Debridement ability of the WaveOne Gold and TruNatomy systems in the apical third of root canals: ex vivo assessment.

Cleaning and shaping the root canal system are essential steps for performing successful endodontic therapy, and are challenging procedures in the apical region. This study aimed to conduct an ex vivo assessment of the debridement ability of the WaveOne Gold (Medium 35/.06) and TruNatomy (Medium 36/.03) systems in the apical third of round root canals of mandibular premolars. Forty-eight teeth, extracted for orthodontic or periodontal reasons, were divided into three groups (n=16), as follows: Group C, control (without instrumentation or irrigation); Group WOG, instrumentation with WaveOne Gold; Group TN, instrumentation with TruNatomy. A total of 40 mL of 2.5% sodium hypochlorite and 5 mL of 17% ethylenediamine tetraacetic acid were used per root canal in all the groups. Ten 0.5-µm serial cross-sections per specimen were obtained every 0.2 mm from a 2-mm segment of the apical region, extending from 1 to 3 mm short of the root apex. The sections were stained with hematoxylin-eosin and analyzed under a digital microscope (100x). The percentages of unprepared walls and remaining debris were quantified using ImageJ software. Generalized linear models were used to analyze the results (α=5%). Groups WOG and TN had significantly lower percentages of unprepared walls and remaining debris than Group C (p<0.05). There was no significant difference between groups WOG and TN for either of the variables studied (p>0.05). Instrumentation with the WaveOne Gold Medium and TruNatomy Medium instruments was associated with equivalent percentages of unprepared walls and remaining debris in the apical third of round canals of mandibular premolars.

Analysis of antimicrobial efficacy of sodium hypochlorite and ozonated water against biofilm in oval canals.

This in vitro study compared the antimicrobial efficacy of 2.5% sodium hypochlorite (NaOCl) and 8 µg/mL ozonated water agitated by passive ultrasonic irrigation (PUI) or PUI combined with EndoActivator (EA) against mature multispecies biofilm. One hundred and five oval-shaped mandibular premolars were instrumented, sterilized, and inoculated with Enterococcus faecalis, Candida albicans, and Staphylococcus aureus, divided into: control group - saline; O3 group - ozonated water; O3 PUI group - ozonated water with PUI agitation; O3 PUI+EA group - ozonated water with PUI+EA agitation; NaOCl group - NaOCl; NaOCl PUI group - NaOCl with PUI agitation; and NaOCl PUI+EA group - NaOCl with PUI+EA agitation. Microbiological samples were collected before (S1) and after (S2) the disinfection procedures and the data were statistically analyzed using the Kruskal-Wallis test. In the culture method, there was significant disinfection in the O3 PUI+EA, NaOCl, NaOCl PUI, and NaOCl PUI+EA groups (p˂0.05). The combination of NaOCl with PUI+EA reduced microbial counts to zero (p˂0.05). In the qPCR method, there was a significant reduction in the total count of viable microorganisms in the O3 PUI, O3 PUI+EA, NaOCl, NaOCl PUI, and NaOCl PUI+EA groups (p˂0.05). It can be concluded that 2.5% NaOCl with and without agitation, as well as 8 µg/mL ozonated water with its action enhanced by the agitation techniques, were effective in root canal disinfection, and their antimicrobial efficacy is related to the microorganisms present in the biofilm.

Microtomographic Assessment of the Shaping Ability of the Hyflex CM and XP-endo Shaper Systems in Curved Root Canals.

OBJECTIVE: This study compared the shaping ability of the Hyflex CM and XP-endo Shaper rotary file systems in curved mesial canals of mandibular molars using micro-computed tomography. MATERIAL AND METHODS: Seventeen mesial roots of extracted first mandibular molars with two independent mesial canals were scanned before and after root canal preparation with the tested rotatory file systems. Each mesial canal from the same specimen was prepared with one of the two systems. The parameters analyzed were canal centering (transportation) for the cervical, middle, and apical segments, as well as for the entire canal (0-10 mm from the apex); and canal volume increase, canal surface area increase, and unprepared canal walls for two segments, 0 to 4 mm and 0 to 10 mm from the apex. RESULTS: There was no significant difference between both systems regarding canal centering (transportation), volume increase, and unprepared canal walls for the 0 to 10 mm segment (p> 0.05); however, a significant difference was observed for the 0 to 4 mm segment (p <0.01), where the Hyflex CM left 28.46% of unprepared walls and XP-endo Shaper left 13.26%. CONCLUSIONS: The shaping ability of the two tested rotatory file systems in mesial roots of first mandibular molars was similar for all parameters in all the segments evaluated, except for the 0 to 4 mm segment, where XP-endo Shaper left a smaller area of unprepared canal walls than Hyflex CM.

Microtomographic Evaluation of Canal Centralization and Dentine Removal after Canal Preparation with Two Rotary Systems: HyFlex EDM and ProTaper Next.

OBJECTIVE: This study compared the ProTaper Next (PTN; Dentsply Sirona, Tulsa, Oklahoma, United States) and HyFlex EDM (HEDM; Coltene/Whaledent AG, Alstätten, Switzerland) systems using micro-computed tomography (CT). MATERIALS AND METHODS: Twenty-one mesial roots classified as Vertucci's type IV from extracted mandibular first molars with curvatures between 20 and 40 degrees were selected. The teeth were scanned using a micro-CT before and after root canal preparation by both systems, applied to the same root, in alternating canals. The following parameters were analyzed: canal centering, apical transportation, root canal diameter/root diameter. RESULTS: No statistically significant differences between both systems were observed for any of the assessed morphological parameters (p > 0.05). All canals presented diameter enlargement of more than 40% in relation to root diameter in the cervical and middle segments. No statistically significant difference was noted between the HEDM and PTN groups. The wear percentage for the HEDM group in the cervical and middle thirds were 49.66 ± 8.65 and 46.48 ± 14.29, respectively, and 51.02 ± 11.81 and 45.48 ± 10.79 for the PTN group, respectively. CONCLUSION: Both systems displayed similar mandibular molar mesial canals preparation, with no differences noted for any of the assessed parameters. Both groups showed increased canal diameter in the cervical and middle thirds by more than 40%.

In Vivo Evaluation of Painful Symptomatology after Endodontic Treatment Performed Using Two Different Irrigation Needle Insertion Depths.

OBJECTIVE: The main purpose of this study was to evaluate pain symptoms in patients after endodontic treatment performed in a single session in teeth with vitality or pulp necrosis, comparing two depths of insertion of the NaviTip irrigation needle. MATERIALS AND METHODS: One-hundred upper uniradicular teeth were selected and divided into four groups (n = 25), namely Bio group 1 (live pulp/1 mm from the foramen), Bio group 3 (live pulp/3 mm from the foramen), Necro group 1 (pulp necrosis/1 mm from the foramen), and Necro group 3 (pulp necrosis/3 mm from the foramen). All canals were instrumented with Wave One Gold System. Irrigation was performed using 2.5% NaOCl. The teeth were filled using the single-cone technique with AH Plus sealer using a McSpadden compactor. After treatment, patients answered a questionnaire with a visual analog scale scored from 0 to 10 at 1, 3, and 7 days after treatment. STATISTICAL ANALYSIS: Data were analyzed using Mann-Whitney U, Wilcoxon, and Friedman tests. RESULTS: There was a decrease in average pain levels at the three time points for both vital and necrotic teeth (p < 0.05). There were no significant differences in postoperative pain levels comparing needle depth, or vitality and pulp necrosis (p > 0.05). The percentage of mild pain increased over time and moderate pain decreased, regardless of pulp condition. There was no incidence of acute pain at any time. CONCLUSIONS: Post-treatment endodontic pain levels in upper uniradicular teeth with or without pulp vitality resulted in similar pain scores, regardless of the depth of insertion of the irrigation needle in relation to the apical foramen.

Effect of immersion in sodium hypochlorite on the cyclic fatigue resistance of three rotary instruments.

CONTEXT: It is essential to know if the immersion in sodium hypochlorite (NaOCl) influences the cyclic fatigue resistance of nickel-titaniumm (NiTi) files. AIM: This study was aimed to evaluate the resistance to the cyclic fatigue of three NiTi systems, as well as the influence of 5.25% NaOCl on their resistance. METHODS: Files from the Sequence Rotary File (MK life, Porto Alegre, Brazil), ProTaper Next (PTN) (Dentsply, Maillefer, Baillagues, Switzerland), and HyFlex EDM (Coltène Whaledent, Allstatten, Switzerland) systems were tested and separated into Group 1)-without immersion in NaOCl solution and Group 2 and Group 3-immersed in 5.25% NaOCl solution, for 1 min, and 5 min, respectively. All instruments were submitted to the cyclic fatigue test. Images of the instruments were observed by scanning electron microscopy, to evaluate the type of defect presented on the fractured surface. The test performed for the analysis of two independent factors was a two-way analysis of variance. RESULTS: HyFlex EDM presented a greater number of cycles until fracture when compared to others (P < 0.001). The control group showed a greater number of cycles until fracture than the same instruments submitted to NaOCl (P < 0.001). Sequence instruments showed the lowest values of cycles until fracture (P < 0.001). There was no statistically significant difference between treatments (P = 0.998). PTN, showed intermediate values of fracture resistance when compared to the HyFlex EDM and sequence instruments (P < 0.001), but without intragroup differences (P = 0.437). CONCLUSIONS: Hyflex EDM instruments were the most resistant to cyclic fatigue.

The Effectiveness of Three Irrigation Systems in the Enterococcus faecalis Reduction after Instrumentation with a Reciprocating Instrument.

OBJECTIVE: This study aimed to analyze the effectiveness of three irrigation systems: EndoActivator, passive ultrasonic irrigation (PUI), and Easy Clean in the reduction of Enterococcus faecalis, after instrumentation with the reciprocating system, through microbiological collection and culture method. MATERIALS AND METHODS: A total of 60 extracted human lower premolars were used and standardized at 16 mm in length. The teeth were accessed, contaminated with E. faecalis, and incubated for 21 days at 37°C. Initial collections (S1) were made with an absorbent paper cone to confirm the contamination; subsequently, instrumentation was performed with WaveOne Primary. The teeth were divided into four groups according to the final irrigation protocol (n = 15): group 1. EndoActivator; group 2, PUI; group 3, Easy Clean; and group 4, control group irrigated with saline solution sterile and without agitation. In the final irrigation, the agitation of the 17% ethylene amine tetra-acetic acid (EDTA) solutions was used, then 2.5% sodium hypochlorite (NaOCl); in both for this, three cycles of 20 seconds each. After the chemical-mechanical preparation and agitation of the irrigating solutions, the final collections (S2) for counting the colony-forming units (CFU/mL) occurred. RESULTS: The Kruskal-Wallis test revealed that all the agitation systems reduced by 100% and the control group by 65.7%. CONCLUSION: The control group presented a significantly higher amount of CFU/mL after the chemical-mechanical preparation than the other groups, which were similar to each other (p > 0.05).

Debris Apically Extruded by Two Reciprocating Systems: A Comparative Quantitative Study.

OBJECTIVE: The objective of this study was to quantify the amount of debris apically extruded after instrumentation with two reciprocating systems. MATERIALS AND METHODS: Forty-two single-rooted mandibular premolars with only one straight root canal and apical diameter compatible with a no. 15 K-file were randomly divided into two groups (n = 21) according to the instrument used: ProDesign R (Easy Equipamentos; Belo Horizonte, Minas Gerais, Brazil) and Reciproc Blue (VDW; Munich, Germany). Dry Eppendorf tubes were weighed three consecutive times for the initial mean weight. A silicone stopper was then fitted into the mouth of the tube. Each tooth was inserted through the stopper up to the cementoenamel junction and instrumented with one of the two systems to the predetermined working length (18 mm). The root canals were instrumented per root thirds. At each instrumented root third, the canal was irrigated with 3 mL of double-distilled water, followed by patency control. Each stopper was then separated from the tube and tubes were incubated at 70°C for 5 days. Tubes were again weighed, and the amount of extruded debris was calculated by subtracting the initial mean weight from the final mean weight. STATISTICAL ANALYSIS: Results were analyzed using the Mann-Whitney test at a 5% significance level. RESULTS: No significant difference was observed in debris extrusion between the ProDesign R and Reciproc Blue systems (p = 0.7557). CONCLUSIONS: The two reciprocating systems tested produced similar amounts of postinstrumentation apically extruded debris.

Assessment of Extrusion and Postoperative Pain of a Bioceramic and Resin-Based Root Canal Sealer.

OBJECTIVES: The objective of this study was to compare a bioceramic and a resin-based endodontic sealer with regard to extrusion and postoperative pain. MATERIALS AND METHODS: Sixty-four patients requiring endodontic treatment of single-rooted maxillary teeth with necrotic pulps were included in this study. The root canal treatments were performed in a single visit using a size 40.06 single-file reciprocating system under 2.5% NaOCl irrigation. After irrigation with 17% ethylenediaminetetraacetic acid (EDTA) and 2.5% NaOCl, the canals were dried and randomly divided into two different groups (n = 32) depending on the sealer used: resin-based group (RG) in which the canals were filled with the AH Plus, and the bioceramic group (BG) in which the canals were filled with the Sealer Plus BC. Ibuprofen (600 mg) was prescribed every 6 hours if the volunteers experienced pain. The patients registered their pain sensation in a visual analog scale (VAS) card, ranging from 0 to 10 at 24-hour, 48-hour, 72-hour, and 1-week intervals. STATISTICAL ANALYSIS: For statistical analysis, the level of significance was set at p < 0.05. RESULTS: Sealer extrusion occurred in nine patients of the RG and in 19 patients of the BG (p < 0.05). The average pain level at 24-hour and 48-hour intervals was, respectively, 1.46 ± 1.96 and 0.44 ± 0.86 for RG, and 1.21 ± 2.09 and 0.09 ± 0.38 for BG. There was no report of pain after 48 hours. The mean number of tablets taken for pain relief was 0.03 ± 0.17 for RG and 0.06 ± 0.24 for BG. No statistically significant difference was found with regard to pain level and intake of pain killer tablets (p > 0.05). CONCLUSIONS: The BG sealer presented significantly more extrusion than the RG sealer. Sealer extrusion was not associated with pain. The average pain level and the mean number of tablets taken for pain relief were similar in both groups.

Comparative in vitro analysis of the antifungal activity of different calcium silicate-based endodontic sealers

Aim: This study aimed to perform an in vitro comparative analysis of the antifungal activity of different calcium silicate-based endodontic sealers against three fungal species. Methods: The antifungal properties of three calcium silicate-based sealers were tested: Bio-C Sealer, Cambiar a Sealer Plus BC, and MTA-Fillapex. Two commonly used sealers were used as controls: AH Plus and Endomethasone. An agar diffusion test was performed to analyze the antifungal activity of the sealers against Candida albicans, Candida glabrata, Candida tropicalis, and a mixed microbial culture medium. The results were analyzed using ANOVA (p <0.05). Results: Endomethasone exhibited the highest inhibition against all strains examined, maintaining a consistent level of inhibition throughout 7 days. MTA-Fillapex demonstrated the best performance among the calcium silicate-based sealers for the three fungal species (p < 0.05), maintaining stable values over the 7 days, surpassing that of Endomethasone. Nevertheless, MTA-Fillapex only exhibited antimicrobial effect against the mixed culture for the first 24 hours, and no antimicrobial activity was observed at 48 hours, being surpassed by all tested sealers (p < 0.05). Conclusion: Of all silicate-based sealers tested, only MTA-Fillapex exhibited promising antifungal activity. Nevertheless, care must be taken when extrapolating these results, as MTA-Fillapex exhibited poor antimicrobial activity when tested in mixed microbial cultures

Debridement ability of the WaveOne Gold and TruNatomy systems in the apical third of root canals: ex vivo assessment

Abstract Cleaning and shaping the root canal system are essential steps for performing successful endodontic therapy, and are challenging procedures in the apical region. This study aimed to conduct an ex vivo assessment of the debridement ability of the WaveOne Gold (Medium 35/.06) and TruNatomy (Medium 36/.03) systems in the apical third of round root canals of mandibular premolars. Forty-eight teeth, extracted for orthodontic or periodontal reasons, were divided into three groups (n=16), as follows: Group C, control (without instrumentation or irrigation); Group WOG, instrumentation with WaveOne Gold; Group TN, instrumentation with TruNatomy. A total of 40 mL of 2.5% sodium hypochlorite and 5 mL of 17% ethylenediamine tetraacetic acid were used per root canal in all the groups. Ten 0.5-μm serial cross-sections per specimen were obtained every 0.2 mm from a 2-mm segment of the apical region, extending from 1 to 3 mm short of the root apex. The sections were stained with hematoxylin-eosin and analyzed under a digital microscope (100x). The percentages of unprepared walls and remaining debris were quantified using ImageJ software. Generalized linear models were used to analyze the results (α=5%). Groups WOG and TN had significantly lower percentages of unprepared walls and remaining debris than Group C (p<0.05). There was no significant difference between groups WOG and TN for either of the variables studied (p>0.05). Instrumentation with the WaveOne Gold Medium and TruNatomy Medium instruments was associated with equivalent percentages of unprepared walls and remaining debris in the apical third of round canals of mandibular premolars.

Resumo A limpeza e modelagem do sistema de canais radiculares são etapas fundamentais para o sucesso da terapia endodôntica e são procedimentos desafiadores na região apical. O objetivo deste trabalho foi realizar uma avaliação ex vivo da capacidade de debridamento dos sistemas WaveOne Gold (Medium 35/.06) e TruNatomy (Medium 36/.03) no terço apical de canais radiculares circulares de pré-molares inferiores. Quarenta e oito dentes que haviam sido extraídos por razões ortodônticas ou periodontais foram divididos em três grupos (n=16),da seguinte forma: Grupo C, Controle (sem instrumentação nem irrigação); Grupo WOG, instrumentação com WaveOne Gold; Grupo TN, instrumentação com TruNatomy. Um total de 40 mL de hipoclorito de sódio a 2,5% e 5 mL de ácido etilenodiamino tetraacético a 17% foi utilizado por canal radicular em todos os grupos. Dez secções transversais em série de 0,5 μm por espécime foram obtidas a cada 0,2 mm de um segmento de 2 mm da região apical, estendendo-se desde 1 até 3 mm aquém do ápice radicular. As seções foram coradas com hematoxilina-eosina e analisadas sob um microscópio digital (100x). As porcentagens de paredes não tocadas e detritos remanescentes foram quantificadas utilizando-se o software ImageJ. Modelos lineares generalizados foram utilizados para analisar os resultados (α=5%). Os grupos WOG e TN apresentaram porcentagens significativamente menores de paredes intocadas e detritos remanescentes do que o grupo C (p<0,05). Não houve diferença significativa entre os grupos WOG e TN quanto a nenhuma das variáveis estudadas (p>0,05). A instrumentação com os instrumentos WaveOne Gold Medium e TruNatomy Medium foi associada a porcentagens equivalentes de paredes intocadas e detritos remanescentes no terço apical de canais circulares de pré-molares inferiores.

Analysis of antimicrobial efficacy of sodium hypochlorite and ozonated water against biofilm in oval canals

Abstract This in vitro study compared the antimicrobial efficacy of 2.5% sodium hypochlorite (NaOCl) and 8 µg/mL ozonated water agitated by passive ultrasonic irrigation (PUI) or PUI combined with EndoActivator (EA) against mature multispecies biofilm. One hundred and five oval-shaped mandibular premolars were instrumented, sterilized, and inoculated with Enterococcus faecalis, Candida albicans, and Staphylococcus aureus, divided into: control group - saline; O3 group - ozonated water; O3 PUI group - ozonated water with PUI agitation; O3 PUI+EA group - ozonated water with PUI+EA agitation; NaOCl group - NaOCl; NaOCl PUI group - NaOCl with PUI agitation; and NaOCl PUI+EA group - NaOCl with PUI+EA agitation. Microbiological samples were collected before (S1) and after (S2) the disinfection procedures and the data were statistically analyzed using the Kruskal-Wallis test. In the culture method, there was significant disinfection in the O3 PUI+EA, NaOCl, NaOCl PUI, and NaOCl PUI+EA groups (p˂0.05). The combination of NaOCl with PUI+EA reduced microbial counts to zero (p˂0.05). In the qPCR method, there was a significant reduction in the total count of viable microorganisms in the O3 PUI, O3 PUI+EA, NaOCl, NaOCl PUI, and NaOCl PUI+EA groups (p˂0.05). It can be concluded that 2.5% NaOCl with and without agitation, as well as 8 µg/mL ozonated water with its action enhanced by the agitation techniques, were effective in root canal disinfection, and their antimicrobial efficacy is related to the microorganisms present in the biofilm.

Resumo Este estudo in vitro comparou a desinfecção do hipoclorito de sódio 2,5% (NaOCl) e da água ozonizada 8 µg/mL agitados pela irrigação ultrassônica passiva (PUI) e por associação da PUI com EndoActivator (EA) na redução de biofilme misto maduro. Cento e cinco pré-molares inferiores ovalados foram instrumentados, esterilizados e inoculados com Enterococcus faecalis, Candida albicans e Staphylococcus aureus, divididos em: Grupo controle: soro; Grupo O3: água ozonizada; Grupo O3 PUI: água ozonizada agitada por PUI; Grupo O3 PUI + EA: água ozonizada agitada por PUI e EA: Grupo NaOCl: hipoclorito de sódio; Grupo NaOCl PUI: hipoclorito de sódio agitado por PUI; Grupo NaOCl PUI + EA: hipoclorito de sódio agitado por PUI e EA. Amostras microbiológicas foram coletadas antes (S1) e após (S2) os procedimentos de desinfecção e os dados foram analisados estatisticamente pelo teste de Kruskal-Wallis. No método de cultura, houve desinfecção significativa nos grupos O3 PUI + EA, NaOCl, NaOCl PUI e NaOCl PUI + EA (p˂0.05), sendo que no grupo NaOCl PUI + EA não houve crescimento de microrganismo (p˂0.05). No método de qPCR, nas contagens dos microrganismos antes e após os protocolos de desinfecção, houve redução microbiana nos grupos O3 PUI, O3 PUI + EA, NaOCl, NaOCl PUI, NaOCl PUI + EA (p˂0.05). Concluiu-se que o NaOCl 2,5% com e sem agitação foi eficiente, assim como a água ozonizada 8 µg/mL potencializada pelos métodos de agitação na desinfecção e que a mesma está relacionada com os microrganismos presentes no biofilme.

In vitro study of solubilization ability of bovine pulp tissue using different irrigating solutions

Introduction and Objective: The aim of this study was to evaluate in vitro the capacity of solubilization of bovine pulp tissue, promoted by the following auxiliary chemical solutions: 2.5% sodium hypochlorite at pH 9, 5.25 % sodium hypochlorite at pH 9, 2% chlorhexidine gel at pH 6, 17% EDTA at pH 7, and Smear-Clear®. Material and methods: A total of ten specimens of bovine pulp tissue, weighing 1.65 g each, were placed into flasks connected to a device developed for the study in order to reproduce irrigation dynamics. The flasks with the specimens received a volume of 80 ml of irrigating solution and the experimental times were 15, 30, 45 and 60 minutes. Results: The results were analyzed statistically by Kruskal-Wallis test to compare the different experiment times (15, 30, 45 and 60 minutes) of each irrigating solution. To compare the variation among the times of one solution, Kolmogorov-Smirlov test (Lilliefors) was used. Conclusion: Considering the results obtained and the limitations of the study, it can be concluded that 5.25% sodium hypochlorite exhibited the greatest solubilization ability, followed by 2.5% sodium hypochlorite, Smear-Clear®, 17% EDTA and 2% chlorhexidine gel.

Comparação entre os sistemas rotatórios Pathfile + Protaper Universal e Twisted Files quanto à preservação da morfologia e ao tempo de trabalho despendido na preparação de canais curvos / Comparison of preparation time and ability to maintain canal morphology in curved canals: Pathfile + Protaper Universal versus Twisted Files

Introdução: Instrumentos rotatórios em níquel-titânio (NiTi) reduzem erros processuais e o tempo requerido para a preparação do canal radicular. Objetivo: Comparar dois sistemas de instrumentação rotatória NiTi - Pathfile + ProTaper Universal e Twisted Files - quanto à capacidade de preservação da morfologia do canal e quanto ao tempo de trabalho necessário para a preparação de canais curvos. Material e Método: Os canais mesiais de 32 molares inferiores humanos (com ângulos de curvatura entre 20 e 40 graus) foram selecionados para o estudo. As amostras foram divididas aleatoriamente em dois grupos de 16 canais. Os preparos foram realizados por um Endodontista, utilizando-se a combinação dos instrumentos rotatórios Pathfile e ProTaper Universal (grupo PT) e os instrumentos rotatórios Twisted Files (grupo TF). Três Endodontistas analisaram imagens com a técnica da dupla radiografia digital, pré e pós-instrumentação, para avaliar se ocorreu transporte apical e/ou aberrações na morfologia dos canais. Por meio de uma análise computadorizada e com o auxílio de magnificação, as imagens inicial e final do canal radicular foram comparadas por meio de sua sobreposição. O teste de odds ratio foi utilizado para a comparação dos níveis de preservação da morfologia do canal, e ANOVA, complementada pelo teste de Tukey, foi utilizada para a comparação dos tempos de preparo. O nível de significância adotado foi de 5%. Resultado: Ocorreram desvios na trajetória do canal em ambos os grupos, mas a diferença entre estes não foi significativa. O tempo de trabalho requerido pela combinação dos sistemas Pathfile + ProTaper Universal foi significativamente maior do que o requerido pelo sistema Twisted Files. Conclusão: Os dois sistemas apresentaram performances semelhantes em relação à preservação da trajetória do canal; no entanto, o tempo de trabalho requerido pelo sistema Twisted Files foi menor.

Introduction: Nickel-titanium (NiTi) rotary instruments reduce procedural errors and the time required for root canal preparation. The aim of this study was to compare two rotary NiTi instrumentation systems-Pathfile + ProTaper Universal versus Twisted Files-as to their ability to maintain original canal morphology and the time they require to prepare curved root canals. Material and Method: The mesial canals of 32 human mandibular molars (with curvature angles between 20 and 40 degrees) were selected for the study, and divided at random into two groups of 16 canals each. The canals were prepared by an endodontist using either the combination of Pathfile and ProTaper Universal instruments (Group PT) or Twisted Files (Group TF). The double digital radiograph technique, pre- and post-instrumentation, was used by three endodontists to assess whether apical transportation and/or aberration in root canal morphology occurred. The initial and final images of the root canals were compared by superimposition through computerized analysis and with the aid of magnification. The odds ratio test was used to compare root canal morphology preservation, and ANOVA complemented by Tukey's test was used to compare preparation times. The significance level was set at 5%. Result: Deviation in root canal trajectory occurred in both groups, although the differences were not significant. The preparation time required by the Pathfile + ProTaper Universal combination was significantly longer than that required by the Twisted Files system. Conclusion: Both systems showed similar performances regarding the ability to maintain original root canal morphology; however, the preparation time required by the Twisted Files system was shorter.

Evaluation of cleaning efficacy of a nickel-titanium rotary system, with or without 17% EDTA passive ultrasonic activation: a scanning electron microscopic study

Introduction: The goal of endodontic instrumentation is to promote root canal cleaning and shaping to prepare it for the subsequent three-dimensional filling. Objective: The aim of this study was to evaluate, ex vivo, root canal cleaning ability executed by nickel-titanium rotary system instrumentation and this same system plus ultrasound passive activation of 17% EDTA, through SEM. Material and methods: Seventy upper second single-rooted human bicuspids were used. All teeth presented a single root canal, flattened towards buccal-palatal direction. The teeth were randomly separated into 3 groups. Group 1 (n = 30), had the canals instrumented by using the original operative sequence of ProTaper Universal System, up to instrument #F3. In this group, 5 ml of 5.25% sodium hypochlorite was employed as irrigant, every each instrument change. After group 1 instrumentation, root canals were irrigated with 5 ml of 17% EDTA, which was kept inside the canal for 3 minutes. Next, a final irrigation with 5 ml of 5.25% NaOCl was performed to remove the smear layer in suspension. Group 2 (n = 30) had the canals instrumented by the same system and up to the same instrument size. It was used 5.0 ml of 5.25% NaOCl as irrigant substance every each instrument change. In group 2, however, 17% EDTA (5 ml) was applied through ultrasonic passive activation for 1 minute, and then leaving the substance for 2 minutes within root canal.A final irrigation and with 5.25% NaOCl was also performed. Group 3 (n = 10) was the control group, where the canals were not instrumented and irrigation was executed with saline solution. After that, the teeth were cut into their long axis, metalized and taken for SEM analysis, at x2000 magnification. Each tooth's cervical, middle and apical thirds were observed. The cleaning quality of root canal's walls was observed by the images analyzed by three examiners. Results: Data were statistically analysed by analysis of variance and Tukey test, with a significance level of 5%. The control group showed an average score of the presence of smear layer of 3.41; group 1 (ProTaper) of 2.34; and the group 2 (ProTaper+Ultrassound) of 0.60. Conclusion: None of the studied preparation techniques promoted the total cleaning of the root canal walls. The addition of the ultrasound passive activation, after rotary instrumentation, promoted an increase of the smear layer removal, improving the cleaning of root canal wall. The apical third obtained the smallest cleaning rate, regardless of the technique employed.

Location of three canals in the mesiobuccal root of the maxillary first molar

Introduction:The knowledge on the complex anatomy of the maxillary first molar and location of extra canals are essential for diagnosis and endodontic treatment success. Objective:The purpose of this study was to report a clinical case showing a varied number of root canals in maxillary molars with the aid of the operating microscope (OM). Case report: The endodontic retreatment of the right maxillary first molar with unusual anatomical variation was performed, displaying three canals in the mesiobuccal root (MB), a root canal in the distobuccal root (DV) and a root canal in the palatal root (P). To remove the resin core inside pulp chamber with and without the aid of dental operating microscope, a high-speed drill and ultrasonic tip (diamond round) was used, respectively, for the refinement of the pulp chamber walls. The dental operating microscopewas used during the access surgery, location, negotiation of canals and checking of the completion of all stages of the retreatment. Subsequently, the cleaning, shaping and filling of the root canal system was completed. The presence of three canals in the mesiobuccal root, one in the distobuccal root and one in the palatal root was found. Conclusion: Variations in the number of canals could be confirmed during the surgery access in endodontic retreatment cases with the aid of dental operating microscope.

Comparison of the effectiveness of the protaper system versus hand instrumentation in endodontic retreatment: a scanning electron microscopy study

Introduction: Several rotary systems have been evaluated for removal of endodontic filling materials from the canal. Moreover, studies focusing on the comparison of the effectiveness of rotary systems versus hand instrumentation have yielded mixed results in terms of the efficacy and amount of time required by each technique. Objective: To compare the effectiveness of a nickel-titanium rotary system and of hand instrumentation using stainless steel files and Gates-Glidden burs in the removal of gutta-percha from root canals, as well as the time required to complete the procedure by each method. Material and methods: Forty single-rooted teeth were prepared and obturated then divided in two groups, according to the method employed for removal of the gutta-percha: ProTaper Universal rotary retreatment system (rotary instrumentation) and stainless steel hand files with Gates-Glidden burs (hand instrumentation). The time required to remove gutta-percha by each method was recorded. Roots were then sectioned lengthwise and the apical, middle, and coronal thirds were analyzed by SEM under two magnifications: x400 and x1,000. Results: Rotary instrumentation promoted better cleansing compared with hand instrumentation. The apical third was less clean than the coronal and middle thirds (Kruskal-Wallis p < 0.05). Rotary instrumentation was faster than hand instrumentation (Tukey p < 0.05). Conclusion: Although none of the methods promoted complete cleanliness of the canal walls, ProTaper Universal system showed better results and was faster than hand instrumentation.

Persistent infection in root-filled tooth: an SEM morphological analysis after apical microsurgery

Introduction and Objective: Endodontic failure can be associated to well-conducted treatments due to microbial factors characterized by intra or extraradicular infections not eliminated during endodontic treatment. Case report: This report describes a case of persistent apical periodontitis of an asymptomatic maxillary lateral incisor endodontically retreated and subsequently subject to apical surgery. Conclusion: After SEM morphological analysis of the apical fragment, areas of cementum-dentin resorption that were probably responsible for the perpetuation of the disease process were observed.

Comparison of MTA Fillapex radiopacity with five root canal sealers

Introduction: The endodontic sealer is a filling material whose physicochemical properties are mandatory for the achievement of endodontic therapy final goal. An ideal endodontic sealer should have some properties, including radiopacity. Objective: This study compared MTA Fillapex™ radiopacity with the radiopacity of five others endodontic sealers: Endométhasone-N™, AH Plus™, Acroseal™, Epiphany SE™ and RoekoSeal™. Material and methods: Five cylindrical samples of each sealer were used, constructed with the aid of a matrix. On an occlusal film, a sample of each sealer was placed along with an aluminum stepwedge and five radiographic shots were taken. The radiographic images were digitized and each sample's gray scales were compared with each shade of the aluminum stepwedge, by using software. Results: The results, in decreasing order of radiopacity, were: AH Plus™ was statistically the most radiopaque sealer (9.4 mm Al), followed by Epiphany SE™ (7.8 mm Al), MTA Fillapex™ (6.5 mm Al), RoekoSeal™ (5.8 mm Al), Endométhasone-N™ (4.5 mm Al), and Acroseal™, the least statistically radiopaque (3.5 mm Al). Conclusion: It can be concluded that MTA Fillapex™ was the third most radiopaque sealer among all tested sealers. Also, MTA Fillapex™ has the radiopacity degree in agreement with ADA specification No. 57 (1983).

Radiopacidade de sete cimentos endodônticos avaliada através de radiografia digital / Radiopacity of seven endodontic sealers evaluated using digitized radiograph

Objetivo: Determinar a radiopacidade de sete cimentos endodônticos, dois à base de hidróxido de cálcio - Sealapex e Apexit, três resinosos- Sealer 26, AH Plus e EndoRez e dois cimentos à base de óxido zinco e eugenol - Intrafill e Endomethasone, através de imagens radiográficas digitais obtidas pelo método indireto. Métodos: Confeccionaram-se cinco placas de acrílico com nove cavidades cada, nas quais foram inseridos os cimentos estudados. Como controle foi utilizado a guta-percha e para se obter um parâmetro da radiopacidade fragmentos de dentina do mesmo tamanho dos corpos de prova foram utilizados. As placas foram radiografadas e as películas digitalizadas com resolução de 400 dpi no formato de tons de cinza, sendo posteriormente as imagens analisadas com o uso do software Image Tool v.3.00. Este tipo de análise determina os níveis de cinza. Resultados: Com os valores da média em pixels de radiopacidade obtidas, a ordem dos cimentos do mais radiopaco para o menos foi: AH Plus, EndoRez, Intrafill, Sealer 26, Endomethasone, Apexit e Sealapex. Conclusão: Todos os cimentos avaliados apresentaram radiopacidade maior que a da dentina e somente o AH Plus foi maior que a da guta-percha.

Objective: Determine the radiopacity of seven root canal sealers, two based on calcium hydroxide - Sealapex Apexit and three resin - Sealer 26, AH Plus and EndoRez and two cements based on zinc oxide and eugenol - Intrafill and Endomethasone through digital radiographic images obtained by the indirect method. Methods: Five-confected acrylic plates with nine holes each, which were inserted in the cements studied. As control was used gutta-percha and to obtain a parameter of the radiopacity of dentin fragments of the same size of the specimens were used. The plates were radiographed and the film scans with a resolution of 400 dpi in grayscale format, the images were later analyzed using the Image Tool v.3.00 software. This type of analysis determines the levels of gray. Results: With the values of the average pixel radiopacity obtained, the order of the most radiopaque cements to least were: AH Plus, EndoRez, Intrafill, Sealer 26, Endomethasone, Apexit and Sealapex. Conclusion: All sealers showed radiopacity greater than that of dentin and only the AH Plus was greater than that of gutta-percha.