AIM: To compare bacterial leakage in root canals obturated with the modified single-cone, lateral condensation, and continuous wave of condensation techniques. METHODS: Distobuccal root canals of maxillary molars were shaped up to ProTaper F2 and obturated with modified singlecone, lateral condensation or continuous wave of condensation technique. Two-chamber bacterial model using Enterococcus faecalis was employed for bacterial leakage evaluation for 30 days. The chi-square test was applied to evaluate differences between turbid and non-turbid samples, and the Kruskal-Wallis test was used for evaluating the time necessary for microleakage. A significance level of 5% was set for all analyses. RESULTS: The modified single-cone technique showed leakage in 73.3% of samples, lateral condensation in 66.6%, and continuous wave of condensation in 53.3%, but there were no significant differences among the groups (p>0.05). CONCLUSIONS: It can be concluded that the modified single-cone technique shows similar sealing efficacy to that of lateral condensation and continuous wave of condensation technique.

OBJETIVO: O presente estudo verificou o efeito antibacteriano do hidróxido de cálcio e do iodofórmio em Enterococcus faecalis com diferentes tempos de exposição, avaliando as alterações morfológicas bacteriana. MÉTODOS: A ação antibacteriana foi investigada através de caldo de cultura após zero, sete, 14 e 21 dias, e assim, 5 mL das amostras do sétimo dia foram analisadas morfologicamente por microscopia eletrônica de transmissão. Os dados da ação antibacteriana em caldo foram analisados pelo teste Exato de Fisher. RESULTADOS: Os resultados revelaram que entre o 7º e o 14º dia houve diminuição do crescimento bacteriano com ambos os medicamentos (P=0,098), onde a eliminação bacteriana ocorreu entre o 14º e 21º dia. A microscopia eletrônica de transmissão apresentou alterações na estutura morfolófica bacteriana. CONCLUSÃO: Pode-se concluir que ambos os medicamentos destroem o Enterococcus faecalis com tempo de exposição de 7 a 14 dias, onde a viabilidade celular não é observada após este período devido alterações irreversíveis na morfologia celular bacteriana.

PURPOSE: The aim of this study was to verify the antimicrobial effect of calcium hydroxide and iodoform on Enterococcus faecalis with different exposure times evaluating the bacterial morphologic alterations. METHODS: The antibacterial action was investigated in culture broth after zero, seven, fourteen and twenty-one days. Five mL samples were analyzed morphologically on the seventh day by transmission electron microscopy. The data of the antibacterial test were analyzed by Fisher's exact test. RESULTS: The results revealed that between the seventh and fourteenth day, there was a decrease in bacterial growth with both medicaments (P=0.098), where they were eliminated between the fourteenth and twenty-first day. Transmission electronic microscopy showed alterations in the morphologic structures. CONCLUSION: It concluded that both medicaments kill Enterococcus faecalis, with an exposure time of 7 to 14 days, where no cell viability is seen after this period due to irreversible alterations in bacterial cell morphology.

OBJETIVO: O objetivo deste estudo foi avaliar a resposta inflamatória causada pela implantação do iodofórmio ou hidróxido de cálcio em dorso de ratos. Estas drogas podem ser usadas como curativo intracanal para eliminar bactérias residuais do sistema de canal radicular. METODOLOGIA: Foram utilizados 20 ratos albinos (Rattus norvegicus, var Wistar) e divididos em 4 grupos: grupo controle 1 (CG1) representado por tecido normal íntegro; grupo controle 2 (CG2) com ferida e sem medicação; nos grupos 3 e 4, Iodofórmio (IG) e hidróxido de cálcio (CHG) foram, respectivamente, inseridos nas feridas. Após três, cinco e onze dias, cortes microscópicos das áreas implantadas foram observados macroscópica e microscopicamente quanto a seus aspectos qualitativos e quantitativos. RESULTADOS: Na análise macroscópica, o CHG mostrou uma grande área de necrose e edema, o que diminuiu progressivamente, no GI, a presença de iodofórmio rodeada por tecido normal foi observado. A análise qualitativa e quantitativa histológica mostrou que IG promoveu um prazo mais curto na resposta inflamatória do que o CHG. CONCLUSÃO: A reação inflamatória de iodofórmio teve um período de pico de cinco dias após a inserção de drogas. Em comparação, o hidróxido de cálcio mostrou uma grande área de necrose que só poderia ser parcialmente eliminada após onze dias.

PURPOSE: This study evaluated the inflammatory reaction caused by the implantation of iodoform and calcium hydroxide in the back of rats. These drugs may be used as intracanal dressings to eliminate residual bacteria of the root canal system. METHODS: Twenty albinic rats (Rattus norvegicus, var Wistar) were divided into four groups: control group 1 (CG1) had normal skin; control group 2 (CG2) had wounded tissue without drugs; in groups 3 and 4, iodoform (IG) and calcium hydroxide (CHG) were inserted into the wounds, respectively. After 3, 5 and 11 days, slices of the implanted areas were macroscopically and microscopically observed regarding to their qualitative and quantitative aspects. RESULTS: In the macroscopical analysis, the CHG showed a large area of necrosis and swelling, which progressively decreased; in the IG the presence of iodoform surrounded by normal tissue was observed. The qualitative and quantitative histological analysis showed that IG promoted a shorter delay in the inflammatory response than the CHG. CONCLUSION: The inflammatory reaction for iodoform had a peak period five days after the drug insertion. By comparison, calcium hydroxide showed a very large area of necrosis that could only be partially eliminated after eleven days.