-MEM), por 24h (n=4). Meios de cultura contendo dentes retro-obturados com ProRoot MTA e OZE foram usados como controle negativo e positivo, respectivamente. Todos os meios foram armazenados. Posteriormente, foram cultivados osteoblastos humanos (2 x 104 células/amostra), por 24h, em poços com os meios armazenados dos 3 materiais. Foi avaliada a citocompatibilidade utilizando um Kit específico (Cytotox Kit, Xenometrix, Alemanha), que possibilita o estudo de 3 parâmetros (XTT, NR e CVDE) utilizando a mesma amostra. Foi encontrada uma diferença estatisticamente significativa entre os 3 materiais para todos os 3 parâmetros avaliados (ANOVA, p< 0,05). O CC e o MTA foram sempre estatisticamente superiores ao OZE (Duncan, p<0,05). Entretanto, não foram encontradas diferenças entre os 2 cimentos reparadores, CC e MTA (Duncan, p> 0,05). Portanto, pode-se concluir que o Ceramicrete expressa um padrão de citocompatibilidade similar a do MTA, em cultura primária de osteoblastos humanos, quando usado como material retro-obturador.

Ceramicrete is an endodontic material with very promising characteristics. However, information about the response of human osteoblasts to CC is very rare. So, the purpose of this study was to assess the cytocompatibility of CC in primary cultures of human osteoblasts. For this, we used a modelo f retro-obturation, creating conditions close to real clinical situation. The apical portions of canines were retro-obturated with CC or control materials. The, the teeth were placed in Wells containing culture médium (α-MEM) for 24h (n=4). ProRoot MTA and ZOE were used as negative and positive controls, respectively. All media were stored. Subsequently, human osteoblasts were cultured (2x104 cells) for 24 h in Wells with the stored medium. The cytocompatibility was evaluated using a specific kit (Cytotoxic, Xenometrix, Germany), which enables the study of three parameters of cell viability using the same sample (CTT, NR and CVDE). It was found significant difference among the three materials Fo all parameters (ANOVA, p> 0.05). The CC and the MTA were always statistically superior to ZOE (Duncan, p> 0.05). However, no differentes were found between the two cements, CC and MTA (Duncan, p> 0.05). It can be concluded that CC is an endodontic cement as cytocompatible as MTA when used as a retro-obturation material in primary cultures of human osteoblasts.

Avaliação multiparamétrica da citotoxicidade in vitro de um fio ortodôntico à base de resina polimérica reforçada com fibra de vidro / Multiparametric cytotoxicity in vitro evaluation of a glass fiber-reinforced composite orthodontic archwire

O objetivo deste trabalho é avaliar a citotoxicidade dos fios ortodônticos estéticos feitos à base de resina polimérica reforçada com fibras de vidro, por três diferentes parâmetros de viabilidade celular. Foram preparados, de acordo com normas internacionais, extratos de amostras do fio Optis® Preformed Archwire intactos ou multiseccionados (em seções de 10 mm) e, como referência, fios de aço inoxidável do mesmo fabricante. Fenol a 2% e poliestireno denso foram utilizados como controle negativo e positivo respectivamente. Células de fibroblastos de camundongo da linhagem Balb/c-3T3 foram expostas por 24 horas a esses extratos, e a viabilidade celular foi identificada por três parâmetros: atividade mitocondrial, a partir do método do XTT, integridade membranar, pela captação do corante vermelho neutro e densidade celular, por meio do teste de exclusão do corante cristal violeta. Os extratos dos fios (aço inoxidável e fio em resina reforçada por fibra de vidro) foram compatíveis com altos índices de viabilidade celular medido através dos três diferentes parâmetros, sem diferenças estatísticas significativas entre os grupos. O processamento do fio estético em pequenas secções não alterou sua biocompatibilidade medida pelos mesmos métodos, indicando não haver diferença de toxicidade entre sua face externa de resina e seu interior reforçado em fibra de vidro. De acordo com os parâmetros avaliados, o fio estético não apresentou citotoxicidade, similar ao aço inoxidável já em largo uso ortodôntico. No entanto, novos parâmetros devem ser investigados para validá-lo, tanto com relação a aspectos biológicos como a aspectos físicos mais relacionados à sua eficiência na ortodontia.

The purpose of this paper is evaluate the cytotoxicity of orthodontic archwires on polymeric resin reinforced with glass fiber, by three different cell viability parameters. According to international standards, extract samples of Optis® Preformed Archwire, both intact and sectioned into 10 mm pieces and, as reference, of stainless steel archwires, form the same manufacturer. 2% phenol and dense polystyrene were employed as a positive and negative control respectively. Balb/c-3T3 mouse fibroblasts were exposed by 24 hours to the extracts and cell viability was assayed by three parameters: mitochondrial activity (XTT), membrane integrity, measured by Neutral red uptake, and cell density as measured by the Violet Crystal dye exclusion test. Both archwires (stainless steel and fiber glass reinforced resin) were consisted with high levels of cell viability as measured by the three tests, without significative statistical differences among groups. Wire processing by cutting into little sections did not change biocompatibility as measured by the same methods, suggesting that there is no difference between the resin external face and the internal glass fiber reinforced interior. According to the evaluated parameters, the esthetic archwire does not presented cytotoxicity levels, similar to those obtained with a material widely employed in orthodontics. However, other parameters should be investigated in order to validate this material, both related to biological aspects, as well as physical characteristics more associated to its efficacy in orthodontics.

Estudo preliminar da influência do laser de baixa intensidade (GaAlAs) na proliferação de células derivadas de polpa dental decídua humana / Preliminary analysis of the influence of low intensity laser (GaAlAs) in proliferation of human deciduous dental pulp derived cells

O objetivo deste trabalho foi verificar in vitro a influência da fototerapia a laser na biomodulação da proliferação de células derivadas de polpa dental decídua humana. Células derivadas de polpa dental decídua humana (densidade = 8,5x103 células/cm2, passagem 13) foram divididas em dois grupos experimentais: Laser (irradiação diária de laser de GaAlAs na dose de 2,5 J/cm2) e Controle (sem irradiação). O ensaio de proliferação multiparamétrico foi realizado com três técnicas consecutivas de avaliação da viabilidade celular: XTT (atividade mitocondrial), vermelho neutro (integridade lisossomal) e cristal violeta (inclusão em DNA), nos períodos de 12 horas, 1, 3, 5 e 7 dias. Os resultados mostraram aumento significativo (p < 0,001) da redução de XTT no grupo Laser (0,929 ± 0,224) em comparação com o grupo Controle (0,495 ± 0,204) em 7 dias; pico máximo da captação de vermelho neutro no grupo Controle aos 3 dias (p < 0,05) e do grupo Laser em 5 dias; a proliferação celular foi constante e progressiva até o período de 7 dias, semelhante em ambos os grupos. Considerando os resultados obtidos concluiu-se que o laser de baixa intensidade biomodula positivamente a atividade mitocondrial de células derivadas de polpa dental decídua humana, porém sem afetar a taxa de proliferação celular.

The aim of this study was to evaluate, in vitro, the influence of laser phototherapy in biomodulation of proliferation for human deciduous dental pulp derived cells. Human deciduous dental pulp derived cells (density = 8,5x103 cells/cm2, passage 13) were separated in two experimental groups: Laser (daily GaAlAs laser irradiation with a 2,5 J/cm2 dose) and Control (without irradiation). The multiparametric proliferation assay was effectuated with three successive techniques for cell viability evaluation: XTT (mitochondrial activity), neutral red (lisossome integrity) and crystal violet (DNA inclusion), during 12 hours, 1, 3, 5 and 7 days. Our results showed a significant increase of mean absorbance of XTT of Laser (0.929 ± 0.224) in comparison with Control (0.495 ± 0.204) in 7 days; maximal uptake of neutral red at 3 days (p < 0.05) for Control and 5 days for Laser group; a constant and progressive cell growth up to 7 days, similar in both groups. On the basis of these findings, it is possible to conclude that the low intensity laser biomodulates positively the mitochondrial activity of human deciduous dental pulp derived cells without, however, significant effects on cell proliferation rates.