Evaluation of Root Canal Cleaning Efficacy of Selfadjusting Files, Protaper Rotary, and Manual K?Files in Primary Teeth ? An In vitro Comparative Study

Background: The success of pulpectomy depends on complete eradication of microbial load by cleaning and shaping the primary root canals that is difficult to achieve because of anatomical intricacy of primary pulp dentin complex. Numerous instruments were tried, however, they proved to be inadequate. Selfadjusting file (SAF) is a newer file system that facilitates less dentin removal with maximal cleansing of root canals. Aim: To evaluate and compare the in vitro root canal cleaning efficacy with SAF, Protaper Universal, and Hand K?files in primary teeth. Materials and Methods: Sixty extracted primary anterior teeth were randomly divided into three groups by lottery method. Access cavity was prepared, the canals were enlarged up to 20 K file, and an Indian ink was injected into each canal. Then the Group I (n = 20) was treated with SAF, Group II (n = 20) with Rotary Protaper Universal and Group III (n = 20) with Hand K?files and the root canal cleaning efficacy was evaluated based on the amount of Indian ink remaining in the canal walls under stereomicroscopy. Data were analyzed using Kruskal–Wallis one way ANOVA test and post hoc Tuckey test for intragroup and intergroup comparison, respectively. Results: A statistically highly significant difference was observed with SAF (mean = 1.5), Protaper (mean = 2.5), and Hand K?files (mean = 2.9). However, there was no significant difference in root canal cleaning efficacy with Protaper Universal and Hand K?files. Conclusion: The SAFs had shown superior cleaning efficacy compared with rotary Protaper Universal and manual K files.

Comparison of obturation quality, instrumentation time and post-operative pain using manual K-files and pediatric rotary files in primary molars ­ a double blinded randomised clinical trial / Comparação da qualidade de obturação, tempo de instrumentação e dor pós-operatória usando Limas manuais K e Limas rotativas pediátricas em molares decíduos ­ um estudo clínico randomizado duplo-cego

Objective: to compare the quality of obturation, instrumentation time and post-operative pain after pulpectomy in primary molars using manual K-files, Kedo-S and Kedo-S Square rotary file systems. Material and Methods: a double blinded randomized control trial was conducted in 45 children, who were indicated for pulpectomy in any one of the primary mandibular molars. The canal preparation was done using either hand K-files, Kedo-S files, or Kedo-S Square files based on the groups assigned. The time taken for instrumentation was recorded using a stopwatch. The quality of obturation was evaluated using post-operative radiograph and post-operative pain was assessed with modified Wong-Baker Faces Pain scale. Results: instrumentation time was minimum in rotary Kedo-S Square files (53.23 ± 9.60 seconds) followed by Kedo-S files (82.70 ± 11.86 seconds). The preparation time was maximum with manual K-files (121.43 ± 20.18 seconds). Kedo-S square files provided a higher number of optimally filled canals (66.4%). All the three instrumentations equally showed the tendency to produce voids in the obturation. Rotary files Kedo-S Square followed by Kedo-S showed less post-operative pain compared to K-files. Conclusion: the use of pediatric rotary instruments for canal preparation during pulpectomy will result in better quality of obturation in reduced time with least post-operative pain (AU)

Objetivo: comparar a qualidade de obturação, tempo de instrumentação e dor pós-operatória após pulpectomia em molares decíduos usando limas manuais K, limas rotatórias Kedo-S e limas rotatórias Kedo-S Square. Material e Métodos: um estudo clínico randomizado duplo-cego foi conduzido com 45 crianças que foram submetidas à pulpectomia de algum molar decíduo indicado. A preparação do canal foi feita usando limas manuais K, ou limas Kedo-S, ou ainda Limas Kedo-S Square, com base nos grupos que foram selecionados. O tempo para a instrumentação foi registrado com um cronômetro. A qualidade de obturação foi avaliada por meio de uma radiografia após o procedimento e a dor pós-operatória foi avaliada com a escala de dor Wong-Baker Faces modificada. Resultados: o tempo de instrumentação foi mínimo para as limas rotatórias Kedo-S Square (53,23 ± 9,60 segundos) seguido pelas limas Kedo-S (82,70 ± 11,86 segundos). O tempo de preparação foi maior com as limas manuais K (121,43 ± 20,18 segundos). As limas Kedo-S Square promoveram um maior número de canais otimamente obturados (66,4%). Todas as três instrumentações mostraram igualmente a tendência em seproduzir vazios na obturação. As limas rotatórias Kedo-S Square seguidas pelas limas Kedo-S produziram menos dor pós-operatória comparadas às limas manuais K. Conclusão: o uso de instrumentos rotatórios pediátricos para a preparação do canal durante a pulpectomia resultará em melhor qualidade de obturação em tempo reduzido e com menos dor pós-operatória. (AU)

An in vitro comparative evaluation of dentinal crack formation caused by three different nickel–titanium rotary file systems in primary anterior teeth

Context: Cleaning and shaping of the canals damages the root dentin which becomes a gateway to dentinal cracks and thereby causes failure of the treatment. Aim: The aim of this study was to assess and compare dentinal crack formation caused by three different nickel–titanium (NiTi) rotary file systems in primary anterior teeth. Settings and Design: The present in vitro study is an experimental, comparative study. Materials and Methods: One hundred fifty extracted primary anterior teeth were included in this study. The teeth were randomly divided into five groups. Group 1: Pedoflex rotary file system, Group 2: Prime Pedo™ rotary file system, Group 3: Kedo-S2 rotary file system, Group 4: K-files, and Group 5: no instrumentation. Roots were sectioned and viewed under a stereomicroscope for the presence of any cracks. Statistical Analysis Used: The data were analyzed using the Chi-square test and Kruskal–Wallis test. Results: In the coronal, middle, and apical thirds, Group 2 showed a maximum number of crack formations in the middle third (57%), followed by Group 3 (43.3%) and Group 1 (36.7%). Groups 4 and 5 showed no crack formation in all the root sections. The middle third showed a maximum number of crack formations compared to the coronal and apical thirds. Conclusions: Rotary systems render various benefits with an acceptable success in comparison to conventional hand instrumentation. Within the limitation of this study, it was found that Pedoflex rotary file system was the best with the least number of crack formations.

Assessing the quality of root canal filling and instrumentation time using kedo-s files, reciprocating files and k-files / Avaliando a qualidade de obturação e tempo instrumentação usando limas kedo-s, limas reciprocantes e limas k manuais

Objective: Pulpectomy is the conservative treatment approach that retains and preserves the primary tooth in the dental arch in its normal function and non-pathologic state until its exfoliation. Over the years, pulpectomy has been performed using various instrumentation techniques. The aim of this study was to compare the quality of root filing and instrumentation time using Kedo-S files, Reciprocating files and K-files in primary teeth. Material And Methods: A randomized clinical trial was performed on 45 primary molars equally distributed for instrumentation with Kedo-S files, reciprocating files and K-Files. Immediate post-operative digital radiographs were taken to evaluate the quality of root filing and root canal instrumentation time was also recorded. Results: Mean instrumentation time with Kedo-S was 75.6 seconds, reciprocating file was 190.6 seconds and K-file was 95.4 seconds. Highest optimal fill was obtained with Kedo-S file group, highest overfill was obtained with Kedo-S group and highest under fill was obtained with reciprocating file group. Conclusion: Kedo-S rotary system provides better quality of root canal filling in minimum instrumentation time. (AU)

Objetivo: A pulpectomia é o tratamento conservador que retém e preserva o dente decíduo na arcada dentária em sua função normal e estado não patológico até sua esfoliação. Ao longo dos anos, a pulpectomia foi realizada usando várias técnicas de instrumentação. O objetivo deste estudo foi comparar a qualidade da obturação do canal radicular e do tempo de instrumentação usando limas Kedo-S, limas reciprocantes e limas K em dentes decíduos. Material e Métodos: Foi realizado um ensaio clínico randomizado em 45 molares decíduos distribuídos igualmente para instrumentação com limas Kedo-S, limas reciprocantes e limas K. Radiografias digitais pós-operatórias imediatas foram realizadas para avaliar a qualidade da obturação e também foi registrado o tempo de instrumentação do canal radicular. Resultados: O tempo médio de instrumentação com Kedo-S foi de 75,6 segundos, com limas reciprocantes foi de 190,6 segundos e com limas K foi de 95,4 segundos. O maior índice de obturação ideal foi obtido com o grupo de limas Kedo-S, o maior índice de sobreobturação foi obtido com o grupo Kedo-S e o maior índice de infraobturação foi obtido com o grupo de limas reciprocantes. Conclusão: O sistema rotatório Kedo-S fornece melhor qualidade de obturação do canal radicular em tempo mínimo de instrumentação.(AU)

Effect of aging on dentinal crack formation after treatment and retreatment procedures: a micro-ct study

Abstract In order to evaluate the volume of dentinal cracks taking into account the age of the dentin and the type of file system used for endodontic procedures, forty freshly extracted single-rooted lower incisive teeth presenting similar root volume, were divided into two groups according to the age of the patient: Group Young (18 - 30 years old) and Group Old (60 years old or more). Each specimen was scanned by microcomputed tomography (micro-CT) in three stages: (i) before any treatment, (ii) after endodontic treatment with Reciproc files (REC), and (iii) after subsequent endodontic retreatment. Each group was subdivided into two subgroups, according to the retreatment technique used: retreatment with REC or with ProTaper Universal Retreatment (PUR) files. For each subgroup, the images were analyzed for differences in the volume of dentinal cracks in the middle and apical thirds of the teeth , according to the dentin age. In both stages (before and after instrumentation), the micro-CT images of the old root dentin presented with higher volume of cracks than those of the young root dentin, statistical significance notwithstanding (p>0.01). The use of REC files appeared to have no statistically significant differences in the generation of cracks in any type of root dentin when compared with PUR files (p>0.01). When retreated with PUR, the old root dentin presented with a significantly higher volume of cracks (p<0.01) when compared with the old root dentin initially.

Resumo Para avaliar o volume de fissuras dentinárias levando em consideração a idade da dentina e o tipo de sistema de limas utilizadas para procedimentos endodônticos, 40 dentes unirradiculares, incisivos inferiores, apresentando similar volume radicular, recentemente extraídos foram divididos em dois grupos de acordo com a idade do paciente: Grupo Jovem (18 a 30 anos) e Grupo Idoso (60 anos ou mais). Cada espécime foi scaneada por microtomografia computadorizada (micro-CT) em três estágios: (i) antes de qualquer tratamento, (ii) após tratamento endodôntico com limas Reciproc (REC) e (iii) após subsequente retratamento endodôntico. Cada grupo foi subdividido em dois subgrupos, de acordo com a técnica de retratamento utilizada: retratamento com REC ou com lima ProTaper Universal Retreatment (PUR). As imagens foram analisadas quanto às diferenças no volume das fissuras dentinárias nos terços médio e apical dos dentes de acordo com a idade da dentina. Em ambos os estágios (antes e depois da instrumentação), as imagens de micro-CT da dentina radicular idosa apresentaram maior volume de trincas do que as jovens, sem significância estatística (p>0.01). O uso das limas REC mostram não ter diferença estatística significante na geração de fissuras, em qualquer tipo de dentina, quando comparadas às limas PUR (p>0.01). Quando retratada com PUR, a dentina radicular idosa apresentou um volume de trincas significativamente maior (p<0.01) quando comparado com a dentina radicular idosa inicialmente.

Evaluación de la calidad de las obturaciones endodónticas realizadas por estudiantes de posgrado, en molares superiores, con técnicas de instrumentación manual y rotatoria / Evaluation of the quality of root canal fillings made bypostgraduate students in upper molars with manualand rotary instrumentation techniques

Objetivo: el objetivo de este estudio fue evaluar la calidad de las obturaciones endodónticas en molares superiores instrumentados con técnicas manuales y rotatorias, por estudiantes de posgrado. Materiales y métodos: para este estudio, se analizaron las radiografías de endodoncias que fueron realizadas durante un año por alumnos de un curso de posgrado en endodoncia, en primeros y segundos molares superiores, con ténicas de instrumentación manual y rotatoria y posteriormente obturadas con técnica de condensación lateral. Se analizó la calidad de las obturaciones endodónticas en función de la longitud y la homogeneidad de la masa de gutapercha. Resultados: el 53,6 por ciento de las obturaciones estaba dentro de los límites del conducto radicular y en el 65,2 por ciento de los casos, la homogeneidad fue incorrecta. En cuanto a la longitud, no se verificaron diferencias estadísticamente significativas entre las técnicas, como ocurrió con la homogeneidad (p<0,05). La frecuencia de inadecuados en ewsta última fue mayor para la técnica manual. La mayor cantidad de fallas en la obturación se registró en el conducto mesiovestibular. Conclusión: la calidad de las obturaciones no depende de la técnica de instrumentación empleada, sino de la experiencia del profesional interviniente y del tipo de conducto radicular tratado.(AU)

Aim: the aim of this study was to evaluate the quality ofendodontic fillings in upper molars instrumented with manualand rotary techniques by posgraduate students.Materials and methods: Radiographs of first and secondupper molars root canal treatments performed by studentsof a posgraduate endodontic course during a year wereanalyzed. Either manual or rotary instrumentation techniqueswere used and obturation was carried out using lateral condensation.Quality of endodontic obturation was analyzed accordingto length and homogeneity.Results: There were acceptable lengths of root canalfillings in 53.6% and homogeneity was incorrect in 65.2% ofthe cases. There was no statistically significance difference betweentechniques for the case of length, but there were statisticallysignificance difference for homogenity (p>0.05). Moredefective obturations were registered in the mesiobuccal canal.Conclusion: Independent of the instrumentation technique,the quality of root fillings is inherent to the professionalexperience and the type of root canal treated.

Utilidad de la conformación del túnel liso antes de usar limas rotatorias endodónticas de níquel-titanio / Usefulness of shaping the glide path before using rotary nickel-titanium endodontic files

Introducción: para prevenir la fractura de instrumentos endodonticos actualmente se siguen investigando materiales, técnicas y diseños los cuales buscan reducir su incidencia. La conformación de túnel liso (Glide Path) se ha propuesto con este fin, sin embargo su utilidad ha sido controvertida. Objetivo: comprobar teóricamente mediante la utilización de un análisis de elementos finitos, la utilidad de la conformación de túnel liso, antes de la utilización de limas rotatorias endodonticas de níquel-titanio. Métodos: se realizó una simulación numérica mediante un análisis de elementos finitos, para lo cual se construyeron modelos matemáticos de las limas rotatorias de níquel-titanio S1 y S2 de la serie Protaper®. Con el software Simulation multyphisics de Autodesk® se programaron las propiedades mecánicas de las limas y un límite de falla por fractura de 1270,588 MPa. Posteriormente se aplicó el torque recomendado por el fabricante y se fijo la punta del instrumento (sin conformación de túnel liso) aplicando allí restricciones en todos los grados de libertad.Para simular la realización de la conformación de túnel liso, se aplicaron restricciones en todos los grados de libertad a una determinada distancia de la punta del instrumento, simulando de esta forma que la punta del instrumento permanecía libre. Resultados: al fijar la punta de las limas, los esfuerzos máximos fueron 1545,77 MPa para la S1 y 1306,47 MPa para la S2, observando fractura de los instrumentos. Al fijar las limas a distancia de la punta no se observó fractura. Conclusiones: se demostró teóricamente que al impedir que se atrapen la punta de las limas, se previene su fractura y que dicho atrapamiento se evita con una conformación de túnel liso, por lo que se concluye que este procedimiento es útil para prevenir la fractura de los instrumentos rotatorios de níquel-titanio(AU)

Introduction: materials, techniques and designs continue to be studied with the purpose of reducing the incidence of fracture in endodontic instruments. Shaping of the glide path has been proposed for this end; however, its usefulness has been a matter of controversy. Objective: based on the finite element method, carry out a theoretical analysis of the usefulness of shaping the glide path before using rotary nickel-titanium endodontic files. Methods: numerical simulation was performed based on finite element analysis, to achieve which mathematical models were built of rotary nickel-titanium files S1 and S2 of the Protaper™ series. Autodesk™ Simulation Multiphysics software was used to program the mechanical properties of the files, as well as a fracture failure limit of 1270.588 MPa. The torque recommended by the manufacturer was then applied and the instrument tip fixed into place (without shaping the glide path) with restrictions on all degrees of freedom. In order to simulate glide path shaping, restrictions were applied to all degrees of freedom at a certain distance from the instrument tip, thus simulating that the instrument tip remained free. Results: on fixing the file tips, maximum efforts were 1545.77 Mpa for S1 and 1306.47 Mpa for S2. Instrument fracture was observed. When files were fixed at a distance from the tip, no fracture was observed. Conclusions: it was theoretically demonstrated that when file tips are prevented from being caught, fracture is prevented as well, and such catch is avoided by shaping the glide path. It is therefore concluded that the procedure is useful to prevent the fracture of rotary nickel-titanium instruments(AU)

The study of Mtwo in root canal therapy in elderly patients / 中国医师杂志

Objective To assess the effects of Mtwo for root canal therapy in the aged patients .Methods One hundred and fifty-two root canals in 64 teeth for root canal therapy (RCT) in aged patients(60~70years)were randomly divided into M groups and K groups.Mtwo machine with nickel titanium file was used in M group (32 teeth, 78 root canals), and stainless steel file in K group (32 teeth, 74 root canals).Root canal preparation time, root spread reaction, and canal filling effects were compared between two groups.Results The root canal preparation and filling in group M were better than in K group ( P <0.05).The time consumption of RCT in M group was shorter than in group K .Conclusions Mtwo shows good shaping ability and is safe for aged patients in root canal treatment with high efficiency .

A comparison of dimensional standard of several nickel-titanium rotary files

OBJECTIVES: The aim of this study was to compare the dimensional standard of several nickel-titanium (Ni-Ti) rotary files and verify the size conformity. MATERIALS AND METHODS: ProFile (Dentsply Maillefer), RaCe (FKG Dentaire), and TF file (SybronEndo) #25 with a 0.04 and 0.06 taper were investigated, with 10 in each group for a total of 60 files. Digital images of Ni-Ti files were captured under light microscope (SZX16, Olympus) at 32x. Taper and diameter at D1 to D16 of each files were calculated digitally with AnalySIS TS Materials (OLYMPUS Soft Imaging Solutions). Differences in taper, the diameter of each level (D1 to D16) at 1 mm interval from (ANSI/ADA) specification No. 101 were statistically analyzed using one-way ANOVA and Scheffe's post-hoc test at 95% confidence level. RESULTS: TF was the only group not conform to the nominal taper in both tapers (p < 0.05). All groups except 0.06 taper ProFile showed significant difference from the nominal diameter (p < 0.05). CONCLUSIONS: Actual size of Ni-Ti file, especially TF, was different from the manufacturer's statements.

Cyclic Fatigue Resistance of Rotary NiTi Instruments after Simulated Clinical Use in Curved Root Canals

The aim of this study was to assess cyclic fatigue resistance in rotary nickel-titanium instruments after simulated clinical use in curved root canals (40-degree, 5-mm radius curve). Thirty-six RaCe rotary NiTi files, size #5, taper 0.04, were divided into 3 groups: Groups A, B and C with one, three and five cycles of use, respectively. Time to failure was recorded with a stopwatch in seconds and subsequently converted to number of cycles to fracture. The data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Five sets of clinically used files (group C) reached significantly lower cycle-numbers before fracture (mean=197.5 cycles) when compared with one set of clinically used files (mean=309.2) and three sets (mean=287.5). Results showed that the number of simulated clinical uses of RaCe instruments for shaping curved canals affects adversely the fatigue resistance of these instruments after five uses.

Resumo O objetivo deste estudo foi avaliar a resistência à fadiga cíclica de instrumentos rotatórios de níquel-titânio após simulação de uso clinico em canais curvos (curvatura de 40° e raio de 5 mm). Trinta e seis instrumentos, calibre n° 25 conicidade 0,04, foram divididos em três grupos: o Grupo A com um ciclo de uso; Grupo B, três ciclos de uso e grupo C, cinco ciclos de uso. Um cronômetro digital aferiu em segundos o tempo até a fratura do instrumento que, posteriormente, foi convertido em número de ciclos para fratura. Os dados foram analisados por ANOVA e teste de Tukey (p<0,05). O grupo que utilizou o instrumento por cinco ciclos (grupo C) atingiu significativamente menores números de ciclos antes da fratura (média = 197,5 ciclos) quando comparado com os instrumentos utilizados em um ciclo (média = 309,2) e três ciclos (média = 287,5). Os resultados mostraram que o número de uso de instrumentos RaCe para modelar canais curvos afeta negativamente a resistência à fadiga cíclica dos instrumentos após cinco usos. .

Effect of surface defects and cross-sectional configuration on the fatigue fracture of NiTi rotary files under cyclic loading / 대한치과보존학회지

The purpose of this in vitro study was to evaluate the effect of surface defects and cross-sectional configuration of NiTi rotary files on the fatigue life under cyclic loading. Three NiTi rotary files (K3(TM), ProFile(R), and HERO 642(R)) with #30/.04 taper were evaluated. Each rotary file was divided into 2 subgroups: control (no surface defects) and experimental group (artificial surface defects). A total of six groups of each 10 were tested. The NiTi rotary files were rotated at 300rpm using the apparatus which simulated curved canal (40 degree of curvature) until they fracture. The number of cycles to fracture was calculated and the fractured surfaces were observed with a scanning electron microscope. The data were analyzed statistically. The results showed that experimental groups with surface defects had lower number of cycles to fracture than control group but there was only a statistical significance between control and experimental group in the K3(TM) (p<0.05). There was no strong correlation between the cross-sectional configuration area and fracture resistance under experimental conditions. Several of fractured files demonstrated characteristic patterns of brittle fracture consistent with the propagation of pre-existing cracks. This data indicate that surface defects of NiTi rotary files may significantly decrease fatigue life and it may be one possible factor for early fracture of NiTi rotary files in clinical practice.