Effect of reciprocating instrumentation on chlorhexidine substantivity on human dentin: chemical analysis followed by confocal laser microscopy

The present research analyzed the reciprocating instrumentation associated to chlorhexidine (CHX) substantivity as its correlation with E. faecalis viability in ex vivo root canals. Eighty extracted single-rooted human teeth were used, being 40 to high-performance liquid chromatography (HPLC) and 40 to confocal laser scanning microscopy (CLSM). In both, teeth were decoronated and the cervical third was prepared. In the CLSM analysis, the root canals were inoculated with E. faecalis for 14 days. Samples were divided into 4 groups (n=10) according to instrumentation technique: no instrumentation and irrigation with distilled water (control); manual instrumentation (K-File); rotary instrumentation (ProTaper Next); and reciprocating instrumentation (Reciproc R25). Two percent chlorhexidine was applied as irrigating substance in experimental groups. Longitudinal grooves resulted in 2 halves root and 20 proof bodies in each group. Samples were divided by chance in two groups (n=10) and the outcomes were evaluated after two days and one week. The retained chlorhexidine and live cells after instrumentation techniques in each evaluation time was measured by HPLC and CLSM, respectively. Specific analysis was applied for experimental tests (p≤0.05). Both rotary as well as reciprocating techniques significantly reduced the amount of chlorhexidine on dentin in all observation periods (p<0.05). After evaluation times, all experimental groups presented lower live cells compared to control, but without statistically difference. Intragroup comparisons in times of evaluation showed no differences in instrumentation techniques, in chlorhexidine retention and number of live cells (p>0.05). Reciprocating instrumentation does not interfere on chlorhexidine substantivity.

Potencial antimicrobiano e caracterização fitoquímica de extratos da casca do caule de Drimys brasiliensis Miers (Winteraceae) / Antimicrobial potential and phytochemical investigation of stem bark extracts from Drimys brasiliensis Miers (Winteraceae)

Introdução: na área da saúde, a resistência aos antimicrobianos tem se constituído um grave problema, fazendo com que a busca por alternativas farmacológicas assuma grande importância. Produtos de origem natural, como extratos de plantas, têm sido pesquisados para uso potencial no tratamento antibacteriano. Drimys brasiliensis Miers (Winteraceae) é uma árvore nativa do Brasil que tem sido utilizada como medicinal. Objetivo: investigar o perfil fitoquímico e a atividade antimicrobiana de amostras obtidas a partir de extratos da casca do caule de Drimys brasiliensis. Metodologia: frações de características químicas variadas foram obtidas a partir de extratos da casca do caule da planta. Realizou-se o screening fitoquímico destas frações através de reações gerais de caracterização e cromatografia em camada delgada. As amostras foram testadas por difusão em ágar e por microdiluição contra bactérias Grampositivas e Gram-negativas e contra uma levedura. Resultados: o perfil fitoquímico mostrou diferenças entre as frações analisadas. Alcaloides foram detectados nas frações mais apolares. Taninos e flavonoides estavam presentes nas amostras mais polares e obtidas sem o uso de calor. As amostras com maior atividade antimicrobiana foram as obtidas com os solventes hexano e diclorometano, de características mais apolares. Destaca-se a atividade contra Bacillus cereus, Staphylococcus epidermidis, Staphylococcus aureus resistente à meticilina e Candida albicans. Conclusão: extratos da casca do caule de Drimys brasiliensis apresentam potencial ntimicrobiano, com destaque para as frações mais apolares contra bactérias gram positivas.

Introduction: in the health field, antimicrobial resistance has been a serious issue, making the search for pharmacological alternatives very important. Natural products, such as plant extracts, have been researched for potential use in antibacterial treatment. Drimys brasiliensis Miers (Winteraceae) is a tree native to Brazil that has been medicinally used. Objective: to investigate the phytochemical profile and antimicrobial activity of samples obtained from Drimys brasiliensis stem bark extracts. Methodology: fractions of different chemical characteristics were obtained from extracts of the stem bark. Phytochemical screening of these fractions was performed by general reactions and thin layer chromatography. Samples were tested by agar diffusion and microdilution against Gram-positive and Gram-negative bacteria and yeast. Results: the phytochemical profile showed differences between the analyzed fractions. Alkaloids were detected in the most nonpolar fractions. Tannins and flavonoids were present in the most polar samples and obtained without the use of heat. The samples with the highest antimicrobial activity were those obtained with hexane and dichloromethane solvents, which present the most nonpolar characteristics. We highlight the activity against Bacillus cereus, Staphylococcus epidermidis, Methicillin resistant Staphylococcus aureus and Candida albicans. Conclusion: Drimys brasiliensis stem bark extracts have antimicrobial potential, especially the most nonpolar fractions against gram positive bacteria.