RESUMO
The addition of chlorhexidine (CHX) to a resinous experimental Mineral Trioxide Aggregate (E-MTA) based root-end filling material is an alternative to boost its antimicrobial activity. However, the influence of chlorhexidine on the properties of this material is unclear. The aim of this study was to evaluate the influence of 2% chlorhexidine on the pH, calcium ion release and setting time of a Bisphenol A Ethoxylate Dimethacrylate/Mineral Trioxide Aggregate (Bis-EMA/MTA) based dual-cure experimental root-end filling material (E-MTA), in comparison with E-MTA without the addition of CHX and with conventional white MTA (W-MTA). The materials were placed in polyethylene tubes, and immersed in deionized water to determine pH (digital pH meter) and calcium ion release (atomic absorption spectrometry technique). The setting time of each material was analyzed using Gilmore needles. The data were statistically analyzed at a significance level of 5%. E-MTA + CHX showed an alkaline pH in the 3 h period of evaluation, the alkalinity of which decreased but remained as such for 15 days. The pH of E-MTA + CHX was higher than the other two materials after 7 days, and lower after 30 days (p < 0.05). All of the materials were found to release calcium ions throughout the 30 days of the study. The addition of CHX increased the calcium ion release of E-MTA to levels statistically similar to W-MTA. E-MTA showed shorter initial and final setting time, compared with W-MTA (p < 0.05). The addition of 2% CHX to MTA prevented setting of the material. The addition of CHX to E-MTA increased its pH and calcium ion release. However, it also prevented setting of the material.
Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Cálcio/química , Clorexidina/química , Metacrilatos/química , Óxidos/química , Materiais Restauradores do Canal Radicular/química , Silicatos/química , Análise de Variância , Combinação de Medicamentos , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Imersão , Teste de Materiais , Valores de Referência , Estatísticas não Paramétricas , Fatores de TempoRESUMO
The objective of the present study was to evaluate the antimicrobial activity of sodium hypochlorite (NaOCl) associated with a surfactant. Seventy single-rooted extracted human teeth were inoculated with Enterococcus faecalis, and incubated for 21 days (37 °C). The groups were distributed according to the irrigation solution used during root canal preparation: 5%, 2.5% and 1% NaOCl; 5%, 2.5% and 1% Hypoclean(r), a solution containing a surfactant (cetrimide) associated with NaOCl. Three microbiological samples were collected from each tooth: S1 - before instrumentation; S2 - immediately after instrumentation; and S3 - after a seven-day period. Data were submitted to ANOVA and Tukey test with 5% significance level. The results showed that immediately after root canal preparation (S2), E. faecalis was eliminated in all the experimental groups. However, after 7 days (S3), only the groups in which Hypoclean was used, remained contamination-free, including Hypoclean associated with 1% NaOCl, while the root canals irrigated with 1% NaOCl only, presented the highest percentage of bacterial growth. In conclusion, the addition of surfactant increased the antimicrobial activity of 1% NaOCl to levels similar to 5% NaOCl.
O objetivo da presente pesquisa foi avaliar a atividade antimicrobiana de hipoclorito de sódio (NaOCl), associado a um tensoativo. Setenta dentes humanos monorradiculares extraídos foram inoculados com Enterococcus faecalis e incubados durante 21 dias (37 °C). Os grupos foram distribuídos de acordo com a solução irrigadora utilizada no preparo do canal: hipoclorito de sódio a 5%, 2,5% e 1%; Hypoclean(r) a 5%, 2,5% e 1% - uma solução contendo um surfactante (cetrimida) associado com NaOCl. Três amostras microbiológicas foram coletadas de cada dente: S1 - antes de instrumentação; S2 - imediatamente após a instrumentação; e S3 - após um período de sete dias. Os dados foram submetidos à análise de variância e teste de Tukey com 5% de nível de significância. Os resultados mostraram que imediatamente após o preparo do canal radicular (S2), o E. faecalis foi eliminado em todos os grupos experimentais. No entanto, após 7 dias (S3), apenas os grupos em que se utilizou Hypoclean permaneceram livres de contaminação, incluindo Hypoclean 1%, enquanto que os canais radiculares irrigados apenas com hipoclorito de sódio 1% apresentaram a mais elevada percentagem de crescimento bacteriano. Em conclusão, a adição de surfactante aumentou a atividade antimicrobiana de 1% de NaOCl a níveis semelhantes aos do NaOCl 5% .