Assessment of the Performance and Surface Alteration of Two Single-file Systems According to the Number of Uses

Abstract The aim of this study was to assess the performance and surface alteration of two single-file systems according to the number of uses. Ten WaveOne Primary files (25/.08) and ten One Shape NG files (25/.06) were used for instrumentation of mesial root canals of mandibular molars. Each instrument was cleaned and sterilized after the preparation of two root canals and then reused. The time spent for instrumentation of each root canal was recorded and analyzed by using t-test. Microphotographs of the surface of the instruments were taken with a scanning electron microscope at different magnifications (i.e. 18x, 160x, 500x and 1000x) and at a distance of 4 mm from the instrument's tip before being analyzed by four observers. Presence of disruption of cutting edge, crack, craters and unwinding was assessed and submitted to Fisher's exact test. Both systems showed manufacturing defects and cracks. The presence of disruption of cutting edges was major in WaveOne files from the sixth use, whereas One Shape NG files showed more unwinding. Only preparation time using WaveOne files was influenced by the number of uses. One can conclude that WaveOne files had more disruption of cutting edges and took longer time for root canal preparation from the sixth use onwards, whereas the One Shape NG files showed more unwinding at the tenth use.

Influencia de la medicación intracanal con pasta de hidróxido de calcio en la penetración del cemento obturador / obturadorInfluence of intracanal medication with calcium hydroxide paste in the penetration of the shutter cement / Influência da medicação intracanal com pasta de hidróxido de cálcio na infiltração do cimento obturador

La eliminación del hidróxido de calcio en el conducto radicular es determinante para el éxito del tratamiento endodóntico, los remanentes pueden interaccionar negativamente con los selladores endodónticos aumen-tando las filtraciones y disminuyendo la calidad de la obturación. Objetivo: Evaluar el efecto de la medicación intraconducto con pasta de hidróxido de calcio en la penetración del cemento obturador en el interior de los túbulos dentinarios. Materiales y métodos: 20 raíces distales de molares superiores se instrumentaron uti-lizando el Sistema Wave One Large 40/.08. Se dividieron aleatoriamente en dos grupos: uno obturado con técnica de cono único y cemento Ah plus con rodamina-B y otro obturado con la misma técnica y cemento Ah plus con rodamina B, previa colocación por 15 días y remoción mediante recapitulación de la pasta de hidróxido de calcio. Posteriormente los dientes fueron cortados transversalmente y se realizaron fotomicro-grafías del tercio cervical, medio y apical a través de la técnica de microscopia confocal de barrido por láser. La profundidad máxima de penetración fue determinada a través del programa Image J. Resultados: El ce-mento sellador Ah plus presentó menores valores de penetración cuando fue empleada previamente la pasta de hidróxido de calcio como medicación intracanal (p<0,01). El tercio del conducto con mayor penetración fue el tercio cervical seguido por el tercio medio y por último el apical (p<0,01). Conclusión: Los remanentes de hidróxido de calcio disminuyen la penetración del cemento sellador Ah plus en los túbulos dentinarios en todos los tercios del conducto radicular.

The elimination of calcium hydroxide in the root canal is decisive for the success of endodontic treatment, the remnants can interact negatively with endodontic sealants increasing filtrations and decreasing the quality of the seal. Objective: To evaluate the effect of intra-duct medication with calcium hydroxide paste on the pen-etration of the sealing cement inside the dentinal tubules. Materials and methods: 20 distal roots of upper molars were instrumented using the Wave One Large 40 / .08 System. They were randomly divided into two groups: one sealed with a single cone technique and Ah plus cement with rhodamine-B and another sealed with the same technique and Ah plus cement with rhodamine B, previous placement for 15 days and removal by recapping the paste calcium hydroxide. Subsequently, the teeth were cut transversely and photomicro-graphs of the cervical, middle and apical third were performed using the laser scanning confocal microscopy technique. The maximum depth of penetration was determined through the Image J program. Results: The Ah plus sealing cement had lower penetration values when the calcium hydroxide paste was previously used as an intra-channel medication (p <0.01). The third of the duct with the highest penetration was the cervical third followed by the middle third and finally the apical (p <0.01). Conclusion: Remaining calcium hydroxide decreases the penetration of the sealing cement Ah plus in the dentinal tubules in all thirds of the root canal.

A eliminação do hidróxido de cálcio do canal radicular é determinante para o sucesso do tratamento endo-dôntico; os remanescentes podem interagir negativamente com os cimentos endodônticos, aumentando as filtrações e diminuindo a qualidade do selamento. Objetivo: Avaliar o efeito da medicação intracanal com pasta de hidróxido de cálcio na penetração do cimento de selamento no interior dos túbulos dentinários. Materiais e métodos: 20 raízes distais de molares superiores foram instrumentadas usando o sistema Wave One Large 40 /.08. Eles foram divididos aleatoriamente em dois grupos: um selado com técnica de cone único mais cimento Ah plus com rodamina-B e outro selado com a mesma técnica e cimento Ah plus com rodami-na-B, prévia colocação por 15 dias e remoção recolocação da pasta hidróxido de cálcio. Posteriormente, os dentes foram cortados transversalmente e fotomicrografias do terço cervical, médio e apical foram realizadas pela técnica de microscopia confocal de varredura a laser. A profundidade máxima de penetração foi de-terminada pelo programa Image J. Resultados: O cimento selante Ah plus apresentou menores valores de infiltração quando a pasta de hidróxido de cálcio foi utilizada anteriormente como medicamento intracanal (p <0,01). O terço do conduto com maior penetração foi o terço cervical, seguido pelo terço médio e finalmente o apical (p <0,01). Conclusão: O hidróxido de cálcio restante diminui a penetração do cimento selante Ah plus nos túbulos dentinários em todos os terços do canal radicular.

Influencia de la activación ultrasónica del Hipoclorito de Sodio y de la Clorhexidina sobre el biofilm: estudio exvivo / IInfluence of ultrasonic activation of sodium hypochlorite and chlorhexidine on biofilm: ex-vivo study

Objetivo: Determinar la influencia de la activación ultrasónica de dos soluciones irrigadoras sobre biofilm en raíces de piezas dentales recientemente extraídas con diagnóstico de necrosis y periodontitis apical crónica. Materiales y métodos: Se asignaron 8 raíces a cada grupo: NaOCl al 5% (G1) y CHX al 2% (G2). En el G1 se irrigó con 10 ml de NaOCl al 5%, luego se activaron 5 ml de la solución con PUI por 1 minuto, se continuó con EDTA y luego suero fisiológico. Se trabajó de la misma manera con G2, cambiando el irrigante principal. Se realizaron 8 cortes transversales por cada tercio (cervical y medio), se analizaron bajo microscopía óptica. La presencia de biofilm se analizó en el conducto principal, istmos y túbulos dentinarios. Los datos se sometieron al test de Fisher. Resultados: En el tercio cervical solo hubo diferencia estadística al comparar la limpieza en los túbulos dentinarios, ya que el 12,5% de las muestras del G1 presenta biofilm remanente comparado con el 50% correspondiente al G2. En el tercio medio, hubo más muestras de G2 con biofilm en los conductos principales e istmos, representada por el 75% y 60% respectivamente, y solo el 37,5% de las muestras de G1 mostraron resultado positivo al analizar los túbulos dentinarios. Conclusiones: El hipoclorito de sodio al 5% es más eficiente que la clorhexidina al 2% para eliminar el biofilm, porque deja más limpio el tercio medio. Ambas soluciones tienen un omportamiento similar en el tercio cervical de las muestras. (AU)

Objective: To determine the influence of ultrasonic activation of two irrigant solu-tions on biofilm in the roots of freshly extracted teeth diagnosed with necrosis and chronic apical periodontitis. Mate-rials and methods: Eight roots were assigned to each group: 5% NaOCl (G1) and 2% CHX (G2), both activated ultra-sonically. In G1 irrigation was performed with 10ml of 5% NaOCl, then 5ml were activated with PUI for 1 minute, and EDTA and saline were used next. The same procedure was performed with G2, changing the main irrigant. Eight cross sections were produced for each third (cervical and middle), which were analyzed using optical microscopy. The biofilm presence was analyzed in the main canal, isthmus and dentinal tubules. The data was subjected to the Fisher test. Results: In the cervical third, there was only a statistical difference when comparing the cleanness of the dentinal tubules, with 12.5% of the G1 samples displaying remnant biofilm, compared to 50% in G2. In the middle third, a greater number of G2 samples were found with biofilm on the main canals and isthmus (75% and 60%, respectively) and only 37.5% of the G1 samples tested positive when the dentinal tubules were analyzed. Conclusions: 5% sodium hypochlorite is more efficient than 2% chlorhexidine in eliminating biofilm, leaving the middle third cleaner. In the samples, both irri-gant solutions performed similarly in the cervical third. (AU)

Evaluation of the waveone gold and one shape new generation in reducing enterococcus faecalis from root canal

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 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.

Immunohistological study of the effect of vascular Endothelial Growth Factor on the angiogenesis of mature root canals in rat molars

Abstract Tissue bioengineering has been applied to Endodontics to seek a more biological treatment. The presence of blood vessels is crucial for cell nutrition during tissue formation. Objective This study analysed the application of vascular endothelial growth factor (VEGF) in the angiogenesis of mature root canals. Material and methods Upper first molars of twelve 13-week old Wistar male rats were used. The root pulp of the mesiobuccal canal was removed and the root canal instrumented with K-files up to size #25. Periapical bleeding was induced into the root canal by introducing a #15 K-file beyond the apex. The teeth on the right side of the arch were filled up with blood clot (G1), whereas those on the left side were filled up with blood clot plus 50 ng/ml of VEGF (G2). Teeth were sealed with light-curing glass-ionomer cement and the animals were sacrificed after 60 days. The maxilla was dissected and fixed before obtaining serial sections for histological processing with haematoxylin-eosin (HE) and immunohistochemical factor-VIII. Immunohistochemical labelling was evaluated using scores for statistical analysis. Results Immunohistological analysis demonstrated the presence of angiogenesis in both groups, but with higher angiogenic maturation in G2 during the experimental period (p<0.05). HE staining showed connective tissue with absence of odontoblasts in all specimens. Conclusions It can be concluded that it is possible to obtain angiogenesis in mature root canals with or without the use of VEGF, although the latter tends to accelerate blood vessel formation.

Instrument Design May Influence Bacterial Reduction During Root Canal Preparation

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.

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.