Abstract Dental alloys are widely used in fabrication of removable partial dentures, particularly as a dental framework. The present study aimed at studying the effect of the commercial mouthwashes on the corrosion behavior of the Co−Cr dental casting alloy. Corrosion behavior was investigated in alcohol-free and alcohol-containing mouthwashes added to artificial saliva solutions at room temperature by electrochemical tests recorded the open circuit potential (OCP) and current density, after the surface analysis of the samples was performed. During the early 250s, the OCP values showed significant changes, with the exception of one test group containing alcohol, where potential decreased continuously during the test, which also recorded the highest current density, different from the other groups. It was observed that the presence of alcohol increased the current density and the corrosion process in this alloy and the mouthwashes had more aggressive action in specimens submitted to solutions with alcohol in the composition.

Objective The aim of this study was to evaluate the electrochemical behavior of a cobalt-chromium (Co-Cr) dental alloy after immersion in denture cleansers. Method: Twenty-four specimens (Ø13x2mm) of Co-Cr were produced and divided into three groups (n=8) according to their experimental condition. The group 1 (control group) was composed only of distilled water, group 2 received a hygienic tablet (Corega Tabs™) at the moment that electrochemical test started, while the group 3 received the hygienic tablet (Corega Tabs™) 1h after immersion. The electrochemical tests recorded the open circuit potential (OCP) and current density (icorr). The surfaces of specimens were examined using a SEM. Data were statistically analyzed using analysis of variance (ANOVA) and Duncan test’ multiple comparisons post hoc analysis (α=0.05). Results: The values of OCP and icorr revealed statistically differences between the groups. The highest results were recorded for group 2 (-26.87±48.48mV; 0.29±0.22μA), which were similar to group 3 (-47.37±35.36mV; 0.26±0.10μA), and these values were difference to group 1 (-314.87±24.22mV; 0.50±0.17μA). SEM image show high corrosion with Corega Tabs™. Conclusion: The immersion in denture cleanser solution was not detrimental to the Co-Cr dental alloy and presented a lower tendency to corrosion process development than the control group.

Resumo Neste estudo foi avaliado desajuste vertical, a passividade e a distribuição de tensões após o aperto dos parafusos de diferentes próteses. Dois implantes foram usados para simular a reabilitação do espaço edêntulo da mandíbula do segundo pré-molar ao segundo molar. Quarenta próteses dentárias fixas parafusadas de três elementos com cantilever distal foram confeccionadas e separadas em quatro grupos de acordo com o método de obtenção da infraestrutura (n = 10): G1 = fundição convencional estrutura monobloco, G2 = fundição convencional seccionada e soldagem a laser, G3 = fundição convencional seccionada e soldagem com gás inerte de tungstênio (TIG) e G4 = infraestrutura obtida pelo sistema CAD / CAM (computer-aided design/computer-aided manufacturing). Os desajustes verticais com ambos os parafusos apertados e os desajustes relativos à avaliação de passividade com um parafuso apertado foram medidos com microscópio comparador óptico. Os dados foram submetidos ao teste de Shapiro-Wilk para comparação com ANOVA seguida de ajuste de Tukey com Bonferroni (α = 0,05). A análise qualitativa da distribuição de tensões foi realizada pelo método fotoelástico. G2 (24 μm) e G3 (27 μm) apresentaram valores significativamente maiores que G4 (10 μm) (p = 0,006) de desajuste vertical (ambos os parafusos apertados). Os valores de desajustes nos G1 (64 μm) e G3 (61 μm), do lado não apertado, foram significativamente maiores que no G4 (32 μm) (p = 0,009). G1 apresentou maior tensão entre os implantes na análise fotoelástica e G4 apresentou menor tensão. O método CAD/CAM resultou em menor desajuste, maior passividade e melhor distribuição de tensões no osso.

Abstract This study evaluated the vertical misfit, passivity, and stress distribution after tightening the screws of different prosthesis. Two implants were used to simulate the rehabilitation of partially edentulous mandible space from the second premolar to the second molar. 40 three-element screw-retained fixed dental prosthesis with distal cantilever were fabricated and divided into four groups according to the method of production of framework (n = 10): G1 = conventional casting one-piece framework, G2 = conventional casting sectioned and laser welding, G3 = conventional casting sectioned and tungsten inert gas (TIG) welding and G4 = framework obtained by CAD/CAM (computer-aided design/computer-aided manufacturing) system. The vertical misfits (both screws tightened) and the passive fit (one screw tightened) were measured under a comparator optical microscope. The data was submitted to Shapiro-Wilk test to enable comparison with ANOVA followed by Tukey with Bonferroni adjust (α = .05). The qualitative analysis of the stress distribution was performed by the photoelastic method. The vertical misfit (both screws tightened) of the G2 (24 μm) and G3 (27 μm) were significantly higher than G4 (10 μm) (p = 0,006). The passive fit (for the non-tightened) of the G1(64 μm) and G3 (61 μm) were significantly higher than the G4 (32 μm) (p=0,009). G1 showed high stress between the implants in the photoelastic analysis and G4 presented lower stress. In conclusion, CAD/CAM method results in less vertical misfit, more passivity, and consequently better stress distribution to the bone.

Resumo Os efeitos dos fármacos anti-inflamatórios não esteroidais (AINEs) sobre a quantidade e qualidade óssea tem sido investigados ao longo dos anos.Entretanto, há falta de informação sobre o impacto dos AINEs na qualidade do osso alveolar de suporte na ausência de inflamação periodontal. Assim, o objetivo deste estudo foi avaliar, histometricamente, a influência de um AINE seletivo para COX-2 (Meloxicam) na densidade mineral óssea inter-radicular em ratos. Quarenta e nove ratos Wistar, machos e adultos foram divididos aleatoriamente em quatro grupos experimentais: injeções subcutâneas de 0,9% de solução salina estéril por 15 dias (G1, n=12) e 45 dias (G2, n=11); e injeções subcutâneas de Meloxicam por 15 (G3, n=13) e 45 dias (G4, n=13). A densidade mineral foi determinada histometricamente na área inter-radicular dos primeiros molares mandibulares e a análise dos dados realizada por meio de ANOVA (a=5%). Os resultados mostraram nenhuma interação entre tempo e tratamento (p>0,05) e que o meloxicam não afetou a densidade óssea alveolar. Em contraste, foi encontrado que a densidade óssea alveolar inter-radicular aumentou ao longo do tempo (91,88±3,08% e 92,86±2,38% para os grupos 15 e 45 dias, respectivamente) (p<0,05). Dentro dos limites deste estudo, a administração diária de um inibidor seletivo para COX-2 (Meloxicam) não afetou a qualidade do osso alveolar inter-radicular na ausência de infecção periodontal.

Abstract The effects of the non-steroidal anti-inflammatory drugs (NSAIDs) on bone quantity and quality were investigated for years. However, there is lack of information on the impact of NSAIDs on the quality of tooth-supporting alveolar bone in absence of periodontal inflammation. Thus, the aim of this study was to evaluate histometrically the influence of a selective COX-2 NSAID (Meloxicam) on the inter-radicular bone mineral density in rats. Forty-nine adult male Wistar rats were randomly divided into four experimental groups: Subcutaneous injection of 0.9% sterile saline for 15 days (G1; n=12) and 45 days (G2; n=11); and subcutaneous injection of Meloxicam for 15 days (G3; n=13) and 45 days (G4; n=13). Mineral density was histometrically determined in the inter-radicular area of the 1st mandibular molars and data analysis performed by two-way ANOVA (a=5%). Results showed no interaction between time and treatment (p>0.05) and that meloxicam did not affect the alveolar bone density. In contrast, it was found that inter-radicular alveolar bone density increased with time (91.88±3.08% and 92.86±2.38% for groups 15 and 45 days, respectively) (p<0.05). Within the limits of this study, daily administration of a selective COX-2 inhibitor (Meloxicam) did not affect the quality of the inter-radicular alveolar bone in absence of periodontal infection.

Resumo Esta pesquisa avaliou a influência dos cimentos temporários (contendo eugenol [CE]ou livre de eugenol[LE]) na resistência à tração de copingsde Ni-Cr fixados com cimento resinoso auto-adesivo sobre substrato coronário metálico. Trinta e seis coroas provisórias foram divididas em 4 grupos (n=9) de acordo com os cimentos temporários: Provy, Dentsply (contendo eugenol), Temp Cem, Vigodent (contendo eugenol), RelyXTemp NE, 3M ESPE (livre de eugenol) andTemp Bond NE, KerrCorp (livre de eugenol). Após 24 h da cimentação temporária, testes de resistência à tração foram realizados em uma máquina universal de ensaios, com velocidade de 0,5 mm/min. e célula de carga de 1kN (100 kgf). Em seguida, os núcleos metálicos fundidos foram limpos por meio de raspagem com cureta ejatos de ar. Trinta e seis copings de Ni-Cr foram cimentados sobre os núcleos metálicos com cimento resinoso auto-adesivo (RelyX U200, 3M ESPE). Testes de resistência à tração foram novamente realizados. Na cimentação provisória, Temp Bond NE (12,91±2,54) e Temp Cem (12,22±2,96) apresentaram os maiores valores de resistência à tração e foram estatisticamente semelhantes entre si (p>0,05). Diferença estatisticamente significante (p<0.05) foi observada apenas entre Provy (164,44±31,23) e Temp Bond NE (88,48±21,83)após cimentação dos copingsdeNi-Cr com cimento resinoso auto-adesivo. Além disso, Temp Cem (120,68±48,27) e RelyX Temp NE (103,04±26,09) mostraram valores intermediários de resistência à tração. Em conclusão, o cimento temporário contendo eugenol, Proxy, foi associado com a mais alta resistência de união do cimento resinoso, quando os copingsde Ni-Cr foram cimentados sobre os núcleos metálicos fundidos. Entretanto, o eugenol não pode ser considerado como um fator determinante no aumento da resistência de união, já que outros cimentos testados (1 contendo eugenol e 2 livres de eugenol) foram semelhantes.

This research evaluated the influence of temporary cements (eugenol-containing [EC] or eugenol-free [EF]) on the tensile strength of Ni-Cr copings fixed with self-adhesive resin cement to the metal coronal substrate. Thirty-six temporary crowns were divided into 4 groups (n=9) according to the temporary cements: Provy, Dentsply (eugenol-containing), Temp Cem, Vigodent (eugenol-containing), RelyX Temp NE, 3M ESPE (eugenol-free) and Temp Bond NE, Kerr Corp (eugenol-free). After 24 h of temporary cementation, tensile strength tests were performed in a universal testing machine at a crosshead speed of 0.5 mm/min and 1 kN (100 kgf) load cell. Afterwards, the cast metal cores were cleaned by scraping with curettes and air jet. Thirty-six Ni-Cr copings were cemented to the cast metal cores with self-adhesive resin cement (RelyX U200, 3M ESPE). Tensile strength tests were performed again. In the temporary cementation, Temp Bond NE (12.91±2.54) and Temp Cem (12.22±2.96) presented the highest values of tensile strength and were statistically similar to each other (p>0.05). Statistically significant difference (p<0.05) was observed only between Provy (164.44±31.23) and Temp Bond NE (88.48±21.83) after cementation of Ni-Cr copings with self-adhesive resin cement. In addition, Temp Cem (120.68±48.27) and RelyX Temp NE (103.04±26.09) showed intermediate tensile strength values. In conclusion, the Provy eugenol-containing temporary cement was associated with the highest bond strength among the resin cements when Ni-Cr copings were cemented to cast metal cores. However, the eugenol cannot be considered a determining factor in increased bond strength, since the other tested cements (1 eugenol-containing and 2 eugenol-free) were similar.

This research evaluated the fungistatic and fungicidal activities of red propolis alcoholic extract (RPAE) against different Candida species isolated from chronic periodontitis cases, and compared with chlorhexidine (CHX). Nineteen samples of Candida species (C. albicans [n = 12], C. tropicalis [n = 5] andC. glabrata[n = 2]) isolated from chronic periodontitis cases were analyzed. The fungistatic and fungicidal activity of both RPAE and CHX were evaluated using fluconazole and C. parapsilosis (ATCC 6258) as a control. Fungistatic activity was analyzed based on the Clinical and Laboratory Standards Institute (CLSI) reference procedure to determine the minimum inhibitory concentrations. Fungicidal activity was established according to the absence of fungal growth on Sabouraud Dextrose Agar medium. The fungistatic and fungicidal activities of RPAE were observed, respectively, at 32-64 μg/mL and 64-512 μg/mL for C.albicans, 64 μg/mL and 64-256 μg/mL for C. glabrata, and 32-64 μg/mL and 64 µg/mL for C. tropicalis. CHX fungistatic activity was observed at concentrations of 0.003-1.92 µg/mL for C. albicans, 1.92 µg/mL for C. glabrata, and 0.03-1.92 µg/mL for C. tropicalis. Fluconazole fungistatic activity ranged between 1-64 μg/mL, and fungicidal activity occurred at 8-64 μg/mL, for the threeCandida species analyzed. All the Candidaspecies were susceptible to RPAE antifungal activity, but five samples ofC.albicans, one ofC.tropicalis and one ofC.glabrata were resistant to fluconazole antifungal activity. CHX showed fungistatic activity against all the Candida species analyzed. The antifungal potential of these substances suggests that they can be applied as an alternative treatment for diseases affected by these species.