Resumo A proposta deste estudo foi avaliar os sistemas WaveOne Gold e One Shape New Generation em relação à remoção bacteriana de canais infectados com Enterococcus faecalis, comparando-os com seus sistemas convencionais WaveOne e One Shape. Quarenta e oito canais disto vestibulares de molares superiores esterilizados em óxido de etileno foram contaminados com E. faecalis por 21 dias, e então acoleta bacteriana inicial foi feita com cone de papel e plaqueadas em M-enterococcus agar. Os espécimes foram aleatoriamente divididos em quarto grupos de acordo com a instrumentação: WaveOne Gold, One Shape New Generation, WaveOne e One Shape. Após instrumentação, amostras foram coletadas utilizando limagem e cones de papel imediatamente e 7 dias após o preparo. A redução bacteriana foi calculada e então feita análise intra grupos com teste de Friedman, e entre grupos utilizando Kruskal-Wallis e teste de Dunn, todos a 5% de significância. Todas as técnicas reduziram significantemente o número de bactérias do canal radicular (p<0.05). WaveOne Gold e One Shape New Generation promoveram maior redução bacteriana que WaveOne e One Shape (p<0.05), mas nenhuma diferença significante foi encontrada entre WaveOne Gold e One Shape New Generation ou entre WaveOne e One Shape (p>0.05). Novos sistemas de lima-única promovem melhor remoção bacteriana que seus sistemas convencionais.

Abstract The aim of this study was to evaluate the WaveOne Gold and One Shape New Generation systems regarding the bacterial removal from root canals infected with Enterococcus faecalis by comparing them to the conventional WaveOne and One Shape systems. Forty-eight distobuccal root canals of maxillary molars sterilized with ethylene oxide were infected with E. faecalis for 21 days, and then root canal initial bacterial sample was collected with paper cones and plated on M-enterococcus agar. The specimens were randomly divided into 4 groups according to the instrumentation: WaveOne Gold, One Shape New Generation, WaveOne and One Shape. After instrumentation, samples were collected with use of scraping and paper cones at immediate and 7 days after instrumentation. The bacterial reduction was calculated and then made intragroup analysis by Friedman test and intergroup analysis by Kruskal-Wallis with Dunn’s post-hoc test, all at 5% significance. All techniques significantly reduced the number of bacteria in the root canal (p<0.05). WaveOne Gold and One Shape New Generation promoted higher bacterial reduction than WaveOne and One Shape systems (p<0.05), but no significant difference was found between WaveOne Gold and One Shape New Generation or between WaveOne and One Shape (p>0.05). Novel single-file systems promote better bacterial removal than the conventional single-file systems.

Resumo A proposta deste estudo foi avaliar a redução bacteriana promovida pelos sistemas ProTaper Next e Twisted File comparando-os ao sistema ProTaper Universal e técnica manual. Sessenta raízes disto vestibulares de molares superiores esterilizadas com óxido de etileno foram contaminadas com Enterococcus faecalis. Após incubação por 21 dias, amostras foram coletas e cultivadas em m-Enterococcus agar. Os canais foram divididos em 4 grupos de acordo com o sistema de instrumentação: ProTaper Next, Twisted File, ProTaper Universal, e técnica manual crown-down. Outros 8 canais não contaminados foram utilizados como controle de assepsia. Amostra bacteriana foi coletada imediatamente após o prepare e aos 7 dias. A redução bacteriana foi calculada, e então feita a análise intergrupos utilizando teste t-pareado, e análise entre grupos utilizando os testes ANOVA e Tukey, todos com 5% de significância. Todas as técnicas reduziram significantemente o número de bactérias no canal radicular (p<0.05). ProTaper Next e Twisted File resultaram em maior redução bacteriana que ProTaper Universal e técnica manual (p<0.05). ProTaper Next e Twisted File foram semelhantes (p>0.05). Pode-se concluir que ProTaper Next e Twisted File promovem maior redução bacteriana que Protaper Universal e técnica manual.

Abstract The aim of this study was to evaluate the bacterial reduction promoted by ProTaper Next and Twisted File by comparing to ProTaper Universal and manual technique. Sixty distobuccal root canals of maxillary molars sterilized with ethylene oxide were contaminated with Enterococcus faecalis broth culture. After incubation for 21 days, bacterial samples were collected and cultured on m-Enterococcus agar plates. The root canals were divided into 4 groups, according to the system used for instrumentation: ProTaper Next, Twisted File, ProTaper Universal, and crown down manual technique. Other 8 uncontaminated root canals were control asepsis. Bacterial samples were collected immediately and 7 days after instrumentation. The bacterial reduction was calculated and then made intragroup analysis by paired t-test and intergroup analysis by ANOVA and Tukey tests, all at 5% significance. All techniques significantly reduced the bacterial number in the root canal (p<0.05). ProTaper Next and Twisted File resulted in more bacterial reduction than ProTaper Universal and manual technique (p<0.05). ProTaper Next and Twisted File were similar (p>0.05). It can be concluded that ProTaper Next and Twisted File promote a higher bacterial reduction than Protaper Universal and manual technique.

The objective of the present study was to assess the effectiveness of reciprocating instrumentation in disinfecting oval-shaped root canals infected with Enterococcus faecalis. Forty-five human lower premolars were infected with a culture of E. faecalis (ATCC 29212) for 28 days. Five other teeth that were neither contaminated nor instrumented were used as controls. The 45 specimens were divided into three experimental groups (n = 15) based on the root canal preparation technique used: manual (K-type, Dentsply Maillefer, Ballaigues, Switzerland); rotary (MTwo, VDW GmbH, Munich, Germany); and reciprocating (Reciproc R50, VDW GmbH, Munich, Germany) instruments. During chemomechanical preparation, 21 mL of 2.5% NaOCl was used as the irrigating solution. Microbiological sampling was performed before (S1) and immediately after (S2) the chemomechanical preparation using sterilized paper points. Specimens were then cleaved, and 0.02 g of dentine chips was collected from the root thirds to verify the presence of microorganisms in dentinal tubules. All three preparation techniques reduced the number of microorganisms in the root canal lumen and dentine chips from the root thirds, but no significant differences were observed between the three groups (p > 0.05). Reciprocating instrumentation with Reciproc R50 was effective in reducing the number of microorganisms within the root canal system. Although this technique involves the use of only one file to perform the root canal therapy, it is as effective as conventional rotary instrumentation in reducing theE. faecalis biofilm from the root canal system. However, further clinical investigations are warranted in order to ratify these results.

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.

Streptococcus spp são importantes componentes do biofilme dental sendo Streptococus crista considerado um interessante modelo de interações bacterianas que nele ocorrem. No presente trabalho linhagens de S. crista, foram isoladas do biofilme dental de indivíduos brasileiros, e estudadas em relação a suas características biológicas e ao seu perfil molecular através da técnica do AP-PCR, usando-se os iniciadores RR2, 434, OPR2, OPR8 e OPR13. Os resultados nos permitiram construir um dendrograma de similaridade. A análise do dendrograma de similaridade permitiu a separação das linhagens estudadas em grupos de similaridade. Todos os isolados apresentaram tufo de fibrilas, quando estudados por Microscopia Eletrônica de Transmissão (MET). Estes isolados foram capazes de se ligar à amilase salivar e de se aderir a células epiteliais bucais. Algumas linhagens, que apresentam tufo de fibrilas e aderência positiva, não foram capazes de coagregar com a Fusobacterium nucleatum, sugerindo que diferentes grupos de adesinas estão presentes nestas amostras.

Streptococcus ssp are important components of the dental biofilm and Streptococcus crista is considered to be an interesting model of bacterial interactions taking place in this biofilm. In the present work, S. crista strains were isolated from the dental biofilm of Brazilian individuals and studied with respect to their biological characteristics and their molecular profile by means of AP-PCR techniques, using the RR2, 434, OPR2, OPR8, and OPR13 primers. Results allowed us to build a similarity dendrogram. Analysis of the similarity dendrogram allowed the separation of the studied strains into similarity groups. All isolates presented fibril tufts by Transmission Electron Microscopy (TEM). These isolates were able to bind to salivary amylase and to adhere to mouth epithelial cells. Some strains displaying fibril tufts and positive adherence were not able to co-aggregate with Fusobacterium nucleatum, suggesting that different adhesin groups are present in these strains.

Foi conduzido um ensaio clínico aleatório com objetivo de investigar o efeito do gel de clorexidina (CHX) a 0,5% sobre microorganismos superinfectantes da placa bacteriana de pacientes especiais. Trinta internos da instituição "Casas André Luiz" foram aleatoriamente divididos em grupo teste (gel de CHX, n = 15) e controle (gel placebo, n = 15). O gel foi utilizado por oito semanas. Amostras de placa supragengival foram coletadas no início do estudo, após o uso do gel (oito semanas) e 16 semanas após o início do estudo. Foi avaliada a presença de bacilos entéricos Gram-negativos, Staphylococcus e leveduras. Não houve diferença entre os grupos quanto à presença desses microorganismos em qualquer momento do estudo. Os resultados indicam que o gel de CHX não provocou mudanças significativas na composição desses microorganismos.

A randomized clinical trial was conducted to investigate the effect of a 0.5% chlorhexidine (CHX) gel on dental plaque superinfecting microorganisms in mentally handicapped patients. Thirty inmates from the institution "Casas André Luiz" were assigned to either test group (CHX gel, n = 15) or control group (placebo gel, n = 15). The gel was administered over a period of 8 weeks. Supragingival plaque samples were collected at baseline, after gel use (8 weeks) and 16 weeks after baseline. The presence of Gram-negative Enterobacteriaceae, Staphylococcus and yeasts was evaluated. No significant growth of any superinfecting microorganism was observed in the CHX group, when compared to the placebo group. The results indicated that the 0.5% chlorhexidine gel did not produce an undesirable shift in these bacterial populations.

Actinobacillus actinomycetemcomitans está implicado como o agente etiológico da periodontite juvenil localizada. Este organismo possui inúmeros fatores de virulência que podem interferir no reparo tissular. 50 isolados de A. actinomycetemcomitans de pacientes com periodontite foram examinados para avaliar outros possíveis fatores de virulência. Neste estudo, foi avaliada a produção de cápsula, DNase, coagulase, fibrinolisina, atividade proteolítica, hemolisina e bacteriocina, assim como hemaglutinação, sensibilidade ao soro, aderência às células epiteliais, hidrofobicidade e virulência de A. actinomycetemcomitans. Todos os isolados foram resistentes para todos os tipos de soro utilizados. 70% a 94% dos isolados foram alfa-hemolíticos e aglutinaram todos os tipos sanguíneos. A maioria dos isolados produziu substâncias antagonistas e apresentaram baixa hidrofobicidade. Nenhum dos isolados foi patogênico para camundongos. Pouco se sabe, sobre a ação e como esses fatores podem agir no desenvolvimento da doença periodontal, sendo necessários estudos adicionais para uma aplicação em termos de sistemática e de patogênese.

Actinobacillus actinomycetemcomitans is implicated as the causative agent of localized juvenile periodontitis. This organism possesses a large number of virulence factors with a wide range of activities and also interfere with tissue repair. Fifty isolates of A. actinomycetemcomitans from 20 periodontal patients were examined to evaluate other putative virulence factors. In this study, the capsule, DNase, coagulase, fibrinolysin, proteolytic, haemolysin and bacteriocin production, haemagglutination, serum sensitivity, epithelial cells attachment, hydrophobicity and virulence of the A. actinomycetemcomitans isolates were evaluated. All the isolates were resistant to the different tested sera. 70% to 94% were alpha-haemolytics and agglutinated all blood types. Most of isolates produced antagonistic substances and they had a low hydrophobicity. None of the isolates was pathogenic for mice. Little is known as to wether these factors may act in the development of periodontal disease, and further studies are required for an application in pathogenic and systematic terms.