Capacidad de sellado de los conductos laterales con distintas técnicas de obturación del conducto radicular / Sealing capacity of lateral canals with different root canal obturation techniques

Objetivo: Estimar y comparar la eficacia de diferentes técnicas de obturación para impedir el flujo de colorante a través de los conductos laterales. Materiales y métodos: Se emplearon 50 premolares inferiores extraídos y conservados en formol neutro al 5% hasta el momento de su uso, a los cuales se les realizaron conductos laterales artificiales. Una vez instrumentados los conductos principales, los dientes fueron divididos al azar en 5 grupos (n=10) para ser obturados con cuatro técnicas distintas: A) System B + inyección de gutapercha termoplástica del sistema Elements, Extruder; B) obturadores de Thermafil, ProTaper Universal; C) técnica híbrida y D) obturación con inyección de gutapercha termoplástica del sistema Elements, Extruder. Inmersos en tinta china y diafanizadas las raíces, se evaluó la longitud de penetración de la tinta en los conductos laterales. Se empleó el análisis de la varianza para detectar diferencias significativas (P<0,05) entre los niveles medios de penetración del colorante según las técnicas de obturación y las zonas del diente, y se efectuaron pruebas de rango múltiple (HSD de Tukey) para realizar comparaciones dos a dos, manteniendo fija la tasa de error por familia. Resultados: A la técnica B le correspondió el valor medio más bajo (30,63%) de penetración de tinta china. Los valores medios más elevados (54,52% y 51,74%) correspondieron a las técnicas A y C, respectivamente. Conclusión: Ninguna de las técnicas de obturación del conducto radicular empleadas ha sido capaz de impedir la filtración del colorante en los conductos laterales (AU)

Aim: To estimate and compare the different obturation techniques to avoid the flow of colorant through lateral canals. Materials and methods: 50 extracted lower premolars preserved in 5% neutral formol until the moment of use, had artificial lateral canals made. Once canals were instrumented, the teeth were randomly divided into 5 groups (n=10) to be filled with four different techniques: A) System B + injection of thermoplastic gutta-percha, Elements system, Extruder; B) Thermafil, ProTaper Universal obturators; C) hybrid technique, and D) injection of thermoplastic gutta-percha, Elements system, Extruder. Having immersed the premolars in India ink and diaphanized the roots, the penetration length of the India ink inside the canals was assessed. Analysis of variance was used to detect significant differences (P<0.05) between the mean levels of dye penetration according to the filling techniques and tooth areas, and multiple range tests (Tukey's HSD) were performed for two-to-two comparisons, keeping the error rate per family fixed. Results: Technique B had the lowest mean value (30.63%) of penetration. The highest mean values (54.52% and 51.74%) corresponded to techniques A and C, respectively. Conclusion: No obturation technique of the root canal used was able to avoid filtration of colourant in the lateral canals (AU)

Microcomputed tomographic evaluation of techniques for warm gutta-percha obturation.

Transparent epoxy resin root canal models were used to evaluate vertical condensation techniques for obturating lateral canals. The root canal model was configured with a straight main root canal and four right-angled lateral canals at 1.0 and 3.0 mm from the apex. Root canal obturation was performed with Thermafil, Obtura II, or NT condenser. Obturation volume in lateral canals was measured by three-dimensional microcomputed tomography, and one-way analysis of variance was used to analyze differences between groups. Lateral canals at 1.0 and 3.0 mm were uniformly filled by all obturation methods. Among the three obturation methods, Thermafil resulted in the highest obturation volumes for all lateral canals.

Comparison of two negative pressure systems and syringe irrigation for root canal irrigation: an ex vivo study.

AIM: To compare in a laboratory study two negative pressure systems and syringe irrigation, regarding the delivery of a contrast solution (CS) to working length (WL) and into simulated lateral canals and the effective volume of irrigant aspirated during negative pressure irrigation. METHODOLOGY: Twenty single-canaled incisor training models were constructed with six simulated lateral canals each (2, 4 and 6 mm to WL) and a size 40, 0.04 taper apical size canal. Each model underwent all irrigation procedures (EndoVac at WL (EndoVac-0) and WL-2 mm (EndoVac-2), iNP needle with negative pressure (iNPn) and syringe irrigation with the iNP needle (iNPs) and a 30-G side-slot needle placed at WL (SI0) and WL-2 (SI2) mm in a crossover design. CS was delivered at 4 mL min(-1) for 60 s with a peristaltic pump and a recovery device collected the volume (in mL) of irrigant suctioned by the negative pressure groups. The irrigation procedures were digitally recorded, and a still image of the 60-s time-point of irrigation was evaluated for CS distance to WL (in millimetres) after irrigation and penetration into lateral canals (3-point scale). Statistical tests used were Kruskal-Wallis and Dunn's test. RESULTS: EndoVac-0, iNPn and iNPs had median distances of CS to WL of 0 mm, followed by SI0 (0.2 mm), SI2 (0.7 mm) and EndoVac-2 (1.7 mm). There were no significant differences between EndoVac-0, iNPn, iNPs and SI0, but these were significantly different to SI2 and EndoVac-2 (P < 0.05). There were no significant differences between the volume of CS delivered by syringe irrigation and that collected by iNPn (4 mL), but these were significantly greater than EndoVac-0 (2.8 mL, P < 0.001) and EndoVac-2 (2.85 mL, P < 0.001), which were not different to each other (P = 1.0). The irrigation procedures were ineffective at penetration into lateral canals. CONCLUSION: iNPn, EndoVac-0, iNPs and SI0 achieved greater irrigant penetration to WL. iNPn was able to collect a median volume of CS (4 mL) similar to that delivered by syringe irrigation (iNPp, SI0 and SI2). An adequate irrigant penetration into lateral canals could not be achieved by any of the systems.

Comparison of Penetration of Irrigant Activated by Traditional Methods with A Novel Technique.

INTRODUCTION: The effectiveness of irrigation depends upon various irrigation activation methods & devices used. AIM: To compare and evaluate the penetration of irrigant upto working length and into simulated lateral canals using four different irrigation activation techniques. MATERIALS AND METHODS: The root canals of 60 single-rooted teeth were instrumented using the proTaper rotary system. After decalcification of each sample tooth, three simulated lateral canals were created at 2mm, 4mm and 6mm levels from the root apex using a 06-size C+ file. After clearing the samples they were randomly assigned into four experimental groups (n=15) and 1ml of Irrigating Contrast Solution (ICS) was delivered into all samples and then it is activated with 4 different methods Group I-Conventional syringe and needle, Group II - Sonic activation with Endo activator, Group III - Ultrasonic activation with ultrasonic tips and Group IV - Activation using reciprocation movement. All the samples were examined under a stereomicroscope and irrigant penetration was evaluated by means of penetration of ICS. RESULTS: Group III and Group IV resulted in better penetration of ICS into lateral canals at 2mm and 4mm depth (p<0.001), when compared with Group I and II. At lateral canals 6mm all the groups except Group I, had shown 100 % penetration. CONCLUSION: The activation of irrigant using reciprocation was able to achieve penetration of irrigating contrast solution both up to the working length and into lateral canals. Hence the clinical significance of this method of irrigant activation is that it can be used for effective penetration of irrigants both upto working length and into lateral canals.

Filling of simulated lateral canals with gutta percha or resilon when using thermomechanical compaction.

AIMS: To evaluate the filling of simulated lateral canals with gutta-percha or Resilon when using thermomechanical compaction. SETTING AND DESIGN: Forty-five human single-rooted teeth were subjected to tooth decalcification and clearing. MATERIALS AND METHODS: After root canal preparation, artificial lateral canals were made at 2, 5, and 8 mm from the working length (WL), corresponding to the apical, middle, and cervical thirds, respectively. The specimens were divided (n = 15) according to the filling material: Dentsply gutta-percha (GD), Odous gutta-percha (GO), and Resilon cones (RE). Root canals were obturated by thermomechanical compaction using a #45 compactor and no sealer. Lateral canals were analyzed by digital radiography and digital images after tooth decalcification and clearing using the Image Tool software. STATISTICAL ANALYSIS USED: Data were subjected to the Kruskal-Wallis and Dunn tests at 5% significance. RESULTS: In the coronal third, RE and GO presented more filling ability than GD (P < 0.05). In the middle and apical thirds, RE presented the best results. CONCLUSIONS: Resilon demonstrated filling ability as material for root canal obturation by using thermomechanical compaction.

A novel methodology providing insights into removal of biofilm-mimicking hydrogel from lateral morphological features of the root canal during irrigation procedures.

AIM: To introduce and characterize a reproducible hydrogel as a suitable biofilm mimic in endodontic research. To monitor and visualize the removal of hydrogel from a simulated lateral canal and isthmus for the following: I) Ultrasonic-Activated Irrigation (UAI) with water, ii) UAI with NaOCl and iii) NaOCl without UAI. METHODOLOGY: A rheometer was used to characterize the viscoelastic properties and cohesive strength of the hydrogel for suitability as a biofilm mimic. The removal rate of the hydrogel from a simulated lateral canal or isthmus was measured by high-speed imaging operating at frame rates from 50 to 30,000 fps. RESULTS: The hydrogel demonstrated viscoelastic behaviour with mechanical properties comparable to real biofilms. UAI enhanced the cleaning effect of NaOCl in isthmi (P < 0.001) and both NaOCl and water in lateral canals (P < 0.001). A greater depth of cleaning was achieved from an isthmus (P = 0.009) than from a lateral canal with UAI and also at a faster rate for the first 20 s. NaOCl without UAI resulted in a greater depth of hydrogel removal from a lateral canal than an isthmus (P < 0.001). The effect of UAI was reduced when stable bubbles were formed and trapped in the lateral canal. Different removal characteristics were observed in the isthmus and the lateral canal, with initial highly unstable behaviour followed by slower viscous removal inside the isthmus. CONCLUSIONS: The biofilm-mimicking hydrogel is reproducible, homogenous and can be easily applied and modified. Visualization of its removal from lateral canal anatomy provides insights into the cleaning mechanisms of UAI for a biofilm-like material. Initial results showed that UAI improves hydrogel removal from the accessory canal anatomy, but the creation of stable bubbles on the hydrogel-liquid interface may reduce the cleaning rate.

Comparison of irrigant penetration up to working length and into simulated lateral canals using various irrigating techniques.

AIM: To evaluate the effect of an apical negative pressure system, a passive ultrasonic irrigation system and a combination of both apical negative pressure and passive ultrasonic irrigation on the penetration of the irrigating contrast solution (ICS) up to working length and into simulated lateral canals. METHODOLOGY: The root canals of 64 single-rooted teeth were instrumented using the ProTaper rotary system. In each sample, three simulated lateral canals were created at 2, 4 and 6 mm levels from the root apex using a 06-size C+ file (Dentsply Maillefer, Ballaigues, Switzerland). Samples were randomly assigned into 4 experimental groups (n = 16): group I - conventional needle irrigation, group II - passive ultrasonic irrigation, group III - apical negative irrigation system and group IV - combination of passive ultrasonic irrigation and apical negative pressure irrigation system. To examine irrigating solution penetration, Indian ink was mixed with 5.25% NaOCl and delivered into the root canals. Samples were then assessed by direct observation of the images taken using Canon EOS rebel T3. The depth of penetration of ICS up to the working length and into the simulated lateral canals was analysed using chi-squared tests. RESULTS: The combination (ANP and PUI) and ANP group had significantly deeper ICS penetration up to the working length (P < 0.001). The combination (ANP and PUI) and the PUI group exhibited significantly greater ICS penetration into lateral canals at the 6 mm level (P < 0.001). At the 4 and 2 mm levels, the combination of ANP and PUI had significantly greater ICS penetration into the lateral canals than the other groups (P < 0.001). CONCLUSIONS: The combination of ANP and PUI was the only group able to achieve irrigating contrast solution penetration both up to the working length and into lateral canals.

Antibacterial efficacy of HMME-PDT on Enterococcus faecalis within infected simulated lateral canals in vitro model with different energy / 国际生物医学工程杂志

Objective The purpose of this study was to assess the antibacterial effects of hematoporphyrin monomethylether-photodynamic therapy (HMME-PDT) on Enterococcus faecalis within infected simulated lateral canals in vitro with different energy.Methods Simulated lateral canals were prepared on extracted teeth.The specimens were infected with Enterococcus faecalis and then were randomly divided into eight groups.Group A was considered as negative control,its specimens were irrigated with physiological saline.Group B was the positive control,they were irrigated with 5.25％ NaClO.Other groups were incubated with HMME at concentration of 40 μg/ml for 5 min,followed by exposure to light at 532 nm for 120 s with different powers in a spiral pattern.Groups were named C-H,in corresponding with the power 50,60,70,80,90,100 mW.Microbial samples (the dentin chips from simulated lateral canals) were taken before and after the treatments.The survival fractions in each simulated lateral canal was calculated by counting colony-forming units(CFUs).Results 1.The HMME-PDT-treated groups resulted in a significant reduction in the number of E.faecalis in simulated lateral canals compared with the negative controls(P＜0.05).2.The antibacterial effects of group D、E、F、G、H were higher than the NaCl0-irrigated group(P＜0.05).3.The difference of antibacterial effects between the F、G、H groups was in significant(P＞0.05).Conclusion HMME-PDT had significant inhibitive efficacy on Enterococcus faecalis within infected simulated lateral canals and the efficacy was power-depended.It can play the best effect with the power of 80 mW.

Effectiveness of a silicon-based root canal sealer for filling of simulated lateral canals

The purpose of this in vitro study was to evaluate the ability of a silicon-based root canal sealer, compared to zinc oxide and eugenol and an epoxy resin-based sealers, for filling of simulated lateral canals. Thirty extracted single-rooted human teeth were selected, conventional access was made and the working length was established 1 mm from the apical foramen. Three simulated lateral canals, one in each root third (coronal, middle and apical) were prepared in both the mesial and distal surfaces of each tooth using a size 15 reamer adapted to a low-speed handpiece. Each root canal was instrumented using ProTaper rotary files up to file F3 at the working length, and then irrigated with 2.5 percent NaOCl followed by EDTA. The teeth were assigned to 3 groups (n=10), according to the root canal sealer: Roeko Seal (Group 1), Sealer 26 (group 2) and Grossman's sealer (Group 3). Gutta-percha cold lateral condensation technique was performed in all groups. Postoperative radiographs were taken and the images were projected for evaluation of the quality of lateral canal filling. Data were submitted to statistical analysis by Kruskal Wallis test at 5 percent significance level. The results showed that Grossman's sealer filled a larger number of lateral canals than Roeko Seal (p<0.05) and Sealer 26 (p<0.01). It may be concluded that Roeko Seal silicone-based root canal sealer was not as effective as the Grossman's sealer for filling of simulated lateral canals. The lateral canals localized in the apical third of the root were more difficult to be filled.

O objetivo desse estudo in vitro foi avaliar a capacidade de um cimento a base de silicone, em obturar canais laterais simulados, em comparação a um cimento à base de oxido de zinco e eugenol e um cimento resinoso. Trinta dentes humanos unirradiculares extraídos foram selecionados, a abertura coronária foi feita e o comprimento de trabalho foi determinado 1 mm aquém do forame apical. Foram confeccionados três canais laterais, um em cada terço radicular, em ambas as faces mesial e distal da raiz, usando um alargador 15 acoplado a um contra-ângulo em baixa rotação. Os canais foram instrumentados com sistema Protaper até a lima F3, sob irrigação com hipoclorito de sódio a 2,5 por cento, seguido de EDTA. Os dentes foram divididos em 3 grupos (n=10) e obturados com o cimento de Grossman, RoekoSeal ou Sealer 26, pela técnica da condensação lateral da gutta-percha. Foram feitas tomadas radiografias pós-operatórias, projetadas em aumentos de 20X para avaliação da qualidade das obturações. Os dados foram analisados estaticamente pelo teste de Kruskal Wallis com nível de significância de 5 por cento. Os resultados mostraram que o cimento de Grossman obturou um numero maior de canais laterais que o cimento RoekoSeal (p<0,05) e o Sealer 26 (p<0,01). Pode-se concluir que o cimento Roeko Seal não foi tão eficiente quanto o cimento de Grossman para o selamento de canais laterais, bem como, que os canais laterais situados no terço apical da raiz apresentaram maior dificuldade para serem obturados.