Comparative evaluation of post-operative pain after pulpectomy with K-files, Kedo-S files and MTwo files in deciduous molars -a randomized clinical trial / Avaliação comparativa da dor pós-operatória após pulpectomia com limas k, Kedo-S e MTwo em molares decíduos - um ensaio clínico randomizado

Objective: Despite the tortuous course of primary root canal system, a paradigm shift occurred from conventional hand files to rotary system, which lead to faster, cost-effective, uniform and predictable fillings. One of the many advantages being, reduction in post-operative pain with the use of rotary system. Many rotary file systems were introduced, with the recent one, the Kedo-S. So the present study aimed to compare and evaluate the post ­ operative pain after pulpectomy using K-files, MTwo files and Kedo-S files in deciduous molars. Material and Methods: 75 teeth were randomly divided into three groups (group A ­ K-files, group B - Kedo-S files and group C - MTwo files) for pulpectomy of primary molars. Post ­ operative pain was assessed every 6,12,24,48 and 72 hours using facial pain scale. Results: 44% of volunteers in K-file group had moderate pain followed by Kedo-S group (8%) and then MTwo files (4%). Conclusion: The least post-operative pain was found in Mtwo group followed by Kedo-S group and K-file group. (AU)

Objetivo: Apesar do curso tortuoso do sistema de canais radiculares de dentes molares decíduos, uma mudança de paradigma ocorreu das limas manuais convencionais para o sistema rotatporio, o que leva a obturações mais rápidas, econômicas, uniformes e previsíveis. Uma das muitas vantagens é a redução da dor pós-operatória com o uso do sistema rotatório. Muitos sistemas de limas rotátórias foram introduzidas, como o recente Kedo-S. Assim, o presente estudo objetivou comparar e avaliar a dor pós-operatória após pulpectomia utilizando limas K, MTwo e Kedo - S em molares decíduos. Material e Métodos: Setenta e cinco dentes foram divididos aleatoriamente em três grupos (grupo A - limas K, grupo B - limas Kedo-S e grupo C - limas MTwo) para pulpectomia de molares decíduos. A dor pós - operatória foi avaliada a cada 6,12,24,48 e 72 horas, utilizando a escala de dor facial. Resultados: 44% dos voluntários do grupo K apresentaram dor moderada, seguidos pelo grupo Kedo-S, com 8%, e MTwo, com 4%. Conclusão: A menor dor pósoperatória foi encontrada no grupo Mtwo, seguido pelo grupo Kedo-S e pelo grupo K-file. (AU)

Estudio comparativo in vitro sobre la extrusión apical de detritus producida por los sistemas Mtwo y Reciproc / In vitro comparative study about apically extruded debris produced by Mtwo and Reciproc systems

Objetivo: evaluar cuantitativamente la cantidad de residuos extruidos a través del foramen apical, comparando los sistemas Mtwo y Reciproc. Materiales y métodos: se usaron 20 premolares inferiores unirradiculares, con ápice maduro, curvaturas de 0 a 10 grados y oramen permeable a limas tipo K flexibles #10 y #15. Se realizó la cavidad de acceso de manera convencional con piedra redonda de diamante y fresa Endo Z. Se determinó visualmente la longitud de trabajo a 1 mm del foramen apical. Los dientes fueron divididos al azar en dos grupos de 10 especímenes cada uno. Grupo 1: instrumentación con sistema Mtwo (VDW GmbH) a la longitud de trabajo. Grupo 2: instrumentación con sistema Reciproc (VDW GmbH) con movimientos de picoteo por tercios. Se utilizó como irrigante 12,5 ml de agua destilada por elemento dentario. Para la recolección de restos, se usó la técnica de Myers y Montgomery. Los residuos y el irrigante extruidos fueron recolectados en un frasco vial prepesado. El peso de los restos fue calculado por la diferencia de las medidas pre- y posinstrumentación. Resultados: los datos fueron analizados estadísticamente con el test de normalidad de Kolmogorov-Smirnov. Posteriormente, los datos de dichas variables, dependientes pre- y po-, fueron analizados con la prueba T para muestras pareadas. No se registraron diferencias significativas entre ambos grupos (P>0,05). Conclusión: ambos sistemas rotatorios produjeron extrusión apical de residuos de manera similar.

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.

In vitro evaluation of retreatment efficacy of Mtwo rotary instruments / 口腔疾病防治

Objective@# To evaluate the efficacy of Mtwo rotary instruments during root canal retreatment. @*Methods @#Thirty mandibular premolars with oval root canal were prepared with ProTaper rotary instruments and obturated with lateral condensation method. The samples were divided into 2 groups. In Mtwo group, the filling materials were removed with Mtwo retreatment system and Mtwo basic instruments. Inmanual stainless group, the filling material were removed with manual instruments. The percentage of residual filling material was measured with image proplus software and the operating time was recorded. @*Results@#The percentage of residual filling material in Mtwo group was significantly lower than manual group in middle third, but the opposite result can be found in the coronal third. In the whole canal, no significant difference was found between the two groups. The mean operating time in Mtwo group was significantly shorter than manual group. @*Conclusion @#Mtwo rotary instruments can shorten the time of retreatment, neither of the groups can remove the filling material in oval root canal completely.

Sistema rotatório Mtwo para retratamento endodôntico: revisão de literatura / Rotary system Mtwo for endodontic retreatment: literature review

O retratamento endodôntico é sempre a primeira opção indicada para solucionar o fracasso do tratamento. Atualmente, o retratamento vem sofrendo grandes avanços, buscando técnicas e instrumentos que provoquem o mínimo de danos possíveis, com uma maior eficiência e em menor tempo. Dentre esses instrumentos, encontra-se o sistema Mtwo para retratamento (Mtwo-R), que é um sistema rotatório de níquel-titânio da nova geração o qual tem sido alvo de muitas pesquisas nos últimos anos. O objetivo deste trabalho foi realizar um levantamento da literatura com o intuito de ressaltar as vantagens e desvantagens do sistema rotatório Mtwo-R, quando comparado com outros tipos de sistemas rotatórios e com técnicas manuais.

Endodontic retreatment is always the first option to solve the failure of the previous root canal treatment. Currently, the retreatment has undergone great advances, developing techniques and instruments that cause the least possible damage, with greater efficiency and dispending less time. Among these instruments is the Mtwo system for retreatment (Mtwo-R), which is a new generation of nickel-titanium rotary system which has been extensively studied in recent years. The objective of this study was to survey the literature in order to highlight the advantages and disadvantages of rotary system Mtwo-R compared with other types of rotary systems and manual techniques.

Refinement influence in the cleaning efficacy of rotary nickel-titanium Mtwo ® instruments in oval-shaped canals by means of optical microscopy.

Objective: This study evaluated the cleaning efficacy of the rotary nickel–titanium Mtwo® by means of optical microscopy in oval‑shaped root canals and compared refinement influence using ultrasonic files or Hedströem files. Materials and Methods: Twenty mandibular incisors were accessed, included in epoxy resin blocks, and cut transversely at 3, 6, and 9 mm from the apex. Teeth were instrumented using rotary nickel–titanium Mtwo. Digital images of the root cross sections were obtained before and after instrumentation with a digital camera attached to an optical microscope. Subsequently, samples were randomly divided into two groups for refinement. Group I was refined using ultrasonic files #30 and group II with Hedströem files #30. Final digital images of cross sections after refinement were captured and analyzed. The boundaries for the uninstrumented perimeter were measured by the software ImageTool 3.0. The data obtained were statistically analyzed by analysis of variance (ANOVA) and t‑test. Results: Mtwo instrumentation produced 41.48% of the uninstrumented perimeter. The final refinement using Hedströem and ultrasonic files decreased the uninstrumented perimeter. Significant differences (t‑test, P = 0.00) were found at the three thirds after the final refinement, except for the apical third that was enhanced by Hedströem file. However, there was no statistical difference between the two refinement techniques used (P > 0.05). Mtwo instrumentation was not capable of cleaning and shaping the entire perimeter of the root canals walls. Conclusions: The final refinement, either with ultrasonic files or with Hedströem files, resulted in significantly less uninstrumented perimeter.

Comparación de la capacidad de limpieza de tres sistemas rotatorios para la desobturación y retratamiento de conductos radiculares / Comparison of the cleaning ability of three rotary systems for the removal of filling materials in endodontic retreatment

El éxito de la reendodoncia está basado en gran parte en la correcta limpieza y preparación del sistema de conductos radiculares. Esto implica la eliminación de la obturación anterior y el remodelado del conducto. El material de obturación que queda en el conducto puede involucrar microorganismos y dentina infectada que comprometen el pronóstico del tratamiento. En este trabajo se comparó in vitro la eficacia de los sistemas ProTaper Universal Retratamiento (Dentsply Maillefer), D-RaCe Retratamiento (FKG) y Mtwo Retratamiento (VDW) para la remoción de conos de gutapercha y sellador. El sistema que dejó mayor residuo fue RaCe. De los otros dos sistemas, Mtwo tuvo el mejor desempeño,pero no llegó a presentar diferencias estadísticamente significativas con ProTaper. Mtwo logró una limpieza del 79,03 por ciento, seguido por el ProTaper con el 75,94 por ciento y RaCe con el 49,01 por ciento. La eliminación completa de la obturación endodóntica no se logró con ninguno de los sistemas de instrumentos investigados...

Clinical Evaluation of the Combined Application of Pathfile and Mtwo in Preparing Curved Root Canals / 华中科技大学学报(医学版)

Objective To evaluate the clinical efficacy of combined use of Pathfile and Mtwo in the preparation of curved root canals.Methods This study enrolled a total of 90 teeth(313 root canals)that need root canal therapy because of pulpitis or apical periodontitis from December 2013 to February 2014.All root canals were randomly divided into three groups.In group A,both Pathfile and Mtwo NiTi files were used in root canal preparation.In group B,Pathfile and ProTaper were used.ProTaper was employed alone in root canal preparation in group C.The high temperature thermaplasticized inj ectable ver-tical condensation technique was applied in all the three groups.The time of root canal preparation,the number of separated de-vices,root canal transportation and the quality of root canal filling were obtained and compared among the 3 groups.Results In group A,the time of root canal preparation was shortest,(6.01±1.12)min ;there were no instrument separation and ledge for-mation,and the filling rate was highest in group A.The differences were significantly noted in these indexes between group A and groups B,C.Conclusion Combined use of Pathfile and Mtwo for preparation of curved root canals is fast and safe,and the root canal filling is satisfactory.This method is suitable for clinical application.

Uso de rotatórios pathfile e mtwo como acesso inicial no preparo endodôntico: comparação com limas manuais em canais curvos / Use of rotation and pathfile MTwo as initial access in endodontic treatment: a comparison with hand files in curved canals

Introdução: Instrumentos rotatórios em níquel-titânio reduzem erros processuais e o tempo requerido para finalização do preparo do canal radicular. O objetivo deste estudo foi avaliar as ocorrências de transporte apical e aberrações nos canais produzidas com diferentes instrumentos utilizados para a criação de trajetória-guia (“glide path”) no preparo de canais curvos: limas manuais K e limas rotatórias em níquel-titânio PathFile e Mtwo. Material e Métodos: Os canais mesiais de 45 primeiros e segundos molares inferiores (com ângulos de curvatura entre 25 e 35 graus) foram selecionados para o estudo. As amostras foram divididas aleatoriamente em três grupos de 15 canais cada e o preparo foi realizado por um endodontista utilizando limas manuais de aço inoxidável tipo K #10-15-20, conicidade 0,02 (grupo M), instrumentos rotatórios PathFile #13-16-19, conicidade 0,02 (grupo PF) e instrumentos rotatórios Mtwo #10/04- #15/05- #20/06 (grupo MT). Foi utilizada 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 eixo central foram comparadas por meio de sua sobreposição. Os espécimes foram analisados por 3 avaliadores, cuja calibração foi checada por meio do teste de concordância de Kendall. Resultados: Não ocorreu transporte apical nem aberração na morfologia do canal em 100% dos dentes, portanto nenhuma análise estatística foi realizada. Conclusão: Tanto os instrumentos rotatórios PathFile e Mtwo quanto os instrumentos manuais utilizados para a criação de trajetória-guia não exerceram influência sobre a ocorrência de transporte apical nem promoveram aberrações na morfologia dos canais .

Introduction: Nickel-titanium rotary instruments reduce procedural errors and the time required to finish root canal preparation.The goal of this study was to evaluate the occurrences of apical transportation and canal aberrations produced with different instruments used to create a glide path in the preparation of curved root canals, namely: manual K files and PathFile and Mtwo nickel-titanium rotary files. Methods:The mesial canals of 45 mandibular first and second molars (with curvature angles between 25 and 35 degrees) were selected for this study. The specimens were divided randomly into three groups with 15 canals each, and canal preparation was performed by an endodontist using #10-15-20 K-type stainless steel manual files (Group M), #13-16-19 PathFile rotary instruments (Group PF), and #10-15-20 Mtwo rotary instruments (Group MT). The double digital radiograph technique was used, pre- and post-instrumentation, to assess whether apical transportation and/or aberration in root canal morphology occurred. The initial and final images of the central axis of the canals were compared by superimposition through computerized analysis and with the aid of magnification. The specimens were analyzed by 3 evaluators, whose calibration was checked using the Kendall agreement test. Results: No apical transportation or aberration in root canal morphology occurred in any of the teeth; therefore, no statistical analysis was conducted. Conclusion: Neither the manual instruments nor the PathFile or Mtwo rotary instruments used to create a glide path had any influence on the occurrence of apical transportation or produced any canal aberration

A comparative evaluation of smear layer removal using two rotary instrument systems with ethylenediaminetetraacetic acid in different states: A SEM study.

Aim: The aim of the study was to evaluate the ability of 17% ethylenediaminetetraacetic acid (EDTA) solution and 19% EDTA gel to remove debris, and smear layer produced during root canal preparation with two NiTi files systems, Mtwo and Protaper. Materials and Methods: Twenty freshly extracted human anterior teeth with single root canal were collected. The crowns were sectioned at the cemento-enamel junction, and working length was measured. These samples were randomly divided into four groups of five samples each. In each group, 2ml of 3 % sodium hypochlorite solution was used with first instrument. The groupings were as follows. Group 1: 2 ml of 17% EDTA solution and 2 ml of 3% NaOCl were used alternatively each time a new file was employed. This group was prepared with Mtwo rotary files. Group 2: The samples in this group was prepared with Mtwo rotary files. EDTA gel (19%) was used and the samples were irrigated with 2 ml of 3% NaOCl. NaOCl and EDTA gel were used alternatively. Group 3: Five samples were prepared with Protaper file. Irrigation regime was the same as in Group 1. Group 4: Five samples were prepared with Protaper files and irrigation regime was the same as in Group 2. SEM study was done and the collected data were submitted for statistical analysis. Results: There was no statistically significant difference with the varied instruments used (Mtwo and Protaper files), and 17% EDTA solution and 19% EDTA gel. Conclusion: Both the NITI instruments produced a similar dentin surface on root canal wall when used with EDTA gel and EDTA solution.

Cleaning and shaping curved root canals: Mtwo® vs ProTaper® instruments, a lab comparison.

Objectives: The purpose of this study was to compare root canal preparation in curved canals in molar teeth with the rotary NiTi Mtwo and ProTaper systems in terms of canal shape and smear layer. Materials and Methods: Mesiobuccal canals of 60 molar teeth with angles of curvature between 25 and 35 degrees were prepared with a torque controlled low speed engine; 30 canals for each system. Each individual instrument was used to prepare four root canals and the time required for preparation was recorded. Standardized radiographs were taken before and following instrumentation and used to determine changes in canal curvature. Results: There was no significant difference in preparation time between the two systems. No instruments separated during use. The Mtwo system gave a statistically smaller change in canal curvature and thus was better for maintaining the original shape of the root canal, with less transportation (P less than 0.05). The greatest difference was seen for maxillary molar teeth. When prepared root canals were examined by SEM there was no difference between the two systems at the coronal, middle or apical thirds. Conclusion: Overall, the results of this study suggest that Mtwo instruments are preferable for situations where canals are curved, particularly for maxillary molars.

Comparison of shaping ability between single length technique and crown-down technique using Mtwo rotary file / 대한치과보존학회지

The aims of this study were to compare the shaping effect and safety between single length technique recommended by manufacturer and crown-down technique using Mtwo rotary file and to present a modified method in use of Mtwo file. Sixty simulated root canal resin blocks were used. The canals were divided into three groups according to instrument and the manner of using methods. Each group had 20 specimens. Group MT was instrumented with single length technique of Mtwo, group MC was instrumented with crowndown technique of Mtwo and group PT was instrumented with crown-down technique of ProTaper. All of the rotary files used in this study were operated by an electric motor. The scanned canal images of before and after preparation were superimposed. These superimposed images were evaluated at apical 1 to 8 mm levels. Angle changes were calculated. The preparation time, weight loss, instrument failure and binding, canal aberrations, and centering ratio were measured. Statistical analysis of the three experimental groups was performed with ANOVA and Duncan's multiple range tests for post-hoc comparison and Fisher's exact test was done for the frequency comparison. In total preparation time, group MT and group MC were less than group PT. In the aberrations, group MT had more elbows than those of group MC and group PT. The binding of group MC was least and group MT was less than group PT (P < 0.05). Under the condition of this study, crown-down technique using Mtwo rotary file is better and safer method than single length technique recommended by the manufacturer.