Resumo Introdução A habilidade da Candida spp. em produzir enzimas proteolíticas, tais como fosfolipase e proteinases, tem um papel importante na patogenicidade destas leveduras. Objetivo Determinar as espécies causadoras das infecções orais por Candida spp., além de investigar a atividade in vitro das fosfolipases e proteinases em isolados clínicos do gênero Candida, provenientes de pacientes com candidíase oral. Material e método Isolados de Candida spp., pertencentes à Coleção de Cultivos Fúngicos do Laboratório de Microbiologia e Patologia Oral do Departamento de Odontologia da Faculdade da Serra Gaúcha, foram analisados. Produção de fosfolipases foi analisada utilizando-se Ágar gema de ovo. Liberação de proteinases foi medida utilizando-se extrato de levedura adicionado à albumina bovina. Resultado Um total de 35 isolados clínicos do gênero Candida foi testado. C. albicans foi a espécie predominante (77%). Os demais isolados identificados foram: C. parapsilosis (20%) e C. tropicalis (2%). Ao comparar a atividade de fosfolipase do grupo C. albicans com o grupo Candida não-albicans, foi encontrada diferença significativa (P=0,04). Não foi encontrada diferença significativa entre a C. albicans e a C. não-albicans, para a produção de proteinase. A liberação de proteinase foi significativamente maior quando comparada à produção de fosfolipase para o gênero Candida (P=0,04). Diferença estatisticamente significativa foi encontrada quando a atividade de fosfolipase e proteinase da C. albicans foi comparada à atividade das espécies de C. não-albicans (P=0,02). Conclusão Diferentes quantificações de fosfolipase extracelular e atividade de proteinase têm sido atribuídas aos isolados clínicos de C. albicans quando comparados a outras espécies de Candida.

Abstract Introduction The ability of the genus Candida to produce secretory enzimes such as proteinase and phospholipases to play an important role in the patogenicity of these yeasts. Objective To determine the Candida species isolates from oral cavity infections and to investigate in vitro phospholipase and protease activities in clinically important of the genus Candida isolated in oral candidiasis patients. Material and method Candida species isolated of the Fungal Culture Collection of Oral Microbiology and Pathology Testing Service Laboratory of the Dentistry Departament of Faculdade da Serra Gaúcha were evaluated. The phospholipases detection was assayed using the egg yolk agar plate method. Determination of protease production was performed in agar plates containing bovine serum albumine and yeasts extract. Result A total of 35 isolates of the genus Candida were tested. C. albicans was the species predominant (77% of isolates), followed by C. parapsilosis (20%) and C. tropicalis (2%). When compared the phospholipase activity of the C. albicans group with the non-albicans Candida species types group was observed significant difference among of this groups (P=0.04). No statiscally significant difference between the C.albicans and non-albicans Candida species types when was compared to proteinase production. Proteinase production was higher and statiscally significant when compared to phospholipase activity in the genus Candida isolates (P=0.04). Statiscally significant differences were found between phosphoplipases and proteases activity for C. albicans when compared to non-albicans Candida species types (P=0.02). Conclusion Differences in the secretion rates of phospholipase extracellular and proteases activity have been attributed to clinical strains of C. albicans when compared to others Candida species types.

Resumo Este estudo avaliou o efeito dos inibidores de metaloproteinase, clorexidina 2% e fluoreto de sódio (5000 ppm), na resistência de união entre a dentina irradiada por laser Er:YAG e a resina composta após a degradação química da interface de união. A superfície oclusal de quarenta molares humanos hígidos (n=10) foi removida expondo uma superfície de dentina, que foi polida, irradiada com laser Er:YAG, condicionada com ácido e seca. Vinte espécimes foram re-umedecidos com clorexidina 2% (Grupo controle) e 20 com fluoreto de sódio (5000 ppm). O sistema adesivo foi aplicado e um platô de resina composta fotopolimerizável de 4 mm de altura foi construído. Palitos de resina-dentina foram obtidos com secção transversal retangular (0,8-1 mm2). Eles foram armazenados em água (24 h a 37 ?#61616;C) ou submetidos a degradação química. Para a degradação química, foram imersos em solução aquosa de hipoclorito de sódio a 10% durante 5 horas e lavados em água durante 1 h. Os palitos foram submetidos ao teste de microtração em uma máquina de ensaios mecânicos a 0,5 mm/min até a fratura. O padrão de fratura foi analisado em MEV. Os valores de resistência de união foram calculados em MPa e submetidos à análise de variância ANOVA (α=0,05). A análise de variância mostrou que os fatores inibidor de metaloproteinases e degradação (p=0,214 e p=0,093, respectivamente), e a interação entre os fatores não foram estatisticamente significantes (p=0,143). A predominância de falha mista foi detectada para todos os grupos. Em conclusão, a clorexidina a 2% e fluoreto de sódio (ppm 5000) apresentaram resistência de união entre dentina irradiada e resina composta semelhante antes e após a degradação química.

Abstract This study evaluated the effect of matrix metalloproteinase (MMP) inhibitors - 2% (CHX) and sodium fluoride (NaF) (5000 ppm) - on microtensile bond strength (μTBS) of composite resin to Er:YAG laser-irradiated dentin after chemical degradation of the bond interface. The occlusal surface of forty sound human molars was removed exposing the dentin surface (n=10), which was polished, irradiated with Er:YAG laser, acid etched and dried. Twenty specimens were rewetted with 2% CHX (control group) and 20 were rewetted with NaF (5000 ppm). The adhesive system was applied and a 4-mm-high plateau of light-cured composite resin was built up. Resin-dentin sticks were obtained with a rectangular cross-sectional area (0.8-1 mm2) and were either stored in water at 37 ?#61616;C for 24 h or submitted to chemical degradation. For chemical degradation, they were immersed in 10% NaOCl aqueous solution for 5 h and rinsed in water for 1 h. The sticks were submitted to microtensile test in a mechanical testing machine at 0.5 mm/min until failure. Fracture pattern was analyzed using SEM. μTBS values were calculated in MPa and submitted to analysis of variance ANOVA (α=0.05). The variance analysis showed that the 'MMP inhibitor' and 'degradation' factors (p=0.214 and p=0.093, respectively) and interaction between the factors were not statistically significant (p=0.143). Mixed failure predominated in all groups. In conclusion, the 2% CHX and NaF 5000 ppm presented similar μTBS of composite resin to laser-irradiated dentin before and after chemical degradation

Este estudo avaliou, in vitro, o potencial erosivo de medicamentos líquidos pediátricos em esmalte de dentes decíduos, em função do tempo de exposição. Sessenta incisivos decíduos foram divididos aleatoriamente em 4 grupos (n=15), de acordo com a solução de imersão: guaifenesina, sulfato ferroso, sulfato de salbutamol e saliva artificial. Os ciclos de imersão nos medicamentos foram realizados sob agitação por 1 min, três vezes ao dia, durante 28 dias. As medidas de microdureza superficial foram realizadas após 7, 14, 21 e 28 dias. A acidez titulável e capacidade tampão dos meios de imersão foram determinadas. Os dados foram submetidos à Análise de Variância e teste de Tukey (α=0,05). O sulfato de salbutamol causou uma perda gradual na microdureza do esmalte decíduo, em todos os tempos verificados (p<0,005). A exposição à guaifenesina ou ao sulfato ferroso levou à diminuição significante da microdureza do esmalte, apenas após 28 dias (p<0,005). No grupo controle (saliva artificial) não houve alteração (p>0,005) da microdureza em nenhum dos tempos estudados. As imagens de microscopia eletrônica de varredura (MEV) revelaram que após 28 dias, as superfícies expostas aos medicamentos apresentaram perda estrutural, diferindo dos que foram imersos em saliva artificial. A erosão do esmalte decíduo foi dependente do tipo de medicamento e do tempo de exposição.

This study evaluated, in vitro, the erosive potential of pediatric liquid medicines in primary tooth enamel, depending on the exposure time. Sixty deciduous incisors were randomly assigned to 4 groups (n=15), according to the immersion solutions: guaifenesin; ferrous sulfate; salbutamol sulfate and artificial saliva. The immersion cycles in the medicines were undertaken under a 1-min agitation, which wasperformed three times daily, during 28 days. Surface microhardness was measured at 7,14, 21 and 28 days. The titratable acidity and buffering capacity of the immersion media were determined. Data were analyzed by Analysis of Variance and Tukey's test (α=0.05). Salbutamol sulfate caused a gradual loss in enamel microhardness deciduous, observed at all times (p<0.005). Exposure to guaifenesin or ferrous sulfate resulted in significant decrease of enamel microhardness only after 28 days (p<0.005). In the control group (artificial saliva), microhardness did not changed (p>0.005) at any of the studied times. Scanning Electron Microscopy (SEM) images revealed that after 28 days the surfaces clearly exhibited structural loss, which was unlike those immersed in artificial saliva. Erosion of deciduous enamel was dependent on the type of medicine and exposure time.

OBJECTIVE: This study evaluated the effect of ferrule preparation (Fp) on the fracture resistance of endodontically treated teeth, restored with composite resin cores with or without glass fiber posts. MATERIAL AND METHODS: Forty-four bovine teeth were sectioned 19 or 17 mm (2 mm ferrule) from the apex, endodontically treated and assigned to four groups (n = 11): Group 1: Fp and post; Group 2: Fp and without post; Group 3: without Fp and with post; Group 4: without Fp and without post. All specimens were restored with composite resin core and metal crown. Specimens were subjected to fracture resistance testing in a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed by two-way ANOVA and Tukey's tests (α=0.05). RESULTS: The mean fracture resistance values were as follows: Group 1: 573.3 N; Group 2: 552.5 N; Group 3: 275.3 N; Group 4: 258.6 N. Significantly higher fracture resistance was found for the groups with Fp (p<0.001). CONCLUSION: There was no statistically significant interaction between the "Fp" and "post" factors (p = 0.954). The ferrule preparation increased the fracture resistance of endodontically treated teeth. However, the use of glass fiber post showed no significant influence on the fracture resistance.

Chemical substances used during biomechanical preparation of root canals can alter the composition of dentin surface and affect the interaction with restorative materials. OBJECTIVE: The purpose of this study was to evaluate the microtensile bond strength (µTBS) of a self-etching adhesive system to dentin irrigated with sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA). MATERIAL AND METHODS: Thirty human third molars were sectioned 3 mm below the occlusal surface, polished with 600- to 1200-grit silicon carbide papers, and randomly divided into 3 groups: G1 (control): no irrigating solution; G2: 1% NaOCl; and G3: 1% NaOCl followed by the application of 17% EDTA. The specimens received the self-etching adhesive system (XENO III - Dentsply), restored with microhybrid composite resin (Z250 - 3M ESPE), sectioned and trimmed to create 4 hourglass-shaped slabs of each tooth. The slabs were tested in microtensile strength in a universal testing machine (Emic DL 2000) at a crosshead speed of 0.5 mm/min until fracture. The results were analyzed statistically by ANOVA and Newman-Keuls test. RESULTS: Mean µTBS values and standard deviations in MPa were: G1 = 11.89 ± 4.22; G2 = 19.41 ± 5.32; G3 = 11.34 ± 4.73. 1% NaOCl increased the adhesive resistance significantly (p<0.001/F=22.5763). The application of 1% NaOCl/17% EDTA resulted in statistically similar µTBS to the control group. CONCLUSIONS: None of the irrigants affected negatively the µTBS of XENO III to dentin. The use of 1% NaOCl alone resulted in higher bond strength than the other treatments. The combination of 1% NaOCl and 17% EDTA produced similar bond strength to that of untreated dentin.