Comparison of the efficacy of laser-activated and ultrasonic-activated techniques for the removal of tricalcium silicate-based sealers and gutta-percha in root canal retreatment: a microtomography and scanning electron microscopy study.

BACKGROUND: Tricalcium silicate-based sealers have been usually indicated for the single-cone technique and result in more residual filling materials in root canal retreatment. Passive ultrasonic irrigation and photon-initiated photoacoustic streaming have been reported to improve the removal efficacy of root canal filling materials. However, the abilities of both techniques combined with NiTi re-instrumentation to remove residual tricalcium silicate-based sealer and gutta-percha have not been compared. The aim of this study was to evaluate the efficacy of laser-activated and ultrasonic-activated techniques in vitro for the removal of the tricalcium silicate-based sealer iRoot SP and gutta-percha after standard canal retreatment procedures with the use of nickel-titanium (NiTi) rotary instruments.

Efficacy of photon-initiated photoacoustic streaming on apically extruded debris with different preparation systems in curved canals.

AIM: To determine the effect of photon-initiated photoacoustic streaming (PIPS) on the extrusion of debris using multiple-file (ProTaper Next-PTN) and single-file (One Shape-OS) continuous rotary systems in curved canals in human molar teeth. METHODOLOGY: Sixty extracted maxillary first molar teeth with curved mesial roots, mature apices and of similar lengths were selected. Teeth having canals with apical diameters larger than size 15 were discarded. The teeth were randomly divided into four experimental groups (n = 15 teeth per group) according to the file used and irrigation systems: (i) OS with PIPS with a 2940 nm Er:YAG laser (0.3 W, 15 Hz, and 20 mJ), (ii) OS with conventional needle irrigation (CNI) with a 27-G needle, (iii) PTN with PIPS and (iv) PTN with CNI. The PIPS and CNI was applied during each file change for 20 s. Total irrigation and activation time was 1 min, and a total volume of 7.5 mL of bidistilled water was used as the irrigant. The apically extruded debris was collected into pre-weighed Eppendorf tubes. The tubes were then stored in an incubator at 70 °C for 5 days. The weight of dry extruded debris was assessed by subtracting the initial weight of the tube from the final weight. The results were analysed statistically using one-way analysis of variance and Tukey's post hoc tests. Bonferroni correction was used to compare the groups. RESULTS: The PIPS irrigation technique was associated with significantly more debris extrusion than the CNI system (P < 0.05). The single-file (One Shape-OS) rotary system was associated with more debris than the multiple-file (ProTaper Next-PTN) rotary systems when the same irrigation system was used (P > 0.05). The total amount of debris extruded apically by PIPS activation was significantly greater than that by CNI (P < 0.05). CONCLUSIONS: All file and irrigation systems extruded debris apically. PIPS activation was associated with significantly more extrusion debris in curved canals compared with no activation.

Comparison of Conventional Syringe, CanalBrush, EndoActivator, Photon-Induced Photoacoustic Streaming, and Manual Instrumentation in Removing Orange-Brown Precipitate: An In Vitro Study.

OBJECTIVE: The aim of this in vitro study was to compare the various techniques for removing precipitate formed after irrigation with sodium hypochlorite (NaOCl) and chlorhexidine (CHX). BACKGROUND DATA: It is still unclear whether different irrigant activation systems can effectively remove precipitate that is firmly attached to the root canal walls. METHODS: Eighty-two extracted single-rooted human teeth were instrumented by using the ProTaper rotary system. The roots were irrigated with 5% NaOCl and then 2% CHX to form orange-brown precipitate on the root canal walls. The teeth were sectioned longitudinally, and the amount of precipitate on the canal walls was measured under a stereomicroscope at 15 × magnification before the root halves were reassembled. Then, conventional syringe irrigation (CSI), CanalBrush (CB), EndoActivator (EA) system, photon-induced photoacoustic streaming (PIPS), and manual instrumentation (MI) techniques were used to remove the precipitate, during which 5 mL of distilled water was used for 1 min. The amount of precipitate remaining on the canal walls was measured, and the percentage of precipitate removed was calculated. Data were analyzed by using the Kruskal-Wallis and Mann-Whitney U tests (p = 0.05). RESULTS: All experimental groups contained residual precipitate. The precipitate was more effectively removed in the MI group than in the other groups (p < 0.05). The CB and EA groups showed better removal than the CSI and PIPS groups (p < 0.05), and there were no significant differences in removal between these latter two groups (p > 0.05). CONCLUSIONS: None of the techniques used was able to completely remove the orange-brown precipitate from the root canal surfaces.

Comparison of Smear Layer Removal Ability of QMix with Different Activation Techniques.

INTRODUCTION: To evaluate the effectiveness of QMix solution (Dentsply Tulsa Dental Specialties, Tulsa, OK) on the smear layer using the following irrigation activation techniques: the EndoActivator (EA) system (Dentsply Tulsa Dental Specialties), photon-initiated photoacoustic streaming (PIPS), and an Er:YAG laser with an endodontic fiber tip. METHODS: Sixty-four extracted single-rooted human teeth were decoronated and the canals instrumented with ProTaper (Denstply Maillefer, Ballagues, Switzerland) up to size F4. The canals were irrigated with 5.25% sodium hypochlorite and a saline solution for 1 minute each. The specimens were then divided randomly into 4 experimental and 4 control groups (n = 8) according to the final irrigation activation technique. These groups included group 1, 2.5 mL QMix; group 2, QMix + EA; group 3, QMix + PIPS; and group 4: QMix + Er:YAG. Laser activated distilled water was used as control groups 5, 6, 7, and 8. Teeth were split longitudinally, and specimens were observed under a scanning electron microscope. Images were taken at the coronal, middle, and apical thirds of the teeth at a magnification of 1000× and were scored in the presence of the smear layer. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The highest scores were found in the apical third of all groups (P < .05). The QMix + Er:YAG group removed the smear layer more effectively than the nonactivated QMix group in the apical third (P < .05). The QMix + EA group removed the smear layer significantly in all thirds of the teeth when compared with the nonactivated QMix group (P < .05). The QMix + PIPS group showed a significantly better effect than the QMix group in the coronal third (P < .05). CONCLUSIONS: The EA and Er:YAG laser enhanced the smear layer removal ability of QMix in the apical thirds of the canals. QMix removed more smear layer in the coronal thirds when activated with the PIPS technique.

Comparison of different final irrigant agitation techniques for the removal of Enterococcus faecalis biofilms from root canals: an in vitro study / Comparação de diferentes técnicas finais de agitação de irrigantes para a remoção de biofilmes de Enterococcus faecalis de canais radiculares: estudo in vitro

Objective: The aim of this in vitro study was to compare the effectiveness of different final irrigant agitation techniques in the removal of Enterococcus faecalis biofilms from root canals. Material and Methods: In total, the root canals of 85 extracted single-rooted human maxillary incisors teeth were prepared using the Revo-S system to a 40/06 size. The apical foramen of each tooth was sealed by light-cured resin composite material to obstruct bacterial leakage. The specimens were sterilized in an autoclave at 121°C for 15 min and stored until further use. All teeth except five (negative control group) were inoculated with Enterococcus faecalis and incubated in a CO2 chamber at 37°C for 7 days; the trypticase soy broth was changed every 2 days. For the determination of possible biofilm formation, five of the 80 teeth were randomly selected as a positive control group; one tooth of positive control group was analysed for biofilm development by scanning electron microscope (SEM) and these teeth received no final irrigant agitation procedure. Then, the remaining 75 teeth were randomly divided into five test groups (n=15 each) and were sequentially irrigated with 5% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid and 5% NaOCl. Following each irrigant application, different final irrigant agitation techniques were introduced for 60 s (3×20-s sessions). Group 1 received manual­ dynamic agitation, group 2 received passive ultrasonic agitation (PUI), group 3 received EndoActivator agitation, group 4 received photoninitiated photoacoustic streaming (PIPS) with the Er:YAG laser and group 5 received conventional syringe irrigation. Colony-forming units (CFUs) were counted in samples from the positive control and test groups. Data were analysed using Kruskal­ Wallis and post-hoc Mann­Whitney U multiple comparison tests. Results: E. faecalis elimination was significantly better in the experimental groups than in the positive control groups (p < 0.001). Manual­dynamic agitation and conventional syringe irrigation, with no significant differences between the two groups. Conclusion: Essentially, CFU reduction was significantly greater in the PUI, EndoActivator and PIPS groups than in the manual­dynamic agitation and conventional syringe irrigation groups (p <0.001) , with no significant differences among the former three groups. (AU)

Objetivo: O objetivo deste estudo in vitro foi comparar a eficácia de diferentes técnicas finais de agitação de irrigantes na remoção de biofilmes de Enterococcus faecalis de canais radiculares. Material e Métodos: No total, os canais radiculares de 85 dentes incisivos superiores unirradiculares humanos extraídos foram preparados usando o sistema Revo-S para um tamanho 40/06. O forame apical de cada dente foi selado por material compósito de resina fotopolimerizável para obstruir o vazamento bacteriano. Os espécimes foram esterilizados em autoclave a 121 ° C por 15 min e armazenados até uso posterior. Todos os dentes, exceto cinco (grupo controle negativo), foram inoculados com Enterococcus faecalis e incubados em câmara de CO2 a 37 ° C por 7 dias; o caldo de soja tripticase foi trocado a cada 2 dias. Para a determinação da possível formação de biofilme, cinco dos 80 dentes foram selecionados aleatoriamente como grupo controle positivo; um dos dentes do grupo controle positivo foi analisado para o desenvolvimento do biofilme por microscopia eletrônica de varredura (MEV) e estes dentes não receberam nenhum procedimento final de agitação irrigante. Em seguida, os 75 dentes restantes foram aleatoriamente divididos em cinco gruposteste (n = 15 cada) e irrigados sequencialmente com hipoclorito de sódio a 5% (NaOCl), ácido etilenodiaminotetracético a 17% e NaOCl a 5%. Após cada aplicação de irrigantes, diferentes técnicas finais de agitação foram introduzidas por 60 s (3 x 20 s sessões). Grupo 1 recebeu agitação manual-dinâmica, grupo 2 recebeu agitação ultra-sônica passiva (PUI), grupo 3 recebeu agitação EndoActivator, grupo 4 recebeu fotoacústica iniciada por fóton (PIPS) com o laser Er: YAG e grupo 5 recebeu irrigação convencional com seringa. As unidades formadoras de colônia (CFUs) foram contadas em amostras dos grupos controle positivo e teste. Os dados foram analisados utilizando testes de comparação múltipla Kruskal-Wallis e post-hoc Mann-Whitney U. Resultados: A eliminação de E. faecalis foi significativamente melhor nos grupos experimentais do que nos grupos de controle positivo (p < 0,001). Agitação manual-dinâmica e irrigação com seringa convencional, sem diferenças significativas entre os dois grupos. Conclusão: Essencialmente, a redução de UFC foi significativamente maior nos grupos PUI, EndoActivator e PIPS do que nos grupos de agitação manual-dinâmica e de seringa convencional (p < 0,001), sem diferenças significativas entre os três grupos anteriores (AU)