Titanium (Ti) and its alloys are widely used for medical and dental fields due to their excellent biocompatibility, high corrosion resistance, high specific strength and excellent mechanical properties. Different methods have been developed to improve the surface properties of titanium-based implant materials, and consequently the bone-bonding ability. The Ti-7.5Mo alloy was activated by an alkaline treatment with 5M NaOH, heat treatment and subsequent immersion in SBFx5 to investigate the in vitro response of osteoblastic-like cells MG-G3 on altered biomimetic surfaces. Sample surfaces were characterized by scanning electron microscopy. Cytotoxicity was assessed by the MTT assay, total protein content, alkaline phosphatase activity (ALP) and mineralized bone-like nodule formation. It was shown the que alkali treatment led to the formation of sodium titanate and immersion in SBFx5 formed a film of calcium phosphate. The alkaline treatment and heat treatment of 7.5 Ti-Mo alloys followed by soaking them in SBFx5 for 24 hours is a suitable technique once the final samples were biocompatible, allowed the attachment of the osteoblastic-like cells (MG-G3), and increased the mineralized like-bone nodules formation by these cells.

Resumo Os objetivos desse estudo foram avaliar a citotoxicidade, genotoxicidade, atividade antimicrobiana de dentifrícios dessensibilizantes em comparação com um comum e também a rugosidade superficial do esmalte dentário submetido à escovação com esses dentifrícios. Amostras de três dentifrícios dessensibilizantes (Colgate Sensitive, Sensodyne e Oral B Sensitive) e um dentifrício comum (Colgate) foram colocadas em contato com fibroblastos gengivais humanos e a citotoxicidade e genotoxidade foram mensuradas pelo ensaio MTT e teste do micronúcleo. A atividade antimicrobiana dos extratos dos dentifrícios contra C. albicans, S. mutans e S. aureus foi determinada. Para a avaliação da rugosidade superficial, espécimes de dentes bovinos foram submetidas à 10.000 ciclos de escovação. Os resultados foram analisados estatisticamente usando os testes Mann-Whitney U, ANOVA e Teste Z (P<0,05). Todos os dentifrícios causaram efeito citotóxico às células (P<0,05), exceto o Colgate Sensitive. Os dentifrícios não aumentaram o número de micronúcleos em comparação com o grupo não tratado. O Colgate foi capaz de eliminar todos os microorganismos avaliados em concentrações mais baixas em comparação com Colgate Sensitive e Oral B Sensitive, que não foram capazes de eliminar os S. aureus. O Sensodyne não atingiu a concentração microbicida mínima para qualquer microorganismo. A rugosidade superficial do esmalte dentário aumentou após a escovação com Colgate Sensitive e Oral B Sensitive, porém a comparação entre os grupos não mostrou diferença na rugosidade superficial do esmalte apresentada por dentifrícios dessensibilizantes quando comparados ao comum (p>0,05). Com base nesses resultados, podemos concluir que, embora nenhum dentifrício tenha induzido genotoxicidade, o Colgate Sensitive também não foi citotóxico. O Colgate foi o mais eficaz contra os microorganismos, e não houve diferença na rugosidade superficial do esmalte entre os grupos.

Abstract The aims of this study were evaluate cytotoxicity, genotoxicity, antimicrobial activity of desensitizing toothpastes compared to a common one and the surface roughness of tooth enamel submitted to brushing with these toothpastes. Samples of three desensitizing toothpastes (Colgate Sensitive, Sensodyne and Oral B Sensitive) and common toothpaste (Colgate) were placed in contact with gingival human fibroblasts. Cytotoxicity and genotoxocity were measured by MTT assay and micronucleus test. Antimicrobial activity of the toothpastes extracts against C. albicans, S. mutans and S. aureus were assessed. For surface roughness evaluation, bovine teeth were submitted to 10.000 brushing cycles. The results were analyzed statically using Mann-Whitney U, ANOVA and Z tests (p<0.05). All toothpastes caused cytotoxic effect to the cells (p<0.05), except Colgate Sensitive. The toothpastes did not increase the number of micronuclei compared to the untreated control group. Colgate eliminated all the evaluated microorganisms at lower concentrations compared to Colgate Sensitive and Oral B Sensitive, which were not able to eliminate S. aureus. Sensodyne did not reach the minimum microbicidal concentration. The surface roughness of tooth enamel increased after brushing with Colgate Sensitive and Oral B Sensitive, however the comparison between groups showed no difference on the enamel surface roughness presented by desensitizing toothpastes when compared with the common one (p>0.05). Based on these results, we can conclude that although none toothpaste has induced genotoxicity, Colgate Sensitive was also not cytotoxic. Colgate was the most effective against the microorganisms, and there were no differences on the enamel surface roughness between the groups.

Replacement tissues for tissue engineering can be produced by seeding human cells onto scaffolds. In order to guarantee adequate bio-compatibility, porosity and mechanical resistance for promoting cellular growth, proliferation and differentiation within scaffold structures, it is necessary to investigate and improve materials and processing routes. β-tricalcium phosphate can be considered a very suitable bio-ceramic material for bone therapy because of its biocompatibility, osteo-conductivity and neo-vascularization potential. Alumina is commonly used as a sintering additive. In this study, β-TCP and β-TCP/Al2O3 scaffolds were obtained by gel-casting method. The scaffolds showed high porosity (86-88%) and pore sizes ranging from 200 to 500 µm. Even though alumina did not promote improvement in β-TCP/Al2O3 scaffolds in terms of mechanical performance, they showed great cytocompatibility as there was no cytotoxic and genotoxic effect. Therefore, β-TCP and β-TCP/Al2O3 scaffolds are good candidates for application in tissue engineering.

AIM: To evaluate the influence of ovariectomy combined with lack of masticatory force in the evolution of periodontal disease induced in rats. METHODS: Forty rats were bilaterally ovariectomized and 40 were submitted to sham ovariectomy. Periodontal disease was induced in the mandibular left first molar and the maxillary left first molar was extracted from half of the rats. The rats were randomly euthanized at 3, 7, 14 and 30 days post periodontal disease induction. Serial sections were obtained from the furcation area and stained for histological and histomorphometric analysis. The results of the histomorphometric analysis were statistically analyzed by ANOVA and Tukey tests. RESULTS: The results demonstrated statistically significant differences in the percentage of bone tissue when the variables presence or absence of estrogen (p=0.020) and time of euthanasia (p=0.002) were evaluated. However, the extraction procedure did not significantly affect the percentage of bone tissue (p=0.598). CONCLUSIONS : The bone loss resulting from periodontal disease is increased by estrogen deficiency and varies according to the time course of periodontitis. In contrast, masticatory force does not seem to interfere in bone loss derived from periodontal disease.