Infiltração microbiana em dentes portadores de restaurações provisórias / Microbial leakage in teeth with temporary restorative materials

O objetivo deste estudo foi avaliar a infiltração microbiana em dentes restaurados provisoriamente com omaterial restaurador intermediário (IRM, Intermediate Restorative Material), Cavit ou Vitremer. Para tanto,foram utilizados 50 dentes humanos extraídos unirradiculares, distribuídos aleatoriamente em três gruposexperimentais e dois grupos controle (positivo e negativo). Para o modelo de estudo, empregou-se uma plataforma,dividida em duas partes: câmara superior - onde foi introduzida a suspensão microbiana contendoos indicadores biológicos (E. faecalis + S. aureus + P. aeruginosa + B. subtilis + C. Albicans); e, câmarainferior, com o meio de cultura (Brain Heart Infusion), onde os dentes permaneceram imersos com 5 mm doremanescente apical radicular (correspondente ao terço cervical) durante o período de 60 dias. Observou-sea partir dos resultados, que nos dentes dos grupos 1 (IRM) e 2 (Cavit) ocorreu infiltração microbiana a partirde 7 dias. No grupo 3 (Vitremer) não foi verificada infiltração microbiana no período de 7 a 60 dias.

This study aimed to determine the microbial coronal leakage of temporary restorative materials when employingIRM, Cavit or Vitremer, by means of differents microbial indicators. Thus, 50 single-rooted humanteeth were used, which were shaped until the file size 50 and assigned to 3 experimental groups. Two groupswas used as control. In the study model, a platform was employed, which was split in two halves: an upperchamber - where the microbial suspension containing the biological indicators was introduced (E. faecalis +S. aureus + P. aeruginosa + B. subtilis + C. albicans); and a lower chamber containing the culture mediumBrain Heart Infusion, in which 5 mm of the apical region of teeth (coronal third) were kept immersed. Interpretationsof the time to occur microbial leakage were made daily for 60 days, using the turbidity of the culturemedium which is indicative of microbial contamination, as a reference. The results showed that in the teethfrom groups 1 (IRM) and 2 (Cavit) occurred microbial leakage after 7 days. In the group 3 (Vitremer) it wasnot observed microbial leakage at intervals of 7 to 60 days.

Antimicrobial effect of 2 percent sodium hypochlorite and 2 percent chlorhexidine tested by different methods

The objective of this study was to analyze the antimicrobial effect of 2 percent sodium hypochlorite (NaOCl) and 2 percent chlorhexidine (CHX) by agar diffusion test and by direct exposure test. Five microorganisms: Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans, and one mixture of these were used. These strains were inoculated in brain heart infusion (BHI) and incubated at 37ºC for 24 h. For the agar diffusion test (ADT), 18 Petri plates with 20 ml of BHI agar were inoculated with 0.1 ml of the microbial suspensions, using sterile swabs that were spread on the medium, obtaining growth in junction. Fifty-four paper disks (9 mm in diameter) were immersed in the experimental solutions for 1 min. Subsequently, three papers disks containing one of the substances were placed on the BHI agar surface in each agar plate. The plates were maintained for 1 h at room temperature, and then incubated at 37ºC for 48 h. The diameter of microbial inhibition was measured around the papers disks containing the substances. For the direct exposure test, 162 #50 sterile absorbent paper points were immersed in the experimental suspensions for 5 min, and were then placed on Petri plates and covered with one of the irrigant solutions, or with sterile distilled water (control group). After intervals of 5, 10 and 30 min, the paper points were removed from contact with the solutions and individually immersed in 7 ml of Letheen Broth, followed by incubation at 37ºC for 48 h. Microbial growth was evaluated by turbidity of the culture medium. A 0.1 ml inoculum obtained from the Letheen Broth was transferred to 7 ml of BHI, and incubated at 37ºC for 48 h. Bacterial growth was again evaluated by turbidity of the culture medium. Gram stain of BHI cultures was used for verification of contamination and growth was determined by macroscopic and microscopic examination. The best performance of antimicrobial effectiveness of NaOCl was observed in the direct exposure test, and of CHX was observed in the agar diffusion test. The magnitude of antimicrobial effect was influenced by the experimental methods, biological indicators and exposure time

Açäo antimicrobiana de solventes de guta-pecha / Antimicrobial action of gutta-percha solvents

Estudou-se a açäo antimicrobiana de solventes de guta-percha (halotano, óleo de laranja, eucaliptol e xilol) sobre os microrganismos Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans e uma mistura destes. Duzentos e quarenta cones de papel contaminados foram mantidos em contato com os solventes por períodos de 5, 10, 15 e 30 minutos e, a seguir, transportados para 7mL de Brain Heart Infusion e incubados a 37ºC por 48 horas. Posteriormente, foi analisada a presença ou ausência de turvaçäo, indicativa ou näo de crescimento e multiplicaçäo dos microrganismos. Para a confirmaçäo dos resultados, empregou-se a coloraçäo de Gram. O halotano mostrou efetividade antimicrobiana em todos os tempos de análise para a C. albicans; a partir de 10 minutos para o E. faecalis e P. aeuruginosa; a partir de 15 minutos para o S. aureus e foi inefetivo para o B. subtilis e sobre a mistura. Os demais solventes foram enefetivos sobre todos os microrganismos testados, em todos os períodos de observaçäo