Estudio comparativo de los tiempos registrados por los instrumentos TruNatomy y ProTaper Next para alcanzar la longitud de trabajo en conductos curvos simulados obturados con GuttaCore / Comparative study of the times recorded by the TruNatomy and ProTaper Next instruments to reach the working length in simulated curved canals filled with GuttaCore

Objetivo: Comparar el tiempo empleado por los instrumen- tos TruNatomy Medium y ProTaper Next X3 para penetrar hasta la longitud de trabajo la masa de obturaciones realizadas con Gut- taCore Primary y sellador en conductos curvos simulados. Materiales y métodos: Se prepararon 20 conductos curvos simulados con instrumentos rotatorios WaveOne Gold Primary y se obturaron con GuttaCore Primary y AH Plus. Las muestras fueron divididas en dos grupos de 10 cada uno. Grupo 1: El material de obturación fue penetrado hasta la lon- gitud de trabajo con instrumentos TruNatomy Medium. Gru- po 2: El material de obturación fue penetrado hasta la longitud de trabajo con instrumentos ProTaper Next X3. Se registraron los tiempos de penetración requeridos para cada grupo y los valores obtenidos fueron analizados mediante la prueba t de Student. Resultados: Los instrumentos ProTaper Next X3 pe- netraron la masa del material de obturación más rápidamente que los instrumentos TruNatomy MediumTM. Las diferencias observadas entre ambos instrumentos fueron estadísticamente significativas (P <0.01). Conclusión: Si bien los instrumentos ProTaper Next X3 y TruNatomy MediumTM penetraron la masa de Gutta- Core Primary de manera eficiente, ProTaper Next X3 penetró hasta la longitud de trabajo más rápidamente (AU)

Aim: Compare the time required by the instruments TruNatomy Medium and ProTaper Next X3 to penetrate up to the working length the mass of fillings made with GuttaCore Primary and sealant in simulated curved canals. Materials and methods: The simulated canals of 20 EndoTraining Blocks were prepared with WaveOne Gold Pri- mary and obturated with GuttaCore Primary and AH Plus. The sample was divided into two groups of 10 each. Group 1: The sealing material was penetrated up to working length with TruNatomy Medium. Group 2: The sealing material was penetrated up to working length with ProTaper Next X3. The penetration time was recorded in each group and the obtained values were statistically analyzed with the Student's t test. Results: ProTaper Next X3 instruments penetrated the sealing material mass faster than TruNatomy Medium. Statis- tically significant differences were observed between the two instruments (P <0.01). Conclusion: While the ProTaper Next X3 and TruNat- omy Medium penetrated the GuttaCore mass to the working length efficiently, the ProTaper Next X3 did it in less time (AU)

Análisis Elemental de las Propiedades Morfológicas, Físicas y Químicas de Dos Instrumentos Rotatorios Protaper Universal / Elemental Analysis of the Morphological, Physical and Chemical Properties of Two Protaper Universal Rotary Instruments

Los instrumentos rotatorios utilizados en el tratamiento de conductos dentales necesitan cumplir con ciertas características físicas que le confieran un uso correcto, adecuado y seguro para su uso clínico. En el mercado comercial existen una serie de instrumentos importados que dejan en duda la autenticidad de estos debido a sus bajos costos. En este estudio evaluamos física, química y morfológicamente dos kits de instrumentos rotatorios Protaper universal (Dentsply) mediante análisis de MEB, EDX, microdureza y EDS. Uno de los kits (grupo 1) se adquirió directamente de la casa comercial y otro kit importado que a simple vista no parecía cumplir con los estándares de calidad de un correcto empaquetado (grupo 2). En el análisis de MEB se observaron características morfológicas muy diferentes entre ambos kits, el grupo 2 presentó diversas irregularidades en la superficie de las limas, sin embargo, en el EDS no se encontró diferencia alguna. En cuanto al análisis de microdureza se observó una estadística estadísticamente significativa y en el EDS se observaron mayores picos de intensidad en cuanto a la aleación de Ni-Ti en el grupo 2. Estos resultados sugieren que existen instrumentos rotatorios importados que a pesar de su bajo costo pueden presentar ciertas características muy similares a los kits auténticos, sin embargo, física y químicamente pueden resultar en un riesgo para su uso clínico debido a la diferencia entre estos.

Rotatory files are instruments used in the treatment of dental canals roots. These instruments need to comply with certain physical characteristics for a correct, adequate and safe use for clinical use. In the commercial market there are a series of imported instruments that cast doubt on their authenticity due to their low costs. In this study we physically, chemically and morphologically evaluated two Protaper universal rotary instrument kits (Dentsply) using SEM, EDX, microhardness and EDS analysis. One of the kits (group 1) was purchased directly from the commercial house and another imported kit that a simple view did not seem to meet the quality standards of a correct packaging (group 2). In the SEM analysis, very different morphological characteristics were observed between both kits, group 2 presented various irregularities on the surface of the files, however, no difference was found in the EDS. Regarding the microhardness analysis, a statistically significant statistic was observed and in the EDS, higher intensity peaks were observed in terms of the Ni-Ti alloy in group 2. These results suggest that there are imported rotary instruments that despite their low cost can present characteristics very similar to authentic kits, however, physically and chemically they can result in a risk for their clinical use due to the difference between them.

In Vitro Evaluation of a Recently Developed Rotary File: AF Rotary / Avaliação in vitro de um arquivo rotativo desenvolvido recentemente: AF Rotary

Objective: Aim of the present study is to evaluate mechanical properties of a newly developed rotary file, AF Rotary (Fanta Dental, Shanghai, China), and to compare these features with a worldwide spread rotary file, Protaper Gold F2 (PTG F2; Dentsply Maillefer, Ballaigues, Switzerland). Material and Methods: 60 AF Rotary 25.06 and 60 PTG F2 were divided in three groups of 20 files each. A group underwent to cyclic fatigue resistance tests, second group underwent to torsional resistance tests, third group underwent to bending tests. The statistical analysis was performed using t student test with significance level set at 95% (p < 0.05). Results: AF Rotary showed significantly higher torsional resistance and cyclic fatigue resistance (p < 0.05) when compared to the PTG F2. AF Rotary also showed significantly lower bending resistance (p < 0.05) when compared to the PTG F2. Conclusion: Therefore, within the limitations of this study, the results show better performances for AF Rotary compared to PTG F2 regarding the cyclic fatigue test, the torsional test and the bending test. Since the PTG F2 is a commonly used and widely investigated instrument it could be possible to state that the AF Rotary exhibits remarkable in vitro performances. (AU)

Objetivo: O objetivo do presente estudo é avaliar as propriedades mecânicas de uma lima rotativa recém-desenvolvida, AF Rotary (Fanta Dental, Shanghai, China), e comparar essas características com uma lima rotativa mundialmente difundida, Protaper Gold F2 (PTG F2; Dentsply Maillefer, Ballaigues, Suíça). Material e Métodos: 60 AF Rotary 25.06 e 60 PTG F2 foram divididos em três grupos de 20 arquivos cada. Um grupo foi submetido a testes de resistência à fadiga cíclica, o segundo grupo foi submetido a testes de resistência à torção, o terceiro grupo foi submetido a testes de flexão. A análise estatística foi realizada por meio do teste t student com nível de significância de 95% (p <0,05). Resultados: AF Rotary apresentou resistência torcional e resistência à fadiga cíclica significativamente maiores (p <0,05) quando comparado ao PTG F2. AF Rotary também apresentou resistência à flexão significativamente menor (p <0,05) quando comparado ao PTG F2. Conclusão: Portanto, dentro das limitações deste estudo, os resultados mostram melhores desempenhos do AF Rotary em relação ao PTG F2 no que diz respeito ao teste de fadiga cíclica, ao teste de torção e ao teste de flexão. Uma vez que o PTG F2 é um instrumento comumente usado e amplamente investigado, pode-se afirmar que o AF Rotary exibe desempenhos in vitro notáveis. (AU)

Evaluación de la resistencia a la flexión de limas rotatorias Protaper Gold, 2Shape, V-Taper Fanta Gold / Evaluation of flexion resistance of Protaper Gold rotary limes, 2Shape, V-Tapert Fanta Gold

Antecedentes: Las limas rotatorias de níquel-titanio con tratamiento termomecánico se desarrollaron para permitir una mayor flexibilidad al instrumentar los conductos radiculares. Los instrumentos permitieron a los operadores tratar las curvaturas de los conductos con mayor facilidad. Los fabricantes están tratando de producir limas que funcionen de manera más eficiente y segura. Conocer las propiedades de las limas comercializadas es especialmente importante porque ayuda a elegir un sistema de lima apropiado. El objetivo de este estudio fue evaluar la flexibilidad de tres limas diferentes de níquel-titanio (NiTi) con tratamiento termomecánico en dos puntos diferentes. Materiales y métodos: Se midió la flexibilidad de tres limas NiTi con tratamiento termomecánico (ProTaper Gold, 2Shape y V-Taper Fanta Gold). Cada lima fue sujetada a 3 mm y 7 mm (n = 10/longitud/lima) y se utilizó una máquina de ensayo universal para doblarla a una fuerza máxima. Todos los datos fueron analizados estadísticamente por análisis de varianza de una vía y prueba de Tukey post hoc (p = 0,05) para determinar cualquier diferencia significativa. Resultados: Se halló diferencias estadísticamente significativas (p < 0,05). En general, V-Taper Fanta Gold fue la más rígida, ProTaper Gold mostró los mayores valores de fuerza y su deformación fue significativamente más flexible. Conclusión: Las limas ProTaper Gold mostraron una mayor flexibilidad en comparación con las otras limas estudiadas. (AU)

Background: Nickel-titanium rotary files with thermomechanical treatment were developed to allow greater flexibility when instrumenting the root canals. The instruments allowed operators to deal with duct curvatures more easily. Manufacturers are trying to produce files that work better efficiently and safely. Knowing the properties of marketed files is especially important in helping you choose an appropriate file system. The objective of this study was to evaluate the flexibility of three different nickel-titanium (NiTi) files with thermomechanical treatment at two different points along the file. Materials and methods: The flexibility of three NiTi files with thermomechanical treatment (Protaper Gold, 2Shape and V-Taper Fanta Gold) was measured. Each file was clamped at 3 mm and 7 mm (n = 10 / length / file) and a universal testing machine was used to bend the files to a maximum strength. All data were statistically analyzed by one-way analysis of variance and post-hoc Tukey test (P = 0.05) to determine any significant differences. Results: There were statistically significant differences (P <0.05). In general, V-Taper Fanta Gold was the most rigid, Protaper Gold showed the highest values of force and deformation was significantly more flexible. Conclusión: Protaper Gold files showed greater flexibility compared to the other files studied. (AU)

Shaping ability of XP-endo Shaper and ProTaper Next in long oval-shaped canals: a micro-computed tomography study.

AIM: To evaluate the shaping ability of the single-file XP-endo Shaper system (XP-S; FKG Dentaire, La Chaux-de-Fonds, Switzerland) employing a different working time and of the multiple-file ProTaper Next system (Dentsply Sirona, Ballaigues, Switzerland) using micro-computed tomography (micro-CT) technology. METHODOLOGY: Twenty long oval-shaped canals in mandibular incisors were matched anatomically and scanned by micro-CT (Skyscan 1172; Bruker micro-CT, Kontich, Belgium). The canals were divided into two groups (n = 10) according to the canal preparation protocol: XP-endo Shaper (XP-S) with an extra 45 s of instrumentation and ProTaper Next (PTN X4). The images recorded before and after preparation were evaluated for morphometric measures of volume, surface area, structure model index and untouched walls. The data were compared statistically (Student's t-test for homogenous variances and Mann-Whitney test) between the two groups (XP-S and PTN X4) at α = 5%. RESULTS: Root canal preparation significantly increased all parameters (volume, surface area, structure model index and untouched walls) tested in each group (P < 0.05). There was no significant difference (P > 0.05) in the percentage increase of volume (107.50%-93.13%), surface area (27.74%-29.68%) or untouched canal wall (13.08%-11.74%) between XP-S and PTN X4, respectively. CONCLUSIONS: The XP-endo Shaper system (single-file) with an extra 45 s of instrumentation and the ProTaper Next system (multiple files) had a similar root canal shaping ability. Neither technique was able to fully prepare the long oval-shaped canals of mandibular incisors.

Análise do transporte apical e da capacidade de centralização de instrumentos mecanizados de níquel-titânio em molares inferiores: protaper gold e prodesing logic / Analysis of apical transport and centralization capacity of mechanized nickel-titanium instruments in lower molars: protaper gold and prodesing logic

Esta pesquisa objetivou avaliar as alterações morfológicas resultantes da instrumentação de 20 raízes mesias de molares humanos inferiores consideradas severamente curvas, e comparar os sistemas ProTaper Gold (PTG) e ProDesign Logic (PDL), através da análise do transporte apical e da capacidade de centralização, além do tempo necessário para preparo do canal radicular. A amostra foi constituída por vinte raízes mesiais de molares inferiores pareadas anatomicamente com base em dimensões morfológicas semelhantes usando avaliação por microtomografia computadorizada (micro-CT) (resolução = 19 µm) atribuídas a dois grupos experimentais (n = 10) de acordo com o sistema usado para a preparação do canal radicular: Grupo 1 ­ PTG e Grupo 2 ­ PDL. Em seguida, os espécimes foram novamente digitalizados e as imagens correspondentes dos canais mesias, pré e pós-instrumentação, foram examinadas em três níveis de secção transversal (3, 5 e 7 mm da extremidade apical da raiz) para analisar o transporte e a centralização do canal. Aplicou-se o teste estatístico de ANOVA, apresentando distribuição normal em relação ao transporte apical, não observando diferença estatística entre os grupos (p > 0,05). Para análise da capacidade de centralização foi observado distribuição não normal, e aplicou-se o teste Mann-Whitney, onde foi observado diferença estatística entre os grupos no nível de 5mm (p = 0,0410) onde PTG apresentou menor capacidade de centralização quando comparado ao grupo PDL. Não houve correlação entre as variáveis em questão. Em relação ao tempo efetivo para instrumentação, a análise demonstrou que houve diferença estatisticamente significativa entre os grupos (p < 0,0001), sendo realizado um pós-teste t de amostras relacionadas confirmando a diferença estatística (72.200; t = 9.3203; p < 0.001), sendo PDL mais rápido para alcançar o comprimento de trabalho (CT) do que o grupo PTG. Todos os procedimentos estatísticos foram realizados com nível de significância de 5%. Portanto, PTG e PDL tiveram resultados semelhantes em relação a ausência de transporte do canal, já PDL apresentou maior capacidade de centralização quando se refere ao nível de 5mm e se mostrou mais rápido que PTG por ter sido necessário um tempo menor de instrumentação. Ademais, todos os sistemas se apresentaram seguros para o uso clínico uma vez seguindo as recomendações dos fabricantes (AU).

This research aimed to evaluate the morphological changes resulting from the instrumentation of 20 mesial roots of severely curved lower human molars, and to compare the ProTaper Gold (PTG) and ProDesign Logic (PDL) systems through the analysis of apical canal transportation and centering ability beyond the time required for root canal preparation. The sample consisted of twenty anatomically paired lower molar mesial roots based on similar morphological dimensions using micro-CT evaluation (resolution = 19 µm) assigned to two experimental groups (n = 10) according to the system used for the preparation of root canal: Group 1 - PTG and Group 2 - PDL. The specimens were then digitized again and the corresponding mesial canal images, pre and post-instrumentation, were examined at three cross-sectional levels (3, 5 and 7 mm from the apical root end) to analyze apical canal transportation and centering ability. The ANOVA statistical test was applied, presenting normal distribution in relation to the apical canal transportation, not observing statistical difference between the groups (p> 0.05). For analysis of the centering ability, non-normal distribution was observed, and the Mann-Whitney test was applied, where a statistical difference was observed between the groups at the 5mm level (p = 0.0410) where PTG presented lower centering ability when compared to the PDL group. There was no correlation between the variables in question. Regarding the effective instrumentation time, the analysis showed that there was a statistically significant difference between the groups (p <0.0001), and a t-test was performed on related samples confirming the statistical difference (72.200; t = 9.3203; p < 0.001), being PDL faster to reach CT than the PTG group. All statistical procedures were performed with a significance level of 5%. Therefore, PTG and PDL had similar results in relation to the absence of apical canal transportation, PDL presented greater centering ability when referring to the 5mm level and was faster than PTG because a shorter instrumentation time was required. In addition, all systems were safe for clinical use once following manufacturers' recommendations (AU).

Changes in Geometry and Transportation of Root Canals with Severe Curvature Prepared by Different Heat-treated Nickel-titanium Instruments: A Micro-computed Tomographic Study.

INTRODUCTION: The aim of this study was to compare the shaping ability of 4 different nickel-titanium systems, considering their variation in alloy treatment, kinematics, and design, used to prepare canals with severe curvature using micro-computed tomographic analysis. METHODS: Thirty-two mesial roots of mandibular molars with severe curvature were matched based on similar morphologic dimensions and assigned to 4 experimental groups (n = 8) according to the canal preparation: ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (RC; VDW GmbH, Munich, Germany), Reciproc Blue (RCB, VDW GmbH), and TRUShape (TRU; Dentsply Tulsa Dental Specialties, Tulsa, OK) systems. Changes in 2-dimensional (area and perimeter) and 3-dimensional (volume, surface area, and structure model index) morphologic parameters as well as canal transportation were compared among groups using the analysis of variance post hoc Tukey tests with the significance level set at 5%. RESULTS: Preparation significantly increased all analyzed parameters. No statistically significant differences (P > .05) were observed between RC and RCB or between PTN and TRS in any of the analyzed parameters. In the cervical third, RC and RCB presented higher mean increases than PTN and TRU. In the apical third, there were no statistically significant differences (P > .05) among the systems. CONCLUSIONS: The instruments of greater taper may promote greater morphologic changes. However, regardless of the number of instruments (multiple or single), the type of movement (rotation or reciprocating), the type of heat treatment of alloys, and the particular characteristics of each instrument (taper and design), the evaluated systems did not result in different dimensional changes and canal transportation in the critical apical area.

Eficacia de dos sistemas mecanizados para la desobturación de conductos radiculares curvos obturados con GuttaCore / Efficacy of two engine-driven systems for the removal of GuttaCore fillings from curved root canals

Objetivo: Comparar ex vivo la eficacia del instrumento WaveOne Gold Primary con la del sistema ProTaper Retratamiento para la remoción del material de obturación en conductos mesiales de molares inferiores obturados con GuttaCore y sellador. Materiales y métodos: Se seleccionaron raíces mesiales de 15 molares inferiores humanos extraídos con dos conductos radiculares cada una, forámenes independientes y curvaturas de entre 20o y 40o. Los conductos se prepararon con el sistema WaveOne Gold hasta una longitud de trabajo prefijada y hasta el instrumento Primary. La irrigación fue realizada con NaClO al 2,5%. Todos los conductos fueron obturados mediante GuttaCore empleando el obturador Primary y el sellador AH Plus con el agregado de una gota de azul de metileno al 1%. Los 30 conductos (15 mesio-vestibulares y 15 mesio-linguales) fueron divididos al azar en dos grupos de 15 (n=15) conductos cada uno. Los del grupo 1 fueron desobturados con el instrumento de movimiento recíproco WaveOne Gold Primary; los del grupo 2, con el sistema rotatorio ProTaper Retratamiento. Las muestras fueron incluidas en bloques de resina acrílica y se realizaron secciones transversales de 1 mm de espesor a nivel de 1,5, 3 y 9 mm de la longitud de trabajo con micrótomo para tejidos duros. Luego se observaron con un microscopio óptico bajo luz reflejada y se fotografiaron con una cámara digital. Las imágenes se analizaron mediante un programa informático. En cada grupo y en cada uno de los niveles prefijados, los resultados fueron expresados como la diferencia entre el área cubierta por restos de gutapercha/sellador y el área total perimetral del conducto radicular, y analizados mediante ANOVA y la prueba de Tukey, con un nivel de significación de P<0,05. Resultados: Se observaron remanentes del material de obturación en todos los niveles de ambos grupos. No hubo diferencias significativas (P>0,05) entre grupos. Las diferencias observadas entre los niveles prefijados fueron significativas (P<0,05), especialmente cuando se compararon los resultados obtenidos a 1,5 y 9 mm de la longitud de trabajo. Conclusiones: El empleo de WaveOne Gold Primary o ProTaper Retratamiento no permitió remover completamente el material de obturación en conductos mesiales de molares inferiores obturados con GuttaCore y AH Plus (AU)

Incidence of ProTaper Universal System Instrument Fractures - A Retrospective Clinical Study.

OBJECTIVE: The aim of this retrospective clinical study was to evaluate the incidence of ProTaper Universal System instrument fractures, associated with observation of the arch, group of teeth, and root thirds in which these fractures occurred. METHODS: From analysis of charts, clinical record cards and radiographs of endodontic treatments performed by postgraduate students using the ProTaper Universal System at a reference center, a total of 1031 teeth and 2355 canals were analyzed. The general incidence of instrument fractures and their frequency, considering the group of teeth, arch and root thirds, were cataloged and the data obtained were statistically analyzed (Exact Fischer test, with level of significance of 1%). RESULTS: The general percentage of fractures, considering the number of teeth and number of root canals evaluated was 4.4% and 1.9%, respectively. Instrument fractures occurred more frequently in the mandibular first (8.8%) and second (9.6%) molars, however, without statistically significant difference between them (P=0.81). In the first and second maxillary molars, the incidence of fracture was 4.7% and 5.1%, respectively, also without significant difference (P=0.81). Considering the dental arches (maxillary and mandibular), the fractures occurred with significantly higher frequency in the mandibular arch (66.7%), in comparison with the maxillary arch (33.3%) (P<0.01). A significantly higher percentage of fractures occurred in the apical third (84.4%) compared with the middle third (15.6%) (P<0.01). CONCLUSION: The general percentage of fractures, considering the number of teeth and number of root canals evaluated was 4.4% and 1.9%, respectively. However, the arch (mandibular) and root third (apical) had a significant effect on the incidence of instrument fractures.

Evaluación cualitativa pos instrumentación ex vivo comparando tres técnicas: escalonada con retroceso programado-oregón modificada por la FOB-técnica rotatoria protaper / Ex vivo post-instrumentation qualitative evaluationcomparing three techniques: step back - oregonmodified by F O B – protaper rotary technique

El objetivo de este trabajo fue evaluar cualitativamente las regularidades de los conductos radiculares preparados con diferentes técnicas: técnica escalonada de retroceso programado, técnica Oregón modificada por la F.O.B. y técnica rotatoria Protaper. Fueron utilizados 30 conductos radiculares ex vivo de dientes unirradiculares de un único conducto. Los conductos fueron instrumentados de la siguiente manera: G1 (n=10) con la técnica escalonada de retroceso programado, G2 (n=10) con Oregon modificada por la F.O.B y G3 (n=10) con técnica rotatoria Protaper. Una vez acabada la instrumentación el material de impresión fue inyectado en el conducto radicular; después del fraguado del material de impresión los dientes fueron descalcificados para obtener los moldes de los conductos que fueron fotografiados con aumento 20x con microscopio digital Dino Lite plus para analizar la uniformidad de la instrumentación por tercios por las tres diferentes técnicas, clasificándolas en: CBI (conducto bien instrumentado), CRI (conducto regularmente instrumentado), CPI (conducto pobremente instrumentado). Los resultados mostraron predominancia de CBI para la técnica Protaper en los tercios medio y apical; en el tercio cervical para las tres técnicas y el tercio apical para la técnica Oregon modificada, siendo los peores resultados para la técnica escalonada de retroceso programado y Oregon modificada en el tercio medio, tercio apical en la Escalonada de Retroceso Programado. No hubo diferencias estadísticamente significativas en la efectividad de las técnicas escalonada de retroceso programado, Oregon modificada y Protaper cuando fueron analizados cualitativamente los moldes de los tercios. Concluimos que las técnicas coronoapicales resultaron en una instrumentación más uniforme y de mejor calidad que la técnica escalonada.

The aim of this study was to evaluate qualitatively the regularities of root canalsprepared with different techniques: Step Back – Oregon modified by F.O.B andProtaper. Thirty ex vivo root canals of single-rooted teeth with a single root canal wereused. The canals were instrumented as follows: G1 (n=10) Step Back, G2 (n=10)Oregon modified by FOB and G3 (n=10) Protaper tecniques. Once instrumentation finished, impression material was injected into the root canal. After casting of theimpression material, the teeth were decalcified to obtain molds of the root canals thatwere photographed with 20x magnification using a digital Dino Lite plus microscope toanalyze the uniformity of the instrumentation on the thirds using the three techniquesthat were classified into: WIC (well instrumented canal), RIC (regularly instrumentedcanal) and PIC (poorly instrumented canal). The results shown predominance of WICfor the Protaper technique in the middle and apical thirds, in the apical third for thethree techniques and the apical third for the modified Oregon technique, being theworst results for the Step Back and Oregon techniques in the middle third, and for theStep Back in the apical third. There were no statistically significant differences in theeffectiveness of the Step Back, modified Oregon and Protaper techniques when thethirds molds were analyzed qualitatively. We conclude that the crown-apicaltechniques resulted in more uniform and better quality instrumentation than the StepBack technique.

Protaper Next: la evolución / Protaper Next: the evolution

El objetivo del presente artículo es describir y analizar las características técnicas y de diseño del sistema Protaper Next. Este sistema aparece en el mercado odontológico en el año 2012, transformándose en el sucesor del Protaper Universal. Una de sus principales modificaciones consiste en la disminución del número de instrumentos requeridos para realizar el tratamiento endodóntico.

The objective of this article is to describe and analyze the technical and design characteristics of the Protaper Next System.This system appeared at the dental market in 2012 becoming the successor of Protaper Universal.One of its main modifications is the minor numbers of instruments required for doing an endodontic treatment.

Automatic Electronic Device Used for the Evaluation of Cyclic-Fatigue Resistance of Nickel-Titanium Instruments

he aim of this study was to evaluate the cyclic-fatigue fracture of different Nickel-Titanium motor-driven rotary instruments (ProTaper® Universal, ProFile®, and Mtwo® systems) in artificial canals by means of an Automatic Electronic Device (AED). The study was performed using NickelTitanium instruments 25/0.06 evaluated in canals with a 45-degree curvature and 2-mm radius. The analyses evaluated two parameters: fracture by cyclic fatigue, and time of fracture; in addition, the length of separated fragment was evaluated. Medians and range values were calculated for each group. Data were analyzed by the Kruskall-Wallis and Mann-Whitney U tests to determine statistical difference. The ProFile motor-driven rotator system exhibited highest resistance to fracture due to cyclic fatigue and highest fracture time compared with the ProTaper and Mtwo systems (p <0.05). The equipment proposed in this study (AED) demonstrated efficiency for recording information, automation, scheduled work times and durations, cycle number, time of fracture, pressure changes and, principally control of the human factor.

l objetivo del presente estudio fue evaluar la fractura a la fatiga cíclica de diferentes instrumentos rotatorios de Niquel-Titanio (sistemas ProTaper® Universal, ProFile® y Mtwo®) en conductos artificiales por medio de un Dispositivo Electrónico Automático (DEA). Se usaron instrumentos de Niquel-Titanio 25/0.06, los cuales se evaluaron en conductos con una curvatura de 45 grados y 2 milímetros de radio. Se analizaron dos parámetros: Fractura a la fatiga cíclica y tiempo a la fractura; además se evaluó la longitud del fragmento separado. Medianas y rangos fueron calculados para cada uno de los grupos. Los resultados fueron analizados por las pruebas de Kruskall-Wallis y U de Mann-Whitney para determinar diferencias estadísticas. El Sistema ProFile mostró una mayor resistencia y tiempo a la fractura en comparación con los sistemas ProTaper y Mtwo (p <0.05). El equipo propuesto en este estudio (DEA) demostró eficiencia para el registro de la información, tiempos de trabajo y duración, número de ciclos, tiempo a la fractura, cambios en la presión y principalmente control del factor humano.

On the Causality Between Dentinal Defects and Root Canal Preparation: A Micro-CT Assessment

Abstract This study aimed to evaluate the cause-effect relationship between canal preparation with ProTaper Universal (PTU) system and dentinal defects formation using micro-computed tomography (micro-CT) analysis. Forty mesial canals of mandibular molars with a type II Vertucci's canal configuration were scanned at an isotropic resolution of 14.16 µm. The sample was assigned to an experimental (n = 30) and a control (n = 10) groups, and the mesial canals were prepared with PTU system up to F2 instrument. The specimens from the experimental group were scanned and the cross-section images of the mesial roots, before and after preparation, were screened to identify the presence of dentinal defects. In the control group, the specimens were sectioned perpendicularly to the long axis of the root into 1-mm-thick slices (n = 80) and examined under optical microscope. Once a dentinal defect was detected, the slice was scanned through micro-CT. In the experimental group, dentinal micro-cracks were observed in 4,828 slices (24.04%). In all cross-section images, dentinal defects identified in the postoperative images were already present in the corresponding preoperative image. In the control group, 13 out of 80 slices (16.25%) had at least one dentinal defect visualized under stereomicroscopy, which was identified after a further micro-CT scanning. Micro-CT showed reliability as similar as optical microscopy in detecting dentinal defects, adding the possibility of tracking the dentinal tissue, before and after canal preparation, and providing a clear visualization of micro-cracks. Root canal preparation with PTU system did not induce the formation of new dentinal defects.

Resumo O objetivo deste estudo foi avaliar a relação de causa-efeito entre o preparo do canal radicular com o sistema ProTaper Universal (PTU) e a formação de defeitos dentinários usando a análise por micro-tomografia computadorizada (micro-CT). Quarenta raízes mesiais de molares inferiores com a configuração tipo II de Vertucci foram escaneadas com resolução isotrópica de 14.16 μm. A amostra foi distribuída em um grupo experimental (n = 30) e um grupo controle (n = 10), e os canais mesiais foram preparados com o sistema PTU até a lima F2. As amostras do grupo experimental foram escaneadas e as imagens de secção transversal das raízes mesiais, antes e após o preparo, foram analisadas ​​para identificar a presença de defeitos dentinários. No grupo controle, os dentes foram seccionados perpendicularmente em relação ao longo eixo da raiz em fatias de 1 mm de espessura (n = 80) e examinados ao microscópio óptico. Uma vez detectado um defeito dentinário, a fatia foi escaneada através da micro-CT. No grupo experimental, defeitos dentinários foram observados em 4.828 secções transversais (24,04%). Em todas as imagens de secção transversal, os defeitos dentinários após os procedimentos experimentais já estavam presentes na secção pré-operatória correspondente. No grupo controle, 13 das 80 fatias (16,25%) apresentaram pelo menos um defeito dentinário visualizado através do microscópio, o qual foi identificado em um escaneamento posterior. A micro-CT mostrou confiabilidade com a microscopia óptica para detecção e visualização dos defeitos dentinários, permitindo acompanhar o tecido dentinário antes e depois do preparo do canal. O preparo do canal radicular com o sistema PTU não induziu a formação de novos defeitos dentinários.

Eficiencia de tres técnicas en la remoción de gutapercha / Efficiency of three different techniques in the removal of gutta-percha

Cuando la terapia endodóntica fracasa, las opciones para solucionar este problema incluyen preservar el diente a través del retratamiento ortógrado o cirugía apical. Siempre que sea posible, el retratamiento endodóntico no quirúrgico debe ser la opción elegida. Diferentes sistemas rotatorios han sido propuestos como una alternativa a la instrumentación manual para la remoción de la gutapercha.El objetivo de este trabajo fue comparar la eficacia y la eficiencia en la desobturación total del canal radicular, utilizando dos tipos de instrumentos rotatorios: limas Protaper Universal® y limas Protaper Retratamiento® con limas manuales tipo K. Se instrumentaron 45 canales radiculares, con limas mecanizadas del sistema Mtwo®, hasta la 25/06 y terminados de conformar con lima K #40 e irrigados con hipoclorito de sodio al 2,5 % entre cada instrumento. Los dientes fueron obturados con técnica de condensación lateral, utilizando conos de gutapercha y cemento Tubliseal®.La muestra se dividió al azar en tres grupos A, B y C, de 15 canales cada uno, el grupo A se desobturó con limas Protaper Universal. El grupo B se desobturó con limas Protaper retratamiento y el grupo C se desobturó totalmente con limas K. Se cronometró cada procedimiento de desobturación y al término de esta, se tomó una radiografía en sentido buco-lingual y otra en sentido mesio-distal para cuantificar la remoción de gutapercha en cada grupo. Los resultados muestran que no existe diferencia significativa en la eliminación total del relleno endodóntico entre los tres grupos (p= 0,271) pero que los tiempos empleados en la desobturación total de los canales entre los grupos, muestra diferencias significativas entre Protaper Retratamiento y limas K, y entre Protaper Universal y limas K (p <0,05). Bajo las condiciones de este estudio, ningún sistema fue capaz de remover toda la gutapercha del interior del canal radicular.

When primary endodontic treatment fails, the treatment alternatives for root preservation are orthograde retreatment or apical surgery. Whenever possible, orthograde retreatment must be the first option. Different rotary systems have been proposed as an alternative to manual instrumentation for the removal of gutta-percha. The aim of this study was to compare the efficacy and efficiency of the total removal of gutta-percha from root canals, using two types of rotary instruments: Protaper Universal Files® and Protaper Retreatment Files®, compared to manual K type Files. A total of forty-five canals were instrumented with Mtwo files® up to a 25.06 file and the shaping was completed with a 40 K-type File and irrigated with 2.5 % Sodium Hypochlorite between each instrument. The teeth were obturated with Lateral Condensation Technique, using gutta-percha and Tubliseal® sealer. Samples were divided in groups A, B and C, 15 canals each, and gutta-percha was removed using the following protocols: group A with Protaper Universal; Group B using Protaper Retreatment and Group C using K type Files. Each procedure was timed and at the end of it, two periapical radiographs were taken: one buccolingual and one mesiodistal, in order to quantify the amount of gutta-percha removed. The results analysis show that there is no significant difference in the amount of gutta-percha removed between the three groups (p= 0.271) but that the time invested to perform the removal of the gutta-percha was significantly less between for the rotary systems, when compared to manual instrumentation (p <0.05). Under the conditions of this study, no system was able to remove all gutta percha inside the root canal.

Microfiltración apical in vitro causada por las técnicas de obturación con cono único, System B y condensación lateral clásica / In vitro apical microleakage causade by single-cone, System B and cold lateral condensation obturation techniques

La obtención de un sellado hermético en la obturación del conducto radicular es una etapa coadyuvante del éxito endodóntico. Objetivo: Comparar la microfi ltración apical in vitro, calidad de relleno y presencia de espacios vacíos en conductos radiculares obturados con los métodos de obturación cono único, condensación lateral clásica y System B. Material y métodos: Noventa raíces mesiales de molares inferiores fueron instrumentados con ProTaper a un calibre F3 y asignados aleatoriamente para su obturación a tres grupos (n = 30 raíces), grupo 1: condensación lateral clásica con gutapercha #30.02, grupo 2: cono único con gutapercha F3 y grupo 3: System B con gutapercha #30.02; en todas las técnicas se usó una mezcla de óxido de zinc eugenol como sellador.Obturados los conductos las muestras se sumergieron en azul de metileno al 0.5 por ciento, se centrifugaron a 3,200 rpm durante cinco minutos, se diafanizarony se llevaron al microscopio estereoscópico a 12.5x para la mediciónde microfi ltración apical, calidad de relleno y presencia de espacios vacíospor un observador calibrado. Resultados: No se encontraron diferencias significativas en la microfi ltración apical entre el grupo de condensación lateral clásica y System B (p > 0.05) siendo el cono único la técnica que presenta mayor fi ltración. La técnica que ofrece la menor cantidad de espacios vacíos y mejor calidad de relleno es System B. Conclusiones:El método System B y condensación lateral clásica dejan una baja microfiltración apical y adecuada calidad de relleno comparada con la que sepresenta con cono único utilizando como sellador óxido de zinc eugenol...

Evaluación ex vivo del material de obturación extruido durante el retratamiento endodóntico con el empleo de dos técnicas de remoción / Ex vivo evaluation of the amount of extruded filling material during endodontic retreatment using wo removal techniques

Objetivo: evaluar ex vivo la cantidad de material de obturación durante el retratemiento endodóntico ortógrado con el uso de dos técnicas de desobturación. Materiales y métodos: se utilizaron 30 caninos humanos extraídos, de conducto único y raíces rectas. Los conductos se instrumentaron con ProGlider (Dentsply/Maillefer, Ballaigues, Suiza) y ProTaper Next X1, X2 y X3 (Dentsply/Maillefer, Ballaigues, Suiza) hasta la longitud de trabajo (LT), luego, se sobrepasó 1 mm del foramen apical con una lima tipo K #20. A continuación se obturaron con conocs de gutapercha ProTaper Next X3 (Dentsply / Maillefer, Ballaigues, Suiza), condensación lateral y termocompactación. Como sellador endodóntico, se utilizó el AHPlus (Dentsply DeTrey, Konstanz, Alemania), coloreado con tinta china azul. Los especímenes se dividieron aleatoriamente en dos grupos de 15 dientes. Las raíces se montaron en tubos Eppendorf, que fueron pesados previamente en una balanza de precisión. En el grupo 1 (n=15) se removió la gutapercha con instrumentos D1, D2 del sistema ProTaper Universal, hasta el tercio medio y luego hasta la LT con D3 y limas Hedstroem #40 (Dentsply/Maillefer, Ballaigues, Suiza), empleando xilol. La remoción se completó con ProTaper Next x4 hasta la LT. En el grupo 2 (n=15) se removió la gutapercha con el sistema ProTaper Universal D1, D2 y D3 hasta el tercio apical y se completó con ProTaper Next x4 hasta la LT. En ambos grupos se realizaron lavajes con 3 ml de agua destilada a cada cambio de instrumento y al finalizar la instrumentación. Se retiraron las tapas con los especímenes de los tubos Eppendorf, los cuales fueron colocados en una estufa de cultivo a 27ºC durante 5 días. Los tuvos se pesaron nuevamente (sin sus tapas) para determinar la diferencia de peso correspondiente al material de obturación extravasado. La comparación de las diferencias de peso promedio entre los dos grupos se realizó mediante la prueba no paramétrica de Mann-Whitney.

Comparison of canal transportation in simulated curved canals prepared with ProTaper Universal and ProTaper Gold systems.

OBJECTIVES: The purpose of this study was to assess the ability of ProTaper Gold (PTG, Dentsply Maillefer) in maintaining the original profile of root canal anatomy. For that, ProTaper Universal (PTU, Dentsply Maillefer) was used as reference techniques for comparison. MATERIALS AND METHODS: Twenty simulated curved canals manufactured in clear resin blocks were randomly assigned to 2 groups (n = 10) according to the system used for canal instrumentation: PTU and PTG groups, upto F2 files (25/0.08). Color stereomicroscopic images from each block were taken exactly at the same position before and after instrumentation. All image processing and data analysis were performed with an open source program (FIJI). Evaluation of canal transportation was obtained for two independent canal regions: straight and curved levels. Student's t test was used with a cut-off for significance set at α = 5%. RESULTS: Instrumentation systems significantly influenced canal transportation (p < 0.0001). A significant interaction between instrumentation system and root canal level (p < 0.0001) was found. PTU and PTG systems produced similar canal transportation at the straight part, while PTG system resulted in lower canal transportation than PTU system at the curved part. Canal transportation was higher at the curved canal portion (p < 0.0001). CONCLUSIONS: PTG system produced overall less canal transportation in the curved portion when compared to PTU system.

Análise comparativa da eficiência de corte de instrumentos rotatórios de níquel-titânio ProTaper NEXT e ProTaper Universal / Comparative analysis of the cutting efficiency of rotational instruments of nickel-titanium ProTaper NEXT and ProTaper Universal

Os instrumentos rotatórios fabricados em Níquel-Titânio possuem características geométricas e dimensionais que influenciam sua eficiência de corte. Torque e força apical exercidos durante o preparo de canais radiculares são parâmetros que definem esta propriedade mecânica. Neste estudo avaliou-se o torque e a força apical exercidos por instrumentos ProTaper Universal (PTU) S2 e F1 e ProTaper NEXT (PTN) X1 e X2, que apresentam diâmetros semelhantes e geometrias diferentes. Os ensaios foram realizados em dispositivo de bancada, onde 10 instrumentos de cada tipo foram testados em blocos de acrílico préfabricados, contendo um canal artificial previamente explorado com limas rotatórias PathFile #13 e #16. Acionados por um motor endodôntico com velocidade de 300 rotações por minuto (rpm) e torque de 4,0 Newton por centímetro (Ncm), os instrumentos foram inseridos no canal a uma velocidade constante de 0,09 mm/seg. Enquanto uma célula de carga registrou a força axial exercida, um multímetro acoplado ao motor endodôntico registrou o torque requerido pelo instrumento durante seu deslocamento ao longo do canal. Os ensaios foram realizados utilizando um bloco novo para cada sistema, na sequência de S2 e F1 para PTU, e X1 e X2 para PTN. Os resultados mostraram que os instrumentos do sistema PTU apresentaram menores valores de força apical e torque, quando comparados com PTN

The NiTi instruments have geometrical and dimensional characteristics that could play an important hole in the cutting efficiency. Torque and apical force exerted during the root canal preparation are parameters that define this mechanical property. This study evaluated the apical force and torque required by the instruments ProTaper Universal (PTU) S2 and F1, and ProTaper NEXT (PTN) X1 and X2, with similar diameters and different geometries, to penetrate standardized acrylic blocks containing an artificial canal previously explored with rotary instruments Pathfile #13 and #16. The parameters were determined using a bench-testing machine, where the instruments were set to move against the artificial canal in a constant speed of 0.09 mm/sec. The X-Smart Plus motor, with a rotational speed of 300 rpm and torque limitation of 4N.cm, was employed to drive the instruments and the load cell of the machine recorded the apical force exerted, while a digital multimeter attached to the endodontic motor recorded the torque required during the work of the instrument along the canal. Ten instruments of each type were tested using a new acrylic block for each system, in a sequence of S2 and F1 for PTU, and X1 and X2 for PTN. The results showed that the instruments of the PTU system displayed lower torque and apical force during the test, when compared to PTN instruments

Evaluación con tomografía axial computada de haz cónico de la conformación de conductos mesiales de molares inferiores instrumentados con los sistemas WaweOne y ProTaper Universal: estudio ex vivo / Cone beam computed tomography shaping evaluation in mandibular mesial root canals instrumented with WaveOne and Universal ProTaper systems: an ex vivo study

Objetivo: comparar, ex vivo, la conformación obtenida con los sistemas WaveOne y ProTaper Universal en conductos mesiales de molares inferiores humanos. Materiales y métodos: se emplearon 16 raíces mesiales de molares inferiores humanos, extraídos por causa periodontal, con 2 conductos independientes cada uno. Las raíces fueron montadas en un typodont y se tomaron imágenes preoperatorias con un tomógrafo computarizado de haz cónico. Los 32 conductos fueron distribuidos en 2 grupos. En todos los casos, los conductos se instrumentaron hasta la longitud de trabajo. En el grupo A, se empleó la lima Primary del sistema reciprocante WaveOne (Dentsply / Maillefer). En el grupo B, se utilizó la lima F2 del sistema rotatorio ProTaper Universal (Dentsply/Maillefer. A continuación, se tomaron las tomografías posoperatorias. Sobre todas las imágenes obtenidas -pre y posoperatorias- se realizaron las mediciones (en milímetros) del espesor del tejido duro (radiopaco) que rodeaba al conducto radicular, en los sentidos mesial, distal, vestibular y lingual, a tres niveles ubicados a 2,5 mm, 5,5 mm y 8,5 mm desde el ápice hacia oclusal. Para tal fin se empleó el programa GALILEO Viewer (Syrona Dental Systems). Luego, se analizaron las diferencias entre las medidas obtenidas de las imágenes preoperatorias y las posoperatorias de cada especimen hacia la pared distal del conducto radicular, a fin de determinar el nivel de desgaste generado por ambos sistemas. Los resultados fueron evaluados estadísticamente mediante análisis de varianza, complementado con el método de comparaciones múltiples de Bonferroni. Resultados: no se encontraron diferencias estadísticamente significativas entre los valores registrados en cuanto a los dos sistemas evaluados, ni entre los conductos mesiolingual y mesiovestibular. Como la interacción entre ambos factores tampoco fue significativa, se compararon globalmente los tres niveles de corte evaluados.

Evaluación con tomografía axial computada de haz cónico de la conformación de conductos mesiales de molares inferiores instrumentados con los sistemas WaweOne y ProTaper Universal: estudio ex vivo / Cone beam computed tomography shaping evaluation in mandibular mesial root canals instrumented with WaveOne and Universal ProTaper systems: an ex vivo study

Objetivo: comparar, ex vivo, la conformación obtenida con los sistemas WaveOne y ProTaper Universal en conductos mesiales de molares inferiores humanos. Materiales y métodos: se emplearon 16 raíces mesiales de molares inferiores humanos, extraídos por causa periodontal, con 2 conductos independientes cada uno. Las raíces fueron montadas en un typodont y se tomaron imágenes preoperatorias con un tomógrafo computarizado de haz cónico. Los 32 conductos fueron distribuidos en 2 grupos. En todos los casos, los conductos se instrumentaron hasta la longitud de trabajo. En el grupo A, se empleó la lima Primary del sistema reciprocante WaveOne (Dentsply / Maillefer). En el grupo B, se utilizó la lima F2 del sistema rotatorio ProTaper Universal (Dentsply/Maillefer. A continuación, se tomaron las tomografías posoperatorias. Sobre todas las imágenes obtenidas -pre y posoperatorias- se realizaron las mediciones (en milímetros) del espesor del tejido duro (radiopaco) que rodeaba al conducto radicular, en los sentidos mesial, distal, vestibular y lingual, a tres niveles ubicados a 2,5 mm, 5,5 mm y 8,5 mm desde el ápice hacia oclusal. Para tal fin se empleó el programa GALILEO Viewer (Syrona Dental Systems). Luego, se analizaron las diferencias entre las medidas obtenidas de las imágenes preoperatorias y las posoperatorias de cada especimen hacia la pared distal del conducto radicular, a fin de determinar el nivel de desgaste generado por ambos sistemas. Los resultados fueron evaluados estadísticamente mediante análisis de varianza, complementado con el método de comparaciones múltiples de Bonferroni. Resultados: no se encontraron diferencias estadísticamente significativas entre los valores registrados en cuanto a los dos sistemas evaluados, ni entre los conductos mesiolingual y mesiovestibular. Como la interacción entre ambos factores tampoco fue significativa, se compararon globalmente los tres niveles de corte evaluados. (AU)