Essential Oil from Psidium cattleianum Sabine (Myrtaceae) Fresh Leaves: Chemical Characterization and in vitro Antibacterial Activity Against Endodontic Pathogens

Abstract Endodontic infections result from oral pathogenic bacteria which reach and infect dental pulp, as well as surrounding tissues, through cracks, unrepaired caries and failed caries restorations. This study aims to determine the chemical composition of essential oil from Psidium cattleianum leaves (PC-EO) and to assess its antibacterial activity against endodontic bacteria. Antibacterial activity of PC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method on 96-well microplates. Bacteria Porphyromonas gingivalis (MIC = 20 µg/mL), Prevotella nigrescens (MIC = 62.5 µg/mL), Fusobacterium nucleatum (MIC = 12.5 µg/mL), Actinomyces naeslundii (MIC = 50 µg/mL), Bacteroides fragilis (MIC = 12.5 µg/mL), Aggregatibacter actinomycetemcomitans (MIC = 6.25 µg/mL) and Peptostreptococcus anaerobius (MIC = 62.5 µg/mL) were evaluated and compared to chlorhexidine dihydrochloride (CDH), the positive control. PC-EO was obtained by hydrodistillation with the use of a Clevenger-type apparatus whereas its chemical composition was analyzed by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Viridiflorol (17.9%), β-caryophyllene (11.8%), 1,8-cineole (10.8%) and β-selinene (8.6%) were the major constituents found in PC-EO, which exhibited high antibacterial activity against all endodontic pathogens under investigation. Therefore, PC-EO, a promising source of bioactive compounds, may provide therapeutic solutions for the field of endodontics.

Antibacterial Activity of Homeopathic Medications Lycopodium clavatum and Arsenicum album Against Periodontal Bacteria / Evaluación antibacteriana de los medicamentos homeopáticos sobre bacterias periodontales

Abstract There are several controversies regarding the efficacy of homeopathic substances; however, these remedies are used in many countries for the treatment of various pathological conditions. The purpose of this study was to evaluate the in vitro antibacterial activity of two homeopathic tinctures Arsenicum album (mineral extract) and Lycopodium clavatum (plant extract) on the periodontal bacteria Actinomyces israelii, Streptococcus sanguinis, Prevotella intermedia, Aggregatibacter actinomycetemcomitans and Phorphyromonas gingivalis (P. gingivalis). Materials and methods: Equal numbers of bacteria were seeded on agar plates containing enriched media with the homeopathic solutions at 1dH and 1cH dilutions. After 7 days of incubation under anaerobic conditions, colony forming units (CFUs) were counted. The antibacterial effect was calculated based on the total number of CFUs observed on non-tincture containing agar, and on the tincture containing plates. Results: No visible growth of any of the strains was observed on the plates containing Arsenicum album at any of the dilutions tested. In contrast, when Lycopodium clavatum at 1cH dilution was tested, only P. gingivalis was susceptible to this compound. Conclusions: The results suggest that the mineral extract tincture had a greater antibacterial activity than the plant extract tincture, also Lycopodium clavatum preparation could be an effective inhibitor of periodontal pathogens bacteria such as P. gingivalis.

Resumen Se necesita un mayor número de estudios in vitro e in vivo para validar estos resultados.

Removal and killing of multispecies endodontic biofilms by N-acetylcysteine

ABSTRACT Removal of bacterial biofilm from the root canal system is essential for the management of endodontic disease. Here we evaluated the antibacterial effect of N-acetylcysteine (NAC), a potent antioxidant and mucolytic agent, against mature multispecies endodontic biofilms consisting of Actinomyces naeslundii, Lactobacillus salivarius, Streptococcus mutans and Enterococcus faecalis on sterile human dentin blocks. The biofilms were exposed to NAC (25, 50 and 100 mg/mL), saturated calcium hydroxide or 2% chlorhexidine solution for 7 days, then examined by scanning electron microscopy. The biofilm viability was measured by viable cell counts and ATP-bioluminescence assay. NAC showed greater efficacy in biofilm cell removal and killing than the other root canal medicaments. Furthermore, 100 mg/mL NAC disrupted the mature multispecies endodontic biofilms completely. These results demonstrate the potential use of NAC in root canal treatment.

Cymbopogon citratus essential oil: effect on polymicrobial caries-related biofilm with low cytotoxicity

Abstract The objective of this study was to evaluate the effects of Cymbopogon citratus essential oil and its main compound (citral) against primary dental colonizers and caries-related species. Chemical characterization of the essential oil was performed by gas chromatography/mass spectroscopy (GC/MS), and the main compound was determined. Antimicrobial activity was tested against Actinomyces naeslundii, Lactobacillus acidophilus, S. gordonii, S. mitis, S. mutans, S. sanguinis and S. sobrinus. Minimum inhibitory and bactericide concentrations were determined by broth microdilution assay for streptococci and lactobacilli reference, and for clinical strains. The effect of the essential oil on bacterial adhesion and biofilm formation/disruption was investigated. Negative (without treatment) and positive controls (chlorhexidine) were used. The effect of citral on preformed biofilm was also tested using the same methodology. Monospecies and microcosm biofilms were tested. ANOVA or Kruskal-Wallis tests were used (α=0.05). Cytotoxicity of the essential oil to human keratinocytes was performed by MTT assay. GC/MS demonstrated one major component (citral). The essential oil showed an inhibitory effect on all tested bacterial species, including S. mutans and L. acidophilus. Essential oil of C. citratus (10X MIC) reduced the number of viable cells of lactobacilli and streptococci biofilms (p < 0.05). The essential oil inhibited adhesion of caries-related polymicrobial biofilm to dental enamel (p < 0.01). Citral significantly reduced the number of viable cells of streptococci biofilm (p < 0.001). The essential oil showed low cytotoxicity to human keratinocytes. Based on these findings, this study can contribute to the development of new formulations for products like mouthwash, against dental biofilms.

Empyema thoracis due to actinomyces odontolyticus.

Actinomyces odontolyticus has been reported as an opportunistic pathogen causing systemic infections. A case of empyema thoracis due to this organism in a 68-year-old male is reported here. The patient did not have any underlying disease or immunosuppression. The organism was isolated from his oral flora also. Eight cases of thoracopulmonary infections due to A. odontolyticus have been reported from the western countries, but none from India.

Influence of local tetracycline on the microbiota of alveolar osteitis in rats

The aim of the present study was to evaluate the effects of local tetracycline on the occurrence of alveolar osteitis in rats, and on the microbiota associated to this infection. Forty Wistar rats were randomly assigned to 4 groups (n=10): I - the rats had the maxillary right incisor extracted and the alveolar wound did not receive any treatment; II - adrenaline and Ringer-PRAS were introduced into the alveolar wound; III - the alveolar wound was irrigated with sterile saline; and IV - the alveolar wound was irrigated with an aqueous solution of tetracycline. Microbial samples from the alveolar wounds were collected 2 days after surgery and inoculated on blood agar (with and without 8 µg/mL of tetracycline) and other selective media, and were incubated in either aerobiosis or anaerobiosis at 37ºC, for 2 to 14 days. It was verified that tetracycline reduced the occurrence of alveolar osteitis in the rats and caused significant changes in the microbiota of the surgical sites, decreasing the number of anaerobes and increasing the participation of tetracycline-resistant and multi-resistant microorganisms.

O objetivo do presente estudo foi avaliar os efeitos do uso tópico de tetraciclina sobre a ocorrência de alveolite em ratos e sobre a microbiota a ela associada. Quarenta ratos foram divididos, ao acaso, em 4 grupos (n=10): grupo I, realizou-se somente a extração do incisivo superior direito e a ferida alveolar não recebeu nenhum tratamento; grupo II, além da extração dental, soluções de adrenalina e Ringer-PRAS foram introduzidas no interior do alvéolo; grupo III, a ferida alveolar foi irrigada com solução salina estéril; grupo IV, a ferida alveolar foi irrigada com solução aquosa de cloridrato de tetraciclina a 10 por cento. As amostras dos alvéolos para processamento microbiológico foram coletadas dois dias após a realização das cirurgias e foram inoculadas em ágar sangue com ou sem 8 µg/mL de tetraciclina e em outros meios de cultura seletivos, incubadas em aerobiose ou anaerobiose, a 37ºC, de 2 a 14 dias. Verificou-se que a tetraciclina reduziu a ocorrência de alveolite e provocou uma modificação significativa na microbiota do sítio cirúrgico, levando a uma redução nas proporções ocupadas pelos microrganismos anaeróbios e uma elevação da participação de microrganismos resistentes à tetraciclina e outros antimicrobianos.

Comparative study of the antimicrobial efficacy of chlorhexidine gel, chlorhexidine solution and sodium hypochlorite as endodontic irrigants

The purpose of this study was to assess the in vitro the antimicrobial efficacy of chlorhexidine gluconate gel as an endodontic auxiliary chemical substance compared to sodium hypochlorite (NaOCl) and chlorhexidine gluconate solution. The antimicrobial efficacy of the tested substances was evaluated using the agar diffusion test. The growth inhibition zones produced by 0.2 percent, 1 percent and 2 percent chlorhexidine gel were evaluated against 5 facultative anaerobic bacteria and 4 pigmented Gram-negative anaerobes, and compared to the results obtained by NaOCl and chlorhexidine solution. The largest growth inhibition zones were produced when the test bacteria were in contact with 2 percent chlorhexidine gluconate gel (11.79 mm), being significantly different (p<0.05) from the growth inhibition zones produced by all NaOClconcentrations, including 5.25 percent (9.54 mm). However, there was no statistically significant difference (p>0.05) between the growth inhibition zones obtained with equal concentrations of chlorhexidine solution and gel. The results of this study indicate that, as far as its antimicrobial properties are concerned, chlorhexidine gel has a great potential to be used as an endodontic auxiliary chemical substance.

O objetivo deste estudo foi avaliar in vitro a atividade antimicrobiana do gluconato de clorexidina gel, como irrigante endodôntico, comparando-o ao hipoclorito de sódio (NaOCl) e ao gluconato de clorexidina líquido. A atividade antimicrobiana das substâncias testadas foi avaliada pelo teste de difusão em ágar. As zonas de inibição de crescimento bacteriano produzidas pela clorexidina gel a 0,2 por cento; 1 por cento e 2 por cento foram observados frente a 5 espécies de bactérias anaeróbias facultativas e 4 espécies de anaeróbios estritos, Gram-negativos e produtores de pigmento negro; e comparados com os resultados obtidos pelo NaOCl e pela clorexidina líquida. As maiores zonas de inibição foram produzidas quando as bactérias testadas ficaram em contato com a clorexidina a 2 por cento em gel (11,79 mm), apresentando diferença estatisticamente significante (p<0,05) quando comparados às zonas de inibição de crescimento bacteriano produzidas por todas as concentrações avaliadas de NaOCl, incluindo 5,25 por cento (9,54 mm). No entanto, não houve diferença estatisticamente significante (p>0,05) comparando as zonas produzidas por concentrações equivalentes de clorexidina líquida ou gel. Os resultados indicaram que a clorexidina em gel tem grande potencial para ser usada como substância química auxiliar quanto às suas propriedades antimicrobianas.